Impact of growth hormone (GH) treatment on cardiovascular risk factors in GH-deficient adults: a metaanalysis of blinded, randomized, placebo-controlled trials

Patients with hypopituitarism have an increased risk of cardiovascular mortality. GH treatment could modify the cardiovascular risk in adults with GH deficiency, but most published clinical trials involved few patients and the results are variable. We conducted a systematic review of blinded, randomized, placebo-controlled trials of GH treatment in adult patients with GH deficiency published up to August 2003. Thirty-seven trials were identified. We combined the results for effects on lean and fat body mass; body mass index; triglyceride and cholesterol [high-density lipoprotein, low-density lipoprotein (LDL), and total] levels; blood pressure; glycemia; and in sulinemia. Overall effect size was used to evaluate significance, and weighted differences between GH and placebo were used to appreciate the size of the effect. GH treatment significantly reduced LDL cholesterol [-0.5 (SD 0.3) mmol/liter], total cholesterol [-0.3 (0.3) mmol/liter], fat mass [-3.1 (3.3) kg], and diastolic blood pressure [-1.8 (3.8) mm Hg] and significantly increased lean body mass [+2.7 (2.6) kg], fasting plasma glucose [+0.2 (0.1) mmol/liter], and insulin [+8.7 (7.0) pmol/liter]. All effect sizes remained significant in trials with low doses and long-duration GH treatment. Thus, GH treatment has beneficial effects on lean and fat body mass, total and LDL cholesterol levels, and diastolic blood pressure but reduces insulin sensitivity. The global cardiovascular benefit remains to be determined in large trials with appropriate clinical endpoints.