Background: Patients with acromegaly require lifetime monitoring due to the excess mortality and morbidity associated with untreated disease, and the propensity for disease relapse following treatment. There is controversy whether GH or insulin-like growth factor 1 (IGF1), better predicts the onset of cardiovascular complications such as cardiomyopathy and ischaemic heart disease (IHD) in acromegalic patients.
Aim: To examine associations of overall GH and IGF1 exposure with IHD and cardiomyopathy, in patients with treated acromegaly.
Methods: Records of 116 patients with treated acromegaly attending a single Endocrine centre were examined retrospectively. GH and IGF1 burdens were calculated by multiplying the overall mean basal GH and mean IGF1 index during patient follow-up, by the number of years since diagnosis of acromegaly. IGF1 index was defined as serum IGF1 divided by the upper limit of reference range. Mean GH and IGF1 burdens were compared between patients with and without cardiomyopathy and IHD.
Results: IHD was present in 11.2% of treated acromegalic patients. GH burden was significantly higher in patients with IHD when compared with patients without IHD (mean GH burden in years.μg/l: 94.6±32.8, IHD; 56.7±7.4, no IHD; P=0.009). Mean IGF1 burden was not significantly different between patients with and without IHD. Evidence of cardiomyopathy was recorded in 20% of treated acromegalic patients. Mean IGF1 burden was significantly higher in patients with cardiomyopathy when compared with patients without cardiomyopathy (mean IGF1 burden in years: 23.5±4.4, cardiomyopathy; 16.2±1.6, no cardiomyopathy; P=0.011). Mean GH burden was not significantly different between patients with and without cardiomyopathy.
Conclusion: These results suggest that both GH burden and IGF1 burden are useful markers of cardiovascular morbidity in treated acromegalic patients. This study highlights the importance of monitoring both serum GH and IGF1 in treated acromegalic patients.