RESUMEN
OBJECTIVE: To assess whether sleep quality (SQ) at baseline is associated with improvement in pain and disability at 3 months. MATERIALS AND METHODS: Four hundred twenty-two subacute and chronic patients with neck pain (NP) were recruited in 32 physiotherapy, primary care, and specialized centers. NP, referred pain, disability, catastrophizing, depression, and SQ were assessed through validated questionnaires, upon recruitment and 3 months later. Correlations between baseline scores were calculated through the Spearman coefficient. Improvements in NP, disability, and SQ were defined as a reduction of ≥30% of baseline score. Six estimative logistic regression models were developed to assess the association between baseline SQ and improvement of NP, baseline SQ and improvement of disability, baseline NP and improvement of SQ, baseline disability and improvement of SQ, the evolutions of NP and SQ, and the evolutions of disability and SQ. RESULTS: Most patients were subacute and mildly impaired. Regression models showed that better SQ at baseline was associated with improvement of NP (odds ratio=0.91 [95% confidence interval, 0.83-0.99]), but not disability (1.04 [0.95-1.13]); the improvement of SQ was associated with more severe NP at baseline (1.26 [1.07-1.49)], but not with baseline disability (0.99 [0.97-1.02]); and that improvement in SQ was associated with improvements in NP (3.48 [1.68-7.20]), and disability (5.02 [2.39-10.11]). DISCUSSION: NP is less likely to improve in patients with poorer SQ, irrespective of age, sex, catastrophizing, depression, or treatments prescribed for NP. Future studies should confirm these results with more severely impaired patients.