Abstract
Background: The GH/IGF-1 axis is being targeted for therapeutic development in diseases such as short stature, cancer, and metabolic disorders. The impact of IGF-1 in cardiovascular disease remains controversial. We therefore studied whether IGF-1 at admission for acute myocardial infarction (AMI) predicted death, recurrent AMI, and stroke over a 2-year follow-up. Methods: Using data from the French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction registry, we measured IGF-1 among all the 1005 patients with AMI who participated in the serum data bank. Because IGF-1 decreases with age, a standardized IGF-1 score was calculated as previously described [IGF-1 score = (log [IGF-1 (micrograms per liter)] + 0.00625 x age - 2.555)/0.104]. Impact of IGF-1 score (continuous and quartiles) on outcomes were compared using Cox proportional hazards regression models. Results: During follow-up, 190 patients died or had a recurrent AMI or stroke. Patients in the lowest quartile of IGF-1 were older and more frequently female and diabetic compared with patients in the other quartiles. After adjustment for known cardiovascular factors, an increase of five units of IGF-1 score was associated with a 30% decrease of the risk of events during follow-up (adjusted hazard ratio 0.70; 95% confidence interval 0.54-0.92; P = .0093). Similarly, the lowest quartile of IGF-1 was associated with an increased risk of events (adjusted hazard ratio 1.52, 95% confidence interval 1.11-2.08; compared with others quartiles, P = .010). Conclusions: Low IGF-1 score is associated with an increased risk of all-cause death, recurrent myocardial infarction, and stroke in AMI patients. Whether patients treated by IGF-1 axis inhibitors have a specific clinical course after AMI would be worth studying.