title: Venous thromboembolism in patients with HIV/AIDS: a case-control study.
abstract: BACKGROUND
  Retrospective cohort studies of HIV-infected patients suggest an incidence of venous thromboembolism (VTE) of 1% to 2%, which is 10 times that expected among people without HIV. We investigated the prevalence of established risk factors for VTE in this population and explored novel risk factors.
  
  
  METHODS
  We conducted a case-control study using patients in the Johns Hopkins University AIDS Service cohort. We used conditional logistic regression and paired t tests to test for covariates significantly associated with VTE.
  
  
  RESULTS
  We identified 160 patients with VTE diagnosed radiologically or with a clinical course consistent with VTE; 23% of the cases of VTE were diagnosed in hospitalized patients. The incidence of VTE was approximately 0.5% per patient-year. Patients with VTE and control patients did not differ by gender, but black patients were overrepresented among those with VTE (odds ratio [OR]=1.9, 95% confidence interval [CI]: 1.11 to 3.08) and patients with VTE were older than controls (mean: 39 vs. 37 years; P=0.001). Patients with VTE had lower CD4 counts (229 vs. 362 cells/mm; P<0.0001), higher HIV RNA titers (120,254 vs. 71,262 copies/mL; P=0.013), and lower hemoglobin concentrations (11.4 vs. 12.7 g/dL; P<0.0001) preceding the event than those without VTE. The use of highly active antiretroviral therapy was not associated with VTE. In multivariate analyses, independent risks for VTE were age, hospitalization in the past 3 months (OR=13, 95% CI: 6.4 to 27), central venous catheter use in the past 3 months (OR=6.0, 95% CI: 2.3 to 16), and a CD4 count<500 cells/mm (OR=3.0, 95% CI: 1.2 to 7.8).
  
  
  CONCLUSIONS
  The incidence of VTE in our cohort is similar to that reported in other cohorts of patients with HIV. Recent hospitalization was the risk factor most strongly associated with VTE.
authors.affiliation: Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
authors.forename: Aima A
authors.initials: AA
authors.lastname: Ahonkhai
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Gebo
authors.forename: Michael B
authors.initials: MB
authors.lastname: Streiff
authors.forename: Richard D
authors.initials: RD
authors.lastname: Moore
authors.forename: Jodi B
authors.initials: JB
authors.lastname: Segal
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000150:complications*; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D002405:Catheterization, Central Venous / Q000009:adverse effects; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D054928:Validation Studies as Topic; D054556:Venous Thromboembolism / Q000150:complications / Q000453:epidemiology*