Researchers Hyon J. Kwon and colleagues evaluated case reports of heart failure after therapy with the Tumor Necrosis Factor Antagonist (TNF-a) medications etanercept (Enbrel) and infliximab (Remicade). Although specific diseases were not mentioned in the case study review, the information may affect the spondylitis population since some patients with AS or one of its related diseases are currently taking or considering treatment with either of the two TNF-a medications evaluated in the article.

They found the following results:

• 47 patients developed new or worsening heart failure during TNF-a therapy - 38 patients developed new-onset problems, while 9 patients experienced heart failure exacerbation.
  
• Of the 38 patients with new-onset heart failure, 19 (50%) had no identifiable risk factors.
  
• Ten patients younger than 50 years of age developed new-onset heart failure after receiving TNF-a medication. After the therapy was discontinued and heart failure therapy was started in these 10 patients, 3 had complete resolution of heart failure, 6 improved, and 1 died.

The researchers conclude that in a fraction of patients, TNF-a medications might induce new-onset heart failure or exacerbate existing disease. Results were published in the May 2003 volume of the Annals of Internal Medicine.