Prognostic value of new and established cardiovascular risk factors for incident diabetes mellitus in patients with chronic coronary syndrome

Abstract Background and introduction Diabetes mellitus (DM) represents a global public health issue and is increasing worldwide. DM is associated with a significant loss of quality of life, a pronounced increase in the risk for cardiovascular diseases (CVD) and involves a high financial burden for society. Importantly, CVD and DM share many common risk factors. In Germany, all patients discharged after an acute coronary syndrome (ACS) or coronary bypass surgery are offered a comprehensive inpatient rehabilitation. Risk stratification of this patient population might therefore inform selection and targeting of preventive means to prevent the risk for subsequent DM. Purpose To estimate the incidence of DM and the prognostic value of various established and new cardiovascular risk factors in two cohorts of patients with chronic coronary syndrome (CCS) undergoing rehabilitation. Methods The two prospective cohorts included patients with CCS participating in an inpatient cardiac rehabilitation programme in Germany (KAROLA-I: years 1999/2000, KAROLA-II: 2009-2011) (details in ref. 1). Participation rate was 58% in both cohorts. Blood samples and information on sociodemographic factors, lifestyle, and medical treatment were collected at baseline. During follow-up (KAROLA-I median 12.1 years, KAROLA-II median 9.9 years), each patient and their primary care physicians were contacted regularly by post to complete a standardized questionnaire. Development of incident DM was based on information from primary care physicians. Vital status was assessed via the residents’ registration office. Incident rates for DM were calculated. Cox regression analysis was used to estimate the risk for DM for potential risk factors during follow- after adjustment for covariates (including cohort). Results We included 1601 patients with no prior diagnosis of DM (n=835 from KAROLA-I and n=766 from KAROLA-II) in this study (mean age 60.9 years, 85.0% men). 15.4% of patients were obese at baseline and 60.5% were former and 5.4% were current smokers, respectively. At baseline, mean LDL-cholesterol and HDL-cholesterol levels were 161.3 mg/dl and 41.9 mg/dL, respectively. Mean hs-CRP was 7.3 mg/L, hs-cTnT was 17.6 ng/L, hs-cTnI 22.4 ng/L, and NT-proBNP 894.9 ng/L. During a median follow-up of 9.9 years, n=277 incident DM cases were diagnosed (rate per 1000 person-years 19.1 (95% CI 17.0-21.5)). After adjustment for sex, age, and school education the following mutually adjusted risk factors were associated with the risk of DM: obesity HR 2.18 (95% CI 1.63-2.92); smoking (former HR 1.58 (95% CI 1.19-2.09), current HR 1.77 (95% CI 1.01-3.08)), hs-CRP > 2 mg/L HR 1.32 (95% CI 1.03-1.71), hs-TnI ≥ 6 ng/L HR 1.88 (95% CI 1.13-3.12) when compared to respective reference categories. Conclusions Several modifiable risk factors were associated with the increased risk of DM in patients with CCS who participated in an inpatient rehabilitation program and offer targets for prevention.