Increases in duration of first uninterrupted sleep period are associated with improvements in PSQI-measured sleep quality

Objective: Urology clinical trials assessing bladder function have relied on the self-reported duration of the first uninterrupted sleep period (FUSP) as a proxy outcome for sleep, but the relationship between this measure and more conventional self-reported measures of sleep is unknown. In this study, we examined the association between changes in FUSP and a widely used self-reported measure of sleep, the Pittsburgh Sleep Quality Index (PSQI). Methods: We conducted post hoc (secondary) analyses of unpublished data from a previously published randomized clinical trial (NCT00477490) of desmopressin (a medication used to treat nocturia) and examined relationships between baseline and 4-week change in FUSP and PSQI global and subscale scores for participants (N = 580 to N = 606) having complete data. Results: Data indicated strong associations between change in PSQI global score and FUSP change in six of seven subscale scores. A reduction of 1.8 points in the PSQI global score was associated with a 72-min lengthening of FUSP. Conclusions: Results suggest that FUSP is a potentially valuable metric that correlates with changes in perceived sleep duration, depth, quality for the entire night, efficiency, latency, and daytime function. An increase in FUSP was related to improvement in nearly all PSQI subscales. The validity of this measure in the general population remains to be determined. (C) 2014 Elsevier B. V. All rights reserved.