Do Intensivist Staffing Patterns Influence Hospital Mortality Following ICU Admission? A Systematic Review and Meta-Analyses*

Abstract

To determine the effect of different intensivist staffing models on clinical outcomes for critically ill patients. A sensitive search of electronic databases and hand-search of major critical care journals and conference proceedings was completed in October 2012. Comparative observational studies examining intensivist staffing patterns and reporting hospital or ICU mortality were included. Of 16,774 citations, 52 studies met the inclusion criteria. We used random-effects meta-analytic models unadjusted for case-mix or cluster effects and quantified between-study heterogeneity using I. Study quality was assessed using the Newcastle-Ottawa Score for cohort studies. High-intensity staffing (i.e., transfer of care to an intensivist-led team or mandatory consultation of an intensivist), compared to low-intensity staffing, was associated with lower hospital mortality (risk ratio, 0.83; 95% CI, 0.70-0.99) and ICU mortality (pooled risk ratio, 0.81; 95% CI, 0.68-0.96). Significant reductions in hospital and ICU length of stay were seen (-0.17 d, 95% CI, -0.31 to -0.03 d and -0.38 d, 95% CI, -0.55 to -0.20 d, respectively). Within high-intensity staffing models, 24-hour in-hospital intensivist coverage, compared to daytime only coverage, did not improved hospital or ICU mortality (risk ratio, 0.97; 95% CI, 0.89-1.1 and risk ratio, 0.88; 95% CI, 0.70-1.1). The benefit of high-intensity staffing was concentrated in surgical (risk ratio, 0.84; 95% CI, 0.44-1.6) and combined medical-surgical (risk ratio, 0.76; 95% CI, 0.66-0.83) ICUs, as compared to medical (risk ratio, 1.1; 95% CI, 0.83-1.5) ICUs. The effect on hospital mortality varied throughout different decades; pooled risk ratios were 0.74 (95% CI, 0.63-0.87) from 1980 to 1989, 0.96 (95% CI, 0.69-1.3) from 1990 to 1999, 0.70 (95% CI, 0.54-0.90) from 2000 to 2009, and 1.2 (95% CI, 0.84-1.8) from 2010 to 2012. These findings were similar for ICU mortality. High-intensity staffing is associated with reduced ICU and hospital mortality. Within a high-intensity model, 24-hour in-hospital intensivist coverage did not reduce hospital, or ICU, mortality. Benefits seen in mortality were dependent on the type of ICU and decade of publication.