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

Summary: 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 4 years. The research design was a retrospective cohort study. Subjects were 4369 patients diagnosed with ATL aged 18 years 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 3·2% for the no agent group, 9·7% for the chemotherapy group, 10·0% for the chemotherapy + steroids group and 16·6% 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) 3·30 (1·55-7·02), P = 0·002 for the chemotherapy group; AOR 3·35 (2·18-5·17), P < 0·001 for the chemotherapy + steroids group; AOR 6·12 (3·99-9·38), P < 0·001 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.