Prognostic factors for upper limb and shoulder-specific disability and quality of life in participants suffering from frozen shoulder. A multicentric prospective single-cohort study

Background: Identifying prognostic factors for patient outcomes is crucial in research and clinical practice, as these variables significantly impact healthcare journeys. Aim: To investigate prognostic factors for upper limb and shoulder-specific disability and quality of life in patients with frozen shoulder (FS). Method: This multicentric prospective single-cohort study included 120 FS participants (72 females). Demographic and patient-related data were collected. Baseline upper limb and shoulder-specific disability (through DASH and SPADI scores) and quality of life (via EUROQoL 5D-5L) were dependent variables. Putative prognostic factors included daily pain, symptoms' duration, affected arm, kinesiophobia, symptom duration, comorbidities, and corticosteroid injections. Participants underwent 12 weeks of multimodal treatment. Multivariate linear regression, adjusted for age and gender, assessed variable associations. Results: Baseline DASH scores significantly predicted post-treatment upper limb disability (β = 0.317, 95 %CI 0.145 to 0.489). For SPADI, only baseline Tampa Scale was significant (β = 0.630, 95 %CI 0.146 to 1.113). Comorbidities were the sole significant predictor for EUROQoL 5D-5L (β = -0.739, 95 %CI -1.300 to -0.177). Conclusion: Baseline DASH scores predict future upper limb disability, while baseline kinesiophobia predicts shoulder-specific disability. Comorbidities are a significant prognostic factor for quality of life. These findings enhance our understanding of FS prognosis under conservative treatment, facilitating a more precise medical approach.