Background: In spina bifida (SB), health-related quality of life (HRQOL) is an increasingly recognized patient-centered metric. The complexity of SB means that there are multiple potential contributors to overall HRQOL, including bladder health, bowel health, and physical functioning. We examined relative associations of bladder health, bowel health, and physical function with HRQOL in adolescents and young adults with spina bifida, and the amount of variance in HRQOL explained by each health domain.
Methods: We performed a retrospective cross-sectional analysis of clinical questionnaires administered to patients ≥12-years-old (no upper age limit) between May 2019 and March 2024 in a multi-disciplinary SB center. Questionnaires included the Neurogenic Bladder Symptom Score (NBSS, higher score = more bladder symptoms), a modified Neurogenic Bowel Dysfunction Score (NBD, higher score = worse bowel dysfunction), the Patient Reported Outcome Measure Information System Physical Function with Mobility Aid Short Form (PROMIS-PF, higher score = better physical function), and the PROMIS Pediatric Global Health 7 (PGH-7, higher score = better HRQOL) T-score. Questionnaires were completed independently by the patient or with caregiver assistance in English/Spanish. Demographic and clinical characteristics were collected from patients’ medical records. The primary exposures were NBD, NBSS, and PROMIS-PF score. The primary outcome was PGH-7 T-score. Multivariable linear regression was performed to assess the associations of NBD, NBSS, and PROMIS-PF score with PGH-7 T-score while adjusting for other covariates (health literacy level measured by BRIEF Health Literacy Screening Tool, age, sex, SB diagnosis, functional level of lesion, ambulatory status, and ventricular shunt status). R2 was calculated to assess the percent variance in PGH-7 T-score that can be explained by our overall model. ω2 was calculated to assess the proportion of variance in NBD, NBSS, and PROMIS-PF score after adjustment for other covariates.
Results: 454/464 patients with an eligible SB diagnosis approached during the study period returned questionnaires. Of those, 74 were excluded for incomplete or missing data, leaving a final study inclusion of 380 patients (84%). Mean age was 17.0 years, 55% of patients were female, and 50% had a SB diagnosis of myelomeningocele. Decreases in NBD and NBSS score and increases in PROMIS-PF score were all significantly associated with increases in PGH-7 T-score on multivariable analysis (Table). Male sex and younger age were also significantly associated with increased PGH-7 T-score. R2 for the overall model was 0.186. ω2 for NBD, NBSS, and PROMIS-PF scores were 1.3%, 1.6%, and 1.6% respectively. Sex was the variable that explained the most variation in PGH-7 T-score (ω2=2.2%).
Conclusions: Fewer bladder and bowel symptoms and greater physical function were each associated with better HRQOL, but the relative effect sizes were low. Overall, our multivariable model was only able to capture 18.6% of variability in HRQOL score. HRQOL is multifaceted, especially for people with a complex chronic condition like SB. Further research is needed to identify factors associated with HRQOL in this population.
