Looking beyond the eyeball test: A novel vitality index to predict recovery after esophagectomy

To (1) measure 4 physiologic metrics before esophagectomy, (2) use these in an index to predict composite postoperative outcome after esophagectomy, and (3) compare predictive accuracy of this index to that of the Fried Frailty Index and Modified Frailty Index.

Grip strength (kilograms), 30-second chair sit-stands (number), 6-minute walk distance (meters), and normalized psoas muscle area (cm²/m) were measured for 77 consenting patients from January 1, 2018, to April 1, 2019. Imbalanced random forest classification estimated probability of a composite postoperative outcome, which included mortality, respiratory complications, anastomotic leak, delirium, length of stay ≥14 days, discharge to nursing facility, and readmission. G-mean error was used to compare predictive accuracy among indexes.

Median grip strength was 38 kg (25th-75th percentiles, 31-44), number of sit-stands 11 (10-14), psoas muscle area to height ratio 6.9 cm²/m (6.0-8.2), and 6-minute walk distance 407 m (368-451). There was generally weak correlation between these metrics, with the highest between 30-second sit-stands and 6-minute walk distance (r = 0.57). Age, degree of patient-reported exhaustion, and the 4 objective metrics comprised the Esophageal Vitality Index, which had a lower G-mean error of 32% (31-33) than the Fried Frailty Index, 37% (37-38), and the Modified Frailty Index, 48% (47-48).

The Esophageal Vitality Index, an objective, simple assessment consisting of grip strength, 30-second chair sit-stands, 6-minute walk, and psoas muscle area to height ratio outperformed commonly used frailty indexes in predicting postesophagectomy mortality and morbidity. The index provides a robust picture of patients' fitness for surgery beyond the qualitative "eyeball" test.