Prognostic Factors of Prolonged Disability in Patients With Chronic Low Back Pain and Lumbar Degeneration in Primary Care

Study Design. A cohort study with 1-year follow-up. Objective. To identify prognostic factors in patients with chronic nonspecifi c low back pain (LBP). Summary of Background Data. The factors (e. g., sociodemographical, low back-related, radiological, and biological) associated with persistent pain and disability for patients with chronic nonspecifi c LBP are uncertain. Furthermore, sparse information exists about the relationship between biological factors like impaired fasting glucose tolerance and chronic nonspecifi c LBP. Methods. The participants consisted of 250 patients with nonspecifi c LBP of more than 6 months duration and degenerative lumbar osteoarthritis. The patients were originally recruited for a randomized controlled trial from the clinics of general practitioners, physiotherapists, and chiropractors. Potential predictors were evaluated at baseline. The outcome was absolute level of pain-related disability (Roland-Morris Disability Questionnaire [RMDQ]) at 1 year. The association between potential prognostic factors and the outcome was analyzed with multivariate linear backward regression. Results. At baseline and 1 year, the RMDQ scores were 9.5 and 5.1 points, respectively. Mean (SD) baseline values for body mass index (BMI), EuroQol (EQ)-index, EQ-visual analogue scale were 25.4 (4.3), 0.60 (0.3), and 61.2 (20.8), respectively. Higher pain-related disability levels (1-year RMDQ score) were associated with 6.1 mmol/L or more fasting glucose level at baseline (beta, 3.7; 95% confidence interval [CI], 1.2-6.1; P = 0.00), baseline pain-related disability (beta 0.2; 95% CI, 0.1-0.4; P = 0.00), BMI (a, 0.2; 95% CI, 0.1-0.3; P < 0.03), EQ-index (beta, -4.5; 95% CI, 6.9 to 2.1; P = 0.00), and EQ-visual analogue scale (beta, 0.3; 95% CI, -0.6 to -0.0; P = 0.03). However, a limited number of patients had 6.1 mmol/L or more of fasting glucose level at baseline (13/250 patients). The imaging findings, modic changes, and high intensity zones had no predictive ability. Conclusion. Increased pain-related disability at 1 year was seen in patients with impaired fasting glucose tolerance, greater painrelated disability, higher BMI, and lower quality of life at baseline.