One-third of patients with rheumatoid arthritis-associated ILD experience acute exacerbation

The incidence of acute exacerbation was nearly one-third in patients with rheumatoid arthritis-associated interstitial lung disease, researchers reported in Chest.

Ever smoking, lower lung function and exercise capacity were identified as risk factors for acute exacerbation in this patient population.

“Determining the incidence, risk factors and effects of acute exacerbation on the prognosis in patients with rheumatoid arthritis-associated ILD remains challenging,” Byoung Soo Kwon, MD, from the division of pulmonary and critical care medicine at Seoul National University Bundang Hospital, Seongnam, South Korea, and colleagues wrote.

Researchers analyzed data from 310 patients with rheumatoid arthritis-associated ILD (RA-ILD; mean age, 61.9 years; 56.2% women) from Asan Medical Center in Seoul, South Korea.

During a median follow-up of 47.7 months, 28.1% of patients experienced acute exacerbation. The cumulative incidence rate of acute exacerbation in patients with RA-ILD was 9.2% at 1 year, 19.8% at 3 years and 29.4% at 5 years.

Significant risk factors for acute exacerbation occurrence included ever-smoker status (HR = 1.762; 95% CI, 1.129-2.748; P = .013), lower FVC (HR = 0.966; 95% CI, 0.951-0.981; P < .001) and shorter 6-minute walk distance (HR = 0.997; 95% CI, 0.995-0.999; P = .005). After adjustment for age, sex, smoking status, lung function, exercise capacity and high-resolution CT scan pattern, acute exacerbation was a significant prognostic factor for overall survival in this patient population (HR = 2.423; 95% CI, 1.605-3.66; P < .001).

Median survival time for patients with RA-ILD was 137.8 months.

Of 87 patients with acute exacerbations, 18.4% were admitted to the ICU, of whom 87.5% received mechanical ventilation and 68.8% died. There were also six fatalities among patients not admitted to the ICU during hospitalization. The rate of 30-day mortality after acute exacerbation was 12.6% and 90-day mortality was 29.9%.

“Our data suggest that a history of ever smoking, lower FVC and shorter 6-minute walk distance indicate a higher risk of acute exacerbations in patients with RA-associated ILD,” the researchers wrote.