Abstract
Introduction There is inadequate data about outcome predictors for rotator cuff (RC) tendinopathy recovery. This international prospective cohort study aimed to determine outcome predictors of RC tendinopathy recovery and build an explanatory model.
Materials and Methods After completing the baseline survey, which included over 40 potentially plausible bio-psycho-social and demographic variables, recovery was assessed using the Global Rating of Change scale at monthly follow-ups for one year. Univariate cox proportional-hazards regression was used to analyse individual predictive associations, and multivariate cox regression was used for model building. Bootstrapping was used for internal validity.
Results 73 people with RC tendinopathy (43.9±14.0 years; 45 females; Shoulder Pain and Disability Index = 37.7±24.4) provided 15,284 days total analysis time at risk (208±129 days). Recovery rate was 47%, occurring around the 7th month. According to the final model, higher health status (HR = 1.03) and being moderately active (HR = 2.23) were associated with RC tendinopathy recovery. The internal validity showed that there was minimal overestimation in the predicted outcome (average optimism=0.01). The model partially predicted RC tendinopathy recovery with almost acceptable performance (optimism-corrected Harrell’s C discrimination = 0.66 and Calibration Slope = 0.99).
Conclusion Self-reported online surveys may be useful to understand RC tendinopathy prognosis. The combination of self-reported factors, including activity level and health status, partially predicted RC tendinopathy recovery. Therefore, these modifiable self-reported variables could help guide clinical decision making.
