A retrospective analysis of clinical characteristics, hospitalization, and functional outcomes in residents with and without Clostridium difficile infection in US long-term care facilities

Abstract

Objective:

Patients in long-term care (LTC) are at increased risk for acquiring Clostridium difficile infection (CDI). We compared the characteristics and outcomes of matched cohorts with and without CDI in the LTC setting.

Methods:

Using a retrospective cohort design, demographic characteristics, Minimum Data Set (MDS 2.0) assessments (years 2007–2010), and pharmacy records of residents were analyzed. Residents were required to have a CDI diagnosis, ≥1 MDS 2.0 assessment ≤120 days pre- and post-index event, and receipt of metronidazole (MET) or vancomycin (VAN) within ±7 days of index date. Baseline characteristics were compared between cases and controls matched 1:3 on age, gender, and index year. Cox regression (CR) analysis evaluated the relationship between CDI status, and post-index mortality and hospitalization.

Results:

A total of 1145 CDI residents were matched with 3488 non-CDI residents. A second sample used propensity score methods. CDI vs. non-CDI residents had a higher baseline comorbidity burden (Charlson score: 3.0 ± 1.9 vs. 2.2 ± 1.8, respectively), and were more likely to have had a recent hospitalization (63% vs. 9%, respectively) and shorter mean pre-index continuous length of stay (cLOS) in the LTC (386.4 d ± 536.3 d vs. 568.3 d ± 567.4 d, respectively), all P < 0.0001. CR analyses of both samples indicated that CDI was strongly associated with shorter times to hospitalization and mortality (hazard ratio (HR) = 1.3, P = 0.023 and 2.2, P < 0.0001, respectively; propensity-matched group). Pre-index LTC cLOS also remained an important variable in the CR analysis and was the strongest predictor of post-index hospitalization and mortality (HR = 0.999 and 0.996, respectively, P < 0.0001), indicating that residents with longer pre-index LTC cLOS had longer times to post-index hospitalization and mortality. Our reliance on the MDS records for case identification was our chief limitation; misclassification was mitigated by our requirement to include CDI treatment as part of our inclusion criteria.

Conclusions:

Understanding factors that put LTC patients at risk for CDI can help guide better management and improvement of patient outcomes.

Keywords::

• Clostridium difficile infection
• Infectious diarrhea
• Long-term care
• Outcomes
• Retrospective analysis
• Risk factors
• Survival analysis

Transparency

Declaration of funding

Financial support for this research was provided by Cubist Pharmaceuticals, Jersey City, NJ, USA.

Authors’ contributions: H.S.F., P.N., G.R., and M.E.S. contributed to the study design, analysis of data, and interpretation of data. K.P.H. contributed to the interpretation of data. All authors critically reviewed and revised the manuscript for intellectual content and gave final approval for publication.

Declaration of financial/other relationships

H.S.F. and P.N. are owners of DataMed Solutions LLC (DMS), which received payments from Cubist Pharmaceuticals for the research and development of this manuscript. GR is owner of Informagenics LLC, which received payments from DMS as a third party vendor for the research and development of this manuscript. K.P.H. is a professor and practitioner at Wake Forest School of Medicine who received payments from Cubist Pharmaceuticals as a consultant for the research and development of this manuscript. He is also a former member of the Optimer Pharmaceuticals Advisory Council. M.E.S. is a former employee of Cubist Pharmaceuticals who assisted with the research and development of this manuscript.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgments

Medical writing and editorial assistance was provided by Jamie Banks PhD and Erin P. Scott PhD, former employees of Complete Publication Solutions LLC, which received payments from DMS as a third party vendor.

Congress presentations: The data in this manuscript were presented in part as a new poster presentation at the 2012 American Medical Directors Association Long Term Care Medicine Annual Meeting, 8–12 March 2012, San Antonio, TX, USA; and as an encore poster presentation at the 2012 American Geriatrics Society Annual Scientific Meeting, 3–5 May 2012, Seattle, WA, USA; and the 2012 Association of Consultant Pharmacists Annual Meeting, 2–9 November 2012, National Harbor, MD, USA.