Role of renal function in cardiovascular risk assessment: A retrospective cohort study in a population with low incidence of coronary heart disease.

ABSTRACT

BACKGROUND: Early-stage chronic kidney disease (CKD), a marker of cardiovascular risk, is susceptible to therapeutic intervention but need further study in populations with low incidence of coronary heart disease (CHD). Incorporating glomerular filtration rate (GFR) could improve cardiovascular risk prediction in these patients. OBJECTIVE: To determine if decreased GFR is associated with increased risk of cardiovascular morbidity and all-cause mortality and to analyse GFR effect on cardiovascular risk prediction in a population with low CHD incidence. METHODS: Retrospective, observational, population-based study of 1,081,865 adults (35-74years old). Main exposure variable GFR. OUTCOMES: CHD, cerebrovascular disease, cardiovascular diseases, all-cause mortality. Association between GFR categories of CKD (G1-G5) and outcomes was tested with Cox survival models. G1 was defined as the reference category. Predictive value of GFR was evaluated by integrated discrimination improvement (IDI) and net reclassification improvement (NRI) indices. RESULTS: Beginning at stage-3a CKD, increased risk was observed for coronary (HR 1.27 (95%CI 1.14-1.43)), cerebrovascular (HR 1.19 (95%CI 1.06-1.34)), cardiovascular (HR 1.23 (95%CI 1.13-1.34)) and all-cause mortality risk (HR 1.17 (95%CI 1.07-1.27)). GFR did not increase discrimination and reclassification indices significantly for any outcome. CONCLUSION: In general population with low CHD incidence and stage-3 CKD, impaired GFR was associated with increased risk of all cardiovascular diseases studied and all-cause mortality, but adding GFR values did not improve cardiovascular risk calculation. Despite a four-fold higher rate of CHD incidence at GFR G3a compared to G1, this represents moderate cardiovascular risk in our context.