The increasing incidence of infective endocarditis in Denmark, 1994-2011

BACKGROUND: Little updated population-based evidence exists of temporal trends in infective endocarditis (IE).

METHODS: For the 1994-2011 period, we used Danish nationwide registries to identify cases with first-time IE and to estimate the population size. We calculated the incidence rate of IE in 3-year intervals. To evaluate time trends in incidence, we used the 1994-1996 period as reference and computed incidence ratios and 95% confidence intervals (CI) as the incidence in each of the subsequent 3-year intervals divided by the incidence in the reference period.

RESULTS: We identified 5486 incident IE patients (65% men) and the mean age at diagnosis was 63years. Men tended to be younger at diagnosis than women; 62years vs. 65years. Mean age at IE diagnosis steadily increased from 57years in 1994-1996 to 65years in 2009-2011. The IE incidence rate increased from 3.93 per 100,000 person-years in 1994-1996 to 7.55 per 100,000 person-years in 2009-2011, corresponding to an incidence ratio of 1.92 (95% CI: 1.74-2.12). The increase in incidence over time was more pronounced in men (2.28, 95% CI: 2.02-2.59) than in women (1.39, 95% CI: 1.18-1.64). We observed no increase in incidence over time for subjects younger than 50years, whereas the incidence increased substantially over time for elderly patients, with the highest incidence ratio of 3.38 (95% CI: 2.55-4.52) for patients more than 80years at IE onset.

CONCLUSION: The incidence of IE increased over time particularly among men and for the older age groups.