JACR: More inpatient imaging could lower hospital mortality rates
Hospitals that more frequently use inpatient imaging exams could achieve lower in-hospital mortality rates, according to a study published in the November issue of the Journal of the American College of Radiology.

The researchers, David Lee, PhD, senior director for health economics and outcomes research at GE Healthcare, and David Foster, PhD, of Thomson Reuters of Ann Arbor, Mich., examined data from the Thomson Reuters Drug Database (HDD) exploring the relationship between the utilization of hospital imaging services and mortality and costs.

The HDD contains information that allows researchers to evaluate patient- and admission-level utilization from 580 U.S. hospitals based on more than 31 million hospital discharges. The authors examined data from 1.1 million inpatient admissions at 102 hospitals during 2007 that allowed them to assess the utilization of inpatient diagnostic imaging services in those cases.

The majority of patients in the study were female (53.7 percent), 32.8 percent were age 45 to 64 years, and another 29.9 percent were age 70 to 84. The hospitals in the survey ranged in size from less than 200 beds (26.5 percent) to more than 500 beds (12.8 percent). Most of the hospitals (70.6 percent) were in the southern U.S..

According to the authors, the use of any imaging services “seems to be more tightly correlated with lower mortality than the number of imaging services received,” suggesting that while some imaging “may be better than none”  there could be diminishing returns with additional imaging. In any event, the authors said, their results “suggest that performing imaging on more patients may improve outcomes.”

There could be several noncausal explanations for these findings, the authors said. For example, hospitals that make a practice of imaging more patients could be more likely to attract better doctors and staff members, or use better quality control systems, all of which could help improve patient outcomes.

The authors also said that the use of increased imaging services not only appears to be associated with lower mortality, but with little added cost. “Because providers are only compensated for the professional components of inpatient diagnostic services, the use of these services likely reflects their perceived clinical or cost-saving benefit,” the authors wrote.

There were limitations to the study, the authors said. Risk adjustment methods may have been incomplete and the authors suggested that “one might argue that a terminal patient would be less likely to receive an imaging service, and so mortality would be lower in imaged patients not because of the contribution of imaging to their care but simply because the patients most likely to die were selected out of the imaged population.”

On the other hand, the authors noted that heavy hospital resource use is more likely in the last year of life, and “it is reasonable to expect” that very sick patients could be more likely to be imaged than patients who are less ill.

The authors also pointed out that while their study included a large number of admissions, only a small percentage of hospitals--mostly from the southern U.S.--were represented in their study base.