Prognostic impact of cardiac events in asymptomatic mitral regurgitation

Abstract Background Mitral regurgitation (MR) is the most common valvular heart disease in adults and is associated with increased morbidity and mortality. Treatment recommendations of degenerative MR have been liberalized, however, the role of asymptomatic patients is still insufficiently defined. Purpose The purpose of this study were to evaluate the prevalence of cardiac events in a large asymptomatic MR cohort, based on health insurance data analysis, in comparison with healthy propensity score-matched general population and to define the prognostic impact of such cardiac events on ten-year survival. Methods We retrospectively analyzed health insurance claims data from Germany’s second largest health insurance fund, which maintains longitudinal data on outpatient and inpatient medical services for 8.7 million German residents. We included all patients with an outpatient diagnosis of MR (I34.0) in a minimum of two quarters during a calendar year and first recorded diagnosis between 2008 and 2011. To identify an asymptomatic MR cohort (study group), all patients with at least one complication attributable to MR / mitral valve intervention during the incidence quarter of MR were excluded. Ten-year outcomes were compared between study group vs. age- and sex-matched healthy control group. Cardiac events of interest were new congestive heart failure, new-onset atrial fibrillation, pulmonary hypertension, or cardiac decompensation. Results A total of 56.577 (62.7%) asymptomatic MR patients were identified from the whole cohort of 90.245 individuals with a newly diagnosed MR in the BARMER database. During a ten-year follow-up, 26.282 (46.5%) patients in the study group experienced at least one cardiac event vs. 11.763 (20.8%) individuals in the control group (OR: 3.31, 95%CI: 0.251-0.262, P<0.0001). The occurrence of at least one cardiac event (i.e., congestive heart failure, new-onset atrial fibrillation, pulmonary hypertension or cardiac decompensation) in the study group was associated with a significantly worse ten-year survival as compared to the control group. The risk of cardiac events was age- and sex-dependent, while female patients with an asymptomatic MR had a lower risk as compared to males in all age groups (OR: 0.38, 95%CI: -1.193- -0.754, P<0.0001). Only 1.530 (2.7%) patients underwent mitral valve (MV) intervention in the study group during ten-year follow-up. Conclusions Our study reveals high incidence of asymptomatic MR in a representative cohort of health insurance claims data in Germany. Every second patient with an asymptomatic MR experiences at least one cardiac event during a ten-year follow-up period that is associated with a significantly worse survival. The definition of asymptomatic MR cohort at risk of developing cardiac events may potentially improve early treatment strategies and lead to better outcome in the future.Abstract picture