Interpreting the risk analysis index of frailty in the context of surgical oncology

Preoperative Frailty and Malnutrition in Surgical Oncology Patients Predicts Higher Postoperative Adverse Events and Worse Survival: Results of a Blinded, Prospective Trial

BACKGROUND

Frailty, a multidimensional state leading to reduced physiologic reserve, is associated with worse postoperative outcomes. Despite the availability of various frailty tools, surgeons often make subjective assessments of patients' ability to tolerate surgery. The Risk Analysis Index (RAI) is a validated preoperative frailty assessment tool that has not been studied in cancer patients with plans for curative-intent surgery.

METHODS

In this prospective, surgeon-blinded study, patients who had abdominal malignancy with plans for resection underwent preoperative frailty assessment with the RAI and nutrition assessment by measurement of albumin, prealbumin, and C-reactive protein (CRP). Postoperative outcomes and survival were assessed.

RESULTS

The study included 220 patients, 158 (72%) of whom were considered frail (RAI ≥21). Frail patients were more likely to be readmitted within 30 and 90 days, (16% vs. 3% [P = 0.006] and 16% vs. 5% [P = 0.025], respectively). Patients with abnormal CRP, prealbumin, and albumin experienced higher rates of unplanned intensive care unit admission (CRP [27% vs. 8%; P < 0.001], albumin [30% vs. 10%; P < 0.001], prealbumin [29% vs. 9%; P < 0.001]) and increased postoperative mortality at 90 and 180 days. Survival was similar for frail and non-frail patients. In the multivariate analysis, frailty remained an independent risk factor for readmission (hazard ratio, 5.58; 95% confidence interval, 1.39-22.15; P = 0.015). In the post hoc analysis using the pre-cancer RAI score, the postoperative outcomes did not differ between the frail and non-frail patients.

CONCLUSION

In conjunction with preoperative markers of nutrition, the RAI may be used to identify patients who may benefit from additional preoperative risk stratification and increased postoperative follow-up evaluation.

A Retrospective Cohort Study to Evaluate Adding Biomarkers to the Risk Analysis Index of Frailty

INTRODUCTION

The Risk Analysis Index (RAI) is a frailty assessment tool associated with adverse postoperative outcomes including 180 and 365-d mortality. However, the RAI has been criticized for only containing subjective inputs rather than including more objective components such as biomarkers.

METHODS

We conducted a retrospective cohort study to assess the benefit of adding common biomarkers to the RAI using the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database. RAI plus body mass index (BMI), creatinine, hematocrit, and albumin were evaluated as individual and composite variables on 180-d postoperative mortality.

RESULTS

Among 480,731 noncardiac cases in VASQIP from 2010 to 2014, 324,320 (67%) met our inclusion criteria. Frail patients (RAI ≥30) made up to 13.0% of the sample. RAI demonstrated strong discrimination for 180-d mortality (c = 0.839 [0.836-0.843]). Discrimination significantly improved with the addition of Hematocrit (c = 0.862 [0.859-0.865]) and albumin (c = 0.870 [0.866-0.873]), but not for body mass index (BMI) or creatinine. However, calibration plots demonstrate that the improvement was primarily at high RAI values where the model overpredicts observed mortality.

CONCLUSIONS

While RAI's ability to predict the risk of 180-d postoperative mortality improves with the addition of certain biomarkers, this only observed in patients classified as very frail (RAI >49). Because very frail patients have significantly elevated observed and predicted mortality, the improved discrimination is likely of limited clinical utility for a frailty screening tool.