Growth hormone may have a beneficial effect on bone in patients who are growth hormone-deficient new research suggests, but an expert says there is still a long way to go before firm conclusions can be made.

The Hypopituitary Control and Complications Study (HypoCCS) followed  8374 patients who received growth hormone and 1267 patients that did not for more than four years.

They found the annual incidence of clinical fractures was decreased in patients that received growth hormone compared with those that did not (hazard ratio [HR] 0·69, 95% CI 0·54–0·88) after adjusting for confounders.

However the HR for patients with pre- existing osteoporosis who received growth hormone was 0·97 (95% CI 0·48–1·96), suggesting that treatment with growth hormone is neither a protective factor nor a risk factor for fracture for such patients, reported the researchers in The Lancet Diabetes & Endocrinology. 

The study is one of the first attempts to show potential protection from incidence of fractures by growth hormone replacement therapy in a large population of adults with growth hormone deficiency said Andrea Giustina from the University of Brescia in Italy in an accompanying editorial.

However the findings do not signal the end of a “long-lasting quest for clinically convincing data to support growth hormone replacement therapy in adults with growth hormone deficiency”.

The data should be considered proof-of-concept, and there is a still a long way to go before firm conclusions can be drawn on this issue, she said.

HypoCCS is a post-marketing surveillance study, which has several intrinsic limitations that cannot be overcome by statistical adjustments.

“The study opens avenues for further studies that might show that skeletal integrity can be an important endpoint in deciding to use growth hormone replacement therapy in patients with growth hormone deficiency” she concluded.

The study was supported by Eli Lilly, and one of the authors was an employee.