Acute exacerbation most frequent cause of death in patients with rheumatoid arthritis-ILD, IPF

The most frequent cause of death in patients with rheumatoid arthritis-associated interstitial lung disease and also those with idiopathic pulmonary fibrosis is acute exacerbation, researchers reported.

The prognosis after acute exacerbation was significantly better in patients with rheumatoid arthritis-ILD compared with those with IPF, according to results published in Respiratory Medicine.

“In Japan, malignancy and respiratory disease are major causes of death in rheumatoid arthritis patients,” Junji Otsuka, MD, PhD, from the department of respiratory medicine at the National Hospital Organization Fukuoka Hospital and the department of respiratory medicine at the National Hospital Organization Omuta Hospital in Japan, and colleagues wrote. “However, the cause of death between rheumatoid arthritis-associated ILD and IPF are not well known.”

Otsuka and colleagues conducted a retrospective review of data from 149 patients with rheumatoid arthritis-ILD (RA-ILD; mean age, 71 years; 61.7% women) and 305 patients with IPF (mean age, 72 years; 25.9% women) in Japan. Researchers evaluated the frequency of acute exacerbations and risk factors in patients with and without RA-ILD with and also compared prognosis after acute exacerbation between patients with RA-ILD and IPF.

Eighteen percent of patients with RA-ILD and 27.5% of patients with IPF had acute exacerbations during the study period.

Following acute exacerbation, the median survival time for patients with RA-ILD was 277 days and 60 days for patients with IPF (P log-rank test = .038).

In a univariate analysis, the following were identified as factors associated with acute exacerbation:

• ILD diagnosis before RA onset (OR = 3.821; 95% CI, 1.441-10.131; P < .01);
• honeycomb change on high-resolution CT (OR = 3.42; 95% CI, 1.389-8.424; P < .01);
• previous methotrexate use (OR = 0.14; 95% CI, 0.031-0.619; P < .01);
• methotrexate use at time of acute exacerbation (OR = 0.079; 95% CI, 0.01-0.602; P = .013);
• serum albumin level (OR = 0.146; 95% CI, 0.059-0.365; P < .01);
• percent predicted vital capacity (OR = 0.925; 95% CI, 0.885-0.967; P < .01);
• percent predicted FVC (OR = 0.023; 95% CI, 0.880-0.968; P < .01); and
• percent of carbon monoxide diffusion capacity (OR = 0.887; 95% CI, 0.839-0.939; P < .01).

Serum albumin level (OR = 0.09; 95% CI, 0.011-0.733; P = .012) and percent of carbon monoxide diffusion capacity (OR = 0.81; 95% CI, 0.814-0.964; P < .01) were independent risk factors for acute exacerbations in a multivariate analysis, the researchers reported.

Thirty-two patients with RA-ILD and 133 patients with IPF died during the study period. Acute exacerbation was the most frequent cause of death among patients with RA-ILD and patients with IPF, at 34.4% and 44.4%, respectively, the researchers wrote.