Long-term impact of mild chronic kidney disease in patients with acute coronary syndrome undergoing percutaneous coronary interventions

Background. Accumulating evidence shows that chronic kidney disease (CKD) is an independent risk factor for major adverse cardiac and cerebrovascular events (MACCE) after acute coronary syndrome (ACS). However, it is not known whether mild renal insufficiency affects long-term clinical outcomes. Methods. This is a post-hoc analysis from the Extended-ESTABLISH trial, which was designed to estimate the impact of renal insufficiency on patients with ACS after percutaneous coronary intervention over the long term. One hundred and eighty patients were divided into three groups based on the estimated glomerular filtration rate (eGFR) at time of ACS: moderate-to-severe CKD,< 60 mL/min/1.73 m(2) (n = 31, 17.2%); mild CKD, 60-90 mL/min/1.73m(2) (n = 100, 55.6%) and non-CKD, >= 90 mL/min/1.73 m(2) (n = 47, 26.1%). The eGFR was calculated using the new Japanese equation. Long-term outcomes were compared over a follow-up period of 1538 +/- 707 days. Results. Cumulative incidence rates of MACCE did not significantly differ between groups 1 year after ACS onset (P = 0.384), whereas significant differences appeared during the long-term follow-up (10.6 versus 27.0% versus 35.4% in the non-CKD, mild CKD and moderate-to-severe CKD groups, respectively; log-rank test, P = 0.022). In a multivariate Cox hazard regression model, moderate-to-severe CKD and mild CKD were associated with a higher rate of MACCE after adjusting for confounding variables (hazard ratios = 3.46 and 2.67, respectively; P = 0.043). Conclusions. The presence of mild CKD at ACS occurrence is associated with a worse outcome in the long term, but not the short term.