Finding Predictive Factors of Stabilization Exercise Adherence in Randomized Controlled Trials on Low Back Pain: An Individual Data Reanalysis Using Machine Learning Techniques.

OBJECTIVE

To identify predictors of adherence in supervised and self-administered exercise interventions for individuals with low back pain.

DESIGN

Cohort study.

SETTING

Rehabilitation.

PARTICIPANTS

This preplanned reanalysis within the Medicine in Spine Exercise Network included 1511 participants with low back pain (57% female, mean age 40.9 years, SD ±14 years).

INTERVENTIONS

Participants underwent an initial 3-week supervised phase of sensorimotor exercises, followed by a 9-week self-administered phase.

MAIN OUTCOME MEASURES

Biological, psychological, and social factors potentially impacting training adherence were evaluated. During the supervised phase, adherence was tracked through a standardized training log. During the self-administered phase, adherence was monitored via a diary, with adherence calculated as the percentage of scheduled versus completed sessions. Adherence was analyzed both as an absolute percentage and as a dichotomized variable (adherent vs nonadherent, with a 70% adherence cut-off). Predictors for adherence were identified using Gradient Boosting Machines and Random Forests (R package caret). Seventy percent of the observations were used for training, whereas 30% were retained as a hold-out test-set.

RESULTS

The average overall adherence was 64% (±31%), with 81% (±28%) adherence during the supervised phase and 58% (±39%) in the self-administered phase. The root mean square error for the test-set ranged from 36.2 (R=0.18, self-administered phase) to 19.3 (R=0.47, supervised phase); prediction accuracy for dichotomized models was between 64% and 83%. Predictors of low to intermediate adherence included poorer baseline postural control, decline in exercise levels, and fluctuations in pain intensity (both increases and decreases).

CONCLUSION

Identified predictors could aid in recognizing individuals at higher risk for nonadherence in low back pain exercise therapy settings.