Different clinical outcomes for cardiovascular events and mortality in chronic kidney disease according to underlying renal disease: the Gonryo study

Chronic kidney disease (CKD) can result from a wide variety of diseases, but whether clinical outcomes differ in the same CKD stages according to the underlying renal disease remains unclear. Clarification of this issue is important for stratifying risk of cardiovascular disease (CVD) and death in patients before dialysis. The study comprised 2,692 patients recruited from 11 outpatient nephrology clinics, classified by underlying disease of primary renal disease (PRD) (n = 1,306), hypertensive nephropathy (HN) (n = 458), diabetic nephropathy (DN) (n = 283), or other nephropathies (ON) (n = 645). Risks of events such as ischemic heart disease, congestive heart failure, stroke, and all-cause mortality within 12 months were examined by logistic regression analysis in each group. During the 12-months' observation from recruitment, 200 cases were lost to follow-up, and 113 cases were introduced to chronic dialysis therapy. A total of 69 CVD events occurred (stroke in 27 cases), and 24 patients died. In total, increased odds ratios (OR) for the events by CKD stage (cf. CKD1 + 2: unadjusted) were CKD3, 1.29 [95% confidence interval (CI), 0.70-2.17]; CKD4, 2.73 (1.55-4.83); and CKD5, 4.66 (2.63-8.23). Regarding events in respective groups, no significant differences were seen by CKD stage except for the group with HN, but significant differences were seen by underlying diseases (cf. PRD: adjusted for confounding factors, including estimated glomerular filtration rate): HN, 2.57 (1.09-6.04); DN, 12.21 (3.90-38.20); and ON, 4.14 (1.93-8.89). Risk of CVD and mortality due to CKD needs to be stratified according to the underlying renal diseases.