Longitudinal follow-up of bladder function in children who participated in the Swedish Reflux Trial

Several publications have reported the coexistence of vesicoureteral reflux (VUR) and bladder dysfunction in children. Whether this dysfunction remains in the longer term is not yet known.

This study revisited children who participated in the Swedish Reflux Trial (SRT) with the primary aim of evaluating whether bladder and bowel dysfunction (BBD) in these patients persisted until adolescence. The secondary aim was to evaluate two BBD subgroups, and relations to recurrent urinary tract infections (UTI).

Of the 161 eligible children at SRT study-end, 73 children participated. Their bladder function was evaluated longitudinally using a validated BBD questionnaire with symptom score (cut-off ≥7) and uroflowmetry, at five (T2) and ten years (T3) after study-end. T1 was the SRT study-end. Besides BBD, the sub-diagnoses overactive bladder (OAB) and dysfunctional voiding symptoms (DVS) were calculated from symptom scores.

BBD was diagnosed in 37% of children at mean age 3.7 years, which decreased with age to 23% of adolescents (mean age 15.7). DVS and OAB subgroups were equally common at T1, but only DVS was identified at the last follow-up (T3) (p = 0.0008). Recurrent UTIs were seen in 17% at T3 and were more common in patients with BBD (p = 0.038). The gender distribution of BBD also changed, from being equally common at the end of the SRT to affecting mainly adolescent girls at the last follow-up (p = 0.022). Information was available regarding VUR status after repeat VCUGs during follow-up in 22 patients, 12 of them after endoscopic treatment. An improvement in VUR grade was found in the 22, but during follow-up numbers with BBD or UTI did not differ between treated and non-treated groups.

The prevalence of BBD decreased from 37% at 3-4 years of age to 23% in adolescence, when it was almost exclusively seen in girls. BBD and the subgroup DVS were associated with UTI. Even if epidemiological studies have established a predisposition to bladder symptoms and UTI in girls, little is known about bladder function in adolescents with a history of VUR during the first years of life. One limitation of the study was the number of patients participating. Also, the number of patients with kidney damage was more common in the cohort.

In this longitudinal follow-up of BBD in children with VUR, the number of children with BBD decreased with age. In adolescence, both BBD and recurrent UTIs mainly affected girls.