Do intensivist staffing patterns influence hospital mortality following ICU admission? A systematic review and meta-analyses.

Objective: To determine the effect of different intensivist staffing models on clinical outcomes for critically ill patients.

Data Sources: A sensitive search of electronic databases and hand-search of major critical care journals and conference proceedings was completed in October 2012.

Study Selection: Comparative observational studies examining intensivist staffing patterns and reporting hospital or ICU mortality were included.

Data Extraction: 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.

Data Synthesis: 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.

Conclusions: 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.