Changing patterns of routine laboratory testing over time at children's hospitals

Abstract

Background: Research into low-value routine testing at children's hospitals has not consistently evaluated changing patterns of testing over time.

Objectives: To identify changes in routine laboratory testing rates at children's hospitals over ten years and the association with patient outcomes.

Design, settings, and participants: We performed a multi-center, retrospective cohort study of children aged 0-18 hospitalized with common, lower-severity diagnoses at 28 children's hospitals in the Pediatric Health Information Systems database.

Main outcomes and measures: We calculated average annual testing rates for complete blood counts, electrolytes, and inflammatory markers between 2010 and 2019 for each hospital. A >2% average testing rate change per year was defined as clinically meaningful and used to separate hospitals into groups: increasing, decreasing, and unchanged testing rates. Groups were compared for differences in length of stay, cost, and 30-day readmission or ED revisit, adjusted for demographics and case mix index.

Results: Our study included 576,572 encounters for common, low-severity diagnoses. Individual hospital testing rates in each year of the study varied from 0.3 to 1.4 tests per patient day. The average yearly change in hospital-specific testing rates ranged from -6% to +7%. Four hospitals remained in the lowest quartile of testing and two in the highest quartile throughout all 10 years of the study. We grouped hospitals with increasing (8), decreasing (n = 5), and unchanged (n = 15) testing rates. No difference was found across subgroups in costs, length of stay, 30-day ED revisit, or readmission rates. Comparing resource utilization trends over time provides important insights into achievable rates of testing reduction.

FIGURE 1

Heat map of hospital-level routine testing rates over time. Hospital-level variation in routine testing rates displayed as a heat map. Individual hospitals are displayed as rows and year is displayed in columns. Color values correspond to quartiles of testing rate for each specific year. Median testing rate and 25th percentile (Q1) and 75th percentile (Q3) testing rates for a specific year displayed at the bottom of the chart. Rate ratio is the average annual change in testing rate. Clinically meaningful changes to rates of testing determined by a rate ratio >1.02 or <0.98 (i.e., annual change of ≥2%). Hospitals were sorted by 2010 testing rate.

FIGURE 2

Trends in routine testing rates over time by hospital groups. Annual hospital-specific rates of routine laboratory testing per patient day. Each figure represents a subgroup of hospitals based on increasing, decreasing, or no change in testing rates over time. Gray lines indicate individual hospital testing rates. Black lines indicate unweighted average of hospital testing rates by year.