This study has shown, in a non-invasive way, that 82% of all bedwetting children and a normal daytime voiding diary appear to have a reduced nighttime voided volume[1]. Via a simple and pragmatic study design the authors assesed 103 children with nocturnal enuresis by measuring their voided volumes during the day and a 2 weeks observation of their nighttime urine production using diaper weights. Yeung et al using continuous urodynamic investigation have shown in children with nocturnal enuresis 1/3 have bladder overactivity during sleep[2]. In this study, Borg et al have used non-invasive measurements and in addition have therefore been able to observe for a longer time period. The results of this study are an important addition in our knowledge of diagnostic tools, knowing that a so-called normal voided volume measurement does not eliminate the possibility of a nighttime overactive bladder. It also explains the fact that adding an anticholinergic medication to the desmopressin may have a higher success rate.
Sometimes it is nice to have a confirmation of what you think you already know, and more precisely that, in the treatment of children for a bedwetting problem, desmopressin has a similar efficacy as the nighttime alarm treatment but a higher relapse rate. Song et al have recently performed a meta-analysis of 18 randomized controlled trials [3]. In addition, and in line with another recent study where Borg et al have found a high incidence of nighttime overactive bladder in children with nocturnal enuresis, the studies where desmopressin was combined with anticholinergic treatment, the success rate was higher when compared to desmopressin alone, but the same high relapse rate is seen when the treatment was stopped [1]. The authors have correctly addressed the fact that there is not just one simple reason why children are still bedwetting, that the etiology is complex and multifactorial, so the more studies, the better quality of studies, the stronger the results can be.
[1] Borg B, Kamperis K, Olsen LH, Rittig S. Evidence of reduced bladder capacity during nighttime in children with monosymptomatic nocturnal enuresis. J Pediatr Urol 2018;14:160.e1-160.e6. doi:10.1016/j.jpurol.2017.09.021.
[2] Yeung CK, Sit FKY, To LKC, Chiu HN, Sihoe JDY, Lee E, et al. Reduction in nocturnal functional bladder capacity is a common factor in the pathogenesis of refractory nocturnal enuresis. BJU Int 2002;90:302–7. doi:10.1046/j.1464-410X.2002.02884.x.
[3] Wang Q, Wang W, Cui L, Feng J, Yue Y, Wen J, et al. Comparison of desmopressin, alarm, desmopressin plus alarm, and desmopressin plus anticholinergic agents in the management of paediatric monosymptomatic nocturnal enuresis: a network meta-analysis. BJU Int 2018:388–400. doi:10.1111/bju.14539.
