Copeptin improves prediction of treatment response in children with monosymptomatic nocturnal enuresis.

Objective: One of the main medical treatment options for monosymptomatic nocturnal enuresis (MNE) is the vasopressin analog desmopressin. But not all children respond to desmopressin treatment, and no reliable treatment predictor has yet been established. We hypothesize that plasma copeptin, a surrogate marker for vasopressin, can be used to predict treatment response to desmopressin in children with MNE.

Design/methods: In this prospective observational study, we included 28 children with MNE. At baseline, we assessed the number of wet nights, morning, and evening plasma copeptin, and plasma sodium and started treatment with desmopressin (120 µg daily). Desmopressin was increased to 240 µg daily if clinically necessary. The primary endpoint was reduction in the number of wet nights following 12 weeks of treatment with desmopressin using plasma copeptin ratio (evening/morning copeptin) at baseline.

Results: Eighteen children responded to desmopressin treatment at 12 weeks, while 9 did not. A copeptin ratio cutoff of 1.34 (sensitivity 55.56%, specificity 94.12%, area under the curve 70.6%, P = .07) was best at predicting treatment response, with a lower ratio indicating a better treatment response. In contrast, neither the number of wet nights at baseline (P = .15) nor serum sodium (P = .11) alone or in combination with plasma copeptin improved outcome prediction.

Conclusions: Our results indicate that, of our investigated parameters, plasma copeptin ratio is the best predictor for treatment response in children with MNE. Plasma copeptin ratio could thus be useful to identify children with the highest benefit of desmopressin treatment and improve individualized treatment of MNE.