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THU0075 The risk of venous thromboembolism in patients with rheumatoid arthritis compared to the general population: A very large cohort study
  1. S.C. Kim1,
  2. S. Schneeweiss2,
  3. J. Liu3,
  4. D.H. Solomon2
  1. 1Brigham and Women’s Hospital
  2. 2Brigham and Women’s Hospital, Boston, MA
  3. 3Brigham and Women’s Hospital, Boston, United States

Abstract

Background Some data suggest that rheumatoid arthritis (RA) is associated with an increased risk of venous thromboembolism (VTE). Prior studies have been relatively small and used a very limited set of covariates to adjust for potential confounding.

Objectives To examine the risk of VTE in patients with RA compared to non-RA subjects.

Methods We conducted a retrospective cohort study using health care utilization data collected by a large US commercial insurance plan. The RA cohort included adults with at least two diagnoses of RA and at least one prescription for a disease-modifying anti-rheumatic drug (DMARDs). Follow-up began with the first prescription for a DMARD, defined as the index date. Subjects who never had a diagnosis of RA were selected and matched to RA patients on age, sex, and index date with a 5:1 ratio. Patients with history of malignancy and VTE were excluded. The primary outcome was VTE, defined as the composite of deep vein thrombosis (DVT) or pulmonary embolism (PE), as a principal hospital discharge diagnosis. Incidence rates (IR) and rate ratios (RR) of VTE with 95% confidence intervals (CI) were calculated. Multivariable Cox proportional hazards models compared the risk of VTE events between RA and non-RA patients.

Results The study population included 22,143 RA and 88,572 non-RA patients with a mean (SD) age of 52 (12) years with 75% women. During a mean follow-up of 2 years, 1.2% of RA patients and 0.5% non-RA patients developed VTE. The IR for VTE among RA patients was 6.1 per 1,000 person-years, 2.4 times higher (95% CI: 2.1-2.8) than the rate of non-RA patients. The IRs for both DVT (RR, 2.2, 95% CI: 1.9-2.6) and PE (RR 2.7, 95% CI: 2.2-3.5) were higher in RA patients compared with non-RA subjects. After adjusting for known risk factors of VTE, a moderately elevated risk for VTE was noted in RA (hazard ratio 1.4, 95% CI: 1.1-1.7) compared to non-RA patients.

Conclusions Our results showed an increased risk of VTE, both DVT and PE, for RA patients compared with non-RA patients. The risk was attenuated but remained elevated after adjusting for known risk factors for VTE such as cardiovascular disease, surgery, hospitalization, and medications.

Disclosure of Interest S. Kim Grant/Research support from: Pfizer, Takeda, S. Schneeweiss Grant/Research support from: Pfizer, Consultant for: WHISCON, RTI Health Solutions, the Lewin Group, and HealthCore, J. Liu: None Declared, D. Solomon Grant/Research support from: Amgen, Abbot, and BMS

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