Background Knee osteoarthritis (OA) is a degenerative disease in which pain and functional disability progression tend to increase with reducing the health-related quality of life (HRQOL). Factors related to healthy lifestyles, such as physical activity and sleep, are known to have restorative benefits on function and pain in these patients. A previous study found that patients with reparative sleep achieved better WOMAC and SF-36 HRQOL questionnaire dimension scores.
Objectives To determine the influence of physical activity and sleep on functional capacity and pain in patients with long-term knee OA.
Methods Cross-sectional study. Sociodemographic and clinical variables, physical activity (PA) (regular physical exercise ≥3 times a week ≥30 minutes per session (PE) and sitting ≤6 hours/day [S]) and sleep quality/reparative sleep (RS) were determined using the question: How do you usually sleep? (1=well [RS], 2=regular, 3=badly, 4 =with medication/treatment [NRS]). Functional capacity and pain were evaluated using the WOMAC (specific) and SF-36 (generic) HRQOL questionnaires. Associations were analysed using multiple regression models.
Results 453 patients (84.3% female), mean age 69.73 (8.4), BMI 35.27 [SD 6.3], comorbidities 2.43 (SD 1.5), 78.6% with obesity (BMI 33.68 [SD 6.7]), depression/anxiety in 36.4%, PE 60.5%, S 72.2% and PA 48.6%, were included. 22.5% reported RS. Bivariate analysis showed patients with PA and those with RS had better functional capacity and less pain intensity (>10, p>0.001, in both WOMAC and SF-36). The four multiple regression showed that patients with PA and SR had better scores, both in functional capacity (dependent variables, WOMAC and SF-36) and pain (dependent variables, WOMAC and SF-36), p<0.006. Age, gender, number of comorbidities and obesity were included in the models as potential confounders. Obesity was associated with worse function and more pain in the four models (p<0.05). Being female and greater comorbidity were associated with poorer functional capacity and pain assessed by the SF-36.
Conclusions Physical activity and sleep were associated with less pain and better functional capacity, suggesting these variables should be determined systematically in clinical practice due to their significant relationship with HRQOL. Obesity was negatively associated with function and pain. There was also a negative relationship between female gender and comorbidity according to the SF-36. Differences in generic and specific questionnaires mean they should be used together to provide more detailed information.
Acknowledgements This work was funded by project PI/13/00948, integrated in the Plan Nacional I+D+I and cofounded by ISCIIISubdirecciόn General de Evaluaciόn and European Regional Development Fund (ERDF).
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Disclosure of Interest None declared