Clinical risk score for postoperative pneumonia following heart valve surgery

Background:Postoperative pneumonia(POP)is one of the most common infections following heart valve surgery(HVS)and is associated with a significant increase in morbidity,mortality,and health care costs.This study aimed to identify the major risk factors associated with the occurrence of POP following HVS and to derive and validate a clinical risk score.Methods:Adults undergoing open HVS between January 2016 and December 2019 at a single institution were enrolled in this study.Patients were randomly assigned to the derivation and validation sets at 1:1 ratio.A prediction model was developed with multivariable logistic regression analysis in the derivation set.Points were assigned to independent risk factors based on their regression coefficients.Results:POP occurred in 316 of the 3853 patients(8.2%).Multivariable analysis identified ten significant predictors for POP in the derivation set,including older age,smoking history,chronic obstructive pulmonary disease,diabetes mellitus,renal insufficiency,poor cardiac function,heart surgery history,longer cardiopulmonary bypass,blood transfusion,and concomitant coronary and/or aortic surgery.A 22-point risk score based on the multivariable model was then generated,demonstrating good discrimination(C-statistic:0.81),and calibration(Hosmer-Lemeshowχ^(2)=8.234,P=0.312).The prediction rule also showed adequate discriminative power(C-statistic:0.83)and calibration(Hosmer-Lemeshowχ^(2)=5.606,P=0.691)in the validation set.Three risk intervals were defined as low-,medium-,and high-risk groups.Conclusion:We derived and validated a 22-point risk score for POP following HVS,which may be useful in preventive interventions and risk management.Trial Registration:Chictr.org,ChiCTR1900028127;http://www.chictr.org.cn/showproj.aspx?proj=46932.