ABSTRACT
Background/Case Studies: TACO is a leading cause of reported fatalities, presenting as respiratory distress with cardiogenic pulmonary edema. The objective was to assess TACO occurrence and potential risk factors among the U.S. population ages 65 and older transfused in the inpatient setting before and during COVID-19 pandemic. Study Design/Methods: This is a hypothesis-generating study utilizing large Medicare databases for January 1, 2011-December 31, 2021. Transfusions were identified by recorded procedure and revenue center codes, and TACO by diagnosis codes. We evaluated unadjusted TACO rates (per 100,000 inpatient transfusion stays): overall, 2 years pre- and during pandemic, by immunocompromised (IC) and COVID-19 status, calendar year, demographics, blood components and number of units. We also assessed inpatient mortality, Charlson Comorbidity Index (CCI) score, ICU/CCU admission, and length of stay (LOS). Fisher's exact tests were performed to compare rates, and Cochran-Armitage tests to ascertain trends by year, age, and units. Results/Findings: Of 13,352,710 inpatient transfusion stays, 12,483 had a TACO diagnosis, an overall rate of 93.5 per 100,000 stays, with 2-year pre- and pandemic rates of 122.7 and 117.4. The annual TACO rates ranged from 61.9 in 2011 to 122.3 in 2021 (p < 0.001). Rates by units increased from 47.2 for 1 unit to 200.8 for >9 units (p < 0.001). Rates by blood components were for convalescent plasma only: 26.5;platelets only: 52.3;plasma only: 64.5;RBCs only: 97.9;RBCs and plasma: 203.0;RBCs and platelets: 237.8;and RBCs, plasma, and platelets: 223.1. Rates by age group ranged from 69.8 for 65-69 to 118.2 for 85+ (p < 0.001). Rates among females and males were 102.2 and 82.8 (p < 0.001);whites and nonwhites: 98.0 and 71.7 (p < 0.001). For IC vs. non-IC, rates were 138.9 vs. 81.7 [rate ratio 1.7 (95% CI 1.6-1.8)]. During pandemic, TACO rates were 39.3 for transfusion stays with vs. 127.8 without COVID-19 (p < 0.001). TACO cases with vs. without COVID-19 were ages 85+ (18.1% vs. 25.0%), females (50.0% vs. 58.4%);had CCI>=3 (50.0% vs. 66.2%), ICU/CCU admission (69.4% vs. 59.3%), mechanical ventilation (40.3% vs. 11.1%), LOS>=11 - days (51.4% vs. 28.1%), and inpatient mortality (45.8% vs. 8.5%). Conclusion(s): Our 11-year population-based study shows significantly increasing TACO trends over time, with greater number of units and advancing age. The study identified similar TACO risk during and pre-pandemic. By components, the highest TACO risk was for RBCs, either alone or in combination, while one of the lowest risks was for convalescent plasma only. Findings show higher rates for IC vs. non-IC, females vs. males, and whites vs. non-whites. For stays with COVID-19, TACO rates were substantially lower, but with marked case severity, which requires further investigation.