Does acromegaly enhance mortality?

John Ayuk, Michael C. Sheppard

The increased mortality associated with acromegaly was first demonstrated in early epidemiological studies. Since the seminal paper by Wright et al. in 1970, nearly 20 studies have analyzed mortality rates in over 5,000 patients with acromegaly. Overall standardized mortality rates are approximately two times higher than in the general population, relating to an average reduction in life expectancy of around 10 years. The excess deaths are due predominantly to cardiovascular, cerebrovascular and respiratory disease. Malignancy deaths have been high in some studies but not others; in the largest series looking at cancer mortality in acromegaly, overall cancer deaths were not increased, but colon cancer mortality was higher than expected. In 1993, Bates et al. first demonstrated that outcome was related to the latest measurable growth hormone (GH), and treatment to reduce GH levels led to improved outcomes. Other factors predicting poor outcome include the presence of hypertension and diabetes. On the basis of current evidence, a latest GH of less than 2-2.5 mug/L is a better predictor of good outcome than a normal insulin-like growth factor-1 (IGF-1), possibly due to discrepancy between GH and IGF-1 at low GH levels. There is some evidence to suggest a more stringent GH cut-off (less than 1 mug/L) may yield additional benefit but further studies are required to investigate any added risk of increased mortality from hypopituitarism. Radiotherapy has been linked specifically to cerebrovascular mortality and its use in patients with acromegaly must involve a careful risk-benefit analysis in each case.