Use of the Electronic Frailty Index (eFI) to identify older adults with increased healthcare needs after receiving CAR-T therapy.

Abstract

546 Background: Chimeric antigen receptor T-cell therapy (CAR-T) has transformed treatment for hematologic malignancies. Frailty is broadly associated with poor outcomes in older adults, but the relationship of frailty with healthcare utilization in patients receiving CAR-T remains incompletely characterized. Methods: We conducted a retrospective study of 260 patients aged ≥65 years receiving CAR-T at Massachusetts General Brigham (MGB) for B-cell non-Hodgkin lymphoma and multiple myeloma. We used data from the electronic health record to calculate the validated eFI, which produces a numeric score based on 31 age-related health deficits and categorizes patients as robust, pre-frail, frail, or very frail. We conducted multivariable analyses evaluating the association of frailty (robust/pre-frail vs frail vs very frail) with >1 hospitalization within 60 days of infusion and CAR-T admission length of stay (LOS) adjusting for age, sex, CAR-T product, baseline LDH, and ECOG performance status. We also assessed exploratory univariate associations of frailty with subsequent post-acute care (PAC), infection within 30 days, and ICU admission within 30 days. For analyses we considered outpatient CAR-T infusions as LOS of 0 days. Results: The eFI categorized patients as robust (10%), pre-frail (25%), frail (28%), and very frail (37%). In multivariable analyses compared to robust/pre-frail patients, very frail patients had significantly higher odds of >1 hospitalizations (OR=2.92, p<0.01) and significantly longer LOS (β =6.36 days, p<0.01); frail patients had significantly higher odds of >1 hospitalizations (OR=2.28, p<0.05) but did not have significantly longer LOS (β=2.51 days, p=0.15). In exploratory analyses compared to robust/pre-frail patients, frail patients had increased odds of PAC (OR=3.05, p<0.05) and infection within 30 days (OR=2.64, p=0.01) but not ICU admission (OR=8.06, p=0.06). Very frail patients had higher odds of PAC (OR=4.24, p<0.01), infection (OR=2.21, p=0.02), and ICU admission (OR=11.6, p=0.02). Conclusions: Frailty is associated with increased healthcare utilization in older adults who received CAR-T. The eFI is a promising tool for predicting patients who may require increased short-term healthcare needs following CAR-T infusion. Multivariable and univariable analyses assessing frailty and healthcare utilization following CAR-T. Outcome Category OR (95% CI), p value >1 hospitalizations within 60 days of CAR-T infusion Robust/prefrailFrailVery frail Reference2.28 (1.01-5.12), 0.0472.92 (1.33-6.39), 0.007 Length of stay for CAR-T hospitalization Robust/prefrailFrailVery frail Reference2.51 (-0.90-5.92), 0.1486.36 (3.04-9.67), <0.001