LAUSR

No externally validated presurgical risk score for chronic postsurgical pain (CPSP) is currently available. We tested the generalizability of a six-factor risk model for CPSP developed from a prospective cohort of 2929 patients in four surgical settings. Seventeen centers enrolled 1225 patients scheduled for inguinal hernia repair, hysterectomy (vaginal or abdominal), or thoracotomy. The six clinical predictors were surgical procedure, younger age, physical health (Short Form Health Survey-12), mental health (Short Form Health Survey-12), preoperative pain in the surgical field, and preoperative pain in another area. CPSP was confirmed by physical examination at 4 months. The model's discrimination (c-statistic), calibration, and diagnostic accuracy (sensitivity, specificity and positive and negative likelihood ratios) were calculated to assess geographic and temporal transportability in the full cohort and two subsamples (historical and new centers). The full dataset after exclusions and losses included 1088 patients; 20.6% had developed CPSP at 4 months. The c-statistics (95% CI) were similar in the full validation sample and the two subsamples: 0.69 (0.65-0.73), 0.69 (0.63-0.74) and 0.68 (0.63-0.74), respectively. Calibration was good (slope b and intercept close to 1 and 0, respectively and nonsignificance in the Hosmer-Lemeshow goodness-of-fit test). The validated model based on six clinical factors reliably identifies risk for CPSP risk in about 70% of patients undergoing the surgeries studied, allowing surgeons and anesthesiologists to plan and initiate risk reduction strategies in routine practice and researchers to screen for risk when randomizing patients in trials.