Including modifiable and non-modifiable factors improves injury risk assessment in professional baseball pitchers.

OBJECTIVE to 1) evaluate an injury risk model that included modifiable and non-modifiable factors into an arm injury risk prediction model in Minor League Baseball (MiLB) pitchers; and 2) compare model performance separately for predicting the incidence of elbow and shoulder injuries. DESIGN Prospective cohort. METHODS A 10-year MiLB injury risk study was conducted. Pitchers were evaluated during preseason and pitches and arm injuries were documented prospectively. Non-modifiable variables included: arm injury history, professional experience, arm dominance, year, humeral torsion. Modifiable variables included: BMI, pitch count, total range of motion, and horizontal adduction. We compared modifiable, non-modifiable, and combined model performance by R2, calibration (Best = 1.00), and discrimination (Area Under the Curve (AUC); Higher number is better). Sensitivity analysis included only arm injuries sustained in the first 90 days. RESULTS 407 MiLB pitchers (141 arm injuries) were included. Arm injury incidence was 0.27 injuries per 1000 pitches. The arm injury model (Calibration 1.05 (0.81-1.30); AUC: 0.74 (0.69-0.80)) had improved performance compared to only using modifiable predictors (Calibration: 0.91 (0.68-1.14); AUC: 0.67 (0.62-0.73) and only shoulder ROM (Calibration: 0.52 (0.29, 0.75); AUC: 0.52 (0.46, 58)). Elbow injury model demonstrated improved performance (Calibration: 1.03 (0.76-1.33); AUC: 0.76 (0.69-0.83)) compared to the shoulder injury model (Calibration: 0.46 (0.22-0.69); AUC: 0.62 (95% CI: 0.55, 0.69)). The sensitivity analysis demonstrated improved model performance compared to the arm injury model. CONCLUSIONS Arm injury risk is influenced by modifiable and non-modifiable risk factors. The most accurate way to identify professional pitchers who are at risk for arm injury is to use a model that includes modifiable and non-modifiable risk factors.