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ABSTRACT: The WHO Fracture Risk Assessment Tool (FRAX; http://www.shef.ac.uk/FRAX) estimates the 10-year probability of major osteoporotic fracture. Clodronate and bazedoxifene reduced nonvertebral and clinical fracture more effectively on a relative scale in women with higher FRAX scores. We used data from the Fracture Intervention Trial (FIT) to evaluate the interaction between FRAX score and treatment with alendronate. We combined the Clinical Fracture (CF) arm and Vertebral Fracture (VF) arm of FIT. The CF and VF arm of FIT randomized 4432 and 2027 women, respectively, to placebo or alendronate for 4 and 3 years, respectively. FRAX risk factors were assessed at baseline. FRAX scores were calculated by WHO. We used Poisson regression models to assess the interaction between alendronate and FRAX score on the risk of nonvertebral, clinical, major osteoporotic, and radiographic vertebral fractures. Overall, alendronate significantly reduced the risk of nonvertebral fracture (incidence rate ratio [IRR] 0.86; 95% confidence interval [CI], 0.75-0.99), but the effect was greater for femoral neck (FN) bone mineral density (BMD) T-score ≤ -2.5 (IRR 0.76; 95% CI, 0.62-0.93) than for FN T-score > -2.5 (IRR 0.96; 95% CI, 0.80-1.16) (p = 0.02, interaction between alendronate and FN BMD). However, there was no evidence of an interaction between alendronate and FRAX score with FN BMD for risk of nonvertebral fracture (interaction p = 0.61). The absolute benefit of alendronate was greatest among women with highest FRAX scores. Results were similar for clinical fractures, major osteoporotic fractures, and radiographic vertebral fractures and whether or not FRAX scores included FN BMD. Among this cohort of women with low bone mass there was no significant interaction between FRAX score and alendronate for nonvertebral, clinical or major osteoporotic fractures, or radiographic vertebral fractures. These results suggest that the effect of alendronate on a relative scale does not vary by FRAX score. A randomized controlled trial testing the effect of antifracture agents among women with high FRAX score but without osteoporosis is warranted.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 04/2012; 27(8):1804-10. · 6.04 Impact Factor
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Wendy L Cook,
Karim M Khan,
Michelle H Bech,
Penelope M Brasher,
Roy A Brown,
Stirling Bryan, Meghan G Donaldson,
Pierre Guy,
Heather M Hanson,
Cheryl Leia,
Erin M Macri,
Joanie Sims-Gould,
Heather A McKay,
Maureen C Ashe
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ABSTRACT: BACKGROUND: Fall-related hip fractures result in significant personal and societal consequences; importantly, up to half of older adults with hip fracture never regain their previous level of mobility. Strategies of follow-up care for older adults after fracture have improved investigation for osteoporosis; but managing bone health alone is not enough. Prevention of fractures requires management of both bone health and falls risk factors (including the contributing role of cognition, balance and continence) to improve outcomes. METHODS/DESIGN: This is a parallel group, pragmatic randomized controlled trial to test the effectiveness of a post-fracture clinic compared with usual care on mobility for older adults following their hospitalization for hip fracture. Participants randomized to the intervention will attend a fracture follow-up clinic where a geriatrician and physiotherapist will assess and manage their mobility and other health issues. Depending on needs identified at the clinical assessment, participants may receive individualized and group-based outpatient physiotherapy, and a home exercise program. Our primary objective is to assess the effectiveness of a novel post-discharge fracture management strategy on the mobility of older adults after hip fracture. We will enrol 130 older adults (65 years+) who have sustained a hip fracture in the previous three months, and were admitted to hospital from home and are expected to be discharged home. We will exclude older adults who prior to the fracture were: unable to walk 10 meters; diagnosed with dementia and/or significant comorbidities that would preclude their participation in the clinical service. Eligible participants will be randomly assigned to the Intervention or Usual Care groups by remote allocation. Treatment allocation will be concealed; investigators, measurement team and primary data analysts will be blinded to group allocation. Our primary outcome is mobility, operationalized as the Short Physical Performance Battery at 12 months. Secondary outcomes include frailty, rehospitalizations, falls risk factors, quality of life, as well as physical activity and sedentary behaviour. We will conduct an economic evaluation to determine health related costs in the first year, and a process evaluation to ascertain the acceptance of the program by older adults, as well as clinicians and staff within the clinic. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT01254942.
BMC Geriatrics 06/2011; 11:30. · 2.34 Impact Factor
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Ann V Schwartz,
Eric Vittinghoff,
Douglas C Bauer,
Teresa A Hillier,
Elsa S Strotmeyer,
Kristine E Ensrud, Meghan G Donaldson,
Jane A Cauley,
Tamara B Harris,
Annemarie Koster,
Catherine R Womack,
Lisa Palermo,
Dennis M Black
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ABSTRACT: Type 2 diabetes mellitus (DM) is associated with higher bone mineral density (BMD) and paradoxically with increased fracture risk. It is not known if low BMD, central to fracture prediction in older adults, identifies fracture risk in patients with DM.
To determine if femoral neck BMD T score and the World Health Organization Fracture Risk Algorithm (FRAX) score are associated with hip and nonspine fracture risk in older adults with type 2 DM.
Data from 3 prospective observational studies with adjudicated fracture outcomes (Study of Osteoporotic Fractures [December 1998-July 2008]; Osteoporotic Fractures in Men Study [March 2000-March 2009]; and Health, Aging, and Body Composition study [April 1997-June 2007]) were analyzed in older community-dwelling adults (9449 women and 7436 men) in the United States.
Self-reported incident fractures, which were verified by radiology reports.
Of 770 women with DM, 84 experienced a hip fracture and 262 a nonspine fracture during a mean (SD) follow-up of 12.6 (5.3) years. Of 1199 men with DM, 32 experienced a hip fracture and 133 a nonspine fracture during a mean (SD) follow-up of 7.5 (2.0) years. Age-adjusted hazard ratios (HRs) for 1-unit decrease in femoral neck BMD T score in women with DM were 1.88 (95% confidence interval [CI], 1.43-2.48) for hip fracture and 1.52 (95% CI, 1.31-1.75) for nonspine fracture, and in men with DM were 5.71 (95% CI, 3.42-9.53) for hip fracture and 2.17 (95% CI, 1.75-2.69) for nonspine fracture. The FRAX score was also associated with fracture risk in participants with DM (HRs for 1-unit increase in FRAX hip fracture score, 1.05; 95% CI, 1.03-1.07, for women with DM and 1.16; 95% CI, 1.07-1.27, for men with DM; HRs for 1-unit increase in FRAX osteoporotic fracture score, 1.04; 95% CI, 1.02-1.05, for women with DM and 1.09; 95% CI, 1.04-1.14, for men with DM). However, for a given T score and age or for a given FRAX score, participants with DM had a higher fracture risk than those without DM. For a similar fracture risk, participants with DM had a higher T score than participants without DM. For hip fracture, the estimated mean difference in T score for women was 0.59 (95% CI, 0.31-0.87) and for men was 0.38 (95% CI, 0.09-0.66).
Among older adults with type 2 DM, femoral neck BMD T score and FRAX score were associated with hip and nonspine fracture risk; however, in these patients compared with participants without DM, the fracture risk was higher for a given T score and age or for a given FRAX score.
JAMA The Journal of the American Medical Association 06/2011; 305(21):2184-92. · 30.03 Impact Factor
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Meghan G Donaldson,
Peggy M Cawthon,
John T Schousboe,
Kristine E Ensrud,
Li-Yung Lui,
Jane A Cauley,
Teresa A Hillier,
Brent C Taylor,
Marc C Hochberg,
Douglas C Bauer,
Steven R Cummings
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ABSTRACT: Fracture prediction models help to identify individuals at high risk who may benefit from treatment. Area under the curve (AUC) is used to compare prediction models. However, the AUC has limitations and may miss important differences between models. Novel reclassification methods quantify how accurately models classify patients who benefit from treatment and the proportion of patients above/below treatment thresholds. We applied two reclassification methods, using the National Osteoporosis Foundation (NOF) treatment thresholds, to compare two risk models: femoral neck bone mineral density (BMD) and age (simple model) and FRAX (FRAX model). The Pepe method classifies based on case/noncase status and examines the proportion of each above and below thresholds. The Cook method examines fracture rates above and below thresholds. We applied these to the Study of Osteoporotic Fractures (SOF). There were 6036 (1037 fractures) and 6232 (389 fractures) participants with complete data for major osteoporotic and hip fracture, respectively. Both models for major osteoporotic fracture (0.68 versus 0.69) and hip fracture (0.75 versus 0.76) had similar AUCs. In contrast, using reclassification methods, each model classified a substantial number of women differently. Using the Pepe method, the FRAX model (versus the simple model) missed treating 70 (7%) cases of major osteoporotic fracture but avoided treating 285 (6%) noncases. For hip fracture, the FRAX model missed treating 31 (8%) cases but avoided treating 1026 (18%) noncases. The Cook method (both models, both fracture outcomes) had similar fracture rates above/below the treatment thresholds. Compared with the AUC, new methods provide more detailed information about how models classify patients.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2011; 26(8):1767-73. · 6.04 Impact Factor
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Teresa A Hillier,
Jane A Cauley,
Joanne H Rizzo,
Kathryn L Pedula,
Kristine E Ensrud,
Douglas C Bauer,
Li-Yung Lui,
Kimberly K Vesco,
Dennis M Black, Meghan G Donaldson,
Erin S Leblanc,
Steven R Cummings
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ABSTRACT: Bone mineral density (BMD) is a strong predictor of fracture, yet most fractures occur in women without osteoporosis by BMD criteria. To improve fracture risk prediction, the World Health Organization recently developed a country-specific fracture risk index of clinical risk factors (FRAX) that estimates 10-year probabilities of hip and major osteoporotic fracture. Within differing baseline BMD categories, we evaluated 6252 women aged 65 or older in the Study of Osteoporotic Fractures using FRAX 10-year probabilities of hip and major osteoporotic fracture (ie, hip, clinical spine, wrist, and humerus) compared with incidence of fractures over 10 years of follow-up. Overall ability of FRAX to predict fracture risk based on initial BMD T-score categories (normal, low bone mass, and osteoporosis) was evaluated with receiver-operating-characteristic (ROC) analyses using area under the curve (AUC). Over 10 years of follow-up, 368 women incurred a hip fracture, and 1011 a major osteoporotic fracture. Women with low bone mass represented the majority (n = 3791, 61%); they developed many hip (n = 176, 48%) and major osteoporotic fractures (n = 569, 56%). Among women with normal and low bone mass, FRAX (including BMD) was an overall better predictor of hip fracture risk (AUC = 0.78 and 0.70, respectively) than major osteoporotic fractures (AUC = 0.64 and 0.62). Simpler models (eg, age + prior fracture) had similar AUCs to FRAX, including among women for whom primary prevention is sought (no prior fracture or osteoporosis by BMD). The FRAX and simpler models predict 10-year risk of incident hip and major osteoporotic fractures in older US women with normal or low bone mass.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2011; 26(8):1774-82. · 6.04 Impact Factor
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Meghan G Donaldson,
Peggy M Cawthon,
Lily Y Lui,
John T Schousboe,
Kristine E Ensrud,
Brent C Taylor,
Jane A Cauley,
Teresa A Hillier,
Thuy T Dam,
Jeff R Curtis,
Dennis M Black,
Douglas C Bauer,
Eric S Orwoll,
Steven R Cummings
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ABSTRACT: The new US National Osteoporosis Foundation's (NOF's) Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck or spine bone mineral density (BMD) T-scores of -2.5 or less, and presence of low bone mass at the femoral neck or spine plus a 10-year risk of hip fracture of 3% or greater or of major osteoporotic fracture of 20% or greater. The proportion of men who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to men participating in the Osteoporotic Fractures in Men Study (MrOS). To determine how the MrOS population differs from the general US population of Caucasian men aged 65 years and older, we compared men in MrOS with men who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, men in MrOS had higher femoral neck BMD values. Application of NOF guidelines to MrOS data estimated that at least 34% of US white men aged 65 years and older and 49% of those aged 75 years and older would be recommended for drug treatment. Application of the new NOF guidelines would result in recommending a very large proportion of white men in the United States for pharmacologic treatment of osteoporosis, for many of whom the efficacy of treatment is unknown.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2010; 25(7):1506-11. · 6.04 Impact Factor
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ABSTRACT: A Web-based risk assessment tool (FRAX) using clinical risk factors with and without femoral neck bone mineral density (BMD) has been incorporated into clinical guidelines regarding treatment to prevent fractures. However, it is uncertain whether prediction with FRAX models is superior to that based on parsimonious models.
We conducted a prospective cohort study in 6252 women 65 years or older to compare the value of FRAX models that include BMD with that of parsimonious models based on age and BMD alone for prediction of fractures. We also compared FRAX models without BMD with simple models based on age and fracture history alone. Fractures (hip, major osteoporotic [hip, clinical vertebral, wrist, or humerus], and any clinical fracture) were ascertained during 10 years of follow-up. Area under the curve (AUC) statistics from receiver operating characteristic curve analysis were compared between FRAX models and simple models.
The AUC comparisons showed no differences between FRAX models with BMD and simple models with age and BMD alone in discriminating hip (AUC, 0.75 for the FRAX model and 0.76 for the simple model; P = .26), major osteoporotic (AUC, 0.68 for the FRAX model and 0.69 for the simple model; P = .51), and clinical fracture (AUC, 0.64 for the FRAX model and 0.63 for the simple model; P = .16). Similarly, performance of parsimonious models containing age and fracture history alone was nearly identical to that of FRAX models without BMD. The proportion of women in each quartile of predicted risk who actually experienced a fracture outcome did not differ between FRAX and simple models (P > or = .16).
Simple models based on age and BMD alone or age and fracture history alone predicted 10-year risk of hip, major osteoporotic, and clinical fracture as well as more complex FRAX models.
Archives of internal medicine 12/2009; 169(22):2087-94. · 11.46 Impact Factor
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ABSTRACT: The validity of the WHO 10-yr probability of major osteoporotic fracture model (FRAX) for prediction of vertebral fracture has not been tested. We analyzed how well FRAX for major osteoporotic fractures, with and without femoral neck BMD (FN BMD), predicted the risk of vertebral fracture. We also compared the predictive validity of FRAX, FN BMD, and prevalent vertebral fracture detected by radiographs at baseline alone or in combination to predict future vertebral fracture. We analyzed data from the placebo groups of FIT (3.8-yr follow-up, n = 3221) with ORs and areas under receiver operating characteristics (ROC) curves (AUC). FRAX with and without FN BMD predicted incident radiographic vertebral fracture. The AUC was significantly greater for FRAX with FN BMD (AUC = 0.71) than FRAX without FN BMD (AUC = 0.68; p = 0.002). Prevalent vertebral fracture plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture as well as a combination of prevalent vertebral fracture and FRAX with FN BMD (AUC = 0.75; p = 0.76). However, baseline vertebral fracture status plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture significantly better than FRAX with FN BMD (AUC = 0.71; p = 0.0017). FRAX for major osteoporotic fractures (with and without FN BMD) predicts vertebral fracture. However, once FN BMD and age are known, the eight additional risk factors in FRAX do not significantly improve the prediction of vertebral fracture. A combination of baseline radiographic vertebral fracture, FN BMD, and age is the strongest predictor of future vertebral fracture.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 06/2009; 24(11):1793-9. · 6.04 Impact Factor
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Meghan G Donaldson,
Peggy M Cawthon,
Li-Yung Lui,
John T Schousboe,
Kristine E Ensrud,
Brent C Taylor,
Jane A Cauley,
Teresa A Hillier,
Dennis M Black,
Doug C Bauer,
Steven R Cummings
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ABSTRACT: The new U.S. National Osteoporosis Foundation Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck (FN), or spine BMD T-scores <or=-2.5 and presence of low bone mass at the FN or spine plus a 10-yr risk of hip fracture >or=3% or of major osteoporotic fracture >or=20%. The proportion of women who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to women participating in the Study of Osteoporotic Fractures (SOF). To determine how the SOF population differs from the general U.S. population of white women >or=65 yr of age, we compared women in SOF with women who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, women in SOF had higher FN BMD and were younger. Application of NOF guidelines to SOF data estimated that at least 72% of U.S. white women >or=65 yr of age and 93% of those >or=75 yr of age would be recommended for drug treatment. Application of the new NOF Guidelines would result in recommending a very large proportion of white women in the United States for pharmacologic treatment of osteoporosis.
Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 01/2009; 24(4):675-80. · 6.04 Impact Factor
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ABSTRACT: there are several well-developed statistical methods for analysing recurrent events. Although there are guidelines for reporting the design and methodology of randomised controlled trials (RCTs), analysis guidelines do not exist to guide the analysis for RCTs with recurrent events. Application of statistical methods that do not account for recurrent events may provide erroneous results when used to test the efficacy of an intervention. It is unknown what proportion of RCTs of falls prevention studies have utilised statistical methods that incorporate recurrent events.
we conducted a systematic review of RCTs of interventions to prevent falls in community-dwelling older persons. We searched Medline from 1994 to November 2006. We determined the proportion of studies that reported using three statistical methods appropriate for the analysis of recurrent events (negative binomial regression, Andersen-Gill extension of the Cox model and the WLW marginal model).
fewer than one-third of 83 papers that reported falls as an outcome utilised any appropriate statistical method (negative binomial regression, Andersen-Gill extension of the Cox model and Cox marginal model) to analyse recurrent events and fewer than 15% utilised graphical methods to represent falls data.
RCTs that have a recurrent event end-point should include an analysis appropriate for recurrent event data such as negative binomial regression, Andersen-Gill extension of the Cox model and/or the WLW marginal model. We recommend that researchers and clinicians seek consultation with a statistician with expertise in recurrent event methodology.
Age and Ageing 01/2009; 38(2):151-5. · 3.09 Impact Factor
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ABSTRACT: To primarily ascertain the effect of the Otago Exercise Program (OEP) on physiological falls risk, functional mobility, and executive functioning after 6 months in older adults with a recent history of falls and to ascertain the effect of the OEP on falls during a 1-year follow-up period.
Randomized controlled trial.
Dedicated falls clinics.
Seventy-four adults aged 70 and older who presented to a healthcare professional after a fall.
The OEP, a home-based program that consists of resistance training and balance training exercises.
Physiological falls risk was assessed using the Physiological Profile Assessment. Functional mobility was assessed using the Timed Up and Go Test. Three central executive functions were assessed: set shifting, using the Trail Making Test Part B; updating, using the verbal digits backward test; and response inhibition, using the Stroop Color-Word Test. Falls were prospectively monitored using daily calendars.
At 6 months, there was no significant between-group difference in physiological falls risk or functional mobility (P>or= .33). There was a significant between-group difference in response inhibition (P=.05). A falls histogram revealed two outliers. With these cases removed, using negative binomial regression, the unadjusted incidence rate ratio of falls in the OEP group compared with the control group was 0.56. The adjusted incidence rate ratio was 0.47.
The OEP may reduce falls by improving cognitive performance.
Journal of the American Geriatrics Society 10/2008; 56(10):1821-30. · 3.74 Impact Factor
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ABSTRACT: Evidence-based medicine has been advanced by the use of standards for reporting the design and methodology of randomized controlled trials (RCT). Indeed, without this information it is difficult to assess the quality of evidence from an RCT. Although a variety of statistical methods are available for the analysis of recurrent events, reporting the effect of an intervention on outcomes that recur is an area that remains poorly understood in clinical research. The purpose of this paper is to outline guidelines for reporting results from RCTs where the outcome of interest is a recurrent event.
We used a simulation study to relate an event process and results from analyses of the gamma-Poisson, independent-increment, conditional, and marginal Cox models. We reviewed the utility of regression models for the rate of a recurrent event by articulating the associated study questions, preenting the risk sets, and interpreting the regression coefficients.
Based on a single data set produced by simulation, we reported and contrasted results from statistical methods for evaluating treatment effect from an RCT with a recurrent outcome. We showed that each model has different study questions, assumptions, risk sets, and rate ratio interpretation, and so inferences should consider the appropriateness of the model for the RCT.
Our guidelines for reporting results from an RCT involving a recurrent event suggest that the study question and the objectives of the trial, such as assessing comparable groups and estimating effect size, should determine the statistical methods. The guidelines should allow clinical researchers to report appropriate measures from an RCT for understanding the effect of intervention on the occurrence of a recurrent event.
BMC Medical Research Methodology 02/2008; 8:35. · 2.67 Impact Factor
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ABSTRACT: Falls are the most common cause of injury among elderly people; half of those people fall recurrently. The objective of these simulation studies was to describe the Mean Cumulative Function (MCF) and to evaluate the utility of the MCF in detecting differences between groups experiencing different patterns of event intensities.
We specified 250 participants per group with a maximum follow-up time of 365 days. A participant could experience 0, 1, 2, 3, or 4 falls. In the baseline experiment, Groups A and B had an average intensity of 60 and 90 days to the first fall event. These event intensities remained constant for events 2-4. Group C represents a short term "strong" initial impact of the intervention modeled for falls 1 and 2, with an average intensity of one fall per 117 days; however, the intervention wanes to "moderate" for falls 3 and 4 with an average intensity of one fall per 90 days. Group D represents a long-term "strong" impact of the intervention modeled by an average intensity of one fall per 117 days for all subsequent events.
The MCF was able to detect differences between groups that had varying intensities of subsequent falls. In Group A, all participants experienced at least one fall, whereas Groups B, C, and D had 4, 9, and 15 participants, respectively, who did not experience any falls. The proportion of participants who had 4 falls declined from 84% to 40% in Groups A and D, respectively. When Group A was compared to Group D, the MCF difference detected the prevention of, on average, one fall per person within 175 days. Discussion. A novel instrument for this field of clinical research--the MCF--allows investigators to compare the average number of falls per participant when the intervention reduces the intensity of subsequent falls.
The Journals of Gerontology Series A Biological Sciences and Medical Sciences 05/2007; 62(4):415-9. · 4.60 Impact Factor
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ABSTRACT: It is currently unknown whether falling is independently associated with measures of balance and mobility in older adults after accounting for relevant physiological functions. This cross-sectional study assessed the independent association of falls-related self-efficacy to balance and mobility after accounting for age, current physical activity, and performances in relevant physiological domains in 98 older women, aged 75-86 years, with low bone mass.
Falls-related self-efficacy was assessed by the Activities-Specific Balance Confidence Scale (ABC Scale). Measures of balance and mobility included the 13-item Community Balance and Mobility Scale (CB & M Scale) and gait speed under two conditions: normal-paced and fast-paced. Physiological assessment included postural sway, foot reaction time, dominant quadriceps and dorsiflexor strength, proprioception, tactile sensitivity, edge contrast sensitivity, and visual acuity.
Falls-related self-efficacy was independently associated with both balance and mobility after accounting for age, current physical activity level, and performances in relevant physiological domains. Based on the standardized beta coefficients, the ABC Scale score was more associated with measures of balance and mobility than measures of physiological function.
These results highlight the independent association of falls-related self-efficacy with physical performance in older women with low bone mass. Thus, clinicians may need to consider falls-related self-efficacy when assessing and treating balance and mobility in this population, and falls-related self-efficacy may be useful as a screening tool to identify those persons with impaired balance and mobility.
The Journals of Gerontology Series A Biological Sciences and Medical Sciences 08/2006; 61(8):832-8. · 4.60 Impact Factor
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ABSTRACT: To study the effects of a therapeutic dose of pseudoephedrine on anaerobic cycling power and aerobic cycling efficiency.
Eleven healthy moderately trained males (VO (2peak) 4.4 +/- 0.8 L x min(-1) participated in a double-blinded crossover design. Subjects underwent baseline (B) tests for anaerobic (Wingate test) and aerobic (VO (2peak) test) cycling power. Subjects ingested either 60 mg of pseudoephedrine hydrochloride (D) or a placebo (P) and, after 90 min of rest, a Wingate and a cycling efficiency test were performed. During the cycling efficiency test, heart rate (HR) and VO(2) were averaged for the last 5 min of a 10-min cycle at 40% and 60% of the peak power achieved during the VO (2peak) test.
There were no significant differences in peak power (B = 860 +/- 154, D = 926 +/- 124, P = 908 +/- 118 W), total work (B = 20 +/- 3, D = 21 +/- 3, P = 21 +/- 3 kJ), or fatigue index (B = 39 +/- 8, D = 45 +/- 5, P = 43 +/- 5%). There were no significant differences in HR at 40% power (D = 138 +/- 10, P = 137 +/- 10 beats.min-1) or 60% power (D = 161 +/- 11, P = 160 +/- 11 beats x min(-1). There were no significant differences in cycling efficiency at 40% power (D = 18.8 +/- 1.8, P = 18.5 +/- 1.8%) or 60% power (D = 20.3 +/- 2.0, P = 20.1 +/- 2.1%).
A therapeutic dose of pseudoephedrine hydrochloride does not affect anaerobic cycling performance or aerobic cycling efficiency.
Medicine & Science in Sports & Exercise 09/2003; 35(8):1316-9. · 4.43 Impact Factor
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ABSTRACT: HODGES, A. N. H., B. M. LYNN, J. E. BULA, M. G. DONALDSON, M. O. DAGENAIS, and D. C. MCKENZIE. Effects of Pseudoephedrine on Maximal Cycling Power and Submaximal Cycling Efficiency. Med. Sci. Sports Exerc., Vol. 35, No. 8, pp. 1316-1319, 2003.
Purpose: To study the effects of a therapeutic dose of pseudoephedrine on anaerobic cycling power and aerobic cycling efficiency.
Methods: Eleven healthy moderately trained males (V̇O2peak 4.4 ± 0.8 L·min-1) participated in a double-blinded crossover design. Subjects underwent baseline (B) tests for anaerobic (Wingate test) and aerobic (V̇O2peak test) cycling power. Subjects ingested either 60 mg of pseudoephedrine hydrochloride (D) or a placebo (P) and, after 90 min of rest, a Wingate and a cycling efficiency test were performed. During the cycling efficiency test, heart rate (HR) and V̇O2 were averaged for the last 5 min of a 10-min cycle at 40% and 60% of the peak power achieved during the V̇O2peak test.
Results: There were no significant differences in peak power (B = 860 ± 154, D = 926 ± 124, P = 908 ± 118 W), total work (B = 20 ± 3, D = 21 ± 3, P = 21 ± 3 kJ), or fatigue index (B = 39 ± 8, D = 45 ± 5, P = 43 ± 5%). There were no significant differences in HR at 40% power (D = 138 ± 10, P = 137 ± 10 beats·min-1) or 60% power (D = 161 ± 11, P = 160 ± 11 beats·min-1). There were no significant differences in cycling efficiency at 40% power (D = 18.8 ± 1.8, P = 18.5 ± 1.8%) or 60% power (D = 20.3 ± 2.0, P = 20.1 ± 2.1%).
Conclusion: A therapeutic dose of pseudoephedrine hydrochloride does not affect anaerobic cycling performance or aerobic cycling efficiency.
Pseudoephedrine is a sympathomimetic drug commonly found in nonprescription cold and flu medications. It is clinically useful in the treatment of mucosal congestion accompanying hay fever, allergic rhinitis, sinusitis, and other respiratory conditions. Pseudoephedrine is an α1 and β1 agonist similar in structure to ephedrine and amphetamines, and is listed as a banned substance by the International Olympic Committee for its classification as a stimulant. This drug has resulted in several positive drug tests in international athletic competitions in recent years. Cold and flu medications that do not contain pseudoephedrine are generally acceptable for athletes in international competition. Thus, its role as a possible ergogenic aid restricts the general clinical use of pseudoephedrine containing medications by athletes. Pseudoephedrine acts to increase heart rate (HR) and cardiac contractility. It is these chronotropic and inotropic effects that may lead to abuse of this drug during competition in an effort to attain an ergogenic effect. However, a therapeutic dose of pseudoephedrine, for treatment of mucosal congestion, should be considered separately than much greater doses used intentionally for ergogenic gain.
Although several studies have shown some increase in performance with the use of ephedrine and/or caffeine (1-3,5), there is very limited evidence of an ergogenic effect from pseudoephedrine. It has been shown that pseudoephedrine is without ergogenic effects during prolonged high-intensity exercise (9), during time to exhaustion tests (16), and during an incremental exercise test to exhaustion (6) and has limited ergogenic properties during a 30-s all-out cycle test (8). Thus, we saw a need to examine the effects of pseudoephedrine on two types of exercise: 1) maximal anaerobic exercise applicable to short-duration or intermittent high-intensity sport performance and 2) submaximal efficiency applicable to long-duration continuous sport performance.
The aim of the current investigation was to examine the effects of a therapeutic dose of pseudoephedrine on applied exercise performance, and for this reason, the following considerations were instrumental in the development this study. The normal therapeutic dose of 60-mg pseudoephedrine was used in this study as an appropriate representation of the dose typically taken by athletes in an attempt to treat symptoms from a common cold or flu. Although anaerobic cycle tests have been shown to be reliable, there is some debate as to what they measure. According to Inbar et al. (10), there is lack of agreement on the terminology used to describe the output of anaerobic tests. Nevertheless, peak power and total work are objective measures that may be compared between subjects and conditions. It is for this reason, and because the Wingate is the most commonly used anaerobic ergometric test, that the Wingate was used in this study. Efficiency of human muscle contraction has been defined as the ratio of energy output to energy consumption (12). Gross efficiency does not distinguish between energy consumption related to the work performed and basal energy consumption, and was calculated as the ratio of work output to total energy consumption (7,14,15).
Medicine & Science in Sports & Exercise 07/2003; 35(8):1316-1319. · 4.43 Impact Factor
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Nick D Carter,
Karim M Khan,
Heather A McKay,
Moira A Petit,
Constance Waterman,
Ari Heinonen,
Patti A Janssen, Meghan G Donaldson,
Arthur Mallinson,
Lenore Riddell,
Karen Kruse,
Jerilynn C Prior,
Leon Flicker
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ABSTRACT: Exercise programs improve balance, strength and agility in elderly people and thus may prevent falls. However, specific exercise programs that might be widely used in the community and that might be "prescribed" by physicians, especially for patients with osteoporosis, have not been evaluated. We conducted a randomized controlled trial of such a program designed specifically for women with osteoporosis.
We identified women 65 to 75 years of age in whom osteoporosis had been diagnosed by dual-energy X-ray absorptiometry in our hospital between 1996 and 2000 and who were not engaged in regular weekly programs of moderate or hard exercise. Women who agreed to participate were randomly assigned to participate in a twice-weekly exercise class or to not participate in the class. We measured baseline data and, 20 weeks later, changes in static balance (by dynamic posturography), dynamic balance (by a timed figure-eight run) and knee extension strength (by dynamometry).
Of 93 women who began the trial, 80 completed it. Before adjustment for covariates, the intervention group tended to have greater, although nonsignificant, improvements in static balance (mean difference 4.8%, 95% confidence interval [CI] -1.3% to 11.0%), dynamic balance (mean difference 3.3%, 95% CI -1.7% to 8.4%) and knee extension strength (mean difference 7.8%, 95% CI -5.4% to 21.0%). Mean crude changes in the static balance score were -0.85 (95% CI -2.91 to 1.21) for the control group and 1.40 (95% CI -0.66 to 3.46) for the intervention group. Mean crude changes in figure-eight velocity (dynamic balance) were 0.08 (95% CI 0.02 to 0.14) m/s for the control group and 0.14 (95% CI 0.08 to 0.20) m/s for the intervention group. For knee extension strength, mean changes were -0.58 (95% CI -3.02 to 1.81) kg/m for the control group and 1.03 (95% CI -1.31 to 3.34) kg/m for the intervention group. After adjustment for age, physical activity and years of estrogen use, the improvement in dynamic balance was 4.9% greater for the intervention group than for the control group (p = 0.044). After adjustment for physical activity, cognitive status and number of fractures ever, the improvement in knee extension strength was 12.8% greater for the intervention group than for the control group (p = 0.047). The intervention group also had a 6.3% greater improvement in static balance after adjustment for rheumatoid arthritis and osteoarthritis, but this difference was not significant (p = 0.06).
Relative to controls, participants in the exercise program experienced improvements in dynamic balance and strength, both important determinants of risk for falls, particularly in older women with osteoporosis.
Canadian Medical Association Journal 11/2002; 167(9):997-1004. · 8.22 Impact Factor
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ABSTRACT: We wanted to determine whether women aged 70 years and older, who presented to the emergency department (ED) with a fall and injury, received guideline care within 18 months of presentation. Women aged 70 years and older who presented to the ED with a fall were recorded prospectively from August 1, 2001 to May 1, 2002 (n=226). Structured telephone interviews were performed 18 months after the ED fall to obtain details of patient management (n=63). The most frequently reported referral was to the family physician (32%) and to physiotherapy (24%). We concluded that most older women who presented to the ED with a fall did not appear to be receiving current guideline care. We propose that future research use a prospective study design to assess whether or not guideline care is being delivered by a variety of health care providers after the patients leave the ED.
Archives of Gerontology and Geriatrics 41(3):311-7. · 1.45 Impact Factor
