Comparison of medical care and long-term mortality in two cohorts of patients 10 years apart with chronic coronary syndrome

Abstract

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Bundesministerium für Bildung und Forschung. Background and introduction Cardiovascular diseases (CVD) remain the most common cause of death, although mortality due to CVD in Germany has decreased continuously over the past 20 years. The reasons for this decline are manifold. Besides the identification of risk factors, the application of algorithms for risk stratification, and the promotion of preventive means, the improvement in treatment strategies was of crucial importance [1, 2]. The ABC-CHD risk model combines novel biomarkers such as N-terminal pro-B-natriuretic peptide (NT-proBNP) and cardiac troponin T (hs-cTnT) with conventional factors in a unifying risk score which has been shown to reliably assess risk for CV mortality in patients with chronic coronary syndrome (CCS) [3]. However, data from the tertiary prevention setting, comparing its performance during different time periods, are scarce. Aims This study aimed to describe the characteristics and mortality of two cohorts of patients with CCS with identical study designs recruited in the same rehabilitation clinics approximately 10 years apart. Methods The KAROLA cohorts included patients with CCS participating in an inpatient cardiac rehabilitation programme in Germany (KAROLA-I: 1999/2000, KAROLA-II: 2009-2011) [details in 4]. Blood samples and information on sociodemographic factors, lifestyle, and medical treatment were collected at baseline, at the end of rehabilitation, and after 1-year follow-up. A biomarker-based risk model (ABC-CHD model) [3] and Cox regression analysis were used to predict cardiovascular (CV) and non-CV mortality risk during 10 years of follow-up. Results We included 1130 patients from KAROLA-I (mean age 58.7 years, 84.4% men) and 860 from KAROLA-II (mean age 60.4 years, 83.4% men). Patients in the KAROLA-I cohort had significantly higher concentrations of CV biomarkers and fewer patients were taking CV medications, except for statins. The ABC-CHD model which also included age, current smoking, history of diabetes, peripheral arterial disease, as well as hs-cTNT, NT-proBNP, and LDL-cholesterol provided a higher estimate of CV death risk for patients in the KAROLA-I cohort (mean 3-year risk, 3.8%) than for patients in the KAROLA-II cohort (mean 3-year risk, 2.7%, p for difference <0.001). After 10 years of follow-up, 91 (8.1%) patients in KAROLA-I and 45 (5.2%) in KAROLA-II had died from a CV event. Non-CV mortality was quite similar among the two cohorts. Notably, when statin medication upon discharge was included as an exposure variable in the Cox model that included age, sex, biomarkers, and clinical variables for the combined analysis with both cohorts, the HR for CV mortality was 0.54 (95% CI 0.31-0.93) in patients taking high-potency statins compared with patients not on statin medication. Conclusions Advances in disease management including pharmacological treatment over the past 20 years may have led to modest improvement of long-term prognosis of patients with CCS.