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Member Research & Reports

Member Research & Reports

UAB Investigates Risk of Hospitalized Infection Associated with RA Patients

In a recent retrospective cohort study, a team led by Dr. Huifeng Yun, assistant professor in the department of epidemiology at the University of Alabama at Birmingham, compared the risks of hospitalized infection associated with biologics used to treat patients with rheumatoid arthritis (RA). UAB co-investigators are department colleagues Dr. Emily B. Levitan, associate professor, and Dr. Elizabeth Delzell, professor emeritus; Mr. Lang Chen, research associate in the Division of Clinical Immunology and Rheumatology and previous graduate student in the department of biostatistics, section on statistical genetics; Dr. Timothy G. Beukelman, associate professor in the division of pediatric rheumatology; and Dr. John William Baddley, professor in the division of infectious diseases; along with Mr. Fenglong Xie, statistician; Dr. Kenneth Saag, professor; and Dr. Jeffrey R. Curtis, professor, in the division of clinical immunology and rheumatology.

[Photo: Dr. Elizabeth Delzell]

The researchers used Medicare data from 2006 through 2011 to identify new treatment episodes of biologics, including abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab, rituximab, and tocilizumab. According to the study, “Patients were required to have used another biologic previously and have been continuously enrolled in Medicare medical and pharmacy plans during baseline and throughout follow-up. Follow-up started from the initiation date of the new biologic treatment, after previous treatment with a different biologic, and ended at the earliest date of: hospitalized infection, 12 months, > 30 days exposure gap, death, or loss of Medicare coverage. Cox regression was used to calculate the adjusted hazard ratio of hospitalized infection adjusting for an infection risk score and other confounders.”

Of 31,801 new biologic treatment episodes where patients previously used another biologic, 28.9 percent were with abatacept, 15.2 percent adalimumab, 5.9 percent certolizumab, 12.0 percent etanercept, 4.4 percent golimumab, 12.4 percent infliximab, 14.8 percent rituximab, and 6.3 percent tocilizumab. At follow-up, the scientists discovered 2,530 hospitalized infections, with incidence rates varying from 13.1 (abatacept) to 18.7 (rituximab) per 100 person years. After adjustment, etanercept (hazard ratio [HR]=1.24, 95 percent confidence interval [CI]: 1.07-1.45), infliximab (HR=1.39, CI: 1.21-1.60), and rituximab (HR=1.36, CI: 1.21-1.53) had substantially higher HRs of hospitalized infection compared with abatacept.

Dr. Yun and colleagues noted, “Among RA patients with prior biologic exposure, etanercept, infliximab and rituximab were associated with a greater one year risk of hospitalized infection compared to abatacept.”

“Comparative Risk of Hospitalized Infection Associated with Biological Agents among Medicare Rheumatoid Arthritis Patients” was published in August in the journal Arthritis & Rheumatology.

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