Evaluating nocturnal polyuria in Japanese children with nocturnal enuresis.

BACKGROUND

The purpose of this study was to assess whether enuretic Japanese patients with nocturnal polyuria (NP) who met Hoashi's criteria (6-9 years: ≥200 mL; 10 years and older: ≥250 mL) met the International Children's Continence Society (ICCS; expected bladder capacity × 130%) and Rittig's criteria for nocturnal polyuria (>[age+9] × 20 mL). We also compared the effectiveness of 1-desamino-8-d-arginine vasopressin (DDAVP) with the three criteria.

METHODS

Fifty-four patients who had NP with normal bladder capacity were enrolled: 36 boys (67%); median age, 8 (interquartile range: 7-9). We compared the diagnostic differences between the Hoashi's criteria and international standards (ICCS and Rittig's) for NP and the short-term effects of DDAVP. The patients received DDAVP for 8 weeks; we evaluated the association between each evaluation method and the effects of therapy.

RESULTS

Only 17% of the patients met both Hoashi's and ICCS criteria, whereas 26% met both Hoashi's and Rittig's criteria. The therapeutic effect of DDAVP did not differ significantly between these two groups: there was an effective rate of 73% (Hoashi's criteria) versus 50% (ICCS criteria), P = 0.19, and an effective rate of 71% (Hoashi's criteria) versus 62% (Rittig's criteria), P = 0.84.

CONCLUSIONS

Hoashi's criteria are widely used but, according to both the ICCS and Rittig's criteria, approximately 80% of the patients did not fulfill the definition of NP. However, 8 weeks after the DDAVP treatment began, no significant difference was observed in the therapeutic effect of DDAVP according to each set of criteria. The definition of NP should account for the physical disparities between Japanese people and Westerners.