title: Expanding the statistical toolbox: analytic approaches for cohort studies with healthcare-associated infectious outcomes.
abstract: OBJECTIVE
  Healthcare-associated infections (HAIs) are a leading cause of adverse patient outcomes. Further elucidation of the etiology of these infections and the pathogens that cause them has been a primary goal of research in infection control and healthcare epidemiology. Longitudinal studies, in particular, afford a range of statistical methods to better understand the process of pathogen acquisition or HAI development. This review intends to convey the scope of available statistical methodology.
  
  
  RESULTS
  Despite the range of methods available, logistic regression remains the dominant statistical approach in use. Poisson regression, survival methods, and mechanistic (mathematical) models remain underutilized. Recent studies that use these approaches are looking beyond associations to answer questions about the timing, duration, and mechanism of infectious risk.
  
  
  CONCLUSIONS
  Logistic regression remains an important approach to the study of HAIs, but in the context of cohort studies, it is most appropriate for short observation periods, during which mechanism is not of primary interest. Additional statistical methodologies are available to build upon risk factor analysis to better inform the process of risk and infection in the hospital setting.
authors.affiliation: aDepartment of Epidemiology, The Johns Hopkins Bloomberg School of Public Health bDepartment of Pediatrics, Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine cDepartment of Hospital Epidemiology and Infection Control, The Johns Hopkins Hospital, Baltimore, Maryland, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Pierce
authors.forename: Justin
authors.initials: J
authors.lastname: Lessler
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Milstone
mesh_terms: D056808:Biostatistics / Q000379:methods*; D003428:Cross Infection / Q000188:drug therapy* / Q000453:epidemiology*; D004812:Epidemiologic Methods; D006268:Health Facilities; D006801:Humans; D008137:Longitudinal Studies; D016896:Treatment Outcome