Survival of vascular access during daily and three times a week hemodialysis

A major cause of morbidity for hemodialysis patients is vascular access failure and/or occlusion. It is commonly believed that an increased frequency of dialysis sessions, among other factors, might lead to a higher rate of fistula complications.

To evaluate if patients on daily hemodialysis carry a higher risk of vascular access occlusion, we examined the incidence rate of access occlusion and the survival function of native vascular accesses in patients undergoing daily dialysis (DD; n = 24) as compared to patients on standard three times a week hemodialysis (TWD; n = 124).

The mean follow-up time was 3.6 years. In the TWD group 42 patients had a first-access closure, whereas only 2 patients out 24 had a similar event in the DD group. The proportion of first-access closure was 33.9% for TWD and 8.3% for DD (p < 0.01). The incidence rate was 9.8 (95% CI: 7.2 -13.2) and 2.2 (95% CI: 0.4 - 7.1) events per 100 patient-years for TWD and DD, respectively. The rate difference was 7.6 (95% CI 3.4 - 11.9) events per 100 patient-years, and the unadjusted risk ratio was 4.5 (95% CI: 1.2 - 16.9; p < 0.01). The mean vascular access survival before closure was 3.3 years in TWD and 3.7 years in DD. Survival curves, obtained considering the first-access closure as the endpoint, showed a significant difference between DD and TWD (log-rank 5.16; p < 0.05). In a Cox-proportional hazard model the relative risk (RR) of vascular-access closure in TWD remained significant (RR = 4.3; 95% CI 1.1 - 18.2) after adjustment for age.

The results of this observational study, conducted on a limited number of DD patients, suggest that daily dialysis might not have an adverse prognostic significance for access closure.