Validity of diagnoses of SARS-CoV-2 infection in Canadian administrative health data: a multiprovince, population-based cohort study.

BACKGROUND: Accurate coding of diagnoses of SARS-CoV-2 infection in administrative data benefits population-based studies about the epidemiology, treatment and outcomes of COVID-19. We describe the validity of diagnoses of SARS-CoV-2 infection recorded in hospital discharge abstracts, emergency department records and outpatient physician service claims from 3 Canadian provinces. METHODS: In this cohort study, population-based inpatient, emergency department and outpatient records were linked to SARS-CoV-2 polymerase chain reaction (PCR; reference standard) test results from British Columbia, Manitoba and Ontario for Apr. 1, 2020, to Mar. 31, 2021. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of diagnoses of SARS-CoV-2 infection were estimated for each quarter in the study period, overall and by province, age group and sex. RESULTS: Our study encompassed more than 13 million SARS-CoV-2 PCR test results. Specificity and NPV of diagnoses of SARS-CoV-2 infection were consistently high (i.e., most estimates were > 95%). Overall sensitivity estimates were 86.2%, 60.4% and 20.3% in the first quarter for inpatient, emergency department and outpatient cohorts, and 66.2%, 47.5% and 25.0% in the last quarter, respectively. For inpatients, overall PPV estimates ranged from 50.0% to 66.4%. For emergency department patients, overall PPV estimates were 76.9% and 68.3% in the first and last quarters, respectively. For outpatients, PPV estimates were 6.8% and 29.1% in the first and last quarters, respectively. INTERPRETATION: We found variations in the validity of diagnoses for SARS-CoV-2 infection recorded in different health care settings, geographic areas and over time. Our multiprovince validation study provides evidence about the potential use of inpatient and emergency department records as an alternative to population-based laboratory data for identification of patients with SARS-CoV-2 infection, but does not support the use of outpatient claims for this purpose.

Patterns of antiemetic medication use during pregnancy: A multi-country retrospective cohort study.

OBJECTIVE: To compare patterns in use of different antiemetics during pregnancy in Canada, the United Kingdom, and the United States, between 2002 and 2014. METHODS: We constructed population-based cohorts of pregnant women using administrative healthcare data from five Canadian provinces (Alberta, British Columbia, Manitoba, Ontario, and Saskatchewan), the Clinical Practice Research Datalink from the United Kingdom, and the IBM MarketScan Research Databases from the United States. We included pregnancies ending in live births, stillbirth, spontaneous abortion, or induced abortion. We determined maternal use of antiemetics from pharmacy claims in Canada and the United States and from prescriptions in the United Kingdom. RESULTS: The most common outcome of 3 848 734 included pregnancies (started 2002-2014) was live birth (66.7% of all pregnancies) followed by spontaneous abortion (20.2%). Use of antiemetics during pregnancy increased over time in all three countries. Canada had the highest prevalence of use of prescription antiemetics during pregnancy (17.7% of pregnancies overall, 13.2% of pregnancies in 2002, and 18.9% in 2014), followed by the United States (14.0% overall, 8.9% in 2007, and 18.1% in 2014), and the United Kingdom (5.0% overall, 4.2% in 2002, and 6.5% in 2014). Besides use of antiemetic drugs being considerably lower in the United Kingdom, the increase in its use over time was more modest. The most commonly used antiemetic was combination doxylamine/pyridoxine in Canada (95.2% of pregnancies treated with antiemetics), ondansetron in the United States (72.2%), and prochlorperazine in the United Kingdom (63.5%). CONCLUSIONS: In this large cohort study, we observed an overall increase in antiemetic use during pregnancy, and patterns of use varied across jurisdictions. Continued monitoring of antiemetic use and further research are warranted to better understand the reasons for differences in use of these medications and to assess their benefit-risk profile in this population.

Off-label postpartum use of domperidone in Canada: a multidatabase cohort study.

BACKGROUND: Trends in off-label postpartum use of domperidone and the impact of safety advisories on its use remain unknown. Our objectives were to describe postpartum use of domperidone in Canada, to evaluate the impact of Health Canada advisories on prescribing patterns, and to describe the association between domperidone use and a composite end point of sudden cardiac death or ventricular tachycardia (VT) among postpartum patients. METHODS: We conducted a multidatabase cohort study involving pregnant patients with live births between 2004 and 2017 using administrative health databases from 5 Canadian provinces (British Columbia, Alberta, Saskatchewan, Manitoba and Ontario). We excluded patients with less than 1 year of prepregnancy database history and with approved indications for domperidone. We assessed domperidone use in the 6 months postpartum and the impact of the 2012 and 2015 Health Canada advisories on prescribing via interrupted time series analysis. We estimated crude rates of VT and sudden cardiac death. RESULTS: We included 1 190 987 live births. Mean maternal age was 28.6 (standard error 0.6) years. Domperidone use increased over time, from 7% in 2003-2005 to 12% in 2009-2011, when it plateaued. The 2012 advisory was followed by a drop in use and a reduction in slope, and the 2015 advisory had a more modest impact. Crude analysis suggests that domperidone may be associated with increased VT or sudden cardiac death (0.74 v. 0.37 per 10 000 person-years; difference per 10 000 person-years: 0.37, 95% confidence interval -0.67 to 1.41). INTERPRETATION: Postpartum domperidone use increased between 2004 and 2017, with prescribing attenuated after Health Canada advisories and a very low absolute rate of VT or sudden cardiac death. These findings suggest that Health Canada advisories affected prescribing; any potential increase in VT or sudden cardiac death with use of domperidone is small and could not be confirmed in this large study STUDY REGISTRATION: ClinicalTrials.gov, no. NCT04024865.

Comparison of Pregnancy Outcomes of Patients Treated With Ondansetron vs Alternative Antiemetic Medications in a Multinational, Population-Based Cohort.

Importance: Ondansetron is frequently used to treat nausea and vomiting during pregnancy. Although some studies reported important safety signals, few studies have been sufficiently large to assess rare pregnancy outcomes. Objective: To study the association between ondansetron exposure during pregnancy and the risks of spontaneous abortion, stillbirth, and major congenital malformations. Design, Setting, and Participants: This is a cohort study conducted in 3 countries, with a meta-analysis. Participants included women and girls aged 12 to 55 years who experienced spontaneous abortion, induced abortion, stillbirth, or live birth between April 2002 and March 2016, as recorded in administrative data from 5 Canadian provinces (British Columbia, Alberta, Saskatchewan, Manitoba, and Ontario), the US IBM MarketScan Research Databases, and the UK Clinical Practice Research Datalink. The statistical analysis was completed in October 2020. Exposures: Exposure to ondansetron during pregnancy was compared with exposure to other commonly used antiemetics to minimize confounding by indication. Main Outcomes and Measures: The primary outcome was fetal death, defined as either spontaneous abortion or stillbirth. Secondary outcomes were the 2 components of the primary outcome and major congenital malformations identified during the year after a live birth. Adjusted hazard ratios were estimated using Cox proportional hazards models with time-dependent drug exposures and were adjusted using high-dimensional propensity scores. For major congenital malformations, adjusted odds ratios were estimated from logistic models. Site-level results were pooled using random-effects meta-analysis. Sensitivity analyses considered second-line antiemetic exposure and exposure specifically during 4 to 10 weeks of gestation. Results: Data from 456 963 pregnancies were included in this study of fetal death (249 787 [54.7%] in Canada, 197 913 [43.3%] in the US, and 9263 [2.0%] in the UK; maternal age, ≤24 years, 93 201 patients [20.4%]; 25-29 years, 149 117 patients [32.6%]; 30-34 years, 142 442 patients [31.2%]; and ≥35 years, 72 203 patients [15.8%]). Fetal death occurred in 12 907 (7.9%) of 163 810 pregnancies exposed to ondansetron, and 17 476 (5.7%) of 306 766 pregnancies exposed to other antiemetics. The adjusted hazard ratios were 0.91 (95% CI, 0.67-1.23) for fetal death with time-dependent ondansetron exposure during pregnancy, 0.82 (95% CI, 0.64-1.04) for spontaneous abortion, and 0.97 (95% CI, 0.79-1.20) for stillbirth. For major congenital malformations, the estimated odds ratio was 1.06 (95% CI, 0.91-1.22). Results of sensitivity analyses were generally consistent with those of the primary analyses. Conclusions and Relevance: In this large, multicenter cohort study, there was no association between ondansetron exposure during pregnancy and increased risk of fetal death, spontaneous abortion, stillbirth, or major congenital malformations compared with exposure to other antiemetic drugs.

Domperidone and the risks of sudden cardiac death and ventricular arrhythmia: A systematic review and meta-analysis of observational studies.

AIMS: Concerns exist regarding the cardiovascular safety of domperidone. However, many of the previous studies addressing this issue had important limitations. We aimed to examine domperidone and the risks of sudden cardiac death and ventricular arrhythmia through a systematic review and meta-analysis of observational studies, including an in-depth methodological assessment. METHODS: We systematically searched MEDLINE, PubMed, EMBASE, Scopus and CINAHL Plus to identify observational studies examining the association of domperidone and sudden cardiac death and/or ventricular arrhythmia. We assessed study quality in duplicate using the ROBINS-I tool supplemented by an assessment of specific biases and the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) approach. Data were pooled across studies using DerSimonian and Laird random-effects models. RESULTS: Six case-control studies, 1 case-crossover study and 1 retrospective cohort study were included (n = 480 395). Based on ROBINS-I, 3 studies had moderate risk of bias, 4 had serious risk, and 1 had critical risk. The overall GRADE rating is moderate. When data were pooled across nonoverlapping studies, domperidone was associated with an increased risk of composite endpoint of sudden cardiac death or ventricular arrhythmia compared to nonuse (adjusted odds ratio: 1.69; 95% confidence interval: 1.46, 1.95; I2 : 0%; τ2 : 0). This association persisted when restricted to higher-quality studies (odds ratio: 1.60; 95% confidence interval: 1.30, 1.97; I2 : 0%; τ2 : 0). CONCLUSION: Domperidone is associated with an increased risk of sudden cardiac death and ventricular arrhythmia compared to nonuse. Further investigation comparing domperidone to an active comparator and in younger populations are warranted.

Development of an Item Pool Reflecting Cognitive Concerns Expressed by People With HIV.

OBJECTIVE: The overall aim of this study is to create an item pool reflecting the cognitive concerns expressed by people with HIV as a first step toward developing such a measure. METHOD: Semiqualitative interviews with 292 people with HIV were carried out. Their concerns were mapped to neurocognitive domains to identify concern content areas and were compared with existing cognitive questionnaires. A questionnaire was developed to estimate the prevalence and importance of the items. RESULTS: Sixty of 125 items were retained in the questionnaire based on ratings of their prevalence, importance, and clarity. Memory and behavioral and emotional concerns were the most common content areas (15 each); other domains were attention (7), executive function (6), language (5), and cognitive change (12). CONCLUSION: People living with HIV experience difficulties in all domains of cognition. By recognizing all domains, this new measure can help clinicians better understand areas of perceived cognitive difficulty and plan interventions accordingly.

Where have all the pilot studies gone? A follow-up on 30 years of pilot studies in Clinical Rehabilitation.

INTRODUCTION: Pilot studies are meritorious for determining the feasibility of a definitive clinical trial in terms of conduct and potential for efficacy, but their possible applications for planning a future trial are not always fully realized. The purpose of this review was to estimate the extent to which pilot/feasibility studies: (i) addressed needed objectives; (ii) led to definitive trials; and (iii) whether the subsequent undertaking of a definitive trial was influenced by the strength of the evidence of outcome improvement. METHODS: Trials published in the journal Clinical Rehabilitation, since its inception, were eligible if the word 'pilot' or 'feasibility' was specified somewhere in the article. A total of 191 studies were reviewed, results were summarized descriptively, and between-group effect sizes were computed. RESULTS: The specific purposes of piloting were stated in only 58% ( n = 110) of the studies. The most frequent purpose was to estimate the potential for efficacy (85%), followed by testing the feasibility of the intervention (60%). Only 12% of the studies were followed by a definitive trial; <4% of studies had a main study underway or a published study protocol. There was no relationship between observed effect size and follow-up of pilot studies, although the confidence intervals were very wide owing to small number of trials that followed on. DISCUSSION: Labelling and reporting of pilot studies needs to be improved to be concordant with the recently issued CONSORT guidelines. Feasibility needs to be fully tested and demonstrated prior to committing considerable human and monetary resources.

In support of an individualized approach to assessing quality of life: comparison between Patient Generated Index and standardized measures across four health conditions.

BACKGROUND: Individualized measures of health-related quality life (HRQL) have been used for decades and shown to provide unique information, but little work has been done to explain this uniqueness particularly across health conditions. AIMS: To estimate, across four health conditions, the magnitude of the association between scores derived from the Patient Generated Index (PGI) and those from fully standardized generic and disease-specific measures of the HRQL; to identify the extent to which the areas generated from the PGI are covered by the content of the fully standardized measures. METHODS: The PGI and other generic and disease-specific measures had been used in four different samples of people: stroke (n = 222), multiple sclerosis (MS; n = 185); advanced cancer (n = 173), and HIV+ (n = 690). Areas nominated on the PGI were harmonized to a standard nomenclature. Pearson correlations were estimated between PGI and other measures. RESULTS: Data from 1263 people indicated that PGI provided the lowest rating for HRQL across all health conditions. The areas nominated differed across conditions with walking/mobility: the most common for stroke (42%), work/school for MS (62%), health for HIV+ (97%), and fatigue for cancer (39%). Many of the aspects of health included in generic measures were not nominated using the PGI and vice versa. The highest correlations between the PGI and other measures were observed for people with MS, with correlations between 0.53 and 0.59; lowest correlations were observed for people with HIV and cancer, ≤0.33. DISCUSSION: The PGI scores reflect those aspects of quality of life that are important to patients in which they would most value an improvement. Heterogeneity in HRQL across health conditions is poorly discriminated using standardized measures. A "one-size-fits-all" approach to HRQL assessment may not provide the most useful representation of this important construct.

How have research questions and methods used in clinical trials published in Clinical Rehabilitation changed over the last 30 years?

Research in rehabilitation has grown from a rare phenomenon to a mature science and clinical trials are now common. The purpose of this study is to estimate the extent to which questions posed and methods applied in clinical trials published in Clinical Rehabilitation have evolved over three decades with respect to accepted standards of scientific rigour. Studies were identified by journal, database, and hand searching for the years 1986 to 2016.A total of 390 articles whose titles suggested a clinical trial of an intervention, with or without randomization to form groups, were reviewed. Questions often still focused on methods to be used (57%) rather than what knowledge was to be gained. Less than half (43%) of the studies delineated between primary and secondary outcomes; multiple outcomes were common; and sample sizes were relatively small (mean 83, range 5 to 3312). Blinding of assessors was common (72%); blinding of study subjects was rare (19%). In less than one-third of studies was intention-to-treat analysis done correctly; power was reported in 43%. There is evidence of publication bias as 83% of studies reported either a between-group or a within-group effect. Over time, there was an increase in the use of parameter estimation rather than hypothesis testing and there was evidence that methodological rigour improved.Rehabilitation trialists are answering important questions about their interventions. Outcomes need to be more patient-centred and a measurement framework needs to be explicit. More advanced statistical methods are needed as interventions are complex. Suggestions for moving forward over the next decades are given.

Development of a Bilingual MS-Specific Health Classification System: The Preference-Based Multiple Sclerosis Index.

OBJECTIVE: The global aim of this study was to contribute to the development of the Preference-Based Multiple Sclerosis Index (PBMSI). The specific objective of this foundational work was to qualitatively review the items selected for inclusion in the PBMSI using expert and patient feedback. METHODS: Cognitive interviews were conducted with patients with multiple sclerosis (MS) in English and French. The verbal probing method was used to conduct the interviews. For each PBMSI item, the interviewer probed for specific information on what types of difficulty participants had with the item and the basis for their response for each item. Furthermore, respondents were asked to provide information on the clarity of the item, the meaning of the item, the appropriateness of the response options, and the recall period. All interviews were recorded using a digital voice recorder and were transcribed onto a computer. RESULTS: The mean age of the 22 respondents was 52 years, and 82% were women. Mean time since diagnosis was 12 years, and the highest level of education completed was university or college for 86% of the sample. Modifications were made to each item in terms of recall period, instructions, and phrasing. CONCLUSIONS: Patient and expert feedback allowed us to clarify items, simplify language, and make items more uniform in terms of their instructions and response options. This qualitative review process will increase accuracy of reporting and reduce measurement error for the PBMSI.

Getting on with the rest of your life following stroke: a randomized trial of a complex intervention aimed at enhancing life participation post stroke.

OBJECTIVE: To enhance participation post stroke through a structured, community-based program. DESIGN: A controlled trial with random allocation to immediate or four-month delayed entry. SETTING: Eleven community sites in seven Canadian cities. SUBJECTS: Community dwelling persons within five years of stroke onset, cognitively intact, able to toilet independently. INTERVENTIONS: Evidence-based program delivered in three 12-week sessions including exercise and project-based activities, done as individuals and in groups. MAIN MEASURES: Hours spent per week in meaningful activities outside of the home and Reintegration to Normal Living Index; Stroke-Specific Geriatric Depression Scale, Apathy Scale, gait speed, EuroQuol EQ-5D, and Preference-Based Stroke Index. All measures were transformed to a scale from 0 to 100. Assessments prior to randomization, after the first session at three months, six months, 12 months, and 15 months. RESULTS: A total of 186 persons were randomized. The between-group analysis showed no disadvantage to waiting and so groups were combined and a within-person analysis was carried out at three time points. There were statistically significant increases in all study outcomes on average over all persons. Over 45% of people met or exceeded the pre-specified target of a three hour per week increase in meaningful activity and this most often took a full year of intervention to achieve. Greatest gains were in satisfaction with community integration (mean 4.78; 95% CI: 2.01 to 7.55) and stroke-specific health-related quality of life (mean 4.14; 95% CI: 2.31 to 5.97). CONCLUSIONS: Community-based programs targeting participation are feasible and effective, but stroke survivors require time to achieve meaningful gains.

Pedometer-facilitated walking intervention shows promising effectiveness for reducing cancer fatigue: a pilot randomized trial.

OBJECTIVE: Mechanisms for cancer related fatigue suggest that exercise but "not too much and not too little" could be effective. This study aimed to investigate feasibility and estimate the potential effects of a walking exercise program in people with advanced cancer and fatigue. DESIGN: A pilot randomized trial. SETTING: McGill University Health Centre (MUHC), Montreal, Canada. SUBJECTS: People with advanced cancer undergoing interdisciplinary assessment and rehabilitation with a fatigue level of 4 to 10 on a visual analogue scale. INTERVENTIONS: An 8-week fatigue-adapted, walking intervention, facilitated using a pedometer (STEPS), and offered at the same time as or after rehabilitation. MEASURES: Measures of fatigue, physical function and well-being were administered at entry, and 8, 16 and 24 weeks. Generalized estimating equations (GEE) estimated the odds of response for people receiving the STEPS program in comparison to the odds of response in the controls (odds ratio, OR). RESULTS: Twenty-six persons were randomized to three groups: during rehabilitation, after rehabilitation, and usual care. For the fatigue measures the OR for STEPS offered at any time using an intention-to-treat approach was 3.68 (95%CI: 1.05-12.88); for the physical function measures, the OR was 1.40 (95%CI: 0.41- 4.79) and 2.36 (95%CI: 0.66-8.51) for the well-being measures. CONCLUSION: Fifty percent of eligible people were able to participate. This small trial suggests that a personalized exercise program reduces fatigue and that 100 people are needed in a full strength trial.

A randomized trial of two home-based exercise programmes to improve functional walking post-stroke.

OBJECTIVE: To estimate the relative effectiveness in improving walking ability and other mobility and health outcomes post-stroke of two home-based exercise programmes - stationary cycling and an exercise and walking programme. DESIGN: An observer-blinded, randomized, pragmatic, trial with repeated measures. SETTING: Hospital centers in two Canadian cities. SUBJECTS: People within 12 months of acute stroke who were able to walk >10 meters independently and healthy enough to engage in exercise. INTERVENTIONS: Two dose-equivalent interventions, one involving stationary cycling and the other disability-targeted interventions were tested. Both protocols required daily moderate intensity exercise at home building up to 30 minutes per day. One group exercised on a stationary bicycle, the second group carried out mobility exercises and brisk walking. MAIN MEASURES: The primary outcome was walking capacity as measured by the six-minute walk test (6MWT). Secondary outcomes were physical function, role participation, health-related quality of life exercise adherence, and adverse events. RESULTS: The study failed to meet recruitment targets: 87 participants (cycle group, n = 43; exercise group, n = 44) participated. No significant effects of group or time were revealed for the 6MWT, which was approximately 320 m at randomization. A significant effect for role participation was found in favor of the exercise group (global odds ratio (OR) for cycling vs. exercise was 0.51; 95% confidence interval (CI), 0.27-0.95). Change in the 6MWT between highest and lowest adherence categories was statistically significant (p = 0.022). CONCLUSIONS: Both programmes were equally effective in maintaining walking capacity after discharge from stroke rehabilitation; or were equally ineffective in improving walking capacity. Clinical Trials Gov number: NCT00786045.

Relationship between muscle strength and functional walking capacity among people with stroke.

The purpose of this study was to estimate, using the Position-Specific Global Index (PSGI) of Lower-Limb Muscle Strength, the extent to which muscle strength is independently associated with functional walking capacity. We performed an observational, cross-sectional study with 63 patients poststroke (onset between 3 and 12 months) at a major teaching hospital in an urban Canadian city. We assessed functional walking capacity with the six-minute walk test (6MWT) and muscle strength with handheld dynamometry. We established the relationship between the lower-limb muscles and functional walking capacity with the PSGI. The PSGI explained 70% (p < 0.001) of the variability in the 6MWT, whereas the index of alternate against-gravity muscle strength explained 39% and the hip flexors in a supine position explained 51%.

The extent to which common health-related quality of life indices capture constructs beyond symptoms and function.

PURPOSE: This study proposes to identify for 5 widely used generic HRQL and QOL measures the extent to which function and global feelings of well-being are represented in their content. METHODS: The 5 indices were the EQ-5D, the HUI, the SF-36, SF-12, and the WHOQOL-Bref. A total of 15 raters with a variety of health and research backgrounds mapped the items. Raters independently identified all codes that could possibly map to the item and indicated the code that best reflected the underlying intent of the item, using the standardized mapping rules and methodology. A Delphi process aided consensus for each of the items. The consensus rounds involved reconsideration of item codes for which 70% of raters did not agree on the "best" code. These consensus rounds were terminated when item codes reached the threshold of 70% agreement or when it became evident from that consensus would not be reached. RESULTS: Function was a predominant construct for the 5 indices, with the proportion of items capturing function ranging from a low of 27% for the WHOQOL-Bref to a high of 92% for the SF-12. Less than 50% of items within the indices mapped to the granularity of function as described by the ICF. CONCLUSIONS: This paper demonstrates an additional method to validate the content of health-related indices to supplement the qualitative methods of consulting with experts and patients.

Mapping the Stroke Impact Scale (SIS-16) to the International Classification of Functioning, Disability and Health.

OBJECTIVE: To demonstrate how the International Classification of Functioning, Disability and Health (ICF) can be used to create coded functional status indicators specific for stroke from a simple stroke-specific functional index, the Stroke Impact Scale-16 (SIS-16). SUBJECTS: Nineteen professionals for the mapping portion and 8 persons with stroke for the cognitive debriefing portion. METHODS: Participants were asked to identify appropriate codes for the corresponding items of the SIS-16 following a structured protocol for mapping measures to the ICF. A Delphi technique was used in order to reach consensus for as many items as possible. In addition, cognitive debriefing was conducted with persons with stroke. RESULTS: A total of 13 items had Functional Status Indicators endorsed (8 items at the 4 digit level and 5 items at the 3 digit level). There were 3 items that did not reach consensus. The cognitive debriefing sessions demonstrated the differences in interpretation from the persons with stroke and the intentions by the developers. CONCLUSION: This study has shown how the ICF can capture most items from functional status measures, such as the SIS-16. Furthermore, the items can be used to map onto a standard coding framework, illustrating the potential for increased use of Functional Status Indicators.

Validating the six-minute walk test as a measure of recovery after elective colon resection surgery.

OBJECTIVE: To provide evidence for construct and longitudinal validity of the six-minute walk test (6MWT) as a measure of postsurgical recovery. DESIGN: Data from a randomized clinical trial. SETTING: A major teaching hospital in a Canadian urban city. PARTICIPANTS: Patients (N=63) undergoing elective colon resection. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Functional walking capacity was measured using the 6MWT at before surgery and at 3 and 6 weeks after surgery. RESULTS: At 3 weeks, 26 (41%) patients recovered to baseline or greater on the 6MWT distance, and 37 (59%) were at baseline or better by 6 weeks postdischarge. At all time points, the 6MWT distance correlated with age, the American Society of Anesthesiologists (ASA) score of surgical risk, albumin, the physical function subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and the physical component summary score of the SF-36. Baseline 6MWT distance correlated with postoperative 6MWT recovery, and baseline SF-36 and ASA were associated with postoperative recovery. Patients with intraoperative complications had a clinically relevant lower 6MWT than those without complications at all time points. CONCLUSIONS: This study provides evidence for construct validity and sensitivity to change for the 6MWT as a measure of surgical recovery.

Development of a position-specific index of muscle strength to be used in stroke evaluation.

OBJECTIVE: To develop a position-specific index of muscle strength for individuals with stroke. DESIGN: Cross-sectional design. SETTING: A major teaching hospital in a Canadian urban city. PARTICIPANTS: Sixty-three patients with poststroke onset between 3 and 12 months. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The muscle strength of the lower-extremity muscles was tested bilaterally in multiple positions using hand-held dynamometry. RESULTS: A principal components analysis resulted in grouping the muscles of the affected and unaffected sides of the gravity related and gravity eliminated positions into 5 indices. The 5 indices were moderately to highly correlated (r2 range, .59-.81) with each other and so were combined into 1 global index. The gravity related muscle strength on the affected side was, on average, 85% of the unaffected side (range, 37%-157%); the gravity eliminated muscle strength of the affected side was, on average, 92% of the unaffected side (range, 53%-121%). CONCLUSIONS: This study resolves the methodologic issue of how to summarize multiple data points that relate to one construct, namely, strength of different muscle groups assessed in several positions.