title: Rethinking guidelines for VTE risk among nursing home residents: a population-based study merging medical record detail with standardized nursing home assessments.
abstract: BACKGROUND
  Nursing home (NH) residents are at increased risk for both VTE and bleeding from pharmacologic prophylaxis. Construction of prophylaxis guidelines is hampered by NH-specific limitations with VTE case identification and characterization of risk. We addressed these limitations by merging detailed provider-linked Rochester Epidemiology Project (REP) medical records with Centers for Medicare and Medicaid Services Minimum Data Set (MDS) NH assessments.
  
  
  METHODS
  This population-based nested case-control study identified all Olmsted County, Minnesota, residents with first-lifetime VTE October 1, 1998, through December 31, 2005, while a resident of an NH (N = 91) and one to two age-, sex-, and calendar year-matched NH non-VTE control subjects. For each NH case without hospitalization 3 months before VTE (n = 23), we additionally identified three to four nonhospitalized NH control subjects. REP and MDS records were reviewed before index date (VTE date for cases; respective REP encounter date for control subjects) for numerous characteristics previously associated with VTE in non-NH populations. Data were modeled using conditional logistic regression.
  
  
  RESULTS
  The multivariate model consisting of all cases and control subjects identified only three characteristics independently associated with VTE: respiratory infection vs no infection (OR, 5.9; 95% CI, 2.6-13.1), extensive or total assistance with walking in room (5.6, 2.5-12.6), and general surgery (3.3, 1.0-10.8). In analyses limited to nonhospitalized cases and control subjects, only nonrespiratory infection vs no infection was independently associated with VTE (8.8, 2.7-29.2).
  
  
  CONCLUSIONS
  Contrary to previous assumptions, most VTE risk factors identified in non-NH populations do not apply to the NH population. NH residents with infection, substantial mobility limitations, or recent general surgery should be considered potential candidates for VTE prophylaxis.
authors.affiliation: Division of Epidemiology, Department of Internal Medicine, Mayo Clinic, Rochester, MN. Electronic address: leibson@mayo.edu.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Leibson
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Tanya M
authors.initials: TM
authors.lastname: Petterson
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Carin Y
authors.initials: CY
authors.lastname: Smith
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Kent R
authors.initials: KR
authors.lastname: Bailey
authors.affiliation: Division of Epidemiology, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Jane A
authors.initials: JA
authors.lastname: Emerson
authors.affiliation: Department of Health Sciences Research, and the Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Aneel A
authors.initials: AA
authors.lastname: Ashrani
authors.affiliation: Division of Primary Care, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: Paul Y
authors.initials: PY
authors.lastname: Takahashi
authors.affiliation: Department of Health Sciences Research, and the Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN; Division of Cardiovascular Disease, Department of Internal Medicine, Mayo Clinic, Rochester, MN.
authors.forename: John A
authors.initials: JA
authors.lastname: Heit
mesh_terms: D000369:Aged, 80 and over; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D015994:Incidence; D008297:Male; D008499:Medical Records; D008910:Minnesota / Q000453:epidemiology; D051346:Mobility Limitation; D009735:Nursing Homes; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000517:prevention & control