Androgen treatment and muscle strength in elderly men: A meta-analysis

OBJECTIVES: To review published, randomized trials examining the effect of androgen treatment on muscle strength in older men. DESIGN: Systematic review using meta-analysis procedures. SETTING: Computerized and manual searches. PARTICIPANTS: MEDLINE, EMBASE, CINAHL, and the Cochrane Register were searched for trials. Key words included testosterone, androgen, sarcopenia, muscle loss, aged, aging, elderly, older, geriatric, randomized controlled trials, and controlled clinical trials. Sixty-five nonoverlapping studies were found. Meta-analysis methods were used to evaluate the 11 randomized, double-blind trials. INTERVENTION: Testosterone or dihydrotestosterone (DHT) replacement therapy in healthy men aged 65 and older. MEASUREMENTS: Tests of muscle strength. RESULTS: The studies included 38 statistical comparisons. The mean g-index (g_i) adjusted for sample size was 0.53 (95% confidence interval (CI)=0.21-0.86). Subanalyses revealed larger effects for measures of lower extremity muscle strength (g_i=0.63, 95% CI=0.03-1.28) than for upper extremity muscle strength (g_i=0.47, 95% CI=0.12-0.84). A larger mean g-index was found for injected (g_i=0.95, 95% CI=0.33-1.58) than topical (g_i=0.26, 95% CI=0.08-0.42) or oral (g_i=-0.21, 95% CI=-1.40-1.02) administration of testosterone/DHT. Effect sizes were related to study characteristics such as subject attrition and design-quality ratings. Sensitivity analyses revealed that the elimination of one study reduced the mean g-index from 0.53 to 0.23. CONCLUSION: The results suggest that testosterone/DHT therapy produced a moderate increase in muscle strength in men participating in 11 randomized trials. One study influenced the mean effect size.