Background Acute hypoxic respiratory failure (AHRF) is associated with significant acute mortality. It is unclear whether later mortality is predominantly driven by pre-existing comorbid disease, the acute inciting event or is the result of AHRF itself.
Methods Observational cohort study of elderly US Health and Retirement Study (HRS) participants in fee-for-service Medicare (1998–2012). Patients hospitalised with AHRF were matched 1:1 to otherwise similar adults who were not currently hospitalised and separately to patients hospitalised with acute inciting events (pneumonia, non-pulmonary infection, aspiration, trauma, pancreatitis) that may result in AHRF, here termed at-risk hospitalisations. The primary outcome was late mortality—death in the 31 days to 2 years following hospital admission.
Results Among 15 075 HRS participants, we identified 1268 AHRF and 13 117 at-risk hospitalisations. AHRF hospitalisations were matched to 1157 non-hospitalised adults and 1017 at-risk hospitalisations. Among patients who survived at least 30 days, AHRF was associated with a 24.4% (95%CI 19.9% to 28.9%, p<0.001) absolute increase in late mortality relative to adults not currently hospitalised and a 6.7% (95%CI 1.7% to 11.7%, p=0.01) increase relative to adults hospitalised with acute inciting event(s) alone. At-risk hospitalisation explained 71.2% of the increased odds of late mortality, whereas the development of AHRF itself explained 28.8%. Risk for death was equivalent to at-risk hospitalisation beyond 90 days, but remained elevated for more than 1 year compared with non-hospitalised controls.
Conclusions In this national sample of older Americans, approximately one in four survivors with AHRF had a late death not explained by pre-AHRF health status. More than 70% of this increased risk was associated with hospitalisation for acute inciting events, while 30% was associated with hypoxemic respiratory failure.
- Assisted Ventilation
- Clinical Epidemiology
- Respiratory Infection
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TJI and DFMA contributed equally.
Contributors HP designed the study, analysed the data, interpreted the data and drafted the manuscript. DFM and TJI designed the study, interpreted the data and edited the manuscript for critical intellectual content. MWS and KML interpreted the data and edited the manuscript for critical intellectual content. TJI and DFM contributed equally.
Funding This work was supported by grants K08 GM115859 [HCP] and T32HL007749 [MWS] from the National Institutes of Health. The Health and Retirement Study is sponsored by the National Institute on Aging (U01 AG009740) and performed at the Institute for Social Research, University of Michigan.
Disclaimer The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the US government.
Competing interests None declared.
Ethics approval University of Michigan IRB approved this study. Informed consent was obtained on enrolment into Health and Retirement Study and again for Medicare linkage.
Provenance and peer review Not commissioned; externally peer reviewed.
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