Relationship Between Sleep, Pain, and Disability in Patients with Spinal Pathology

Objective: To characterize sleep and its relationship with disability and pain in patients with spine pathology.

Design: A survey study.

Setting: A university-based hospital spine clinic.

Participants: Subjects (N=121) with mixed-etiology spine pathology.

Interventions: Not applicable.

Main Outcome Measures: Self-reported disability (Oswestry Disability Index [ODI]), back and leg pain intensity, the effect of back or leg pain on function, and sleep (Pittsburgh Sleep Quality Index [PSQI]) assessments were completed.

Results: Severe disability was evident with a mean ODI ± SD of 54.9±14, with mean pain intensities ± SD of 50±30 mm and 54±27 mm of 100mm for the leg and back, respectively. The mean PSQI ± SD was 10.4±5.3, with 87% of participants scoring greater than the sleep-disordered threshold of 5. PSQI was correlated to ODI (r=.53, P<.001), and ODI without the sleep component (r=.47, P<.001). Six of the subscales of PSQI were all also significantly correlated to ODI (.25<r<.42, P<.05). Stepwise regression (ODI dependent variables; PSQI, pain intensity and function, age, body mass index as independent variables) was performed. PSQI was retained in the model along with 2 pain measures (r(2)=.50, P<.001). Substitution of the 7 subscales for the overall PSQI score revealed 2 subscales (sleep quality, use of sleep medications) as predictors of ODI (r(2)=.490, P<.001).

Conclusions: Despite its being intuitive that sleep disorders will be present in patients with spinal disorders, it was surprising that sleep quality was an independent predictor of disability along with pain. Furthermore, sleep quality is more closely correlated to disability than leg pain, which is the current focus of medical interventions.