Long-term effects of anti-tumour necrosis factor therapy on weight in patients with rheumatoid arthritis.

In patients with rheumatoid arthritis (RA), weight is an important prognostic factor. Preliminary evidence has indicated that treatment with anti-tumour necrosis factor (TNF) therapy can affect the weight of patients with RA, but the relationship between improved prognosis and weight changes remains to be clarified. Our aim was to investigate the effects of anti-TNF therapy on the weight of patients with RA following 24 months of treatment. Patients (n = 168) were selected for this retrospective analysis on the basis of having received anti-TNF therapy for the first time. Change in body weight after 12 and 24 months of treatment was calculated and analysed by multiple regression analysis using age, sex, baseline body mass index (BMI), baseline DAS28 score, disease-modifying antirheumatic drug use, steroid use and specific anti-TNF drug as explanatory variables. The mean weight change of the patient group after 12 months of treatment was +1.58 kg (95% CI 0.71 to 2.46 kg) and after 24 months was +1.80 kg (95% CI 0.69 to 2.67 kg). After 24 months, 64.3% of patients had gained weight. There was no statistically significant association between weight gain at 12 or 24 months and age, sex, steroid use at baseline, anti-TNF drug or baseline DAS28 score. Baseline BMI had a statistically significant negative association with weight gain at 12 and 24 months. RA patients with lower BMIs tend to gain weight with anti-TNF therapy. Further studies are required to determine if the weight gained is fat and/or muscle and the effects upon general health outcomes.

Neutropenia in patients receiving anti-tumor necrosis factor therapy.

OBJECTIVE: To examine the rates of and risk factors for neutropenia together with the dynamics of neutrophil and other white cell subset counts in a cohort of patients treated with a tumor necrosis factor (TNF) inhibitor for inflammatory arthritis. METHODS: We performed a retrospective cohort study examining the association between baseline demographics, clinical features, medications used, and development of neutropenia, and behavior of neutrophil and other white cell subset counts during TNF inhibitor therapy. RESULTS: In 367 patients (298 [81.2%] with rheumatoid arthritis, 38 [10.4%] with ankylosing spondylitis, and 31 [8.4%] with psoriatic arthritis), 69 (18.8%) had at least one episode of neutropenia (<2.0 x 10(9)/liter) during TNF inhibitor therapy, and of these, 6% developed serious infections secondary to neutropenia. There was no significant difference in disease, demographic, or drug variables between patients with and without neutropenia. However, patients with neutropenia had significantly lower baseline neutrophil counts (4.2 x 10(9)/liter; 95% confidence interval [95% CI] 3.8, 4.6 versus 6.2 x 10(9)/liter; 95% CI 6.0, 6.5), and a previous history of neutropenia while receiving disease-modifying antirheumatic drugs increased the risk while receiving TNF inhibitors (hazard ratio 2.97; 95% CI 1.69, 5.25). A significant drop in mean neutrophil count (1.12 x 10(9)/liter; 95% CI 0.92, 1.32) was observed after 2 weeks of TNF inhibitor therapy. Other white cell subsets tended to significantly increase. CONCLUSION: TNF inhibitor therapy is associated with a significant reduction in peripheral blood neutrophil count, leading to 19% of patients becoming neutropenic. Risk of neutropenia is significantly higher in patients with a low baseline neutrophil count or previous history of neutropenia. We suggest that patients receiving TNF inhibitor therapy would benefit from regular complete blood cell count monitoring.