Variation of disability courses in Danish chiropractic patients with low back pain: a one-year cohort study with four follow-ups

The clinical course of low back pain (LBP) is highly variable. While some recover quickly, others experience prolonged or fluctuating disability. Understanding this heterogeneity, and the factors that influences it, is important for effective clinical management and for communicating realistic prognosis to patients. The aims of this study were to describe the variation in disability courses among chiropractic patients with LBP and to investigate how selected biopsychosocial characteristics measured at baseline can predict these courses and potentially explain the observed variation.

Longitudinal data from 2,777 Danish adults consulting chiropractors for a new episode of LBP were analysed. Disability was measured at baseline, 2, 13, and 52 weeks using the Roland Morris Disability Questionnaire (0-100 scale). Latent Class Analysis was applied to identify disability trajectories. Associations between baseline patient characteristics and trajectory class membership were examined across demographic, psychological and social domains. A post hoc composite index score was developed to summarize the cumulative burden of unfavourable baseline characteristics.

Nine distinct disability trajectories were identified, ranging from rapid recovery to persistent high disability, and fluctuating patterns. Six classes accounted for approximately 90% of patients, while three smaller classes with more irregular trajectories accounted for 10%. Higher number of MSK pain sites, comorbidities, and higher levels of BMI, depression, anxiety, kinesiophobia, prescription analgesic use, and poorer general health were associated with increased likelihood of belonging to less favourable trajectories. Both individual baseline characteristics and the index score combining these characteristics showed a clear dose-response relationship with disability trajectories. Patients with higher burden were more likely to follow less favourable trajectories. However, substantial variation remained within index groups, indicating that baseline characteristics alone cannot fully predict individual outcomes.

Among chiropractic patients with LBP, trajectories of disability over one year can vary substantially in pattern. Baseline biopsychosocial characteristics influence trajectories and prognosis in a cumulative, dose-dependent manner. Clinicians should be aware of this variability and tailor communication about expectations accordingly.