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ABSTRACT: Depressive symptoms following myocardial infarction (MI) are often assessed using self-report questionnaires, such as the Beck Depression Inventory (BDI). No studies have examined whether depressive symptom scores assessed by self-report questionnaires during hospitalization post-MI are influenced by factors related to the acute event or hospitalization compared to subsequent outpatient assessments of the same patients. The objective of this study was to compare BDI total scores, somatic scores, and cognitive/affective scores among post-MI patients in-hospital versus at post-discharge follow-up.
Secondary analysis of data from two existing cohorts of post-MI patients (Groningen, The Netherlands and Toronto, Canada). In-hospital BDI scores and follow-up scores were compared using paired samples t-tests.
There were 1556 patients from the Groningen sample with BDI data in-hospital and at 3-months post-MI and 229 patients from Toronto with data in-hospital and at 6-months post-MI. BDI total, somatic, and cognitive/affective scores did not differ significantly between in-hospital and follow-up assessments in either sample. Similarly, there were no substantive differences in symptom composition in either sample. Somatic symptoms accounted for 66.3% of total BDI scores in-hospital versus 64.9% at 3-months post-MI for Groningen patients and for 62.1% of total scores in-hospital versus 64.3% at 6-months post-MI for Toronto patients.
Overall BDI total scores, somatic scores, and cognitive/affective scores did not differ between in-hospital and subsequent outpatient assessments. The timing of when depressive symptoms are assessed post-MI does not appear to influence the overall level of BDI scores or the composition of symptoms that are reported.
Journal of psychosomatic research 11/2012; 73(5):356-61. · 2.91 Impact Factor
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Anesthesiology 11/2012; 117(5):1139. · 5.36 Impact Factor
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ABSTRACT: : The threat of being sued is a concern for many anesthesiologists. This paper asks whether litigation brought against anesthesiologists is associated with the age of the anesthesiologist.
: Institutional research ethics approval was granted. We obtained billing data for all procedures performed by specialist anesthesiologists stratified into three age groups (less than 51, 51-64, and 65 and older) from British Columbia, Quebec, and Ontario for the 10-yr period from Jan. 1, 1993 to Dec. 31, 2002. We also obtained all litigations (including disability weighted claims) handled by the Canadian Medical Protective Association during the same time period in which the Canadian Medical Protective Association experts considered the anesthesiologist cited to be at least partially responsible for the adverse event leading to the complaint.
: In univariate analysis with the less than 51 age group as the reference category, the litigation rate ratio for the 51-64 age group was 1.14 (95% CI: 0.99-1.32) and for the 65 and older age group was 1.50 (95% CI: 1.14-1.97). Our analyses using disability weighted claims showed the 51-64 group to have 1.31 (95% CI: 0.95-1.80) and 65 and older group to have 1.94 (95% CI: 1.41-2.67) relative increase in disability compared to the less than 51 age group.
: We found a higher frequency of litigation and a greater severity of injury in patients treated by anesthesiologists in the 65 and older group. The reasons for these findings should become an active field of research.
Anesthesiology 03/2012; 116(3):574-9. · 5.36 Impact Factor
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Ian Shrier,
Patrick Boissy,
Simon Brière,
Jay Mellette,
Luc Fecteau,
Gordon O Matheson,
Daniel Garza,
Willem H Meeuwisse,
Eli Segal,
John Boulay, Russell J Steele
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ABSTRACT: Health care providers must be prepared to manage all potential spine injuries as if they are unstable. Therefore, most sport teams devote resources to training for sideline cervical spine (C-spine) emergencies.
To determine (1) how accurately rescuers and simulated patients can assess motion during C-spine stabilization practice and (2) whether providing performance feedback to rescuers influences their choice of stabilization technique.
Crossover study.
Training studio.
Athletic trainers, athletic therapists, and physiotherapists experienced at managing suspected C-spine injuries.
Twelve lead rescuers (at the patient's head) performed both the head-squeeze and trap-squeeze C-spine stabilization maneuvers during 4 test scenarios: lift-and-slide and log-roll placement on a spine board and confused patient trying to sit up or rotate the head.
Interrater reliability between rescuer and simulated patient quality scores for subjective evaluation of C-spine stabilization during trials (O = best, 10 = worst), correlation between rescuers' quality scores and objective measures of motion with inertial measurement units, and frequency of change in preference for the head-squeeze versus trap-squeeze maneuver.
Although the weighted κ value for interrater reliability was acceptable (0.71-0.74), scores varied by 2 points or more between rescuers and simulated patients for approximately 10% to 15% of trials. Rescuers' scores correlated with objective measures, but variability was large: 38% of trials scored as 0 or 1 by the rescuer involved more than 10° of motion in at least 1 direction. Feedback did not affect the preference for the lift-and-slide placement. For the log-roll placement, 6 of 8 participants who preferred the head squeeze at baseline preferred the trap squeeze after feedback. For the confused patient, 5 of 5 participants initially preferred the head squeeze but preferred the trap squeeze after feedback.
Rescuers and simulated patients could not adequately assess performance during C-spine stabilization maneuvers without objective measures. Providing immediate feedback in this context is a promising tool for changing behavior preferences and improving training.
Journal of athletic training 01/2012; 47(1):42-51. · 1.80 Impact Factor
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ABSTRACT: Medical research increasingly utilizes patient-reported outcome measures administered and scored in different languages. In order to pool or compare outcomes from different language versions, instruments should be measurement equivalent across linguistic groups. The objective of this study was to examine the cross-language measurement equivalence of the Patient Health Questionnaire-9 (PHQ-9) between English- and French-speaking Canadian patients with systemic sclerosis (SSc).
The sample consisted of 739 English- and 221 French-speaking SSc patients. Multiple-Indicator Multiple-Cause (MIMIC) modeling was used to identify items displaying possible differential item functioning (DIF).
A one-factor model for the PHQ-9 fit the data well in both English- and French-speaking samples. Statistically significant DIF was found for 3 of 9 items on the PHQ-9. However, the overall estimate in depression latent scores between English- and French-speaking respondents was not influenced substantively by DIF.
Although there were several PHQ-9 items with evidence of minor DIF, there was no evidence that these differences influenced overall scores meaningfully. The PHQ-9 can reasonably be used without adjustment in Canadian English- and French-speaking samples. Analyses assessing measurement equivalence should be routinely conducted prior to pooling data from English and French versions of patient-reported outcome measures.
PLoS ONE 01/2012; 7(12):e52028. · 4.09 Impact Factor
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Patrick Boissy,
Ian Shrier,
Simon Brière,
Jay Mellete,
Luc Fecteau,
Gordon O Matheson,
Dan Garza,
Willem H Meeuwisse,
Eli Segal,
John Boulay, Russell J Steele
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ABSTRACT: To compare head motions that occur when trained professionals perform the head squeeze (HS) and trap squeeze (TS) C-spine stabilization techniques.
Cross-over design.
Twelve experienced lead rescuers.
Peak head motion with respect to initial conditions using inertial measurement units attached to the forehead and trunk of the simulated patient. We compared both HS and TS during lift-and-slide (L&S) and log-roll (LR) placement on spinal board, and agitated patient trying to sit up (AGIT-Sit) or rotate his head (AGIT-Rot). The a priori minimal important difference (MID) was 5 degrees for flexion or extension and 3 degrees for rotation or lateral flexion.
The L&S technique was statistically superior to the LR technique. The only differences to exceed the MID were extension and rotation during LR (HS > TS). In the AGIT-Sit test scenario, differences in motion exceeded MID (HS > TS) for flexion, rotation, and lateral flexion. In the AGIT-Rot scenario, differences in motion exceeded MID for rotation only (HS >TS). There was similar intertrial variability of motion for HS and TS during L&S and LR but significantly more variability with HS compared with TS in the agitated patient.
The L&S is preferable to the LR when possible for minimizing unwanted C-spine motion. There is little overall difference between HS and TS in a cooperative patient. When a patient is confused, the HS is much worse than the TS at minimizing C-spine motion.
Clinical journal of sport medicine: official journal of the Canadian Academy of Sport Medicine 03/2011; 21(2):80-8. · 1.50 Impact Factor
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ABSTRACT: Previous injury is believed to be a causal risk factor for subsequent injury. Using empirical data on circus artists (n = 1,281 artists) between 2004 and 2008 in Montreal, Canada, as a motivating example, the authors use patient vector plots to demonstrate that a bias away from the null must always occur in the typical analyses cited as evidence (i.e., survival analysis, Poisson regression), except in the improbable context where all subjects have the same inherent risk independent of previous injury. In addition, using simulated data, the authors demonstrate that a simple method that conditions on the individual will approximate conclusions from more complex analytical methods. By using the typical analysis of the authors' empirical data, Kaplan-Meier curves and Cox regression suggested increasing injury rates for both the second and third injuries compared with the first injury. However, conditional analyses using a matched population (i.e., time to first, second, and third injuries among artists with 3 or more injuries) showed that injury rates were unchanged for both the second and third injuries compared with the first injury. These results suggest that previous injury should not be evaluated as a causal risk factor unless one conditions on the individual in some way.
American journal of epidemiology 02/2011; 173(8):941-8. · 5.59 Impact Factor
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ABSTRACT: Fitness testing is used frequently in many areas of physical activity, but the reliability of these measurements under real-world, practical conditions is unknown.
To evaluate the reliability of specific fitness tests using the methods and time periods used in the context of real-world sport and occupational management.
Cohort study.
Eighteen different Cirque du Soleil shows.
Cirque du Soleil physical performers who completed 4 consecutive tests (6-month intervals) and were free of injury or illness at each session (n = 238 of 701 physical performers).
Performers completed 6 fitness tests on each assessment date: dynamic balance, Harvard step test, handgrip, vertical jump, pull-ups, and 60-second jump test.
We calculated the intraclass coefficient (ICC) and limits of agreement between baseline and each time point and the ICC over all 4 time points combined.
Reliability was acceptable (ICC > 0.6) over an 18-month time period for all pairwise comparisons and all time points together for the handgrip, vertical jump, and pull-up assessments. The Harvard step test and 60-second jump test had poor reliability (ICC < 0.6) between baseline and other time points. When we excluded the baseline data and calculated the ICC for 6-month, 12-month, and 18-month time points, both the Harvard step test and 60-second jump test demonstrated acceptable reliability. Dynamic balance was unreliable in all contexts. Limit-of-agreement analysis demonstrated considerable intraindividual variability for some tests and a learning effect by administrators on others.
Five of the 6 tests in this battery had acceptable reliability over an 18-month time frame, but the values for certain individuals may vary considerably from time to time for some tests. Specific tests may require a learning period for administrators.
Journal of athletic training 01/2011; 46(5):505-13. · 1.80 Impact Factor
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ABSTRACT: To investigate the proportion of original studies included in systematic reviews and meta-analyses on the diagnostic accuracy of screening tools for depression that appropriately exclude patients who already have a diagnosis of or are receiving treatment for depression and to determine whether these systematic reviews and meta-analyses evaluate possible bias from the inclusion of such patients.
Systematic review.
Medline, PsycINFO, CINAHL, Embase, ISI, SCOPUS, and Cochrane databases were searched from 1 January 2005 to 29 October 2009. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Systematic reviews and meta-analyses in any language that reported on the diagnostic accuracy of screening tools for depression.
Only eight of 197 (4%) unique publications from 17 systematic reviews and meta-analyses specifically excluded patients who already had a diagnosis of or were receiving treatment for depression. No systematic reviews or meta-analyses commented on possible bias from the inclusion of such patients, even though 10 reviews used quality assessment tools with items to rate risk of bias from composition of the sample of patients.
Studies of the accuracy of screening tools for depression rarely exclude patients who already have a diagnosis of or are receiving treatment for depression, a potential bias that is not evaluated in systematic reviews and meta-analyses. This could result in inflated estimates of accuracy on which clinical practice and preventive care guidelines are often based, a problem that takes on greater importance as the rate of diagnosed and treated depression in the population increases.
BMJ (Clinical research ed.). 01/2011; 343:d4825.
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ABSTRACT: Depression is common among acute coronary syndrome (ACS) patients and is associated with poor prognosis. Cardiac side effects of older antidepressants were well-known, but newer antidepressants are generally thought of as safe to use in patients with heart disease. The objective was to assess rates of antidepressant use or prescription to patients within a year of an ACS.
PubMed, PsycINFO, and CINAHL databases searched through May 29, 2009; manual searching of 33 journals from May 2009 to September 2010. Articles in any language were included if they reported point or period prevalence of antidepressant use or prescription in the 12 months prior or subsequent to an ACS for ≥100 patients. Two investigators independently selected studies for inclusion/exclusion and extracted methodological characteristics and outcomes from included studies (study setting, inclusion/exclusion criteria, sample size, prevalence of antidepressant prescription/use, method of assessing antidepressant prescription/use, time period of assessment).
A total of 24 articles were included. The majority were from North America and Europe, and most utilized chart review or self-report to assess antidepressant use or prescription. Although there was substantial heterogeneity in results, overall, rates of antidepressant use or prescription increased from less than 5% prior to 1995 to 10-15% after 2000. In general, studies from North America reported substantially higher rates than studies from Europe, approximately 5% higher among studies that used chart or self-report data.
Antidepressant use or prescription has increased considerably, and by 2005 approximately 10% to 15% of ACS patients were prescribed or using one of these drugs.
PLoS ONE 01/2011; 6(11):e27671. · 4.09 Impact Factor
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ABSTRACT: The absence of a standardized disease activity index has been an important barrier in systemic sclerosis (SSc) research. We applied the newly derived Valentini Scleroderma Disease Activity Index (SDAI) among our cohort of patients with SSc to document changes in disease activity over time and to assess possible differences in activity between limited and diffuse disease.
Cross-sectional study of a national cohort of patients enrolled in the Canadian Scleroderma Research Group Registry. Disease activity was measured using the SDAI. Depression scores were measured using the Centre for Epidemiologic Studies Depression Scale (CES-D).
A total of 326 out of 639 patients had complete datasets at the time of this analysis; 87% were female, of mean age 55.6 years, with mean disease duration 14.1 years. SDAI declined steeply in the first 5 years after disease onset and patients with diffuse disease had 42% higher SDAI scores than patients with limited disease with the same disease duration and depression scores (standardized relative risk 1.42, 95% CI 1.21, 1.65). Patients with higher CES-D scores had higher SDAI scores relative to patients with the same disease duration and disease subset (standardized RR 1.22, 95% CI 1.14, 1.31). Among the 10 components that make up the SDAI, only skin score (standardized OR 0.59, 95% CI 0.43, 0.82) and patient-reported change in skin (standardized OR 0.64, 95% CI 0.45, 0.92) decreased with increasing disease duration. High skin scores (standardized OR 32.2, 95% CI 15.8, 72.0) were more likely and scleredema (standardized OR 0.58, 95% CI 0.37, 0.92) was less likely to be present in patients with diffuse disease. High depression scores were associated with positive responses for patient-reported changes in skin and cardiopulmonary function.
Disease activity declined with time and patients with diffuse disease had consistently higher SDAI scores. Depression was found to be associated with higher patient activity scores and strongly associated with patient self-response questions. The role of depression should be carefully considered in future applications of the SDAI, particularly as several components of the score rely upon patient recall.
The Journal of Rheumatology 11/2010; 37(11):2299-306. · 3.69 Impact Factor
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ABSTRACT: We consider two difficulties with standard multiple imputation methods for missing data based on Rubin's t method for confidence intervals: their often excessive width, and their instability. These problems are present most often when the number of copies is small, as is often the case when a data collection organization is making multiple completed datasets available for analysis. We suggest using mixtures of normals as an alternative to Rubin's t. We also examine the performance of improper imputation methods as an alternative to generating copies from the true posterior distribution for the missing observations. We report the results of simulation studies and analyses of data on health-related quality of life in which the methods suggested here gave narrower confidence intervals and more stable inferences, especially with small numbers of copies or non-normal posterior distributions of parameter estimates. A free R software package called MImix that implements our methods is available from CRAN.
Statistical Methodology 05/2010; 7(3):351-364.
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ABSTRACT: To determine if the level of self-reported physical activity 1 month after deep vein thrombosis (DVT) is associated with the risk of post-thrombotic syndrome (PTS) in the first 2 years post-DVT.
Prospective cohort study.
Multicenter study (8 hospitals).
Patients presenting with objectively diagnosed acute DVT to 8 hospitals in Quebec and Ontario, Canada.
We used validated questionnaires to measure physical activity (Godin questionnaire) and venous disease severity [generic physical quality of life (SF-36 PCS scale) or VEINES-QOL]. We adjusted for potential confounding effects of age, sex, and body mass index. We used multiple imputation to account for missing data.
Post-thrombotic syndrome (validated Villalta scale).
For the 387 patients enrolled, univariate analysis suggested no association between 1-month activity and risk of PTS. After adjusting for missing data and potential confounders, there was no evidence of a trend toward increasing risk of PTS with increasing physical activity [1.65 (95% confidence interval, 0.87-3.14) for mild-moderate activity and 1.35 (95% confidence interval, 0.69-2.67) for high activity]. The results were similar when PTS was dichotomized as none/mild versus moderate/severe. Finally, patients with PTS had lower levels of activity at 2 years post-DVT.
The level of self-reported exercise in the first month post-DVT is not associated with an increased risk of PTS in the first 2 years after DVT. Post-thrombotic syndrome is associated with decreased levels of physical activity 2 years after DVT.
Clinical journal of sport medicine: official journal of the Canadian Academy of Sport Medicine 11/2009; 19(6):487-93. · 1.50 Impact Factor
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ABSTRACT: The analysis of injury data requires different considerations from the analysis of other types of outcomes because an individual can experience the outcome many times. When describing injury patterns using numerator-only data (e.g., proportion of upper-extremity injuries vs. lower-extremity injuries), simple comparisons of proportions are inappropriate because 1) individuals are compared with themselves and 2) multiple testing increases the potential for incorrect inference. Bootstrapping (resampling) techniques can be used to determine confidence intervals and whether the frequencies significantly differ across categories. When describing injury rates, the authors suggest plotting the observed injury rate against the number of exposures to obtain a visual representation of the heterogeneity of risk across individuals. Because the distribution of injury rates is often skewed, some research questions may be best addressed by comparing the weighted median injury rates instead of the weighted mean injury rates (which are given by standard formulae). Again, resampling techniques can be used to obtain a null distribution for injury rates in order to determine whether there are subjects who have unexpectedly high injury rates. More advanced analyses are required to account for multiplicity.
American journal of epidemiology 10/2009; 170(10):1307-15. · 5.59 Impact Factor
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ABSTRACT: Human circus arts are gaining increasing popularity as a physical activity with more than 500 companies and 200 schools. The only injury data that currently exist are a few case reports and 1 survey.
To describe injury patterns and injury rates among Cirque du Soleil artists between 2002 and 2006.
Descriptive epidemiology study.
The authors defined an injury as any work-related condition recorded in an electronic injury database that required a visit to the show therapist. Analyses for treatments, missed performances, and injury rates (per 1000 artist performances) were based on a subset of data that contained appropriate denominator (exposure) information (began in 2004).
There were 1376 artists who sustained a total of the 18 336 show- or training-related injuries. The pattern of injuries was generally similar across sex and performance versus training. Most injuries were minor. Of the 6701 injuries with exposure data, 80% required < or =7 treatments and resulted in < or =1 completely missed performance. The overall show injury rate was 9.7 (95% confidence interval, 9.4-10.0; for context, published National Collegiate Athletic Association women's gymnastics rate was 15.2 injuries per 1000 athlete-exposures). The rate for injuries resulting in more than 15 missed performances for acrobats (highest risk group) was 0.74 (95% confidence interval, 0.65-0.83), which is much lower than the corresponding estimated National Collegiate Athletic Association women's gymnastics rate.
Most injuries in circus performers are minor, and rates of more serious injuries are lower than for many National Collegiate Athletic Association sports.
The American journal of sports medicine 04/2009; 37(6):1143-9. · 3.61 Impact Factor
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Ian Shrier,
Jean-François Boivin,
Robert W Platt, Russell J Steele,
James M Brophy,
Franco Carnevale,
Mark J Eisenberg,
Andrea Furlan,
Ritsuko Kakuma,
Mary Ellen Macdonald,
Louise Pilote,
Michel Rossignol
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ABSTRACT: Discrepancies between the conclusions of different meta-analyses (quantitative syntheses of systematic reviews) are often ascribed to methodological differences. The objective of this study was to determine the discordance in interpretations when meta-analysts are presented with identical data.
We searched the literature for all randomized clinical trials (RCT) and review articles on the efficacy of intravenous magnesium in the early post-myocardial infarction period. We organized the articles chronologically and grouped them in packages. The first package included the first RCT, and a summary of the review articles published prior to first RCT. The second package contained the second and third RCT, a meta-analysis based on the data, and a summary of all review articles published prior to the third RCT. Similar packages were created for the 5th RCT, 10th RCT, 20th RCT and 23rd RCT (all articles). We presented the packages one at a time to eight different reviewers and asked them to answer three clinical questions after each package based solely on the information provided. The clinical questions included whether 1) they believed magnesium is now proven beneficial, 2) they believed magnesium will eventually be proven to be beneficial, and 3) they would recommend its use at this time.
There was considerable disagreement among the reviewers for each package, and for each question. The discrepancies increased when the heterogeneity of the data increased. In addition, some reviewers became more sceptical of the effectiveness of magnesium over time, and some reviewers became less sceptical.
The interpretation of the results of systematic reviews with meta-analyses includes a subjective component that can lead to discordant conclusions that are independent of the methodology used to obtain or analyse the data.
BMC Medical Informatics and Decision Making 02/2008; 8:19. · 1.48 Impact Factor
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ABSTRACT: We describe the practice profile of Quebec and British Columbia (BC) specialist anesthesiologists. All provincial health-care billings from Quebec and BC were obtained for the period from 1 January 1993 to 31 December 2002. We categorized the specialist anesthesiologists into one of three age categories (<51, 51 6 4 , and 65+) and assigned a case complexity value (low, moderate, high) to every procedure billed. Anesthesiologists who continued working after age 65 provided anesthesia to fewer patients and for less complex surgery than those in the younger age groups. The end-of-career package introduced in Quebec in 1995 led to an overall reduction in the number of cared-for patients. Predictions of manpower shortages in anesthesia must be province specific and may fail to account for government policies or changes in practice. Consequently they are likely underestimates.
Canadian Public Policy 01/2008; 34(4):501-510. · 0.38 Impact Factor
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ABSTRACT: Some authors argue that systematic reviews and meta-analyses of intervention studies should include only randomized controlled trials because the randomized controlled trial is a more valid study design for causal inference compared with the observational study design. However, a review of the principal elements underlying this claim (randomization removes the chance of confounding, and the double-blind process minimizes biases caused by the placebo effect) suggests that both classes of study designs have strengths and weaknesses, and including information from observational studies may improve the inference based on only randomized controlled trials. Furthermore, a review of empirical studies suggests that meta-analyses based on observational studies generally produce estimates of effect similar to those from meta-analyses based on randomized controlled trials. The authors found that the advantages of including both observational studies and randomized studies in a meta-analysis could outweigh the disadvantages in many situations and that observational studies should not be excluded a priori.
American journal of epidemiology 12/2007; 166(10):1203-9. · 5.59 Impact Factor
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American Journal of Epidemiology 08/2007; 166(2):238-9. · 5.22 Impact Factor
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ABSTRACT: In recent years, several authors have suggested there is a need for more very large or "mega-trials" (defined in this manuscript as a trial powered to address subgroup differences/interactions/secondary analyses) to answer important clinical questions. Because mega-trials are expensive and funding for clinical research is limited, increasing the number of mega-trials limits funding for other research. The advantages of this approach compared with funding more focused RCTs needs to be debated. Because there is no method to determine gold standard for which method gives the correct answer, we provide theoretical arguments that demonstrate that the two approaches are similar with respect to sample size requirements and the mega-trial approach provides a small advantage with respect to minimizing confounding by chance. However, the inherent heterogeneity in a series of smaller trials may represent a significant advantage over a single mega-trial.
Contemporary Clinical Trials 06/2007; 28(3):324-8. · 1.81 Impact Factor
