The volume-outcome relationship in critical care: a systematic review and meta-analysis.
Chest. 2015 Apr 30;
Authors: Nguyen YL, Wallace DJ, Yordanov Y, Trinquart L, Blomkwist J, Angus DC, Kahn JM, Ravaud P, Guidet B
Abstract
Purpose: To systematically review the research on volume and outcome relationships in critical care.
Data sources: MEDLINE and EMBASE from January 1st 2001 to April 30th 2014 were searched for studies assessing the relationship between admission volume and clinical outcomes in critical illness. Bibliographies were reviewed to identify other articles of interest and experts were contacted about missing or unpublished studies.
Study selections: Of 127 studies reviewed, 46 met inclusion criteria, covering 7 clinical conditions.
Data extraction: Two investigators independently reviewed each article using a standardized form to abstract information on key study characteristics and results.
Data synthesis: Overall, 29 (63%) of studies reported a statistically significant association between higher admission volume and improved outcomes. The magnitude of the association (mortality odds ratio (OR) between lowest versus highest stratum of volume centers), as well as the thresholds used to characterize high volume, varied across clinical conditions. Critically ill patients with cardiovascular (n=7, OR = 1.49[1.11-2.00]), respiratory (n=12, OR=1.20 [1.04-1.38]), severe sepsis (n=4, OR=1.17 [1.03-1.33]), hepato-gastro-intestinal (n=3, OR=1.30 [1.08-1.78]), neurological (n=3, OR=1.38 [1.22-1.57]) and post-operative admission diagnoses (n=3, OR=2.95 [1.05-8.30]) were more likely to benefit from admission to a higher volume centers compared to lower volume centers. Studies that controlled for ICU or hospital organizational factors were less likely to find a significant volume-outcome relationship then studies that did not control for these factors.
Conclusions: Critically ill patients generally benefit from care in high volume centers, with more substantial benefits in selected high-risk conditions. This relationship may in part be mediated by specific ICU and hospital organizational factors.
Clinical trial registration: PROSPERO registry of systematic reviews (registration number: CRD42011001265).
PMID: 25927593 [PubMed - as supplied by publisher]