Predicting Outcomes in Thyroidectomy and Parathyroidectomy: The Modified Five-Point Frailty Index Versus American Society of Anesthesiologists Classification

Introduction: Thyroidectomy and parathyroidectomy are relatively safe procedures, with overall morbidity rates of 2%-5%. The increasing age is associated with higher likelihood of poor outcomes. The modified five-point frailty index (mFI-5) is associated with complications, but many surgeons are unfamiliar with mFI-5. We assessed the accuracy of the mFI-5 versus the commonly-used American Society of Anesthesiologists (ASA) classification to predict complications following thyroidectomy and parathyroidectomy.

Methods: Patients undergoing thyroidectomy or parathyroidectomy in 2015-2018 NSQIP datasets were identified. The mFI-5 scores were calculated by adding the number of the following comorbidities: congestive heart failure, hypertension requiring medication, chronic obstructive pulmonary disease, diabetes, and nonindependent functional status. Receiver operating characteristics curves were plotted for 30-d mortality and serious morbidity (defined as deep surgical site infection, dehiscence, unplanned intubation, failure to wean from the ventilator 48-h postoperatively, acute renal failure, pneumonia, pulmonary embolism, myocardial infarction, cardiac arrest requiring cardiopulmonary resuscitation, sepsis, septic shock, cerebrovascular accident, or reoperation) using mFI-5 and ASA classification. Areas under these curves (AUC) were compared.

Results: Ninety-two thousand, six hundred and ninety-one patients were studied. The mFI-5 and ASA were fair predictors of 30-d mortality (AUC 0.75 and 0.82, respectively) and good predictors of serious morbidity (AUC 0.61 and 0.64). After stratification by age, ASA was superior to mFI-5 in predicting mortality for patients aged 65, 70, 80 y, and older, for the entire population and for thyroidectomy and parathyroidectomy separately.

Conclusions: The ASA classification is a better predictor of mortality and serious morbidity than mFI-5 among patients undergoing thyroidectomy or parathyroidectomy and may be a better prognostic indicator to use when counseling patients before low-risk neck surgery.