National trends over one decade in hospitalization for acute myocardial infarction among Spanish adults with type 2 diabetes: cumulative incidence, outcomes and use of percutaneous coronary intervention.

Background: This study aims to describe trends in the rate of acute myocardial infarction (AMI) and use of percutaneous coronary interventions (PCI) in patients with and without type 2 diabetes in Spain, 2001-2010.

Methods: We selected all patients with a discharge of AMI using national hospital discharge data. Discharges were grouped by diabetes status: type 2 diabetes and no diabetes. In both groups PCIs were identified. The cumulative incidence of discharges attributed to AMI were calculated overall and stratified by diabetes status and year. We calculated length of stay and in-hospital mortality (IHM). Use of PCI was calculated stratified by diabetes status. Multivariate analysis was adjusted by age, sex, year and comorbidity.

Results: From 2001 to 2010, 513,517 discharges with AMI were identified (30.3% with type 2 diabetes). The cumulative incidence of discharges due to AMI in diabetics patients increased (56.3 in 2001 to 71 cases per 100,000 in 2004), then decreased to 61.9 in 2010. Diabetic patients had significantly higher IHM (OR, 1.14; 95%CI, 1.05-1.17). The proportion of diabetic patients that underwent PCI increased from 11.9% in 2001 to 41.6% in 2010. Adjusted incidence of discharge in patients with diabetes who underwent PCI increased significantly (IRR, 3.49; 95%CI, 3.30-3.69). The IHM among diabetics patients who underwent a PCI did not change significantly over time.

Conclusions: AMI hospitalization rates increased initially but declining slowly. From 2001 to 2010 the proportion of diabetic patients who undergo a PCI increased almost four-fold. Older age and more comorbidity may explain why IHM did not improve after a PCI.