PubMed · 9535675
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E W Campion. 1998-04-09. Aging better.. https://doi.org/10.1056/nejm199804093381512
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Patients in some randomized clinical trials may start additional non-randomized medication because of an exacerbation of symptoms or insufficient therapeutic effect. Typically this rescue medication reduces the observed treatment effect in intention-to-treat analysis. We discuss methods of analysis which take account of rescue medication in order to achieve a more meaningful comparison of the randomized treatments, focusing on trials with a repeated quantitative outcome. Ignoring all data after rescue is likely to be biased because rescued patients are a highly selected group. Instead we propose using methods based on ranks or multilevel models. The rank-based methods assume that rescued patients have especially bad underlying outcomes. The multilevel regression model relates a patient's outcome to allocated treatment and rescue status at each time, and requires correct modelling of all prognostic factors which predict starting rescue medication and of the covariance between outcomes measured at different times. We also describe sensitivity analyses over a range of possible models for the effect of rescue medication. We illustrate these methods in a trial in Parkinson's disease. It appears that adjustment for rescue medication will not radically alter the randomized treatment comparison unless rescue medication is substantially imbalanced between randomized groups and has a substantial effect on the outcome.
Parkinson's disease (PD) profoundly affects activities of daily living (ADL) and quality of human life. Although unilateral pallidotomy has become a common surgical treatment for persons with advanced PD, functional outcome data from previous reports have failed to uniformly support this procedure. In the present investigation, results from 12 studies meeting specific inclusion criteria were subjected to meta-analysis. Only reports featuring unilateral pallidotomy as the exclusive surgery, a sample size of at least five patients, explicit assessment of ADL, and sufficient quantitative data were subjected to analysis. Type of research design was not a factor in the selection process. The results of our analysis suggest that unilateral pallidotomy successfully enhances functional outcome in patients with clinically advanced PD.
BACKGROUND: The prevention of disability in activities of daily living (ADL) may prolong older persons' autonomy (older persons are defined in this study as those aged > or =60 years). However, proved preventive strategies for ADL disability are lacking. A sedentary lifestyle is an important cause of disability. This study examines whether an exercise program can prevent ADL disability. METHODS: A 2-center, randomized, single-blind, controlled trial was conducted in which participants were assigned to an aerobic exercise program, a resistance exercise program, or an attention control group. Of the 439 community-dwelling persons aged 60 years or older with knee osteoarthritis originally recruited, the 250 participants initially free of ADL disability were used for this study. Incident ADL disability, defined as developing difficulty in transferring from a bed to a chair, eating, dressing, using the toilet, or bathing, was assessed quarterly during 18 months of follow-up. RESULTS: The cumulative incidence of ADL disability was lower in the exercise groups (37.1%) than in the attention control group (52.5%) (P =.02). After adjustment for demographics and baseline physical function, the relative risk of incident ADL disability for assignment to exercise was 0.57 (95% confidence interval, 0.38-0.85; P =.006). Both exercise programs prevented ADL disability; the relative risks were 0.60 (95% confidence interval, 0.38-0.97; P =.04) for resistance exercise and 0.53 (95% confidence interval, 0.33-0.85; P =.009) for aerobic exercise. The lowest ADL disability risks were found for participants with the highest compliance to exercise. CONCLUSIONS: Aerobic and resistance exercise may reduce the incidence of ADL disability in older persons with knee osteoarthritis. Exercise may be an effective strategy for preventing ADL disability and, consequently, may prolong older persons' autonomy.