STUDY DESIGN: Prospective, longitudinal, observational cohort. OBJECTIVES: Primary aims were to determine (1) baseline prevalence of directional preference (DP) or no directional preference (no-DP) observed for patients with low back pain whose symptoms centralized (CEN), did not centralize (non-CEN), or could not be classified (NC), and (2) to determine if classifying patients at intake by DP or no-DP combined with CEN, non-CEN, or NC predicted functional status and pain intensity at discharge from rehabilitation. BACKGROUND: Although evidence suggests that patient response classification criteria DP or CEN improve outcomes, previous studies did not delineate relations between DP and CEN findings and outcomes. METHODS: Eight therapists classified patients using standardized definitions for DP and CEN. Prevalence rates for DP and no-DP and CEN,non-CEN, and NC were calculated. Ordinary least-squares multivariate regression models assessed whether multilevel classification combining DP and CEN (DP/CEN, DP/non-CEN, DP/NC, no-DP/non-CEN, and no-DP/NC categories) predicted discharge functional status (scale range, 0 to 100, with higher values representing better function) or pain intensity (scale range, 0 to 10, with higher values representing more pain). RESULTS: Overall prevalence of DP and CEN was 60% and 41%, respectively. For those with DP, prevalence rates for DP/CEN, DP/non-CEN, and DP/NC were 65%, 27%, and 8%, respectively. The amount of variance explained (R² values) for function and pain models was 0.50 and 0.39, respectively. Compared to patients classified as DP/CEN, patients classified as DP/non-CEN or no-DP/non-CEN reported 7.7 and 11.6 functional status units less at discharge (P<.001), respectively, and patients classified as no-DP/non-CEN reported 1.7 pain units more at discharge (P<.001). CONCLUSIONS: Findings suggest that classification by pain pattern and DP can improve a therapist’s ability to provide a short-term prognosis for function and pain outcomes. LEVEL OF EVIDENCE: Prognosis, level 1b–.

J Orthop Sports Phys Ther 2011;41(1):22-31, Epub 22 October 2010. doi:10.2519/jospt.2011.3415

KEY WORDS: computerized adaptive testing, lumbar spine, outcomes