Pharmaceutical Research

More studies need to be done on potential risk of incident heart failure among certain patients taking TNF-alpha antagonists

Tumor necrosis factor alpha (TNF-alpha) antagonists have emerged as an effective therapy for patients with rheumatoid arthritis (RA), Crohn's disease (CD), and other conditions. These drugs block the action of TNF-alpha, one of the key cytokines that triggers and sustains the inflammatory response that often runs unchecked in these diseases. However, a new study of over 4,000 patients under age 50 with RA and CD revealed a few new-onset heart failure cases potentially linked to use of the TNF-alpha antagonists, etanercept and infliximab. Younger patients were studied in order to avoid potential confounding due to age-related cardiovascular comorbidities.

Although the difference in rate of heart failure between those taking the medication and those not taking it was not significant, there were some confounding factors that the sample was too small to adjust for. For example, patients with RA already have a risk of developing heart failure due to their underlying disease. Thus, the authors recommend studying larger groups of patients using these drugs to obtain more precise heart failure risk estimates.

Researchers at the University of Alabama Center for Education and Research on Therapeutics of Musculoskeletal Disorders examined administrative claims data from a large U.S. health care organization to identify RA and CD patients receiving infliximab or etanercept (about half of those studied). They compared their development of new-onset heart failure with similar patients who were receiving non-biologic immunosuppressives (unexposed). Suspected heart failure cases were confirmed with medical records.

Overall, only 0.2 percent or 9 cases of heart failure were found in this large population of relatively young RA and CD patients. Although the absolute rates of heart failure were low, patients with RA taking infliximab or etanercept had 4.3 times more risk of heart failure and those with CD had 20 percent greater risk compared to unexposed patients.

If these absolute risk differences had been significant, the researchers calculated that 294 RA patients and 3,333 CD patients would have to be exposed to this medication for someone to be harmed. Nevertheless, the relative risk of heart failure observed among RA patients is a source of concern, note the researchers. Their study was supported in part by the Agency for Healthcare Research and Quality (HS10389).

See "Heart failure among younger rheumatoid arthritis and Crohn's patients exposed to TNF-alpha antagonists," by Jeffrey R. Curtis, Ph.D., Judith M. Kramer, M.D., M.S., Carolyn Martin, and others, in Rheumatology 46, pp. 1688-1693, 2007.

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