Long-term and continuous nephrology care effects on post-dialysis mortality remain unclear. This study aims to systematically explore the causal effect of nephrology care on mortality for patients with dialysis initiation. We conducted a retrospective cohort study to include incident patients with dialysis for ≥ 3 months in Taiwan from 2004 through 2011. The continuous nephrology care of incident patients in the three years before their dialysis was measured every six months. Continuous nephrology care was determined by 0-6, 0-12, …, 0-36 months and their counterparts; and none, intermittent, 0-6 months, …, and 0-36 months. Simple and weighted hazards ratio (HR) and 95% confidence interval (CI) for one-year mortality were estimated after propensity score (PS) matching. We included a total of 44,698 patients (mean age 63.3 ± 14.2, male 51.9%). Receiving ≥ 1 year predialysis nephrology care was associated with a 22% lower post-dialysis mortality hazard. No different effects were found (ranges of PS matching HR: 0.77-0.80) when comparing the defined duration of nephrology care with their counterparts. Stepped survival benefits were newly identified in the intermittent care, which had slightly lower HRs (weighted HR: 0.88, 95% CI: 0.79-0.97), followed by reviving care over six months to two years (ranges of weighted HR: 0.60-0.65), and reviving care over two years (ranges of weighted HR: 0.48-0.52). There was no existing critical period of nephrology care effect on post-dialysis, but there were extra survival benefits when extending nephrology care to >2 years, which suggests that continuous and long-term care during pre-dialysis/chronic kidney disease phase is required.
Keywords: causal inference; dialysis; end-stage kidney disease; mortality; nephrology care.