Survival with short-daily hemodialysis: association of time, site, and dose of dialysis.
In thrice-weekly hemodialysis, survival correlates with the length of time (t) of each dialysis and the dose (Kt/V), and deaths occur most frequently on Mondays and Tuesdays. We studied the influence of t and Kt/V on survival in 262 patients on short-daily hemodialysis (SDHD) and also noted death rate by weekday. Contingency tables, Kaplan-Meier analysis, regression analysis, and stepwise Cox proportional hazard analysis were used to study the associations of clinical variables with survival. Patients had been on SDHD for a mean of 2.1 (range 0.1-11) years. Mean dialysis time was 12.9 ± 2.3 h/wk and mean weekly stdKt/V was 2.7 ± 0.5. Fifty-two of the patients died (20%) and 8-year survival was 54 ± 5%. In an analysis of 4 groups by weekly dialysis time, 5-year survival continuously increased from 45 ± 8% in those dialyzing <12 hours to 100% in those dialyzing >15 hours without any apparent threshold. There was no association between Kt/V and survival. In Cox proportional hazard analysis, 4 factors were independently associated with survival: age in years Hazard Ratio (HR)=1.05, weekly dialysis hours HR=0.84, home dialysis HR=0.50, and secondary renal disease HR=2.30. Unlike conventional HD, no pattern of excessive death occurred early in the week during SDHD. With SDHD, longer time and dialysis at home were independently associated with improved survival, while Kt/V was not. Homedialysis and dialysis 15+ h/wk appear to maximize survival in SDHD.