Predictors of dysfunction and health-related quality of life in the flexion pattern subgroup of patients with chronic lower back pain: The STROBE study

Findings about predictors of chronic lower-back pain (CLBP) were inconsistent and inconclusive in previous studies because patients with CLBP are heterogeneous. Subgrouping patients with CLBP, according to a CLBP classification system, might thus clarify the research findings. CLBP in the direction of lumbar flexion movement, that is, the flexion pattern, is common in clinical situations. Therefore, the purpose of this study was to determine the predictors of dysfunction (pain, disability) and health-related quality of life in the flexion pattern subgroup of patients with CLBP. A cross-sectional study of prospectively collected data. One hundred eight subjects in the flexion pattern subgroup of CLBP. Thirteen variables were measured: the visual analog scale (VAS), the Oswestry Disability Index (ODI), the Short Form-36 (SF-36), the Beck Depression Inventory (BDI), hip internal rotation range of motion, hip flexion range of motion, knee extension range of motion, knee extension with dorsiflexion range of motion, ratio forward flexion, knee extension strength, hip extension strength, hip flexion strength, and lumbopelvic stability. The models for predictors of lower-back pain in the CLBP flexion pattern subgroup included knee extension and the BDI as predictor variables that accounted for 8.1% of the variance in the VAS (P < .05); predictors for disability included the BDI, age, and hip flexion strength, which accounted for 21.2% of the variance in the ODI (P < .05); predictors for health-related quality of life included the BDI, sex, knee extension with dorsiflexion range of motion, and age, which accounted for 38.8% of the variance in the SF-36 (P < .05) in multiple regression models with a stepwise selection procedure. The current results suggest that knee extension, the BDI, age, hip flexion strength, knee extension with dorsiflexion, and sex should be considered when determining appropriate prediction, prevention, and intervention in the flexion pattern subgroup of patients with CLBP.