Exploring Definitions of Acute Low Back Pain Severity as Predictors of Transition to Chronic Low Back Pain: A Community-Based Longitudinal Pilot Study

The characterization of acute low back pain (LBP) and its association with the transition from acute to chronic LBP is poorly defined. The purpose of this study is to explore acute LBP severity definitions and determine their performance as predictors of transition to chronic LBP in a community-based sample of adults. We enrolled 131 participants with acute (<4 weeks) LBP. We tested three binary definitions of acute LBP severity at baseline: two intensity-based (cut points at 40 or 30 on 0-100 numeric rating scale [NRS]), and one impact-based (limiting work or life activities). Chronic LBP was defined as LBP persisting at 3-month follow-up. We assessed performance of acute LBP severity definitions as predictors of transition to chronic LBP using sensitivity (SN), specificity (SP), negative predictive value (NPV), positive predictive value (PPV), area under the curve (AUC), risk ratios (RR), and differences in receiver operator curves (ROC). 32.2% of participants transitioned from acute to chronic LBP. Acute LBP intensity ≥40/100 definition had SN=57.9%, SP=78.8%, NPV=56.4%, PPV=56.4%, AUC=0.73, RR=2.25 (95% confidence interval [CI] 1.51, 3.34). Acute LBP intensity ≥30/100 definition had SN=79.0%, SP=73.8%, NPV=88.1%, PPV=58.8%, AUC=0.76, RR=3.13 (95%CI: 1.84, 5.30). Acute LBP impact-based definition had SN=10.5%, SP=95.0%, NPV=69.1%, PPV=50.0%, AUC=0.65, RR=1.67 (95%CI: 1.16, 2.42). Differences between ROCs indicated greater discriminative ability for ≥30/100 compared to the impact-based (p=0.03) and the ≥40/100 definitions (p=0.02). The acute LBP ≥30/100 intensity-based definition demonstrated superior overall performance compared to other acute LBP severity definitions. These findings may be used to improve prognostic prediction of acute LBP. Funding: 2R01 AR071440 and K24 AR079594.