Outcomes in Subgroups of Patients with Chronic Low Back Pain Treated With and Without Osteopathic Manipulative Treatment: A Retrospective Cohort Study

Purpose: Chronic low back pain (CLBP) is a public health issue that often causes disability and yields high societal costs due to lost productivity. Clinical practice guidelines in the United States recommend spinal manipulation as a first-line treatment for CLBP. Recent evidence demonstrates that osteopathic manipulative treatment (OMT) may reduce low back pain intensity and back-related disability in patients with CLBP. However, it is unclear if patient subgroups respond differently to OMT. This study aims to determine if OMT effects in patients with CLBP differ according to patient characteristics. Methods: This study was conducted within the Pain Registry for Epidemiological, Clinical, and Interventional Studies and Innovation between April 2016 and December 2021. A total of 1243 registry participants reported data on sociodemographic characteristics, psychological variables, and clinical status at enrollment, and 788 provided complete data over 12 months of follow-up. Participants were classified as OMT users or non-users at enrollment. The primary outcomes were low back pain intensity measured with a numerical rating scale (NRS) from 0 to 10, back-related functioning measured with the Roland-Morris Disability Questionnaire (RMDQ), and pain impact derived from the Patient-Reported Outcomes Measurement Information System. Repeated measures analysis of variance was used to assess longitudinal outcomes according to OMT use. Subgroup analyses were then performed using 14 pre-specified variables to identify interaction effects relating to OMT use. Results: At enrollment, 177 (14.2%) participants reported ever using OMT for CLBP. Osteopathic manipulative treatment use was less likely to be reported by Blacks (P< .001) and participants currently using NSAIDs for low back pain (P=.003). Overall, over 12 months, OMT users reported lower scores than non-users for low back pain intensity (NRS score mean difference, -0.54; 95% CI, -0.87 to -0.21; P=.001); back-related disability (RMDQ score mean difference, -2.10; 95% CI, -3.24 to -0.96; P< .001); and pain impact (mean difference, -2.67; 95% CI, -4.39 to -0.95; P=.002). Subgroup analyses showed that the only interaction effect involved gender. Male OMT users reported better outcomes (as compared with male non-users) than did female OMT users (as compared with female non-users) for all primary outcomes (NRS score mean difference for males, -1.12, 95% CI, -1.76 to -0.47 vs. -0.34; 95% CI, -0.72 to 0.04 for females; P=.04; RMDQ score mean difference for males, -4.29, 95% CI, 6.51 to -2.07 vs. -1.33, 95% CI, -2.65 to -0.01 for females; P=.02; pain impact score mean difference for males, -5.75, 95% CI, -9.10 to -2.40 vs. -1.58, 95% CI, -3.57 to 0.40 for females; P=.04). Conclusion: Patients who were current or former users of OMT reported better longitudinal outcomes over 12 months relating to low back pain intensity, back-related disability, and pain impact. Subgroup analyses found that OMT use (vs. non-use) consistently yielded better longitudinal outcomes in males than in females. However, none of the other 13 pre-specified variables was associated with a significant interaction for OMT effect.