Aspects of growth hormone deficiency and replacement in elderly hypopituitary adults

Normal ageing is associated with a decline in spontaneous growth hormone (GH) secretion, and although elderly hypopituitary adults demonstrate an increase in total and central fat compared with age-matched controls and are distinguishable from control subjects in terms of GH responsiveness on dynamic testing, there are few data available on the response to GH replacement in older subjects. We have studied the baseline characteristics of 295 patients (173 males and 122 females) aged >65 years of age who began GH replacement therapy at the time of entry into the KIMS program (Pfizer International Metabolic Database) and the effects of GH replacement in 125 patients who completed at least 12 months of GH replacement therapy. Data were compared with those of 2469 (1249 males and 1220 females) patients aged <65 years with adult-onset GH deficiency (GHD). The patients were selected using strict criteria in accordance with the recommendations from the Growth Hormone Research Society. There was a higher proportion of pituitary adenoma relative to craniopharyngioma in the older age group (P<0.001), but there was no difference between groups in the degree of hypopituitarism (number of additional hormone deficiencies). Blood pressure, cholesterol and low-density lipoprotein (LDL) cholesterol levels were positively correlated with age, and older patients had a predictably higher prevalence of diabetes mellitus, coronary heart disease, stroke and history of hypertension. Quality of life (Assessment of Growth Hormone Deficiency in Adults (AGHDA) score) was impaired in both groups before the start of GH therapy. GH replacement doses were lower in older patients with GHD as compared with patients <65 years old. After 12 months of GH replacement, significant improvements were evident in waist circumference, waist/hip ratio, lean body mass, diastolic blood pressure, total and LDL cholesterol levels and AGHDA scores in patients aged <65 years. Similar significant reductions were evidenced in patients >65 years old compared with those observed in younger patients. The total number of adverse events was similar in younger and older patients with GHD. However, younger patients had more fluid retention-related adverse events such as headache, oedema and arthralgia; whereas, older patients with GHD had more adverse events related to glucose metabolism, cardiovascular events and neoplasms. These data indicate a positive benefit from GH replacement in older patients with hypopituitarism - particularly in relation to quality of life - using a lower dose of GH for replacement and with appropriate age-related safety controls.