Early predictor for differentiation syndrome in newly diagnosed acute promyelocytic leukaemia patients treated with single-agent arsenic trioxide.

Differentiation syndrome (DS) is the second leading cause of death in acute promyelocytic leukaemia (APL) patients. Few studies have tested predictors of DS events. This study aimed to identify optimized predictors of DS events related to APL. The data of 298 consecutive patients who were newly diagnosed with APL between December 2012 and June 2023 were retrospectively investigated. A systematic review of computer-based patient medical records was conducted to obtain clinical data, including baseline characteristics, routine blood examination findings, biochemical indices and clinical manifestations of DS. Among the 298 patients, 158 were classified into the no-DS group, while 140 had DS. Compared with those of patients without DS, the peripheral blast count, age, and WBC count at each time point were significantly different in patients with DS (P < 0.05 for all time points). Generalized linear mixed models (GLMMs) revealed that WBC Double (Coeff. 0.442, P = 0.000) and WBCPeak (Coeff. 0.879, P = 0.000) were independent risk factors for DS. The frequencies of clinical manifestations of unexplained fever (P = 0.003), dyspnoea (P = 0.002), weight gain of more than 5 kg (P = 0.006), pleural effusion (P = 0.001), pulmonary infiltrates (P < 0.001), pericardial effusion (P = 0.002) and renal failure (P = 0.006) were considerably lower in moderate DS patients than in severe DS patients. The WBCDouble occurs earlier than the WBCpeak occurrence, so WBC Double might be a new indicator of DS.