Potential Benefits and Risks of Twice-Weekly Dialysis vs. Thrice-Weekly Dialysis: A Retrospective Cohort Study

Background: Hemodialysis maintenance dose remains a topic of discussion. In this current study, we compared patients undergoing twice- and thrice-weekly hemodialysis in terms of clinical outcomes. Methods: In this retrospective cohort study, we performed a posteriori, using information and data from chart review of HD patients in a tertiary private hospital. The study population were dichotomized as follows: twice- and thrice-weekly HD cohorts with a dialysis vintage of 1 year duration. Those who were shifted to a different cohort within less than a year were excluded. The primary outcomes are all-cause mortality and hospitalization rates within 36 months. On the other hand, the secondary outcome are adverse events. Results: A total of 212 HD patients with a dialysis vintage of 1 year were included in the study of which 124 (58.49%) underwent twice weekly HD while 88 (41.51%) underwent thrice weekly HD. At baseline, demographic and clinical characteristics were similar across cohorts (p>0.05). Cohorts did not vary significantly in terms of 36-month all-cause mortality rate (63.46% vs 36.54%; p= 0.402) and mean number of times hospitalized (2.05±1.91 vs 1.91±1.74; p=0.588). All-cause mortality was not significantly associated with dialysis frequency both in the simple logistic regression analysis (crude OR: 1.32 [95% CI: 0.69 - 2.51) and multiple logistic regression analysis (adjusted OR: 1.13 [95% CI: 0.57 - 2.23]; p=0.734). Moreover, dialysis frequency was not a predictor of all-cause hospitalization both in the in both simple linear regression (β: 0.14 [95% CI -0.37 - 0.65]; p=0.588) and multiple linear regression (β: 0.04 [95% CI: -0.46 - 0.54]; p=0.875). Finally, dialysis frequency was not significantly associated with hyperkalemia (p=0.785); fluid overload (p=0.250); uremia (p=0.398); infection (p=0.63); and access problems (p=0.956). Conclusion: Patients on twice-weekly HD had similar survival, hospitalization rate, and adverse outcomes at 36 months as patients on thrice-weekly HD.