Abstract 11759: Survival Among Medicare Beneficiaries After Out-of-Hospital Cardiac Arrest Undergoing Interhospital Transfer

Abstract

Intro: Among individuals treated for out-of-hospital cardiac arrest (OHCA), there is hospital-level variability in mortality, but the relationship between interhospital transfer (IHT) OHCA volume and survival remain unclear. We sought to examine the association of OHCA volume and survival for individuals undergoing IHT. Methods: Utilizing age-eligible Medicare fee-for-service claims, we identified an emergency department treated OHCA cohort using ICD-9/10 diagnosis codes. Hospital OHCA volume was defined as the total number of index (first-treated) OHCA claims during the study period and were binned into quartiles. Each claim was assigned the OHCA volume quartile of the index hospital and the index volume of the receiving hospital. Multiple logistic regression was conducted to assess the association between initial and receiving hospital volume categories and survival to 30 days among IHT patients while controlling for patient-level characteristics (age, sex, race), comorbidity index, urbanicity of index hospital and days to transfer. Results: We identified a cohort of 222,018 claims at 4,461 hospitals between 1/2013-12/2015. Median age was 78 years (IQR 71-85); 44% were female; 11% of the cohort was alive at 30 days. IHT occurred in 12,245 cases (5.5%) and 59% of transfers occurred on the day of admission or day 1. Transfers originated from 3411 index hospitals and 1566 receiving hospitals. Median OHCA hospital index volume was 25 [IQR 9, 67]. Adjusted odds of survival at 30 days was significantly lower at index hospitals with lower OHCA volumes compared to the highest volume category (aOR [95%CI] Q2: 0.71 [0.6, 0.83] p<0.001). Additionally, odds of survival at 30 days was significantly lower at low volume receiving hospitals (aOR [95%CI] Q1: 0.73 [0.55, 0.99] p<0.001), and increased for higher OHCA volume receiving hospitals, but these groups did not achieve statistical significance. Conclusion: For Medicare beneficiaries who suffer an OHCA and undergo IHT, lower index and receiving hospital OHCA volume was significantly associated with decreased adjusted odds of 30-day survival. Further exploration of hospital characteristics, timing, and transfer patterns is needed to understand differences in benefit for OHCA patients undergoing IHT.