Endocrine Abstracts

Background: Patients with congestive heart failure (CHF) show muscle mass wasting and decreased testosterone levels. Long-term testosterone supplementation improves walking distance and glucose metabolism of patients CHF. No studies have investigated the integrated effects of testosterone on exercise oxygen uptake muscle strength and glucose metabolism in patients with CHF regardless of the presence of hypogonadism.

Aim: To assess the effect of a 12-week testosterone administration on maximal exercise capacity, muscle strength and insulin resistance in elderly CHF patients.

Methods: Seventy elderly patients with stable CHF, mean age 71±8 years, ejection fraction 34±1%, NYHA class II/III 38/32, were enrolled. Of these, 35 were randomized to receive testosterone therapy (through intramuscular injection every 6 week) and 35 to receive placebo both on top of maximal medical therapy. At baseline and after 12 weeks all patients underwent echocardiogram, cardiopulmonary test, 6-min walking test (6MWT), quadriceps maximal isometric and isokinetic strength.

Results: At baseline 30% of patients had hypogonadism. Peak VO2 (r 0.44; P 0.02) and quadriceps isometric strength (r 0.39; P 0.01) were both positive related to serum testosterone concentration. After three months, peak VO2 (13±4 vs 16±1 P 0.02), VE/VCO2 (33±7 vs 29±5 P 0.01) distance walked at 6MWT (420±45 vs 480±51 P 0.001), significantly improved from baseline in the testosterone group while were unchanged in the control group; HOMA-IR was significantly reduced in the testosterone group (2.6±1.4 vs 1.8±0.8, P 0.002). Maximal quadriceps isometric (130±28 vs 166±32, P 0.04) but not isokinetic strength was significantly increased at three months in the testosterone group. Increase in testosterone levels were significantly related to improvement in peak VO2. No significant changes in left ventricular function were found.

Conclusion: Long-acting testosterone therapy improves exercise capacity, muscle strengthed glucose metabolism in men with moderately severe heart failure. Testosterone benefits seem to be mediated by metabolic and peripheral effects.