Five-year risk of developing clinical diabetes after first myocardial infarction; the FINAMI study

Aim  To investigate the incidence of clinical diabetes as determined by the incidence of diabetes drug reimbursements within a 5-year period after the first myocardial infarction (MI) in patients who were non-diabetic at the time of their first MI. Research design and methods  A population-based MI register, FINMONICA/FINAMI, recorded all coronary events in persons of 35–64 years of age between 1988 and 2002 in four study areas in Finland. These records were used to identify subjects sustaining their first MI (n = 2632). Participants of the population-based risk factor survey FINRISK (surveys 1987, 1992, 1997 and 2002), who did not have diabetes or a history of MI, served as the control group (n = 7774). The FINMONICA/FINAMI study records were linked with the National Social Security Institute's drug reimbursement records, which include diabetes medications, using personal identification codes. The records were used to identify subjects who developed diabetes during the 5-year follow-up period (n = 98 in the MI group and n = 79 in the control group). Results  Sixteen per cent of men and 20% of women sustaining their first MI were known to have diabetes and thus were excluded from this analysis. Non-diabetic men having a first MI were at more than twofold {hazard ratio (HR) 2.3 [95% confidence interval (CI) 1.6–3.4]}, and women fourfold [HR 4.3 (95% CI 2.4–7.5)], risk of developing diabetes mellitus during the next 5 years compared with the control population without MI. Conclusions  Many patients who do not have diabetes at the time of their first MI develop diabetes in the following 5 years.