The prognostic implications of chronic kidney disease and anemia on long-term outcomes in patients undergoing percutaneous coronary intervention

Chronic kidney disease (CKD) and anemia are each individually associated with worse clinical outcomes in patients with coronary artery disease (CAD). However, the prognostic impact of both CKD and anemia on clinical outcomes, when they coexist, remains unclear in CAD patients after percutaneous coronary intervention (PCI). We studied 2484 CAD patients who underwent their first PCI and had available date on preprocedural hemoglobin between 2000 and 2016. The patients were divided into four groups according to the presence of CKD and/or anemia. We evaluated the incidences of all-cause death and major adverse cardiac and cerebrovascular events (MACCEs), including cardiovascular death, non-fatal myocardial infarction, and stroke. Among the patients, 310 patients (12.5%) had both CKD and anemia (CKD with anemia group), 309 (12.4%) had CKD only, 461(18.6%) had anemia only, and 1404 (56.5%) had neither CKD nor anemia. Patients in the CKD with anemia group were older and had a higher incidence of hypertension and diabetes mellitus. During a median follow-up period of 3.7 years, Kaplan–Meier curves showed that patients in the CKD with anemia group had significantly higher incidences of MACCE and all-cause death than the CKD only and anemia only group (both log-rank p < 0.001). Using patients with the no CKD or anemia group as a reference, the adjusted hazard ratios (HRs), 95% confidence interval for MACCE were 1.51 (0.92–2.47) for the CKD only, 1.48 (0.94–2.32) for the anemia only and 2.00 (1.18–3.38) for the CKD with anemia group. Moreover, the adjusted HR for all-cause death were 1.42 (0.96–2.10) for the CKD only, 1.79 (1.28–2.51) for the anemia only, and 1.92 (1.30–2.84) for the CKD with anemia group. In conclusion, the combined effects of both CKD and anemia on outcomes after PCI were worse than either of their individual effects.