<p><strong>BACKGROUND: </strong>Previous studies have demonstrated a relationship between longer interdialytic intervals and hospitalization for cardiovascular causes in adults maintained on hemodialysis (HD). This association has not been previously demonstrated in children. We hypothesized that the risk of hospitalization for hypertension (HTN), fluid overload or electrolyte abnormalities would be increased on the days following a longer interdialytic interval in children.</p>

<p><strong>METHODS: </strong>We queried the Pediatric Hospital Information System for all admissions of patients with chronic kidney disease stage V or V-D who received dialysis during the hospitalization. Admissions were divided into two categories: admissions for HTN, fluid overload or electrolyte abnormalities and admissions for all other causes. We assumed that HD patients did not receive dialysis on weekends, and therefore any admission on Monday occurred following a longer interval from the last dialysis. We assumed that all peritoneal dialysis (PD) patients received dialysis on a daily basis. We used mixed effects logistic regression, clustering by patient within each hospital, to assess the increased odds for cause-specific admission on Monday versus other days of the week. We stratified the analysis by dialysis modality, HD or PD.</p>

<p><strong>RESULTS: </strong>Among HD patients, the odds ratio of admission for HTN, fluid overload or electrolyte abnormalities was 2.6 (95% CI = 1.4-4.7, P = 0.003) if the admission occurred on a Monday versus other days of the week. The odds of cause-specific admission among PD patients was not significantly different on Monday compared with other days of the week (95% CI =0.5-1.3, P = 0.8).</p>

<p><strong>CONCLUSION: </strong>Children receiving chronic HD are more likely to be hospitalized for HTN, fluid overload or electrolyte abnormalities following a longer interdialytic interval. Changes to the frequency of outpatient dialysis treatments may decrease admissions in this population and decrease resource utilization in this high-risk population.</p>