ICU Treatment for Medicare Patients with Pneumonia Associated with Better Outcomes without Increased Costs
The United States has seen considerable growth in ICU use over the last three decades, which partly may be in response to an aging population. Observational studies examining the relationship between ICU admission frequency and patient outcomes often suggest that greater ICU use does not achieve better outcomes; however, these findings may be subject to confounding by indication because sicker patients are more likely to be admitted to the ICU. This retrospective cohort study sought to determine the association between ICU admission and outcomes, 30-day mortality, and costs among Medicare beneficiaries hospitalized for pneumonia (n=1,112,394, ages 65 and older) in 2,988 acute-care U.S. hospitals from 2010 to 2012. To account for unmeasured confounding between groups (ICU vs. general ward admission), an instrumental variable (IV) was used – the differential distance to a high-ICU use hospital. [High-ICU use was defined as an ICU admission rate for pneumonia in the top two quintiles of the included hospitals.] Investigators also examined demographics, comorbid illness, severity of illness, type of pneumonia, and distance from a high-ICU hospital, in addition to hospital characteristics (i.e., medical school affiliation, teaching status, number of beds). The primary outcome was 30-day all-cause mortality measured from the time of hospital admission; secondary outcomes focused on costs.
- Among Medicare beneficiaries who were hospitalized with pneumonia, ICU admission of those for whom the decision appeared to be discretionary (those meeting the IV criteria above, approximately 13% of the total sample) was associated with improved survival and no significant difference in costs.
- Patients living closer (<3 miles) to a high-ICU hospital were significantly more likely to be admitted to the ICU than patients living farther away (36% vs. 23%) – this was the basis of the IV analysis.
- In the IV analysis, ICU admission was associated with significantly lower 30-day mortality compared to general ward admission (15% vs. 21%), with a reduction in 30-day mortality of 6%.
- In the IV analysis, ICU admission was not associated with significant differences in total payment to Medicare ($9,918 vs. $11,238, decrease of $1,320) or total hospital costs ($14,162 vs. $11,320, decrease of $2,842).
- Initial care may compensate for the increased daily cost of ICU care.
- Future studies will better define the patients who benefit from increased access, and clarify the mechanism through which ICU admission may reduce mortality.
- Administrative data were used, which may under-identify or improperly identify pneumonia patients.
- This study included only Medicare patients; results may not generalize to younger or VA patients.
This study was partly funded by HSR&D (IIR 11-109). Dr. Iwashyna is part of HSR&D's Center for Clinical Management Research, Ann Arbor, MI.
Valley T, Sjoding M. Ryan A, Iwashyna TJ, and Cooke C. Association of ICU Admission with Mortality among Older Patients with Pneumonia. JAMA. September 22/29, 2015;314(12):1272-79.Valley T, Sjoding M. Ryan A, Iwashyna TJ, and Cooke C. Association of ICU Admission with Mortality among Older Patients with Pneumonia. JAMA. September 22/29, 2015;314(12):1272-79.