Effects of GH on cognitive function in elderly patients with adult-onset GH deficiency: a placebo-controlled 12-month study.

OBJECTIVE Young adults with childhood-onset GH deficiency (GHD) have reduced memory and attention, which can be improved by treatment with GH. Little information is available on cognitive function in elderly GHD patients. DESIGN Single center, double-blind, randomized, placebo-controlled study of 52-week duration. METHODS Elderly GH therapy naïve GHD patients (n=34; age range 60-77 years) were enrolled and randomized to receive placebo or GH therapy which was titrated to achieve a target IGF-I level of +1 to +2 s.d. of the normal mean for age. Cognitive function was assessed at baseline and after 24 and 52 weeks, using a computerized psychometric test package (Neurobehavioral Examination System-2). RESULTS The mean GH dose was 0.16+/-0.06 mg/day; mean IGF-I increased from 135+/-59 ng/ml at baseline to 213+/-77 ng/ml during active treatment. The GH-treated group had better mean serial digit learning scores compared with placebo group (P<0.05). Assessment of effect sizes showed that improvements in memory occurred with GH after 24 weeks. The overall adverse event rates were similar in the GH and the placebo group. CONCLUSION This study indicates that GH replacement may be accompanied by improvement in certain measures of cognitive function in elderly patients with GHD.