Utilization Trends: Teaching Hospitals Consistently Order More Lab Tests

A new study provides solid evidence for a long-held assumption about how hospitals consume lab tests: teaching hospitals utilize tests at a consistently higher rate than nonteaching hospitals.

The JAMA Study
Published in JAMA Internal Medicine on Nov. 13, the study uses a large statewide all-payer database identifying hospitalizations with a primary diagnosis of bacterial pneumonia (n = 24,118) or cellulitis (n = 19,211; from Jan. 1, 2014, to June 30, 2015) across 11 major teaching hospitals, 12 minor teaching hospitals and 73 nonteaching hospitals in Texas. The researchers selected these particular diagnoses, in part, because the associated conditions generally do not require specialized lab testing and are cause for admission into both teaching and nonteaching hospitals.

Findings
The researchers found that the mean number of lab tests per day varied significantly by hospital type and was highest for major teaching hospitals for both conditions (bacterial pneumonia: major teaching hospitals, 13.21 versus 8.92 at nonteaching hospitals; cellulitis: major teaching hospitals, 10.43 versus 7.29 at nonteaching hospitals). This association held for all levels of illness severity for both conditions, except for patients with cellulitis with the highest illness severity level. The size of the effect amounted to approximately 3.6 additional lab tests per day for pneumonia and 2.6 additional lab tests per day for cellulitis. Hospitals that had more lab tests Sordered for patients with pneumonia also had more lab tests ordered for patients with cellulitis.

Of the 11 major teaching hospitals, eight were above the mean number of lab tests performed across all hospitals for pneumonia and seven were above the mean number of lab tests performed across all hospitals for cellulitis.

Explaining the Disparity
The authors offered up some explanation for why teaching hospital utilization was so much higher. "Our data show that patients with pneumonia at major teaching hospitals are sicker, perhaps leading to learned behaviors by trainees of ordering more laboratory tests." But while higher rates of testing may be justified for a substantial fraction of teaching hospitals, the researchers add that the behavior may then spill over to less acutely ill patients "If this phenomenon exists it could complicate generalized efforts to reduce testing at academic medical centers and could even lead to harm if there is an overall non-targeted reduction in testing," according to the study authors.

Practical Market Impact
In a market with increased focus on value-based care and appropriate test utilization, targeted test reduction interventions are needed to ensure that patients are not receiving unnecessary testing. The authors also say that studying cultural factors in the training environments that may lead to increased use of lab tests is essential to understanding and controlling teaching hospital lab test utilization.