Alison Jennings

University of Ottawa, Ottawa, Ontario, Canada

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Publications (20)94.84 Total impact

  • Article: A systematic review to evaluate the accuracy of electronic adverse drug event detection.
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    ABSTRACT: Adverse drug events (ADEs), defined as adverse patient outcomes caused by medications, are common and difficult to detect. Electronic detection of ADEs is a promising method to identify ADEs. We performed this systematic review to characterize established electronic detection systems and their accuracy. We identified studies evaluating electronic ADE detection from the MEDLINE and EMBASE databases. We included studies if they contained original data and involved detection of electronic triggers using information systems. We abstracted data regarding rule characteristics including type, accuracy, and rationale. Forty-eight studies met our inclusion criteria. Twenty-four (50%) studies reported rule accuracy but only 9 (18.8%) utilized a proper gold standard (chart review in all patients). Rule accuracy was variable and often poor (range of sensitivity: 40%-94%; specificity: 1.4%-89.8%; positive predictive value: 0.9%-64%). 5 (10.4%) studies derived or used detection rules that were defined by clinical need or the underlying ADE prevalence. Detection rules in 8 (16.7%) studies detected specific types of ADEs. Several factors led to inaccurate ADE detection algorithms, including immature underlying information systems, non-standard event definitions, and variable methods for detection rule validation. Few ADE detection algorithms considered clinical priorities. To enhance the utility of electronic detection systems, there is a need to systematically address these factors.
    Journal of the American Medical Informatics Association 01/2012; 19(1):31-8. · 3.61 Impact Factor
  • Article: A meta-analysis of hospital 30-day avoidable readmission rates.
    Carl van Walraven, Alison Jennings, Alan J Forster
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    ABSTRACT: Rationale and objectives  Urgent readmission to hospital is commonly used to measure hospital quality of care. Hospitals that measure the proportion of urgent readmissions judged avoidable need to know previously published rates for comparison. In this study, we generated a literature-based estimate for the proportion of 30-day urgent readmissions deemed avoidable for hospitals to use to gauge their performance in avoidable readmissions. Methods  We searched the Medline and Embase databases to identify published studies that reported the proportion of 30-day urgent readmissions deemed avoidable. We then modelled the overall proportion of 30-day urgent readmissions deemed avoidable. Results  We included 16 studies that used a wide variety of patients and a diverse range of methods to classify readmissions as avoidable. Studies reported a broad range for the proportion of urgent 30-day readmissions deemed avoidable. Overall, 848 of 3669 readmissions (23.1%, 95% confidence interval, 21.7-24.5) of 30-day urgent readmissions were classified as avoidable. This proportion varied significantly based on hospital teaching status and number of reviewers for each case [teaching hospitals: with one reviewer, 9.3% (4.2-19.3); with >1 reviewer, 21.6% (13.2-33.3); non-teaching hospital: with one reviewer, 32.2% (11.4-63.9); with >1 reviewer, 39.9% (37.6-42.2)]. Significant heterogeneity remained between studies even after clustering studies by these covariates. Conclusions  Less than one in four readmissions were deemed avoidable. Health system planners need to use caution in interpreting all cause readmission statistics as they are only partially influenced by quality of care.
    Journal of Evaluation in Clinical Practice 11/2011; · 1.23 Impact Factor
  • Article: Influence of house-staff experience on teaching-hospital mortality: the "July phenomenon" revisited.
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    ABSTRACT: The "July phenomenon" refers to a purported worsening of outcomes in teaching-hospital patients with the arrival of new, inexperienced house-staff. Previous quantitative studies of new house-staff and increased mortality have been limited primarily by a focused patient population and the use of limited data to adjust for severity of patient illness. We included all medicine, surgical, and obstetrical patients admitted to a teaching hospital in Ontario, Canada between April 15, 2004 and December 31, 2008. We calculated the ratio of observed to expected weekly number of deaths in hospital. The expected number of deaths was calculated using a validated, discriminative, and well-calibrated multivariate survival model. Collective house-staff experience was modeled from a minimum on July 1st to a maximum on June 30th using five distinct patterns. We studied 259,748 encounters that included 164,318 people. The mortality rate was 3.0%. The ratio of observed to expected number of weekly deaths was not associated with collective house-staff experience, irrespective of the pattern in which it was modeled. The lack of association between risk of death in hospital and house-staff experience did not vary by admission type (urgent vs elective) or specialty (medicine vs surgery). At our hospital, we found no association between the arrival of new house-staff and the adjusted risk of death in hospital. These data, along with the results of the vast majority of previous studies in this field, make the existence of the "July Phenomenon" for inpatient mortality extremely unlikely.
    Journal of Hospital Medicine 09/2011; 6(7):389-94. · 1.40 Impact Factor
  • Article: Incidence of potentially avoidable urgent readmissions and their relation to all-cause urgent readmissions.
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    ABSTRACT: Urgent, unplanned hospital readmissions are increasingly being used to gauge the quality of care. We reviewed urgent readmissions to determine which were potentially avoidable and compared rates of all-cause and avoidable readmissions. In a multicentre, prospective cohort study, we reviewed all urgent readmissions that occurred within six months among patients discharged to the community from 11 teaching and community hospitals between October 2002 and July 2006. Summaries of the readmissions were reviewed by at least four practising physicians using standardized methods to judge whether the readmission was an adverse event (poor clinical outcome due to medical care) and whether the adverse event could have been avoided. We used a latent class model to determine whether the probability that each readmission was truly avoidable exceeded 50%. Of the 4812 patients included in the study, 649 (13.5%, 95% confidence interval [CI] 12.5%-14.5%) had an urgent readmission within six months after discharge. We considered 104 of them (16.0% of those readmitted, 95% CI 13.3%-19.1%; 2.2% of those discharged, 95% CI 1.8%-2.6%) to have had a potentially avoidable readmission. The proportion of patients who had an urgent readmission varied significantly by hospital (range 7.5%-22.5%; χ(2) = 92.9, p < 0.001); the proportion of readmissions deemed avoidable did not show significant variation by hospital (range 1.2%-3.7%; χ(2) = 12.5, p < 0.25). We found no association between the proportion of patients who had an urgent readmission and the proportion of patients who had an avoidable readmission (Pearson correlation 0.294; p = 0.38). In addition, we found no association between hospital rankings by proportion of patients readmitted and rankings by proportion of patients with an avoidable readmission (Spearman correlation coefficient 0.28, p = 0.41). Urgent readmissions deemed potentially avoidable were relatively uncommon, comprising less than 20% of all urgent readmissions following hospital discharge. Hospital-specific proportions of patients who were readmitted were not related to proportions with a potentially avoidable readmission.
    Canadian Medical Association Journal 08/2011; 183(14):E1067-72. · 8.22 Impact Factor
  • Article: The influence of incidental abdominal aortic aneurysm monitoring on patient outcomes.
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    ABSTRACT: Incidental abdominal aortic aneurysms (AAAs) are identified when the abdomen is imaged for other reasons. These are common, and many undergo incomplete radiological monitoring. The association between monitoring completeness and population-based outcomes has not been studied. A cohort of incidental AAAs (defined as previously unidentified aortic enlargement exceeding 3 cm found on an imaging study done for another reason) was linked to population-based data. Patients were followed to elective AAA repair, AAA rupture, death, or March 31, 2009. Monitoring completeness was gauged as the sequential number of months without a recommended abdominal scan. Its association with time to elective AAA repair and time to death was measured using a multivariable Cox regression model adjusting for other important covariates. We identified 191 incidental AAAs between 1996 and 2004 (median diameter of 3.5 cm [range, 3.0-5.3 cm], median follow up of 4.4 years [range, 0.6-12.7 years]). During the study, patients spent a median of 19.4% of their time with incomplete AAA monitoring (interquartile range [IQR] 0.3%-44%); 56 patients (29.3%) had no follow-up imaging of their aneurysm. Nineteen patients (10.0%; 2.0% per year) underwent elective AAA repair, and 79 patients (37.7%; 7.6% per year) died. Independent of important covariates, people were significantly less likely to undergo elective repair (hazard ratio [HR], 0.03) and significantly more likely to die (HR, 2.99) if their AAA went without radiological monitoring for 1 year. Incomplete incidental AAA radiological monitoring was significantly associated with a decreased risk of elective AAA repair and an increased risk of death. While uncontrolled confounding might explain part of these associations, clinicians should ensure that radiological monitoring of AAAs is complete in appropriate patients.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 07/2011; 54(5):1290-1297.e2. · 3.52 Impact Factor
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    Article: Proportion of hospital readmissions deemed avoidable: a systematic review.
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    ABSTRACT: Readmissions to hospital are increasingly being used as an indicator of quality of care. However, this approach is valid only when we know what proportion of readmissions are avoidable. We conducted a systematic review of studies that measured the proportion of readmissions deemed avoidable. We examined how such readmissions were measured and estimated their prevalence. We searched the MEDLINE and EMBASE databases to identify all studies published from 1966 to July 2010 that reviewed hospital readmissions and that specified how many were classified as avoidable. Our search strategy identified 34 studies. Three of the studies used combinations of administrative diagnostic codes to determine whether readmissions were avoidable. Criteria used in the remaining studies were subjective. Most of the studies were conducted at single teaching hospitals, did not consider information from the community or treating physicians, and used only one reviewer to decide whether readmissions were avoidable. The median proportion of readmissions deemed avoidable was 27.1% but varied from 5% to 79%. Three study-level factors (teaching status of hospital, whether all diagnoses or only some were considered, and length of follow-up) were significantly associated with the proportion of admissions deemed to be avoidable and explained some, but not all, of the heterogeneity between the studies. All but three of the studies used subjective criteria to determine whether readmissions were avoidable. Study methods had notable deficits and varied extensively, as did the proportion of readmissions deemed avoidable. The true proportion of hospital readmissions that are potentially avoidable remains unclear.
    Canadian Medical Association Journal 03/2011; 183(7):E391-402. · 8.22 Impact Factor
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    Article: Radiographic monitoring of incidental abdominal aortic aneurysms: a retrospective population-based cohort study.
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    ABSTRACT: An abdominal aortic aneurysm (AAA) that is identified when the abdomen is imaged for some other reason is known as an incidental AAA. No population-based studies have assessed the management of incidental AAAs. The objective of this study was to measure the completeness of radiographic monitoring of incidental AAAs by means of a population-based analysis. We linked a cohort of patients with incidental AAA (defined as a previously unidentified aortic enlargement exceeding 30 mm in diameter found in an imaging study performed for another reason) to various population-based databases. We followed the patients to elective repair or rupture of the aneurysm, death or 31 Mar. 2009. We used evidence-based monitoring guidelines to calculate the proportion of observation time during which each incidental AAA was incompletely monitored. We used negative binomial regression to determine the association of patient-related factors with this outcome. For the period between January 1996 and September 2008, we identified 191 patients with incidental AAA (mean diameter 37.6 mm, 95% confidence interval [CI] 36.6-38.6 mm; median follow-up 4.4 [range 0.6-12.7] years). Fifty-six of these patients (29.3%) had no radiographic monitoring of the aneurysm. Overall, patients spent one-fifth of their time with incomplete monitoring of the AAA (median 19.4%, interquartile range 0.3%-44.0%). Factors independently associated with incomplete monitoring included older age (relative rate [change in proportion of time with incomplete monitoring] [RR] 1.27, 95% CI 1.10-1.47, per decade), larger size (RR 1.65, 95% CI 1.38-2.01, per 10-mm increase) and detection of the aneurysm while the patient was in hospital or the emergency department (RR 1.34, 95% CI 1.00-1.79). Comorbidities were not associated with monitoring. Radiographic monitoring of incidental AAAs was incomplete, and almost one-third of patients underwent no monitoring at all. Incomplete monitoring did not appear to be related to patients' comorbidity.
    Open Medicine 01/2011; 5(2):e67-76.
  • Article: The association between continuity of care and outcomes: a systematic and critical review
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    ABSTRACT: Background Numerous studies have tried to determine the association between continuity and outcomes. Studies doing so must actually measure continuity. If continuity and outcomes are measured concurrently, their association can only be determined with time-dependent methods.Objective To identify and summarize all methodologically studies that measure the association between continuity of care and patient outcomes.Methods We searched MEDLINE database (1950–2008) and hand-searched to identify studies that tried to associate continuity and outcomes. English studies were included if they: actually measured continuity; determined the association of continuity with patient outcomes; and properly accounted for the relative timing of continuity and outcome measures.Results A total of 139 English language studies tried to measure the association between continuity and outcomes but only 18 studies (12.9%) met methodological criteria. All but two studies measured provider continuity and used health utilization or patient satisfaction as the outcome. Eight of nine high-quality studies found a significant association between increased continuity and decreased health utilization including hospitalization and emergency visits. Five of seven studies found improved patient satisfaction with increased continuity.Conclusions These studies validate the belief that increased provider continuity is associated with improved patient outcomes and satisfaction. Further research is required to determine whether information or management continuity improves outcomes.
    Journal of Evaluation in Clinical Practice 09/2010; 16(5):947 - 956. · 1.23 Impact Factor
  • Article: Incidence, follow-up, and outcomes of incidental abdominal aortic aneurysms.
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    ABSTRACT: Incidental abdominal aortic aneurysms (AAAs) are identified during imaging for other reasons. Incidental AAAs are important findings because they require monitoring and surgical treatment, when indicated, to prevent rupture. The prevalence of incidental AAAs and their management has not been extensively studied. We electronically screened a 25% simple random sample of abdominal computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI) studies conducted between 1996 and 2008 at one academic medical center. Screen-positive reports were manually reviewed to determine if they showed an incidental AAA. We reviewed the medical records of all in-patients to determine whether the incidental AAA was documented, a treatment plan was identified, and whether it was communicated to the patient's family physician through the discharge summary. We used evidence-based recommended schedules to determine the adequacy of AAA monitoring for each person. In 79,121 abdominal images, we identified 812 incidental AAAs (1.0% of all studies) or 364 incidental AAAs annually (95% confidence interval [CI], 349-379). Patients were elderly (mean age, 74 years), and AAAs were a mean diameter of 4.0 cm. For 174 inpatients, AAAs were noted in only 51 patients (29%) and only 25 (15%) were communicated to the family physician. Of 329 patients who were observed beyond their first recommended follow-up scan, only 51 (16%) were monitored appropriately throughout their entire follow-up; the median proportion of follow-up time with recommended monitoring was 56% (interquartile range, 32%-82%). Elective AAA repair was done in 98 patients (13%), the probability of which was significantly increased when AAA monitoring frequency was compliant with that recommended in practice guidelines. Six patients (0.8%) were admitted with aortic rupture, the probability of which was independent of AAA monitoring. Incidental AAAs are common and appear to be poorly monitored. Our data suggested that improved monitoring of incidental AAAs was independently associated with elective AAA repair. Population-based analyses are required to determine the influence that monitoring has on incidental AAA rupture and patient mortality.
    Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 08/2010; 52(2):282-9.e1-2. · 3.52 Impact Factor
  • Article: Effect of exercise training on physical fitness in type II diabetes mellitus.
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    ABSTRACT: Few studies have compared changes in cardiorespiratory fitness between aerobic training only or in combination with resistance training. In addition, no study to date has compared strength gains between resistance training and combined exercise training in type II diabetes mellitus (T2DM). We evaluated the effects of aerobic exercise training (A group), resistance exercise training (R group), combined aerobic and resistance training (A + R group), and sedentary lifestyle (C group) on cardiorespiratory fitness and muscular strength in individuals with T2DM. Two hundred and fifty-one participants in the Diabetes Aerobic and Resistance Exercise trial were randomly allocated to A, R, A + R, or C. Peak oxygen consumption (V O(2peak)), workload, and treadmill time were determined after maximal exercise testing at 0 and 6 months. Muscular strength was measured as the eight-repetition maximum on the leg press, bench press, and seated row. Responses were compared between younger (aged 39-54 yr) and older (aged 55-70 yr) adults and between sexes. VO(2peak) improved by 1.73 and 1.93 mL O(2)*kg(-1)*min(-1) with A and A + R, respectively, compared with C (P < 0.05). Strength improvements were significant after A + R and R on the leg press (A + R: 48%, R: 65%), bench press (A + R: 38%, R: 57%), and seated row (A + R: 33%, R: 41%; P < 0.05). There was no main effect of age or sex on training performance outcomes. There was, however, a tendency for older participants to increase VO(2peak) more with A + R (+1.5 mL O(2)*kg(-1)*min(-1)) than with A only (+0.7 mL O(2)*kg(-1)*min(-1)). Combined training did not provide additional benefits nor did it mitigate improvements in fitness in younger subjects compared with aerobic and resistance training alone. In older subjects, there was a trend to greater aerobic fitness gains with A + R versus A alone.
    Medicine and science in sports and exercise 08/2010; 42(8):1439-47. · 3.71 Impact Factor
  • Article: Effect of point-of-care computer reminders on physician behaviour: a systematic review.
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    ABSTRACT: The opportunity to improve care using computer reminders is one of the main incentives for implementing sophisticated clinical information systems. We conducted a systematic review to quantify the expected magnitude of improvements in processes of care from computer reminders delivered to clinicians during their routine activities. We searched the MEDLINE, Embase and CINAHL databases (to July 2008) and scanned the bibliographies of retrieved articles. We included studies in our review if they used a randomized or quasi-randomized design to evaluate improvements in processes or outcomes of care from computer reminders delivered to physicians during routine electronic ordering or charting activities. Among the 28 trials (reporting 32 comparisons) included in our study, we found that computer reminders improved adherence to processes of care by a median of 4.2% (interquartile range [IQR] 0.8%-18.8%). Using the best outcome from each study, we found that the median improvement was 5.6% (IQR 2.0%-19.2%). A minority of studies reported larger effects; however, no study characteristic or reminder feature significantly predicted the magnitude of effect except in one institution, where a well-developed, "homegrown" clinical information system achieved larger improvements than in all other studies (median 16.8% [IQR 8.7%-26.0%] v. 3.0% [IQR 0.5%-11.5%]; p = 0.04). A trend toward larger improvements was seen for reminders that required users to enter a response (median 12.9% [IQR 2.7%-22.8%] v. 2.7% [IQR 0.6%-5.6%]; p = 0.09). Computer reminders produced much smaller improvements than those generally expected from the implementation of computerized order entry and electronic medical record systems. Further research is required to identify features of reminder systems consistently associated with clinically worthwhile improvements.
    Canadian Medical Association Journal 03/2010; 182(5):E216-25. · 8.22 Impact Factor
  • Article: The Effect of Exercise Training on Physical Fitness in Type 2 Diabetes Mellitus.
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    ABSTRACT: Few studies have compared changes in cardiorespiratory fitness between aerobic training only or in combination with resistance training. Additionally, no study to date has compared strength gains between resistance training and combined exercise training in type 2 diabetes mellitus (T2DM). PURPOSE:: We evaluated the effects of aerobic exercise training (A), resistance exercise training (R), combined aerobic and resistance training (A+R) and a sedentary control group (C) on cardiorespiratory fitness and muscular strength in individuals with T2DM. METHODS:: 251 participants in the Diabetes Aerobic and Resistance Exercise (DARE) trial were randomly allocated to A, R, A+R or C. Peak oxygen consumption (V O2peak), workload and treadmill time were determined following maximal exercise testing at 0 and 6 months. Muscular strength was measured as the 8 RM on the leg press, bench press and seated row. Responses were compared between younger (39-54) and older (55-70) adults and between sexes. RESULTS:: V O2peak improved by 1.73 and 1.93 mLO2/kg/min with A and A+R respectively compared to C (p<0.05). Strength improvements were significant following A+R and R on the leg press (A+R:48%, R:65%), bench press (A+R:38%, R:57%) and seated row (A+R:33%, R:41%) (p<0.05). There was no main effect of age or sex on training performance outcomes. There was however a tendency for older participants to increase V O2peak more with A+R (+1.5 mLO2/kg/min) than with A only (+0.7 mLO2/kg/min). CONCLUSIONS:: Combined training did not provide additional benefits nor did it mitigate improvements in fitness in younger subjects compared to aerobic and resistance training alone. In older subjects, there was a trend to greater aerobic fitness gains with A+R versus A alone.
    Medicine and science in sports and exercise 02/2010; · 3.71 Impact Factor
  • Article: Correlation between serial tests made disease probability estimates erroneous.
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    ABSTRACT: The probability of a disease, given the result of two diagnostic tests, can be calculated by multiplying the odds of disease after the first test by the likelihood ratio of the second test. To illustrate the error that occurs when calculating disease probability by combining the results of tests that are correlated. Simulation study in which we randomly generated disease status and the results of two binary tests for a range of disease prevalence, test-operating characteristics, and correlation between tests. The primary outcome was the absolute difference between calculated and true probability of disease after two positive tests. When the tests were correlated, the calculated probability of a disease exceeded the true probability of the disease. With perfect correlation, the true probability of the disease after two positive tests equaled that after a single positive test. Error arising from correlated tests increased as the difference in the calculated probability between the first and second positive tests increased. We noted several combinations of disease prevalence, test-operating characteristics, and test correlation where the absolute difference between calculated and true probability of disease exceeded 25%. Disease probability is overestimated when the results of correlated tests are combined. Clinicians must consider the correlation between serial tests when calculating the posttest probability.
    Journal of clinical epidemiology 09/2009; 62(12):1301-5. · 2.96 Impact Factor
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    Article: Interactive voice response systems for improving delivery of ambulatory care.
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    ABSTRACT: To comprehensively describe the populations, interventions, and outcomes of interactive voice response system (IVRS) clinical trials. We identified studies using MEDLINE (1950-2008) and EMBASE (1980-2008). We also identified studies using hand searches of the Science Citation Index and the reference lists of included articles. Included were randomized and controlled clinical trials that examined the effect of an IVRS intervention on clinical end points, measures of disease control, process adherence, or quality-of-life measures. Continuous and dichotomous outcomes were meta-analyzed using mean difference and median effects methodology, respectively. Forty studies (n = 106,959 patients) met inclusion criteria. Of these studies, 25 used an IVRS intervention aimed at encouraging adherence with recommended tests, treatments, or behaviors; the remaining 15 used an IVRS for chronic disease management. Three studies reported clinical end points, which could not be statistically pooled. In 6 studies that reported objective clinical measures of disease control (glycosylated hemoglobin, total cholesterol, and serum glucose), the IVRS was associated with nonsignificant improvements. In 14 studies that measured objective process adherence outcomes, the median effect was 7.9% (25th-75th percentile: 2.8%, 19.5%). For the 16 studies that assessed patient-reported measures of disease control and the 11 studies that assessed patient-reported process adherence outcomes, approximately one-third of the outcomes significantly favored the IVRS group. IVRS interventions, which enable patients to interact with computer databases via telephone, have shown a significant benefit in adherence to various processes of care. Future IVRS studies should include clinically relevant outcomes.
    The American journal of managed care 07/2009; 15(6):383-91. · 2.46 Impact Factor
  • Article: The effect of exercise training on resting metabolic rate in type 2 diabetes mellitus.
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    ABSTRACT: Exercise is a possible means to increase resting energy expenditure, which could offset age-related metabolic declines and facilitate weight management, both of which are particularly important for people who have type 2 diabetes mellitus. We sought to determine the effects of aerobic exercise training and resistance exercise training and the incremental effect of combined aerobic and resistance exercise training on resting metabolic rate (RMR) in previously sedentary individuals with type 2 diabetes. After a 4-wk run-in period, 103 participants (72 male, 31 female, 39-70 yr, mean +/- SD body mass index = 32.9 +/- 5.7 kg x m(-2)) were randomly assigned to four groups for 22 wk: aerobic training, resistance training, combined aerobic and resistance exercise training, or waiting-list control. Exercise training was performed three times per week at community-based gym facilities. RMR was measured by indirect calorimetry for 30 min after an overnight fast. Body composition was assessed using bioelectrical impedance. These measurements were taken at baseline, at 3 months, and at 6 months of the intervention. RMR did not change significantly in any group after accounting for multiple comparisons despite significant improvements in peak oxygen consumption and muscular strength in the exercising groups. Adjusting RMR for age, sex, fat mass, and fat-free mass in various combinations did not alter these results. These results suggest that RMR was not significantly changed after a 6-month exercise program, regardless of modality, in this sample of adults with type 2 diabetes.
    Medicine and science in sports and exercise 07/2009; 41(8):1558-65. · 3.71 Impact Factor
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    Article: A modification of the Elixhauser comorbidity measures into a point system for hospital death using administrative data.
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    ABSTRACT: Comorbidity measures are necessary to describe patient populations and adjust for confounding. In direct comparisons, studies have found the Elixhauser comorbidity system to be statistically slightly superior to the Charlson comorbidity system at adjusting for comorbidity. However, the Elixhauser classification system requires 30 binary variables, making its use for reporting and analysis of comorbidity cumbersome. Modify the Elixhauser classification system into a single numeric score for administrative data. For all hospitalizations at the Ottawa Hospital, Canada, between 1996 and 2008, we determined if International Classification of Disease codes for chronic diagnoses were in any of the 30 Elixhauser comorbidity groups. We then used backward stepwise multivariate logistic regression to determine the independent association of each comorbidity group with death in hospital. Regression coefficients were modified into a scoring system that reflected the strength of each comorbidity group's independent association with hospital death. Hospitalizations that were included were 345,795 (derivation: 228,565; validation 117,230). Twenty-one of the 30 groups were independently associated with hospital mortality. The resulting comorbidity score had an equivalent discrimination in the derivation and validation groups (overall c-statistic 0.763, 95% CI: 0.759-0.766). This was similar to models having all Elixhauser groups (0.760, 95% CI: 0.756-0.764) or significant groups only (0.759, 95% CI: 0.754-0.762), but significantly exceeded discrimination when comorbidity was expressed using the Charlson score (0.745, 95% CI: 0.742-0.749). When analyzing administrative data, the Elixhauser comorbidity system can be condensed to a single numeric score that summarizes disease burden and is adequately discriminative for death in hospital.
    Medical care 06/2009; 47(6):626-33. · 3.24 Impact Factor
  • Article: The effects of on-screen, point of care computer reminders on processes and outcomes of care.
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    ABSTRACT: The opportunity to improve care by delivering decision support to clinicians at the point of care represents one of the main incentives for implementing sophisticated clinical information systems. Previous reviews of computer reminder and decision support systems have reported mixed effects, possibly because they did not distinguish point of care computer reminders from e-mail alerts, computer-generated paper reminders, and other modes of delivering 'computer reminders'. To evaluate the effects on processes and outcomes of care attributable to on-screen computer reminders delivered to clinicians at the point of care. We searched the Cochrane EPOC Group Trials register, MEDLINE, EMBASE and CINAHL and CENTRAL to July 2008, and scanned bibliographies from key articles. Studies of a reminder delivered via a computer system routinely used by clinicians, with a randomised or quasi-randomised design and reporting at least one outcome involving a clinical endpoint or adherence to a recommended process of care. Two authors independently screened studies for eligibility and abstracted data. For each study, we calculated the median improvement in adherence to target processes of care and also identified the outcome with the largest such improvement. We then calculated the median absolute improvement in process adherence across all studies using both the median outcome from each study and the best outcome. Twenty-eight studies (reporting a total of thirty-two comparisons) were included. Computer reminders achieved a median improvement in process adherence of 4.2% (interquartile range (IQR): 0.8% to 18.8%) across all reported process outcomes, 3.3% (IQR: 0.5% to 10.6%) for medication ordering, 3.8% (IQR: 0.5% to 6.6%) for vaccinations, and 3.8% (IQR: 0.4% to 16.3%) for test ordering. In a sensitivity analysis using the best outcome from each study, the median improvement was 5.6% (IQR: 2.0% to 19.2%) across all process measures and 6.2% (IQR: 3.0% to 28.0%) across measures of medication ordering. In the eight comparisons that reported dichotomous clinical endpoints, intervention patients experienced a median absolute improvement of 2.5% (IQR: 1.3% to 4.2%). Blood pressure was the most commonly reported clinical endpoint, with intervention patients experiencing a median reduction in their systolic blood pressure of 1.0 mmHg (IQR: 2.3 mmHg reduction to 2.0 mmHg increase). Point of care computer reminders generally achieve small to modest improvements in provider behaviour. A minority of interventions showed larger effects, but no specific reminder or contextual features were significantly associated with effect magnitude. Further research must identify design features and contextual factors consistently associated with larger improvements in provider behaviour if computer reminders are to succeed on more than a trial and error basis.
    Cochrane database of systematic reviews (Online) 02/2009; · 5.72 Impact Factor
  • Article: Anticoagulation intensity and outcomes among patients prescribed oral anticoagulant therapy: a systematic review and meta-analysis.
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    ABSTRACT: Patients taking oral anticoagulant therapy balance the risks of hemorrhage and thromboembolism. We sought to determine the association between anticoagulation intensity and the risk of hemorrhagic and thromboembolic events. We also sought to determine how under-or overanticoagulation would influence patient outcomes. We reviewed the MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and CINAHL databases to identify studies involving patients taking anticoagulants that reported person-years of observation and the number of hemorrhages or thromboemboli in 3 or more discrete ranges of international normalized ratios. We estimated the overall relative and absolute risks of events specific to anticoagulation intensity. We included 19 studies. The risk of hemorrhage increased significantly at high international normalized ratios. Compared with the therapeutic ratio of 2-3, the relative risk (RR) of hemorrhage (and 95% confidence intervals [CIs]) were 2.7 (1.8-3.9; p < 0.01) at a ratio of 3-5 and 21.8 (12.1-39.4; p < 0.01) at a ratio greater than 5. The risk of thromboemboli increased significantly at ratios less than 2, with a relative risk of 3.5 (95% CI 2.8-4.4; p < 0.01). The risk of hemorrhagic or thromboembolic events was lower at ratios of 3-5 (RR 1.8, 95% CI 1.2-2.6) than at ratios of less than 2 (RR 2.4, 95% CI 1.9-3.1; p = 0.10). We found that a ratio of 2-3 had the lowest absolute risk (AR) of events (AR 4.3%/yr, 95% CI 3.0%-6.3%). Conclusions: The risks of hemorrhage and thromboemboli are minimized at international normalized ratios of 2-3. Ratios that are moderately higher than this therapeutic range appear safe and more effective than subtherapeutic ratios.
    Canadian Medical Association Journal 08/2008; 179(3):235-44. · 8.22 Impact Factor
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    Article: Effects of aerobic training, resistance training, or both on glycemic control in type 2 diabetes: a randomized trial.
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    ABSTRACT: Previous trials have evaluated the effects of aerobic training alone and of resistance training alone on glycemic control in type 2 diabetes, as assessed by hemoglobin A1c values. However, none could assess incremental effects of combined aerobic and resistance training compared with either type of exercise alone. To determine the effects of aerobic training alone, resistance training alone, and combined exercise training on hemoglobin A1c values in patients with type 2 diabetes. Randomized, controlled trial. 8 community-based facilities. 251 adults age 39 to 70 years with type 2 diabetes. A negative result on a stress test or clearance by a cardiologist, and adherence to exercise during a 4-week run-in period, were required before randomization. Interventions: Aerobic training, resistance training, or both types of exercise (combined exercise training). A sedentary control group was included. Exercise training was performed 3 times weekly for 22 weeks (weeks 5 to 26 of the study). The primary outcome was the change in hemoglobin A1c value at 6 months. Secondary outcomes were changes in body composition, plasma lipid values, and blood pressure. The absolute change in the hemoglobin A1c value in the combined exercise training group compared with the control group was -0.51 percentage point (95% CI, -0.87 to -0.14) in the aerobic training group and -0.38 percentage point (CI, -0.72 to -0.22) in the resistance training group. Combined exercise training resulted in an additional change in the hemoglobin A1c value of -0.46 percentage point (CI, -0.83 to -0.09) compared with aerobic training alone and -0.59 percentage point (CI, -0.95 to -0.23) compared with resistance training alone. Changes in blood pressure and lipid values did not statistically significantly differ among groups. Adverse events were more common in the exercise groups. The generalizability of the results to patients who are less adherent to exercise programs is uncertain. The participants were not blinded, and the total duration of exercise was greater in the combined exercise training group than in the aerobic and resistance training groups. Either aerobic or resistance training alone improves glycemic control in type 2 diabetes, but the improvements are greatest with combined aerobic and resistance training. ClinicalTrials.gov registration number: NCT00195884.
    Annals of internal medicine 10/2007; 147(6):357-69. · 16.73 Impact Factor
  • Article: Effect of study setting on anticoagulation control: a systematic review and metaregression.
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    ABSTRACT: For patients receiving therapy with oral anticoagulants (OACs), the proportion of time spent in the therapeutic range (ie, anticoagulation control) is strongly associated with bleeding and thromboembolic risk. The effect of study-level factors, especially study setting, on anticoagulation control is unknown. Describe anticoagulation control achieved in the published literature. We also used metaregressive techniques to determine which study-level factors significantly influenced anticoagulation control.Studies: All published randomized or cohort studies that measured international normalized ratios (INRs) serially in anticoagulated patients and reported the proportion of time between INRs ranging from 1.8 to 2.0 and 3.0 to 3.5. We identified 67 studies with 123 patient groups having 50,208 patients followed for a total of 57,154.7 patient-years. A total of 68.3% of groups were from anticoagulation clinics, 7.3% were from clinical trials, and 24.4% were from community practices. Overall, patients were therapeutic 63.6% of time (95% confidence interval [CI], 61.6 to 65.6). In the metaregression model, study setting had the greatest effect on anticoagulation control with studies in community practices having significantly lower control than either anticoagulation clinics or clinical trials (-12.2%; 95% CI, -19.5 to -4.8; p < 0.0001). Self-management was associated with a significant improvement of time spent in the therapeutic range (+7.0%; 95% CI, 0.7 to 13.3; p = 0.03). Patients who have received anticoagulation therapy spend a significant proportion of their time with an INR out of the therapeutic range. Patients from community practices showed significantly worse anticoagulation control than those from anticoagulation clinics or clinical trials. This should be considered when interpreting the results of, and generalizing from, studies involving OACs.
    Chest 06/2006; 129(5):1155-66. · 5.25 Impact Factor