Impact of low back pain on health-related quality of life before and after treatment with an analgesic medication

Abstract

This post hoc analysis of two multicenter, randomized, double-blind, placebo-controlled trials assessed the burden of chronic low back pain (LBP) on health-related quality of life (HRQoL) before and after treatment with an analgesic. The pooled sample included 660 patients with chronic (>3 months), moderate-to-severe LBP (Pain Visual Analogue [PVA] scale score 40-100). Patients in both trials received an oral analgesic or placebo for 13 weeks. Baseline scores on the Short Form 36 Health Survey (SF-36) for trial participants were compared with: (1) U.S. normative scores for the general population; and (2) disease-specific benchmarks from the Medical Outcomes Study (MOS). Overall, patients with chronic LBP had significantly lower mean SF-36 scores than the U.S. norm for all scales (MANOVA F=289.2, p<0.001), including scores >1.5 standard deviations (SD) lower than the U.S. norm for most physical health scales. Patients with moderate-to-severe LBP in the clinical trials had greater HRQoL burden on most SF-36 scales compared with disease-specific benchmarks from patients in the MOS who had LBP (any severity), hypertension, congestive heart failure, type 2 diabetes, recent myocardial infarction, or depression. The burden of LBP was greater among trial patients who experienced more severe pain. SF-36 bodily pain scores were >2 SD lower than U.S. norms among patients with PVA scale scores between 80–100 mm; and they were >1 SD lower among those with PVA scale scores between 40-80 mm. Physical health domains had better discriminant validity than mental health domains. Statistically significant HRQoL benefits emerged in physical health domains when pain improved by 21–30 points on the PVA scale and clear improvement in all aspects of HRQoL occurred when pain improved by at least 31 points on the PVA scale. This analysis confirms the tremendous burden of chronic LBP on HRQoL and demonstrates that pain relief may reduce this major HRQoL burden.