Sleep quality in patients with chronic low back pain: a cross-sectional study assesing its relations with pain, functional status and quality of life.

Objective: The aim of this study was to investigate sleep quality in patients with chronic low back pain (CLBP) and its relationship with pain, functional status, and health-related quality of life (HRQOL).
Methods: Two hundred patients with CLBP aged 20-78 years (mean: 50.2 years) and 200 sex- and age-matched pain-free healthy controls (HCs) aged 21-73 years (mean: 49.7 years) were included in this study. After lumbar region examination, in patients, pain was evaluated with the Short Form-McGill Pain Questionnaire (SF-MPQ), functional capacity with the Functional Rating Index (FRI), and health-related quality of life with the Short Form-36 (SF-36). The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality of both groups.The sleep quality was compared between the patients and HCs. In patients with CLBP, its relations with pain, functional status and HRQOL were also investigated.
Results: The patients had significantly higher total scores (8.1 ± 4.3, 4.6 ± 3.4, P< 0.001, respectively) and subscale scores (P< 0.001) for PSQI compared to HCs. The groups were only similar in use of sleeping medication (P> 0.05) Among the patients, sleep quality was worse in women, in the patients with complaints more than 11 years, in the patients with low back and two leg pain (P< 0.05). Mean scores of the FRI, SF-MPQ, and visual analog scale in the patients were 8.5 ± 3.0, 16.7 ± 8.0, 6.9 ± 1.2, respectively. The PSQI total scores of patients were positively related with both SF-MPQ and FRI scores (P< 0.001). Also, there were negative relationships between the physical component summary score of the SF-36 and all subscale scores of the PSQI, without sleep duration of PSQI (P< 0.001).
Conclusion: The sleep quality of patients with CLBP was worse compared to HCs, and there were positive relations between the sleep quality with pain and functional status. Also, the poor sleep quality had negative effect on the physical component of quality of life.