Kidney Morbidity in Pediatric Patients With Spina Bifida.

Importance: With improved medical care, patients with spina bifida are living longer, making kidney morbidity an increasingly important source of disease burden. Objective: To measure the incidence rate, age of onset, and clinical factors associated with kidney morbidity among a pediatric cohort of patients with spina bifida. Design, Setting, and Participants: This cohort study included all publicly insured individuals born in Ontario, Canada, between April 1, 1992, and March 31, 2023, stratified by those with and without spina bifida. Data was sourced from inpatient and outpatient administrative health record databases. Patients were followed up from birth until August 31, 2023, termination of health insurance, or death. Exposure: Patients with spina bifida were identified and compared with the general population born within the same time frame. Main Outcomes and Measures: Incidence rate and age of onset of chronic kidney disease (CKD) and end-stage renal disease (ESRD) (ie, long-term dialysis and/or kidney transplant), captured through administrative diagnosis codes. A multivariate Cox proportional hazards model identified clinical factors associated with the development of CKD among patients with spina bifida. Results: A total of 4 380 749 individuals were included: 12 868 with spina bifida (median [IQR] age at diagnosis, 1 [0-8] years) and 4 367 881 without spina bifida. The median (IQR) follow-up was 15 (7-23) years. Among patients with spina bifida, the incidence rate of CKD was 2.7 (95% CI, 2.5-2.9) per 1000 person-years compared with 0.3 (95% CI, 0.3-0.3) per 1000 person-years among the general population. The incidence rates of ESRD were 0.3 (95% CI, 0.2-0.4) and 0.01 (95% CI, 0.01-0.01) per 1000 person-years for patients with and without spina bifida, respectively. Patients with spina bifida were diagnosed with CKD earlier than controls (median [IQR], 5 [1-13] years vs 10 [2-18] years; P < .001; standardized difference = 0.411) and progressed to ESRD at a younger age as well (median [IQR], 8 [2-15] years vs 15 [7-22] years; P < .001; standardized difference = 0.614). Earlier birth year, male sex, higher comorbidity score, history of diabetes, upper tract calculi, recurrent complex urinary tract infections, and urologic surgery were significantly associated with CKD among patients with spina bifida. Conclusions and Relevance: In this cohort study, pediatric patients with spina bifida faced a higher risk of CKD and ESRD, with onset about 5 to 7 years earlier compared with the general population. Several identified clinical factors were associated with kidney decline, warranting close pediatric surveillance.