Changes in short- and long-term cardiovascular risk of incident diabetes and incident myocardial infarction--a nationwide study.

Aims/hypothesis: We assessed secular trends of cardiovascular outcomes following first diagnosis of myocardial infarction (MI) or diabetes in an unselected population.

Methods: All Danish residents aged > or = 30 years without prior diabetes or MI were identified by individual-level linkage of nationwide registers. Individuals hospitalised with MI or claiming a first-time prescription for a glucose-lowering medication (GLM) during the period from 1997 to 2006 were included. Analyses were by Poisson regression models. Primary endpoints were death by all causes, cardiovascular death and MI.

Results: The study included 3,092,580 individuals, of whom 77,147 had incident MI and 118,247 new-onset diabetes. MI patients had an increased short-term risk of all endpoints compared with the general population. The rate ratio (RR) for cardiovascular death within the first year after MI was 11.1 (95% CI 10.8-11.5) in men and 14.8 (14.3-15.3) in women, respectively. The risk rapidly declined and 1 year after the index MI, RR was 2.11 (2.00-2.23) and 2.8 (2.64-2.97) in men and women, respectively. Patients with diabetes carried a constantly elevated risk of all endpoints compared with the general population. The cardiovascular death RR was 1.90 (1.77-2.04) and 1.92 (1.78-2.07) in men and women, respectively during the first year after GLM initiation.

Conclusions/interpretation: Incident MI is associated with high short-term risk, which decreases rapidly over time. Incident diabetes is associated with a persistent excessive cardiovascular risk after initiation of GLM therapy. This further strengthens the necessity of early multi-factorial intervention in diabetes patients for long-term benefit.