The Nocturia Impact Diary: a self-reported impact measure to complement the voiding diary

Nocturia is a chronic, fluctuating disease that disrupts sleep and has a wide-ranging impact on quality of life. Valid tools to measure the patient-reported impact of nocturia are essential for evaluating the value of treatment, but the available tools are suboptimal.

This study reports the development and validation of the Nocturia Impact Diary-an augmented form of the Nocturia Quality of Life questionnaire designed to be completed in conjunction with the widely used 3-day voiding diary.

The process comprised three steps: Step 1: Development of a concept pool using the Nocturia Quality of Life questionnaire and data from relevant studies; Step 2: Content validity study; Step 3: Psychometric testing of construct validity, reliability, and sensitivity of the diary in a randomized, placebo-controlled study in patients with nocturia.

Step 1: Fourteen items and 4 domains were included in the first draft of the diary. Step 2: Twenty-three patients with nocturia participated in the cognitive debriefing study. Items were adjusted accordingly, and the content validity was high. Step 3: Fifty-six patients were randomized to desmopressin orally disintegrating tablet or placebo. The diary demonstrated high construct validity, with good sensitivity and a good fit to Rasch model, as well as high internal consistency, discriminatory ability, and acceptable sensitivity to change. Results indicated that the diary was unidimensional.

The Nocturia Impact Diary is a convenient, validated patient-reported outcome measure. It should be used in conjunction with a voiding diary to capture the real-life consequences of nocturia and its treatment.