Quantification of the effect of chemotherapy and steroids on risk of Pneumocystis jiroveci among hospitalized patients with adult T-cell leukaemia

This study aimed to quantify the risks of Pneumocystis pneumonia (PCP) among adult T-cell leukaemia (ATL) patients without prophylaxis. We used hospital administrative data collected nationwide in Japan over 4years. The research design was a retrospective cohort study. Subjects were 4369 patients diagnosed with ATL aged 18years or older. The subjects were categorized into four treatment groups: no agent, chemotherapy, chemotherapy+steroids and steroids. We described the risks of PCP among ATL patients without prophylaxis. Risks of PCP were 32% for the no agent group, 97% for the chemotherapy group, 100% for the chemotherapy+steroids group and 166% for the steroids group. Logistic regression analyses showed that the chemotherapy, chemotherapy+steroids and steroids groups had significantly higher risk of PCP than did the no agent group [adjusted odds ratio (AOR) 330 (155-702), P=0002 for the chemotherapy group; AOR 335 (218-517), P<0001 for the chemotherapy+steroids group; AOR 612 (399-938), P<0001 for the steroids group]. In conclusion, the chemotherapy, chemotherapy+steroids and steroids groups had significantly higher risks of PCP. Prophylaxis for PCP among ATL patients being treated with chemotherapy, chemotherapy+steroids and steroids is highly recommended.