Kidney dysfunction as a risk factor for first symptomatic stroke events in a general Japanese population - the Ohasama study

Background. Chronic Kidney Disease (CKD) has been shown to be a risk factor for mortality as well as for morbidity such as cardiovascular disease (CVD) in the general population. However, in the context of CVD events, there is a difference in the incidence of cardiac and stroke events between Western and Asian populations. Although a high prevalence of stroke is a characteristic feature in Japanese populations, it is unclear whether CKD, constitutes a risk for stroke events. Methods. To clarify this issue, we estimated creatinine clearance and obtained dipstick tests from spot-urine samples in 1977 subjects (mean 62.9-years-old, men/women: 731/1246) from a general Japanese population. First symptomatic stroke events and all-cause mortality were analysed according to stratification of kidney function and by positive tests for macroalbuminuria using a Cox proportional hazards regression model adjusted for possible confounding factors. Results. During the observation period (mean 7.76 years), we recorded 112 events of first symptomatic stroke and 187 deaths (58 cases due to CVD). After adjustment for all variables, we found that increases in relative hazard (RH) for the first symptomatic stroke events were associated with decreasing kidney function (RH, 3.1; 95% CI, 1.24-7.84 in Ccr < 40ml/min, 1.9; 95% CI, 1.06-3.75 in Ccr 40-70ml/min, ref in Ccr > 70 ml/min) and with the presence of macroalbuminuria (RH, 1.4; 95% CI, 0.80-2.41). Conclusion. Decreased kidney function increased the risk of first symptomatic stroke events in a general Japanese population. The high prevalence of stroke in this population prompts the need for greater public awareness about risks for CKD.