Do independent geriatric outpatients with nocturnal polyuria profit from desmopressin?

To compare the efficacy of desmopressin and placebo in independent geriatric outpatients with nocturnal polyuria (NP).

A prospective, randomized, single-center, national, double blind, placebo-controlled, fixed-dose, parallel group comparative trial was carried out. The study included 110 geriatric outpatients, 55 patients per treatment group using desmopressin acetate nasal spray (strength: 0.1 mg/ml) once daily of 10 μg/spray blast or placebo.

The NP positive geriatric outpatients with >33% nocturnal urine output volume, antidiuretic hormone (ADH) positive or negative were treated over 10 days with intranasal spray in the evening time (7 p.m.), drug or placebo. On day 1 voiding frequency, voiding volumes day and night, serum osmolarity and arginine-vasopressin (AVP) were measured at 7 p.m. On days 2, 5 and 10 creatinine, blood urea nitrogen (bun), blood count and C‑reactive protein (CrP), vena cava diameter and bioimpedance were measured and a structured interview was implemented (voiding frequency, sleeping behavior and subjective and cognitive behavior).

The NP patients showed a mean night voiding volume of 50.60%, 39.21% (n = 102) showed a low AVP level at baseline with no correlation to sodium concentration or voiding frequencies. The primary efficacy criterion, a decrease of the nocturnal voiding frequency during the course of the clinical trial as change from baseline at day 10 (visit 4) was 50% versus 41.40% in the verum versus placebo group, respectively but the differences were not significant. The U‑test showed superiority of AVP-positive NP patients to a positive reaction on desmopressin. Sleeping time hours increased in both groups without significant differences.

In this 10-day clinical trial desmopressin was not proven to be therapeutically superior to placebo with respect to micturition frequency or sleeping hours. Independent geriatric outpatients with decreased ADH levels seemed to respond and benefit from active treatment with desmopressin. The unexpected results in the placebo group may be due to the effect of intensive outpatient care and information on NP outpatients with normal AVP levels.