Daily Variation in Sleep Quality is Associated With Health-Related Quality of Life in People With Spinal Cord Injury.

OBJECTIVE:Although sleep difficulties are common after spinal cord injury (SCI), little is known about how day-to-day fluctuations in sleep quality affects health-related quality of life (HRQOL) among these individuals. We examined the effect of sleep quality on same-day HRQOL using ecological momentary assessment methods over a 7-day period. DESIGN:Repeated-measures study involving 7 days of home monitoring; participants completed HRQOL measures each night and ecological momentary assessment ratings 3 times throughout the day; multilevel models were used to analyze data. SETTING:Two academic medical centers. PARTICIPANTS:A total of 170 individuals with SCI (N=170). INTERVENTIONS:Not applicable. MAIN OUTCOME MEASURES:Daily sleep quality was rated on a scale of 0 (worst) to 10 (best) each morning. Participants completed end-of-day diaries each night that included several HRQOL measures (Sleep Disturbance, Sleep-related Impairment, Fatigue, Cognitive Abilities, Pain Intensity, Pain Interference, Ability to Participate in Social Roles and Activities, Depression, Anxiety) and ecological momentary assessment ratings of HRQOL (pain, fatigue, subjective thinking) 3 times throughout each day. RESULTS:Multilevel models indicated that fluctuations in sleep quality (as determined by end-of-day ratings) were significantly related to next-day ratings of HRQOL; sleep quality was related to other reports of sleep (Sleep Disturbance; Sleep-related Impairment; Fatigue) but not to other aspects of HRQOL. For ecological momentary assessment ratings, nights of poor sleep were related to worse pain, fatigue, and thinking. Generally, sleep quality showed consistent associations with fatigue and thinking across the day, but the association between sleep quality and these ecological momentary assessment ratings weakened over the course of the day. CONCLUSIONS:Findings highlight the important association between sleep and HRQOL for people with SCI. Future work targeting sleep quality improvement may have positive downstream effects for improving HRQOL in people with SCI.