Determinants of medication adherence in childhood nephrotic syndrome and associations of adherence with clinical outcomes.

Background: Pediatric patients with nephrotic syndrome take medications long-term with significant toxicity and complex regimens, yet data on medication adherence are limited.

Methods: In a multicenter observational study of patients with nephrotic syndrome, NEPTUNE (NCT01209000), we surveyed caregivers of patients <19 years old and adolescent patients on medication adherence during longitudinal follow-up beginning in June 2015. Data extraction was in October 2020. We described the proportion of nonadherent patients at first survey. Participant social and economic factors, condition-related factors, therapy-related factors, and patient-related factors were examined for relationships with nonadherence by generalized linear mixed models using the longitudinal data. In exploratory fashion, we assessed the relationship between adherence and subsequent steroid response classification by binary logistic regression and adherence with healthcare utilization by Poisson regression.

Results: A total of 225 participants completed a median of 3 surveys during follow-up (IQR, 2-5), with a total of 743 surveys. Overall, 80 (36%) reported nonadherence with medications. In adjusted analysis, older age (per 1 year; OR 1.08; 95% CI, 1.03 1.12), lower maternal educational level (≥ high school vs. < high school; OR 0.47; 95% CI 0.25 to 0.89), and increased parent and self-identification of medications barriers (per 1 point; OR 1.57; 95% CI, 1.15-2.15) were significantly associated with nonadherence. No relationship between nonadherence and subsequent frequency of healthcare utilization was observed. A trend toward increased subsequent steroid resistance classification was seen with nonadherence, though not statistically significant.

Conclusions: Medication nonadherence is common in pediatric nephrotic syndrome. Investigations into the use of surveys in the clinic setting to identify at-risk patients and ways to support families over time are needed. A higher resolution version of the Graphical abstract is available as Supplementary information.