乌鸦传媒

Treatment in the ICU was not associated with a survival advantage in patients hospitalized for acute myocardial infarction and those with COPD or heart failure exacerbations in a retrospective analysis of outcomes among more than 1.5 million Medicare recipients.

Findings from the study, published Feb. 17 in the , suggest that hospital intensive care units may be overused for these conditions, according to researcher , of the University of Michigan Medical Center, and colleagues.

On the other hand, suggested that ICUs may be underutilized in older patients hospitalized with pneumonia.

"These studies also show a lot of variation between hospitals in how ICUs are used," Valley told 乌鸦传媒. "It is clear that there are patients at certain hospitals admitted to ICUs that would do fine in the general ward, but identifying these patients remains a challenge."

He noted that older patients with COPD, heart failure or acute MI are routinely admitted to ICUs in some hospitals, but not in others.

Valley and colleagues examined 30-day mortality and cost of care in their analysis of 1,555,789 records of Medicare beneficiaries admitted to hospitals with COPD exacerbations, heart failure exacerbations, and acute MI between 2010 to 2012.

The retrospective, cohort study included multivariable adjustment and instrumental analysis of each of the three conditions.

"The instrumental variable analysis used differential distance to a high ICU use hospital (defined separately for each condition) as an instrument for ICU admission to examine marginal patients whose likelihood of ICU admission depended on the hospital to which they were admitted," the researchers wrote.

Instrumental variable analysis was used to test the effect of ICU admission on outcomes, because the decision to admit patients to the ICU is likely to be correlated with unmeasured severity of disease, the researchers explained -- thus raising the likelihood that standard multivariable regression results would produce biased estimates when compared to the instrumental variable model.

"Traditional risk adjustment techniques fail to fully address confounding in scenarios where treatment administration is strongly associated with severity of illness," they wrote.

Of the more than 1.5 million patients included in the analysis, 486,272 (31%) were admitted to ICUs.

The instrumental variable analysis found that:

• ICU admission was not associated with significant differences in 30-day mortality for any condition
• ICU admission was associated with significantly greater hospital costs for heart failure ($11,793 versus $9,185, P<0.001; absolute increase $2,608, 95% CI $1,377-$3,840) and acute MI ($19,513 versus $14,590, P<0.001; absolute increase $4,922 , 95% CI $2665-$7180), but not for COPD
• ICU admission did not confer a survival benefit for patients with uncertain ICU needs hospitalized with COPD exacerbation, HF exacerbation, or AMI

"In the instrumental variable analysis, hospital costs for heart failure and acute MI were one-third times greater with ICU admission than with general ward admission. We estimated that approximately 20-25 percent of patients hospitalized with heart failure or acute MI might be considered marginal," the researchers wrote.

"Combined with the lack of mortality benefit seen in patients with these conditions, these findings suggest that there is a substantial population of patients who are admitted to the ICU but could potentially be cared for in the general wards, resulting in higher healthcare costs."

The need to rely on administrative data, which may have under-identified or improperly identified patients, was cited by the researchers as a study limitation, along with the possibility that the instrumental variable analysis did not fully address the issue of unmeasured confounding.

Valley told 乌鸦传媒 that in addition to the increased costs associated with unnecessary ICU treatment, overuse of the ICU could also cause harm to patients who don't need to be there.

He added that the findings also highlight the fact that clinicians often have difficulty determining whether certain patients should be admitted to the ICU.

"The perception that ICUs are safer places for patients to be may drive ICU admissions, but we know that patients in ICUs are more likely to be exposed to dangerous infections, and they are more likely to receive invasive and potentially harmful procedures," he said.

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