Dear Editor,

The availability of intensive care unit (ICU) beds is crucial to the care of critical patients [1]. However, studies regarding the capacity of China's ICU resources are lacking [2]. To provide a first comprehensive overview of China's ICU bed capacity and distribution, we conducted an evaluation of the population-based trends in China's ICU bed supply over 15 years (between 2007 and 2021) based on the official published data, and used the Lorenz curve and Gini coefficient to calculate the equity of China's ICU beds allocation in 2021, and compared the gap of ICU bed capacity between China and Organization for Economic Cooperation and Development (OECD) countries. Data source and analysis are presented in the electronic supplementary material.

Overall, ICU beds supply has largely increased in the last 15 years. From 2007 to 2021, the number of ICU beds increased from 7328 to 67,153 (the average annual percent change, AAPC = 17.56%); ICU beds per 100,000 population increased from 0.55 to 4.75 (AAPC = 16.96%); ICU beds as a proportion of hospital beds increased by 0.64 percent, from 0.27 to 0.91% (Fig. 1a–c, supplementary Table 1).

Fig. 1
figure 1

a The number of ICU beds; b ICU beds per 100,000 population; c ICU beds as a proportion of hospital beds; d the number of ICU beds per 100,000 population by province in china in 2021; e Lorenz curved and Gini coefficients for ICU beds in 2021 by population; f Lorenz curved and Gini coefficients for ICU beds in 2021 by geographical area. g Number of ICU beds per 100,000 population in 25 OECD countries in 2021; h ICU beds as a proportion of hospital beds in 25 OECD countries in 2021

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At a regional level, only four provinces were identified as having more than 6 ICU beds per 100,000 population in 2021, namely Henan, Xinjiang, Zhejiang, and Beijing, with 8, 7.7, 6.8, and 6 respectively (Fig. 1d).

We identified obvious regional differences in China's ICU bed distribution. The Lorenz curve can visually judge the degree of inequality, and the Gini coefficient calculated based on the Lorenz curve is an ideal index to quantify the extent of inequality. The Lorenz curve of China's ICU beds in 2021 allocated by population was close to the absolute equity line, and the Gini coefficient was 0.142, indicating an absolutely fair state (Fig. 1e). However, the Lorenz curve by geographical area was far from the absolute equity line, and the Gini coefficient was 0.682, indicating the distribution was highly inequitable (Fig. 1f).

We collected hospital beds, and ICU beds from 25 OECD countries in 2021 from the OECD database. ICU beds per 100,000 population and ICU beds as a proportion of hospital beds in the 25 OECD countries were 25.84 and 5.28%, respectively, with 24 countries having a higher number of ICU beds per 100,000 population and a higher percentage of ICU beds proportion than China (Fig. 1g, h, supplementary Table 2).

In conclusion, our results suggest that despite the rapid increase in the number of China's ICU beds over the past 15 years, the proportion of ICU beds only reached 0.91% in 2021, far below the 2–8% criterion recommended by the Guidelines for the Construction and Management of Critical Care Medicine in China [2]; the number of beds per 100,000 population was still insufficient, with less than one-fifth of the average for OECD countries, and remained lower than average for low-income regions (6.44) and upper-middle-income regions (9.23) [3]. There were significant regional differences in the distribution of ICU beds in China. It is recommended to take measures to increase China's ICU capacity and improve the inequitable distribution between regions, to meet the greater demands for ICU admissions due to the pandemic outbreak and an aging population in the future [4, 5].