Association between pain and disability in patients with chronic mechanical low back pain

Abstract

INTRODUCTION AND OBJECTIVES: Low back pain is the leading cause of years lived with disability in developed countries as well as in South Asian countries. The aim of this study is to evaluate the association between the intensity of pain and disability in patients with chronic mechanical low back pain (CMLBP) who attended the rheumatology clinic, National Hospital of Sri Lanka (NHSL). METHOD: This is a descriptive study on 675 patients with CMLBP who attended the rheumatology clinic, NHSL, from May 2012 to May 2014, recruited according to inclusion and exclusion criteria. Intensity of pain was measured using the 101-point numerical pain rating scale (NRS) and the disability was measured using the modified Oswestry Disability Index (MODI). A multiple linear regression model adjusted for age, gender, level of education, duration and frequency of pain and duration of treatment was used to assess the association between the intensity of pain and disability. RESULTS: Majority (482, 71.4%) were females. Mean age was 49.19 ± 11.75 years. Mean score for NRS was 46.79 ± 20.38 and for MODI was 31.77 ± 14.16, while 84.3% had daily pain. Intensity of pain was positively associated with the disability (p<0.01) and the standardized regression coefficient was +0.627 after adjusting for confounders. Frequency of pain, female gender and aging were positively associated with disability (p<0.05) while level of education, and durations of pain and treatment did not reach significant level. Conclusion: Intensity of pain explains 63% of the disability associated with CMLBP. Frequency of pain, female gender and age were also associated with disability.