RESPONSE TO DESMOPRESSIN AS A FUNCTION OF URINE OSMOLALITY IN THE TREATMENT OF MONOSYMPTOMATIC NOCTURNAL ENURESIS - A DOUBLE-BLIND PROSPECTIVE-STUDY

To determine if urine osmolality parameters can predict whether childr en with primary monosymptomatic nocturnal enuresis will respond to des mopressin, we conducted a prospective, double-blind, placebo-controlle d study in 96 children 8 to 14 years old. Following a 2-week baseline screening interval patients with at least 6 of 14 wet nights were rand omized to double-blind regimens of desmopressin or placebo. Urine spec imens for osmolality were collected at 6 p.m. and 6 a.m. on 3 consecut ive days during the baseline and the 2, 14-day treatment periods. A si gnificantly greater proportion of desmopressin treated children had an excellent (2 or fewer wet nights in 14 days) or good (greater than 50 % reduction in wet nights) response compared with placebo treated chil dren (p = 0.004 and p = 0.002 for treatment periods 1 and 2, respectiv ely). Children treated with desmopressin reported a significantly lowe r number of wet nights than placebo treated children during both treat ment periods (p = 0.0258 and p = 0.0136, respectively). Children treat ed with desmopressin had a significantly higher 6 a.m. urine osmolalit y during both treatment periods and a higher 6 a.m.-to-6 p.m. osmolali ty ratio (p = 0.004) in the first treatment period compared with the p lacebo group. Within the desmopressin treatment group clinical respond ers had a higher 6 a.m. urine osmolality and 6 a.m.-to-6 p.m. urine os molality ratio than nonresponders during both treatment periods but th ese differences did not achieve statistical significance, In conclusio n, treatment with desmopressin is associated with a significant decrea se in the number of wet nights, and a significant increase in nocturna l urine osmolality and nocturnal/diurnal urine osmolality ratios. Howe ver, clinical response was not predictable based on baseline or treatm ent osmolality parameters.