PAIN INTENSITY, FUNCTIONAL DISABILITY, AND QUALITY OF LIFE IN ADULTS WITH CHRONIC NON-SPECIFIC LOW BACK PAIN ATTENDING OUTPATIENT PHYSIOTHERAPY CLINICS: A CROSS-SECTIONAL STUDY

Abstract

Background: Chronic non-specific low back pain (CNSLBP) is a leading cause of disability worldwide, yet comprehensive data examining the interplay of pain, functional limitation, psychosocial factors, and health-related quality of life in South Asian populations remain scarce. This cross-sectional study investigated the relationships among pain intensity, functional disability, and quality of life, while identifying key physical and psychological predictors in adults with CNSLBP attending outpatient physiotherapy clinics.

Methods: A total of 130 adults (65 male, 65 female) aged 22-68 years with CNSLBP exceeding 12 weeks were recruited from outpatient physiotherapy clinics. Pain intensity was measured using the Numeric Pain Rating Scale (NPRS), functional disability using the Oswestry Disability Index (ODI), and health-related quality of life using the SF-36. Secondary measures included the Fear-Avoidance Beliefs Questionnaire (FABQ), Pain Catastrophizing Scale (PCS), Pittsburgh Sleep Quality Index (PSQI), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), body mass index (BMI), lumbar range of motion (ROM), and the Sorensen trunk endurance test. Descriptive statistics, Pearson correlations, independent samples t-tests, ANOVA, and multiple linear regression analyses were performed (alpha = 0.05).

Results: The mean pain intensity was 6.43 +/- 1.71 (NPRS), mean ODI was 54.11 +/- 14.60, and mean SF-36 score was 40.76 +/- 13.94. The majority of participants (85.4%) demonstrated moderate-to-severe disability, and all participants reported at least moderate pain. Pain intensity demonstrated strong positive correlations with ODI (r = 0.866, p < 0.001) and strong negative correlations with SF-36 (r = -0.923, p < 0.001). In the multiple regression model for ODI, pain intensity (beta = 0.414, p < 0.001) and BMI (beta = 0.292, p < 0.001) were the strongest significant predictors, collectively explaining 84.9% of variance. Pain and ODI were the only significant predictors of quality of life (R-squared = 0.883).

Conclusions: Pain intensity and BMI are the dominant independent predictors of functional disability in CNSLBP, while pain and disability together predominantly determine quality of life. These findings underscore the importance of multidimensional assessment incorporating both physical and psychosocial dimensions, and support early targeted interventions addressing pain management and weight optimization in this population