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

To review published, randomized trials examining the effect of androgen treatment on muscle strength in older men. Systematic review using meta-analysis procedures. Computerized and manual searches. 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. Testosterone or dihydrotestosterone (DHT) replacement therapy in healthy men aged 65 and older. Tests of muscle strength. 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. 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.