ABSTRACT
STUDY OBJECTIVE: We tested the hypothesis that pre-existing chronic pain is associated with prolonged time to reach sustained acceptable pain scores after major surgery. DESIGN: Retrospective study using the German Network for Safety in Regional Anaesthesia and Acute Pain Therapy registry. SETTING: Operating rooms and surgical wards. PATIENTS: 107,412 patients recovering from major surgery who were cared for by an acute pain service. 3.3% of the treatments were in patients who reported chronic pain with functional or psychological impairment. INTERVENTIONS AND MEASUREMENT: We compared time to sustained adequacy of postoperative pain control defined by numeric rating scores <4 at rest and with movement in patients with and without chronic pain using an adjusted cox proportional hazard regression model and Kaplan-Meier analysis. The observation period was censored at 10 days and propensity score matching was used as a sensitivity analysis. MAIN RESULTS: Postoperative pain at rest took significantly longer to resolve in patients with chronic pain than in those without (adjusted hazard ratio HR 1.42, 95% CI 1.36-1.49, P < 0.001). Postoperative pain with movement took even longer to resolve in patients with chronic pain (adjusted HR 1.65, 95%CI 1.56-1.75, P < 0.001). CONCLUSIONS: Patients with chronic pain sustain more surgical pain than those without, and the pain takes longer to resolve. Clinicians providing postoperative pain management should consider the special needs of chronic pain patients.