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Impact of a statewide intensive care unit quality improvement initiative on hospital mortality and length of stay: retrospective comparative analysis

BMJ 2011; 342 doi: (Published 31 January 2011) Cite this as: BMJ 2011;342:d219
  1. Allison Lipitz-Snyderman, postdoctoral fellow1,
  2. Donald Steinwachs, professor1,
  3. Dale M Needham, associate professor2,
  4. Elizabeth Colantuoni, assistant scientist3,
  5. Laura L Morlock, professor1,
  6. Peter J Pronovost, professor4
  1. 1Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, 624 N Broadway, Baltimore, MD 21205, USA
  2. 2Outcomes After Critical Illness and Surgery (OACIS) Group, Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore
  3. 3Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore
  4. 4Quality and Safety Research Group, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore
  1. Correspondence to: A Lipitz-Snyderman alipitz{at}
  • Accepted 3 December 2010


Objective To evaluate whether implementation of the Michigan Keystone ICU project, a comprehensive statewide quality improvement initiative focused on reduction of infections, was associated with reductions in hospital mortality and length of stay for adults aged 65 or more admitted to intensive care units.

Design Retrospective comparative study, using data from Medicare claims.

Setting Michigan and Midwest region, United States.

Population The study period (October 2001 to December 2006) spanned two years before the project was initiated to 22 months after its implementation. The study sample included hospital admissions for patients treated in 95 study hospitals in Michigan (238 937 total admissions) compared with 364 hospitals in the surrounding Midwest region (1 091 547 total admissions).

Main outcome measures Hospital mortality and length of hospital stay.

Results The overall trajectory of mortality outcomes differed significantly between the two groups upon implementation of the project (Wald test χ2=8.73, P=0.033). Reductions in mortality were significantly greater for the study group than for the comparison group 1-12 months (odds ratio 0.83, 95% confidence interval 0.79 to 0.87 v 0.88, 0.85 to 0.90, P=0.041) and 13-22 months (0.76, 0.72 to 0.81 v 0.84, 0.81 to 0.86, P=0.007) after implementation of the project. The overall trajectory of length of stay did not differ significantly between the groups upon implementation of the project (Wald test χ2=2.05, P=0.560). Group differences in adjusted length of stay compared with baseline did not reach significance during implementation of the project (−0.45 days, 95% confidence interval −0.62 to −0.28 v −0.35, −0.52 to −0.19) or during post-implementation months 1-12 (−0.59, −0.80 to −0.37 v −0.42, −0.59 to −0.25) and 13-22 (−0.67, −0.91 to −0.43 v −0.54, −0.72 to −0.37).

Conclusions Implementation of the Keystone ICU project was associated with a significant decrease in hospital mortality in Michigan compared with the surrounding area. The project was not, however, sufficiently powered to show a significant difference in length of stay.


  • We thank Charles Rohde (Johns Hopkins Bloomberg School of Public Health) for providing valuable input in the study design and data analysis and interpretation; Sean Berenholtz and the Johns Hopkins Quality and Safety Research Group for providing data management assistance and valuable input; the Michigan Health and Hospital Association (MHA) for its support and assistance with data management for this study; and the Michigan Health and Hospital Association and all of the hospitals participating in the Keystone ICU project for their commitment to patient safety.

  • Contributors: AL-S is the guarantor and had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. All the authors were involved in preparing this manuscript. AL-S was responsible for the overall study design, data analysis, and interpretation of data, and wrote the initial draft of the manuscript. All other authors contributed to the study design, analysis and interpretation of data, and critical revision of the manuscript. DS, LLM, and PJP also provided supervision.

  • Funding: This study was done as part of AL-S’s PhD dissertation at the Johns Hopkins Bloomberg School of Public Health.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare that they had (1) No financial support for the submitted work. (2) PJP reports: receiving grants from the Agency for Healthcare Research and Quality, the National Patient Safety Agency, and private philanthropy to implement the Michigan programme in all 50 states and to measure and improve patient safety, receiving speaking honorariums and expenses for travel and accommodation from hospitals and healthcare systems, providing expert testimony to the US Congress, receiving royalties from sales of the book Safe Patients, Smart Hospitals, and receiving payment for development of education presentations from Leigh Bureau on quality and safety; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work and (4) No non-financial interests that may be relevant to the submitted work.

  • Ethical approval: This study was considered exempt by the institutional review board (Committee on Human Research) of the Johns Hopkins Bloomberg School of Public Health. Approval from the Centers for Medicare and Medicaid Services was granted for use of the MEDPAR dataset for this study.

  • Data sharing: No additional data available.

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