Risk factors for cryptococcal infection among patients with rheumatoid arthritis receiving different immunosuppressive medications.

Increasing evidence indicates that the risk of cryptococcal infections is increased in patients with rheumatoid arthritis (RA). However, the association between cryptococcosis and immunosuppressive medications in RA patients is still uncertain and little is known about risk factors for cryptococcal disease among RA patients. We conducted a retrospective case-control study to investigate the epidemiology of RA patients with cryptococcosis in a medical centre during the period 2001-14. We estimated ORs with 95% CI for cryptococcosis according to co-morbidities and immunosuppressive medications by using backward stepwise logistic regression. Among 9132 newly diagnosed RA patients, 20 (0.22%) were newly diagnosed with cryptococcal infection after RA identification. All cryptococcosis cases had been receiving corticosteroid treatment for some time (3.9±3.3 years) before infection. After full adjustment, chronic kidney disease (adjusted OR (aOR) 2.72, 95% CI 1.04-7.08, p 0.041) was a significant risk factor for cryptococcosis in RA patients. Exposure to adalimumab (monoclonal anti-tumour necrosis factor (TNF) antibodies) (aOR 4.50, 95% CI 1.03-19.66, p 0.046) were significantly associated with increased risks of cryptococcosis. Time to cryptococcosis diagnosis among RA patients receiving anti-TNF biologicals was shorter than in patients not receiving anti-TNF biologicals (1.5±1.2 years versus 8.4±5.5 years, p<0.001). Among RA patients, the risk for development of cryptococcosis was higher among those who had chronic kidney disease and were receiving the monoclonal anti-TNF antibody adalimumab. Therefore, we suggest that cryptococcal infection should be suspected in RA patients with risk factors.