Improvement and status at four months relate to probability of surgery and one year outcome: nationwide cohort of patients with subacromial pain syndrome

Introduction: First-line treatment for subacromial pain syndrome (SAPS) includes non-surgical interventions with surgery as a secondary option. The relationship between outcome of first line treatment and long-term outcomes remains unclear. We aimed to investigate the relationship between symptom improvement and symptom status 4 months after diagnosis and the probability of subsequent surgery and acceptable symptom status after 1 year. Methods: This is a population-based prospective cohort-study of patients with SAPS from Danish outpatient hospital clinics. The patients completed online questionnaires 4 months and 1 year after diagnosis, including data on symptom improvement (Global Impression of Change) and symptom status (Patient Acceptable Symptom State) at 4-month follow-up, symptom status at 1-year follow-up and information on surgery (yes/no) between 4-month and 1-year follow-up. We used logistic regression analyses, adjusted for potential confounders. Results: In total, 2244 patients completed a 1-year follow-up. Those who did not undergo surgery (n = 1406), those who had surgery before 4-month follow-up (n = 510), and those who had surgery between 4-month and 1-year follow-up (n = 223) had a 64%, 70% and 48% probability of reaching acceptable symptom status at 1-year follow-up, respectively. Symptom improvement or acceptable symptom status at 4-month follow-up significantly reduced the probability of surgery between 4-month and 1-year follow-up (OR 0.32 (95%CI: 0.23–0.46) and 0.26 (95%CI: 0.17–0.42)) and significantly increased the probability of acceptable symptom status at 1-year follow-up for patients not undergoing surgery (OR 1.46 (95%CI: 1.12–1.90) and 4.10 (95%CI: 3.14–5.36), respectively). Conclusion: Symptom improvement and acceptable symptom status after 4-month follow-up relate to a lower probability of surgery and a higher probability of acceptable symptom status.