Critical care bed growth in the United States. A comparison of regional and national trends

Abstract

Rationale: Although the number of intensive care unit (ICU) beds in the United States is increasing, it is unknown whether this trend is consistent across all regions.

Objectives: We sought to better characterize regional variation in ICU bed changes over time and identify regional characteristics associated with these changes.

Methods: We used data from the Centers for Medicare and Medicaid Services and the U.S. Census to summarize the numbers of hospitals, hospital beds, ICU beds, and ICU occupancy at the level of Dartmouth Atlas hospital referral region from 2000 to 2009. We categorized regions into quartiles of bed change over the study interval and examined the relationship between change categories, regional characteristics, and population characteristics over time.

Measurements and main results: From 2000 to 2009 the national number of ICU beds increased 15%, from 67,579 to 77,809, mirroring population. However, there was substantial regional variation in absolute changes (median, +16 ICU beds; interquartile range, -3 to +51) and population-adjusted changes (median, +0.9 ICU beds per 100,000; interquartile range, -3.8 to +5.9), with 25.0% of regions accounting for 74.8% of overall growth. At baseline, regions with increasing numbers of ICU beds had larger populations, lower ICU beds per 100,000 capita, higher average ICU occupancy, and greater market competition as measured by the Herfindahl-Hirschman Index (P < 0.001 for all comparisons).

Conclusions: National trends in ICU bed growth are not uniformly reflected at the regional level, with most growth occurring in a small number of highly populated regions.

Keywords: bed supply; critical care; infrastructure; intensive care unit.

Figure 1.

Violin plots of ICU beds (A), ICU beds per 100,000 persons aged 20 years and older (B), ICU beds per 100,000 persons aged 65 and older (C), and ICU beds as a proportion of regional hospital beds (D) in 306 Dartmouth Atlas hospital referral regions over the years 2000–2009. Violin plots are similar to boxplots but also show the cohort’s distribution density. Wider areas in the violin plot correspond to increased observation frequency at that y-value. The open circle indicates the median and the thick vertical line indicates the first and third interquartile range. ICU = intensive care unit.

Figure 2.

Histogram of change in number of intensive care unit beds in 306 Dartmouth Atlas hospital referral regions between the years 2000 and 2009. ICU = intensive care unit.

Figure 3.

Comparison of regional change in the number of ICU beds and population change among adults aged 20 and older (A) and 65 and older (B). For both plots, the dark solid line represents the linear regression line and each dark circle represents a Dartmouth Atlas hospital referral region. The open circles outside the dashed lines represent outlier regions that increased or decreased the number of ICU beds by more than 100 beds, relative to the predicted change. The light solid line represents the predicted change in ICU beds for change in population, based on year 2000 ICU beds per 100,000 capita. ICU = intensive care unit; K = thousand; M = million.