NEW YORK (Reuters Health) – Stopping long-term growth hormone (GH) replacement in adults with hypopituitarism led to a drop in quality of life (QoL) and untoward metabolic effects, Swedish researchers say.
In a July 12th online paper in the Journal of Clinical Endocrinology & Metabolism, Dr. Helena Filipsson Nystrom of Sahlgrenska University Hospital, Gothenburg and colleagues note that adults with hypopituitarism and untreated GH deficiency have increased cardiovascular mortality.
GH replacement therapy may counteract the cardiovascular risk – and its beneficial metabolic effects have been well-documented in the short term. However, less is known about the impact of long-term treatment on QoL.
The US National Institutes of Health lists hypopituitarism as a rare disorder with an estimated annual incidence of 4.2 cases per 100,000. Some patients are treated with life-long GH replacement.
In the current double-blind crossover study, the researchers enrolled 60 adults who had received GH replacement therapy for a mean of 10 years, but not in childhood.
In random order, patients received four months of GH and four months of placebo, with any other replacement therapies kept constant. At the end of the study open GH treatment was reinstituted.
During the placebo period, mean serum IGF-I decreased from 168 mcg/L to 47 mcg/L. Patients also had significant increases in waist circumference and subcutaneous and visceral fat mass. Extracellular water and muscle area decreased.
Lipid profiles also changed during the placebo period, with increases in C-reactive protein and total-, low-density lipoprotein-, and high-density lipoprotein-cholesterol. Insulin sensitivity improved, however.
Scores on QoL domains covering emotional reactions and positive well-being deteriorated during the placebo phase.
These data, say the investigators, strongly indicate that the metabolic effects seen during long-term GH replacement are due to its continuation.
The deterioration in body composition and metabolism thus underlines the importance of continuous long-term GH replacement in adult hypopituitary patients, the authors say.
Long-term treatment, they conclude, is needed “to maintain therapeutic effects of GH on QoL and cardiovascular risk factors.”
Dr. Nystrom did not respond to requests for comments.
J Clin Endocrinol Metab 2012.