Dose-response relationship and effect modifier of stabilisation exercises in non-specific low back pain: a project-wide individual patient data re-analysis on 1,483 intervention participants.

To derive a dose-response relationship under consideration of further effect modifiers in exercises on low back pain.In this planned MiSpEx-Network re-analysis, 1,483 intervention participants with low back pain (mean age 40.9 years (SD 14 years)) performed stabilisation exercises (3 weeks supervised, 9 weeks self-administered). Patients reported pain intensity, disability and disability days at baseline, 3 weeks, 12 weeks and 6 months post-randomisation. Exercise characteristics and effect modifiers were prospectively monitored. Beyond the comparison to the aggregated control group, linear mixed models were calculated to determine a dose-response-relationship.The interventions led to small but significantly larger symptom reductions than the control at each measurement. Longer durations of the intervention led to larger symptom reductions. Higher exercise frequencies were associated with a decrease in pain intensity: to train once more per week led to a mean decrease of 0.93 points in pain intensity [95% CI= -1.54 to -0.32]. Disability days were also impacted (estimate=-0.07 [-0.14 to 0.00]), disability was not (-0.09 [-0.67 to 0.48]). Adding perturbation was superior to adding stretching or a behavioural module. The relationships were robust when additional effect modifiers were considered and against the control group' effects. The odds ratio for a clinically important effect with higher exercise frequencies decreased at 3 weeks (OR=0.71 [0.618 to 0.813] for >2.5*week -1 ) and increased at 12 weeks (1.13 [1.006 to 1.270], >1.5*week -1 ).Using longer intervention durations, adding a perturbation component to the stabilisation trainings and utilising higher frequencies (up to a certain point) may lead to an even more beneficial response in patients with low back pain. Developing strategies to maintain a training frequency of at least two times per week may be relevant in stabilisation exercises to treat low back pain.