Background/Purpose: Sleep is an important physiological process responsible for regulating several metabolic and hormonal processes; hence, poor sleep may negatively impact health. Reduced sleep duration and restless sleep (i.e., low sleep efficiency) has been related to a higher risk of cardiovascular disease (CVD) in the general population. Individuals with RA commonly report poor sleep quality, and also have greater CVD risk than their healthy counterparts. However, the relationship between sleep quality and CVD risk in RA is not clear. Thus, the aim of the study was to assess associations between objectively measured sleep quality (duration and efficiency) and CVD risk factors in RA.

Methods: This was a secondary, cross-sectional analysis of baseline data from two studies in persons diagnosed with RA based on the ACR classification criteria. Sleep duration and efficiency were measured using a multi-sensor activity monitor, the Sensewear Armband (Bodymedia, Pittsburgh), which has been validated against polysomnography as an accurate measure of sleep duration and efficiency. Sleep efficiency is expressed as a ratio of actual sleep time to lying down time. Subjects wore the monitor for 7 days and average daily sleep duration and efficiency were calculated. Cardiometabolic markers consisted of blood pressure, lipid profile, and insulin resistance measured by homeostatic model of assessment. Demographics, BMI, and disease severity using the DAS-28 were also obtained. Multiple linear regression models were used to determine the association between each cardiometabolic marker and sleep efficiency, and duration after adjusting for age, gender, cohort, BMI and DAS-28 scores.

Results: Complete data for data analysis was available  in 89 subjects with RA, (90% female, 58 ± 9 years, BMI 29 ± 7 kg/m²) who had mild functional limitations (HAQ score 0.8 ± 0.6), moderate disease activity (DAS-28 3.5 ± 1.2), and median RA duration of 15 years. Subjects spent 8.2 ± 1.5 hours lying down and 6.5 ± 1.4 hours in actual sleep, with a sleep efficiency of 80%. Adjusted models demonstrated that greater sleep efficiency significantly associated with lower low-density lipoproteins and higher high-density lipoproteins (p <. 05) (Table). In contrast, sleep duration was not associated with any cardiometabolic markers.

Conclusion: Poor sleep efficiency seems to be more indicative of non-favorable cardiometabolic markers in individuals with RA than sleep duration. Normal circadian rhythms are crucial for regulating several metabolic processes, including lipid metabolism. Hence, it stands to reason that poor sleep efficiency could directly influence certain cardiometabolic markers, independent of body size, and RA severity. Although the current study is limited due to its cross-sectional design, the findings indicate the need to further investigate the influence of sleep quality on CVD risk profile in RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/sleep-efficiency-and-cardiovascular-risk-burden-in-rheumatoid-arthritis/