Tossing and turning with degenerative arthropathy: an assessment of poor sleep quality in knee osteoarthritis

Objectives: To determine the frequency and predictors of sleep abnormalities among patients with knee osteoarthritis (OA) in Nigeria. Material and methods: A multi-centre, hospital-based, cross-sectional study, involving 250 knee OA patients. Consenting patients 18 years and above, who satisfied the American College of Rheumatology (ACR) criteria for knee OA were recruited from five Nigerian tertiary centres over 3 months. An interviewer-administered questionnaire was used to collect demographic and relevant clinical information. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality with scores ≥ 5 indicating poor sleep. Other variables assessed were pain, depression, functional class and family functioning. Data were summarized using appropriate measures of central tendency and dispersion. Multiple logistic regression analysis was done to identify predictors of poor sleep. Analysis was done using SPSS version 21.0 with p < 0.05 considered significant. Study approval was obtained from the ethical committees of each of the study sites. Results: Participants included 209 females (83.6%) with mean age 59.9 ±10.6 years. One hundred and forty-one participants (56.4%) had PSQI scores ≥ 5 (poor sleep). This was significantly associated with depression (p < 0.001), level of education (p = 0.001), higher pain scores (p < 0.001), body mass index (p = 0.040), medial knee OA (p = 0.032) and patello-femoral OA (p = 0.002). Higher level of education, worse depression scores and higher WOMAC pain scores were the best predictors of poor sleep quality. Conclusion: Sleep quality was poor in over half of our knee OA patients and best predicted by depression, pain and level of education. Regular sleep quality assessment for knee OA patients is recommended.