Abstract 1593: Effects of Testosterone on Oxygen Uptake, Insulin Resistance and Muscle Strength in Elderly Patients with Chronic Heart Failure
Background: Testosterone exerts effects on exercise capacity and glucose metabolism of patients(pts) with chronic heart failure (CHF). No studies have evaluated effects of testosterone on exercise oxygen uptake in these patients.
Aim: To assess the effect of a 12 week testosterone administration on maximal exercise capacity, muscle strength and insulin resistance of elderly CHF patients.
Methods: 70 stable CHF men age 71 ± 8, ejection fraction 34 ± 1, NYHA class II/III 32/38, were enrolled in a double bind placebo controlled study. Of these 35 pts received testosterone therapy (through intramuscular injection every 6 weeks); 35 pts received optimized medical therapy and were included in the control group. At baseline and after 12 weeks all patients underwent echocardiogram, cardiopulmonary test, 6-minute walking test (6MWT), quadriceps maximal isometric and isokinetic strength.
Results: At baseline 38% 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 ± 2 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-R 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. No significant echocardio-graphic changes were showed.
Conclusion: Long-acting testosterone therapy improves exercise capacity, muscle strength and glucose metabolism in men with moderately severe heart failure. Testosterone benefits seem to be mediated by metabolic and peripheral effects.