Differences in hospital mortality by ICU staffing models: you cannot always get what you want, but sometimes you get what you need.

www.ccmjournal. org 2433 Many critical care societies recommend that intensive care specialists should be primarily responsible for the medical care of critically ill patients, ideally via 24-hour in-hospital coverage (1–4). However, multiple factors make this a difficult standard to achieve, particularly the current shortage of trained intensivists with a rapid growth in the number of ICUs and the high associated cost of ICU care (4). Hence, presently more than two thirds of ICUs in the United States are neither managed by intensivists nor use a high-intensity staffing model (5, 6). In this issue of the Critical Care Medicine, Wilcox et al (7) present a meta-analysis that explores the association between different ICU staffing models and outcomes in critically ill patients, with hospital mortality as the primary outcome (8). In this meta-analysis, Wilcox et al (7) summarize outcome data from 52 observational studies that compare high-intensity staffing models (i.e., where intensivists are either primarily responsible for patient care via 24-hour in-hospital or daytime-only coverage or required to act as consultants) with low-intensity staffing models (i.e., where the primary physician leads the managements of ICU patients with optional consultation by an intensivist). Wilcox et al (7) found that in the 34 studies that contributed data on hospital mortality, high-intensity staffing was associated with a lower risk of hospital mortality versus low-intensity staffing (risk ratio [RR] = 0.83 [95% CI, 0.70–0.99]). Similar reductions summarized by metaanalysis were also observed in secondary outcomes. In subgroup analysis, however, the benefits of high-intensity staffing appeared to be limited to mixed ICUs (RR = 0.76 [95% CI, 0.66–0.83]) and possibly to surgical ICUs (RR = 0.84 [95% CI, 0.44–1.6]) and did not appear to make a difference in medical ICUs (RR = 1.1 [95% CI, 0.83–1.5]). Finally, in the six studies that contributed data on hospital mortality in closed-format ICUs, the authors found no difference in the risk of death between 24-hour in-hospital intensivist coverage and daytime-only coverage (RR = 0.97 [95% CI, 0.89–1.05]). The results reported by Wilcox et al (7) are consistent with those of a previous meta-analysis of 26 observational studies which found that high-intensity staffing was associated with a reduction in hospital mortality (RR = 0.71 [95% CI, 0.62–0.82]) when compared with low-intensity staffing (9). Furthermore, a high-intensity staffing model is likely more cost effective than the traditional open-format ICU model by improving ICU usage and reducing ancillary costs (7). Wilcox et al (7) also found that there was no difference in hospital mortality among closed ICUs with daytime-only coverage versus those with 24-hour in-hospital coverage. This finding confirms observations of two single-center studies and a large, multi-center retrospective study (10–12) by summarizing multiple studies in a meta-analysis that supports the fact that adequate ICU staffing does not require around the clock intensivist care to achieve better outcomes. A recently published single-center study was a one-year cross-over trial in a high-intensity, academic medical ICU that assigned random blocks of seven days with either night-time staffing with in-hospital intensivists (intervention) or night-time coverage by daytime intensivists who were available for consultation by telephone (control). In this trial, Kerlin et al did not find differences in length of stay in the ICU (primary outcome) or in ICU mortality between the intervention and control blocks (12). This meta-analysis has important strengths but also has potential shortcomings that may limit the interpretation of findings. The authors evaluated the quality of each study using a standardized scale for observational studies (3) and found that more than 90% met high-quality criteria. They also did not appear to identify an important publication bias influencing their results although they are cautious to acknowledge that they cannot exclude this as a possibility. Finally, they conducted careful sensitivity analyses to provide additional support to their study findings and obtained largely consistent results. One potential limitation is that all studies included in this meta-analysis were designed as observational studies; however, the authors point out that a large randomized Copyright © 2013 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins DOI: 10.1097/CCM.0b013e31829cb0aa Francesca Capanni, MD William Checkley, MD, PhD Division of Pulmonary and Critical Care School of Medicine Johns Hopkins University Baltimore, MD