Outcomes and risk factors for mortality in Pneumocystis pneumonia patients with rheumatoid arthritis: A multicentre retrospective cohort study

Objectives: The aim is to evaluate outcomes and risk factors for death in patients with rheumatoid arthritis (RA) who developed Pneumocystis pneumonia (PCP).

Methods: We included RA patients who were diagnosed with PCP at seven participating community hospitals between July 2005 and October 2020. Clinical features were compared between survivors and non-survivors. Disease-modifying antirheumatic drugs (DMARDs) before PCP onset and after PCP recovery were also examined.

Results: Seventy RA patients developed PCP, and among them, 60 (85.7%) received methotrexate (MTX) monotherapy (40%) or MTX combination therapy with other DMARDs (45.7%). PCP was more likely to occur after 12 months of MTX monotherapy and within 3 months of MTX combination therapy. Thirteen patients (18.6%) died despite PCP treatment. Multivariable logistic regression analysis revealed that coexisting RA-associated interstitial lung disease (odds ratio, 6.18; 95% confidence interval, 1.17-32.63) and delayed PCP treatment with anti-Pneumocystis drugs (odds ratio, 15.29; 95% confidence interval, 1.50-156.15) are significant risk factors for PCP mortality in RA patients. Most survivors successfully resumed DMARD therapy without PCP prophylaxis; one recurrent PCP case was observed during follow-up (median, 4.1 years).

Conclusions: To avoid a treatment delay, RA patients should be followed up for signs and symptoms of PCP development, especially those with RA-associated interstitial lung disease.