Inguinal hernia repair among men: development and validation of a preoperative risk score for persistent postoperative pain

Purpose Persistent postoperative pain (PPP) is a prevalent complication after inguinal hernia repair. The aim of this study was to develop and validate a preoperative risk score for PPP. Methods We developed the risk score based on a cohort of 2,508 Danish men, who answered a questionnaire six months after inguinal hernia repair performed 2015-2016. PPP was defined as a numerical rating scale score >= 2 during activity six months postoperatively. Logistic regression analyses were undertaken to determine statistically significant predictors of PPP. Univariable analysis selected potential predictors with a p value <= 0.20, and a subsequent multivariable model was built using backward elimination with a criterion of p value < 0.10. We created a risk score based on the beta coefficients of the multivariable model. The risk score was validated internally using Hosmer-Lemeshow goodness of fit test, calibration belt test, and receiver operating characteristic curve analyses with 95% confidence intervals based on the bootstrap analysis. External validation was performed in a cohort of 293 men recruited preoperatively. Results Predictors of PPP were age 18-49 and 50-59 (versus >= 60) years (p < 0.001), total load lifted > 1,000 kg/day (p = 0.001), working in a bent-over position > 1 h/day (p < 0.001), leisure-time physical activity < 2 h/week (p = 0.009), increasing body mass index (per unit) (p < 0.003), and repair of recurrent hernia (p = 0.001).The preoperative risk score predicted risks of 6-61% in the development population. The model showed good internal and external validity. Conclusion The results suggest that the risk of PPP after inguinal hernia repair can be predicted using a preoperative risk score.

Automated summary

This study developed and validated a preoperative risk score for predicting persistent postoperative pain (PPP) after inguinal hernia repair. Factors such as age, physical activity, and obesity were found to be associated with PPP. The preoperative risk score showed good internal and external validity in predicting the risk of PPP.