Baseline characteristics
Out of 41 patients with nocturnal polyuria, 17 (41,5%) were female and 24 (58,5%) were male. The mean age was 68,7(±9,1) years, the mean body mass index (BMI) was 27,5(±4,3), and the mean diastolic and systolic blood pressure were 84,2(±14,2) and 143,3(±19,7) mmHg, respectively. The mean NPi was 47,5% (±10,3) and mean episodes of nocturia were 4,2(±1,5). Thirty-four patients (83%) were diagnosed with OSA after polygraphy, of whom 12(35%), 12(35%) and 10(30%) patients had mild (AHI 5<15/hour), moderate (AHI 15<30/hour) and severe OSA (AHI≥30/hour), respectively. In seven patients (17%), no OSA was present. Of the thirty-four patients with OSA, thirty-two patients started the CPAP-trial. One patient with OSA preferred alternative treatment with mandibular reposition device (MRA). Another patient did not want a treatment because of mild symptoms. Of 32 patients who started treatment with CPAP, 26(81%) completed the 8 week treatment period, 5(16%) patients were excluded because of non-compliance, and in one case the evaluation after 8 weeks could not be carried out because of a fall of the patient (not during night time).
Effect of treatment
After 8 weeks of compliant treatment with CPAP in 26 patients, the AHI decreased from 24.9(5.7-72.7) to 3,9 (0,9-8,7) per hour (p<0.0001). The mean NPi decreased from 47(32-69)% to 32(16-46)% (p<0.0001), and episodes of nocturia decreased from 3.7(1-5) to 1,9(0-4) (p<0.0001).