Liu P, et al. - Researchers investigated if longer predialysis care provides survival benefit even after accounting for the potential confounding effect of disease course that may also be affected by predialysis care. They found that after accounting for patients’ course of the disease, a weaker and imprecise link was observed between longer predialysis care and lower mortality after dialysis start.

Methods

• In this retrospective cohort study, researchers used data from 3152 adults with end stage kidney failure starting dialysis between 2004 and 2014 in five Canadian dialysis programs.
• They obtained information on the following: duration of predialysis care from the earliest nephrology outpatient visit to dialysis start; markers of disease course, including inpatient or outpatient dialysis start and residual kidney function around dialysis start; and all-cause mortality after dialysis start.

Results

• Data showed that 0, 1–119, 120–364, and ≥365 days of predialysis care was received by 23%, 8%, 10%, and 59% participants, respectively.
• Researchers observed association of longer predialysis care with lower mortality when markers of disease course were ignored (hazard ratio120–364 vs 0–119 days, 0.60; 95% confidence interval, 0.46 to 0.78]; hazard ratio≥365 vs 0–119 days, 0.60; 95% confidence interval, 0.51 to 0.71; standard Cox model adjusted for demographics and laboratory and clinical characteristics).
• They noted that this association was weaker and no longer significant on additionally accounting for markers of disease course using the inverse probability of treatment weighted Cox model (hazard ratio120–364 vs 0–119 days, 0.84; 95% confidence interval, 0.60 to 1.18; hazard ratio≥365 vs 0–119 days, 0.88; 95% confidence interval, 0.69 to 1.13).