Predictive power of modified frailty index score for pulmonary complications after major abdominal surgery in the elderly: a single centre prospective cohort study

OBJECTIVE: The primary aim of this prospective cohort study was to evaluate the usefulness of the modified Frailty Index (mFI) score to predict postoperative pulmonary complications (PPCs) in elderly patients undergoing major open abdominal surgery. The secondary purpose was to compare the prediction power of mFI, Ariscat (Assess Respiratory Risk in Surgical Patients in Catalonia), and American Society physical status classification (ASA) scores. PATIENTS AND METHODS: After local Ethical Committee approval, 105 patients aged ≥65 years undergoing open major abdominal surgery were enrolled. Clinical data were compared between patients with or without PPCs (including respiratory failure, aspiration pneumonia, pulmonary infection, pleural effusion, pneumothorax, atelectasis, bronchospasm or un-planned re-intubation). t-test or χ2-test were performed for univariate analyses. Logistic regression analysis was used to identify independent predictors of PPCs. Non parametric ROC (Receiver Operating Characteristic) was used for cut-off calculation. AUCs (areas under ROC curve) of preoperative scores were compared using χ2-test. RESULTS: PPCs prevalence (11.3%) was associated with increased mFI, ASA, and Ariscat scores, greater age, hemoglobin levels <10 g/dl, peripheral oxygen saturation <95% (p=0.0001) and longer surgery duration. Logistic regression showed that mFI (p=0.0001) and Ariscat (p=0.04) were independent predictors of PPCs. The predictive power of mFI (AUC=0.90) was similar to that of Ariscat (AUC=0.81) (χ2=2.53; p=0.11) but greater than that of ASA (AUC=0.69) (χ2=9.85; p=0.002). An mFI≥0.18 was predictive of PPCs (sensitivity=90.91%; specificity=79.07%). An Ariscat score of 27 was the cut-off identified as determining factor for PPCs occurrence (sensitivity=90.91%; specificity=51.16%). CONCLUSIONS: Elderly patients with an mFI ≥0.18 and/or an Ariscat score ≥27 were at higher risk of PPCs after open major abdominal surgery. More attention should be paid to these patients by implementing both strict monitoring and strategies for PPCs prevention in the perioperative period.