Impact of reduced renal function on prognosis in Japanese patients with coronary artery disease: a prospective cohort of Shinken Database 2007.

Patients with coronary artery disease (CAD) frequently have impaired renal function, but the prevalence and influence of renal dysfunction on their prognosis in Japan remain uncertain. With a prospective study comprising all the new patients who had visited our hospital between 2004 and 2007 (n=6562), we investigated the prevalence of renal dysfunction and its influence on the prognosis of CAD patients. The glomerular filtration rate (GFR) was calculated by using the GFR equation used for the Japanese population. Of those, 797 patients with CAD and blood tests available were analyzed (median follow-up periods of 693 days). Patients were further classified into four subgroups according to estimated GFR value (eGFR): normal (90< or =eGFR, 12.2%), mildly impaired (60< or =eGFR<90, 58.3%), moderately impaired (30< or =eGFR<60, 23.6%) and severely impaired renal function (eGFR<30, 5.9%). The 2-year survival and cardiovascular event (cardiac death, nonfatal myocardial infarction or readmission for heart failure)-free rates were significantly different among the four subgroups: 98.9, 97.7, 89.3 vs. 67.8%, respectively (P<0.001 for trend), and 100, 98.8, 89.0 vs. 70.0%, respectively (P<0.001 for trend). The age- and gender-adjusted mortality increased significantly in moderately impaired (hazard ratio (HR) 3.1, 95% confidence interval (CI) 1.383-7.017) and in severely impaired subgroups (HR 10.1, 95% CI 4.244-24.178) compared with those with eGFR of 60 or more. After adjustment for baseline differences, eGFR was independently associated with death and cardiovascular events (HR 0.983 and 0.981, 95% CI 0.968-0.998 and 0.965-0.998, respectively). In conclusion, our study identified the prevalence and association of eGFR with prognosis in Japanese patients with CAD, suggesting that strict care for not only CAD but also renal dysfunction is needed for further prevention of cardiovascular events.