Initiation of Biologic DMARDs Associated with Increased VTE Risk

Initiation of Biologic DMARDs Associated with Increased VTE Risk
Initiation of Biologic DMARDs Associated with Increased VTE Risk

SAN DIEGO, CA—Initiation of biologic disease-modifying antirhuematic drugs was significantly associated with a 2.5-times elevated risk of venous thromboembolism (VTE) in the first 180 days, according to study results presented at the 2013 ACR/ARHP Annual Meeting.

Seoyoung C. Kim, MD, MSCE, and colleagues, of the Division of Pharmacoepidemiology and Pharmacoeconomics, Division of Rheumatology, Allergy, and Immunology, Brigham and Women's Hospital, Boston, MA, conducted a population-based cohort study to compare the risk of VTE in rheumatoid arthritis (RA) patients initiating treatment with biologic disease-modifying antirheumatic drugs (bDMARD), methotrexate, or non-biologic DMARD (nbDMARD).

The study combined three U.S. commercial insurance claims databases (2001—2012) that identified adult patients (n=29,481) with a new diagnosis of RA based on >2 RA diagnoses that were >7 days apart with a baseline period free of RA diagnosis or DMARD use for >1 year. Patients with a history of VTE, malignancy and use of anticoagulants at baseline were excluded.

The three drug regimens were classified as the following: (1) a biologic DMARD with or without nbDMARDs, (2) MTX without a biologic DMARD, or (3) nbDMARDs without a biologic DMARD or MTX. Incidence rates (IR) of VTE identified by a previously validated algorithm with inpatient diagnosis codes (PPV 75—90%).

Of the total patients, 39,647 treatment episodes were identified. The crude IR of VTE per 1,000 person-years was higher in the bDMARDs group (5.53, 95% CI 3.67—8.32) vs. nbDMARDS (4.43 95% CI 3.13—6.26) and methotrexate. The hazard ratio (HR) of VTE associated with initiation of bDMARDs was 1.83 (95% CI 0.92--3.63) compared to nbDMARDs and 1.39 (95% CI 0.73-2.64) compared to methotrexate.

The HR of VTE associated with initiation of methotrexate vs. nbDMARDs was 0.78 (95% CI 0.50—1.21). In a sensitivity analysis limiting the follow-up up to 180 days, bDMARDs was associated with a significantly increased risk (HR 2.48, 95% CI 1.14—5.40). In the PS-matched analyses, the HR was 1.34 (95% CI 0.65—2.75) in bDMARDs vs. nbDMARDs and 1.73 (95% CI 0.90—3.32) in bDMARDs vs. methotrexate.

“Initiating a bDMARD was associated with a likely increase, but not statistically significant, in the risk of incident VTE compared to those initiating methotrexate or nbDMARDs, albeit low absolute risks of VTE,” concluded Dr. Kim.