Temporal changes in the incidence of infective endocarditis in Denmark 1997-2017: A nationwide study

BACKGROUND

Infective endocarditis (IE) remains a life-threatening disease, yet substantial variation in reported incidences of the disease exist. We aimed to conduct a contemporary, nationwide study of the temporal changes in incidence of IE.

METHODS

We included all Danish cases of first-time IE (1997-2017) using nationwide registries. Patients were grouped into three seven-year intervals (1997-2003, 2004-2010, 2011-2017). Crude annual incidence rates (IR) per 100,000 person-years (PY) were examined overall and per subgroups: age, sex, patients without prior prosthetic heart valve or a cardiac implantable electronic device (CIED). Incidence rate ratios (IRR) were calculated adjusting for age-group, sex and diabetes.

RESULTS

We identified 8675 patients with IE. Over time, patients were older at diagnosis with a median age of 66.2 years (interquartile range, IQR: 51.5-76.5) and 72.2 years (IQR 62.2-79.9) in 1997-2003 and 2011-2017, respectively. The overall IR increased from 5.0/100,000 PY (95% CI: 4.4-5.6) to 10.5/100,000 PY (95% CI: 9.6-11.3) from 1997 to 2017. IR for patients without prior prosthetic heart valve or a CIED increased from 4.9/100,000 PY (95% CI: 4.3-5.5) to 6.4/100,000 PY (95% CI: 5.8-7.1) (P ≤ 0.0001 for interaction). The IR in males increased from 5.6/100,000 PY (95% CI: 4.7-6.5) to 14.2/100,000 PY (95% CI: 12.9-15.6). The IR in females increased from 4.3/100,000 PY (95% CI: 3.6-5.2) to 6.7/100,000 PY (95% CI: 5.8-7.7). IRR (adjusted for age-groups, sex and diabetes) increased over time (IRR = 1.60 (1.39-1.85) in 2017 vs 1997).

CONCLUSION

The incidence of IE more than doubled during the study period. The increase was mainly seen among men and elderly patients only partly explained by the increase in patients with prior heart valve prosthesis or a CIED.

Endocarditis risk with bioprosthetic and mechanical valves: systematic review and meta-analysis

OBJECTIVE

Bioprosthetic valves are being used with increased frequency for valve replacement, with controversy regarding risk:benefit ratio compared with mechanical valves in younger patients. However, prior studies have been too small to provide comparative estimates of less common but serious adverse events such as infective endocarditis. We aimed to compare the incidence of infective endocarditis between bioprosthetic valves and mechanical valves.

METHODS

We searched PubMed, Cochrane, EMBASE, Scopus and Web of Science from inception to April 2018 for studies comparing left-sided aortic and mitral bioprosthetic to mechanical valves for randomised trials or observational studies with propensity matching. We used random-effects model for our meta-analysis. Our primary outcome of interest was the rate of infective endocarditis at follow-up.

RESULTS

13 comparison groups with 43 941 patients were included. Mean age was 59±7 years with a mean follow-up of 10.4±5.0 years. Patients with bioprosthetic valves had a higher risk of infective endocarditis compared with patients receiving mechanical valves (OR 1.59, 95% CI 1.35 to 1.88, p<0.001) with an absolute risk reduction of 9 per 1000 (95% CI 6 to 14). Heterogeneity within the included studies was low (I²=0%). Exclusion of the study with maximum weight did not change the results of the analysis (OR 1.57, 95% CI 1.14 to 2.17, p=0.006). A meta-regression of follow-up time on incidence of infective endocarditis was not statistically significant (p=0.788) indicating difference in follow-up times did not alter the pooled risk of infective endocarditis.

CONCLUSIONS

Bioprosthetic valves may be associated with a higher risk of infective endocarditis. These data should help guide the discussion when deciding between bioprosthetic and mechanical valves in individual patients.