Prognostic significance of glomerular filtration rate estimated by the Japanese equation among patients who underwent complete coronary revascularization

Abstract

An equation that accurately estimates the glomerular filtration rate (GFR) in the Japanese population has been proposed; however, the prognostic significance of estimated GFR (eGFR) defined according to this equation has not been reported. In addition, the prognostic significance of eGFR during long-term follow-up after complete coronary revascularization remains unclear. We assessed the prognostic significance of eGFR values, estimated by the new Japanese equation, in a cohort of patients following complete coronary revascularization. We studied consecutive patients with complete revascularization from 1984 to 1992. Patients on dialysis were excluded. A novel Japanese equation was used to estimate the GFR: eGFR=194×(serum creatinine)(-1.094)×(age)(-0.287)(×0.739 if female). Multivariate Cox proportional hazards regression analyses were performed to determine all-cause and cardiac mortality. We analyzed data of 1809 patients, of whom 571 (31.6%) had an eGFR of ≥90 mlmin(-1) per 1.73 m(2), 917 (50.7%) had an eGFR of 60-89 mlmin(-1) per 1.73 m(2), 298 (16.5%) had an eGFR of 30-59 mlmin(-1) per 1.73 m(2) and 23 (1.3%) had an eGFR of <30 mlmin(-1) per 1.73 m(2). During follow-up (11.4±2.9 years), there were 397 (22.0%) all-cause and 123 (6.8%) cardiac deaths overall. Patients with an eGFR of 30-59 mlmin(-1) per 1.73 m(2), and <30 mlmin(-1) per 1.73 m(2) revealed significantly greater risk of all-cause mortality than those with eGFR of ≥90 mlmin(-1) per 1.73 m(2) (hazard ratio (HR) 1.91, P<0.001, HR 3.35, P<0.001, respectively). Furthermore, incidence of cardiac death was higher in patients with an eGFR of 30-59 mlmin(-1) per 1.73 m(2) than those with an eGFR of ≥90 mlmin(-1) per 1.73 m(2) (HR 2.89, P<0.001). GFR as estimated using the new Japanese equation had a prognostic significance among patients with complete coronary revascularization.