Materials and methods
We retrospectively reviewed the medical records of all children aged under 15 years and diagnosed with AML who received an AML chemotherapy protocol from May 2003 to August 2019 at the Pediatric Oncology Division, Department of Pediatrics, Songklanagarind Hospital, the major tertiary care-referral center in Southern Thailand. The study was approved by the Human Research Ethics Committee of the institute. Clinical data including gender, age, tumour morphology, flow cytometry, treatment courses and laboratory investigations were collected. The treatment protocol was divided into 3 periods. From 2003-2008, most patients received chemotherapy consisting of the Berlin-Frankfurt-Münster (BFM)-83 regimen.11 Between 2008 and 2014, the chemotherapy regimen involved 6 cycles of the BFM-98 regimen.12 After 2014, all patients received chemotherapy according to the Children’s Oncology Group.13 All patients underwent similar laboratory investigation protocols for each session of chemotherapy treatment including renal function. Posttreatment responses were evaluated after patients completed the induction chemotherapy course. Overall survival was calculated from the date of the first diagnosis to date of death or last follow-up.
We defined AKI following the Kidney Disease: Improving Global Outcomes (KDIGO) criteria,14 i.e. a rise in serum creatinine (SCr) ≥ 0.3 mg/dL within 48 hours or 1.5-fold from baseline over 7 days from nadir to peak and higher than upper normal SCr for age. Severe AKI was defined as AKI stage 3 (SCr rise of at least 3-fold from baseline in 7 days). Estimated glomerular filtration rate (eGFR) was used to determine renal function by calculating creatinine clearance using the original Schwartz formula with a modified Jaffe assay15 and modified Schwartz formula with enzymatic creatinine results (after May 2011).16 An eGFR was considered normal if ≥ 90 mL/min/1.73 m2. Tumor lysis syndrome was diagnosed by the presence of two or more of the following abnormal conditions: hyperkalemia (≥ 6 mmol/L), hyperuricemia (≥ 8 mmol/L), hyperphosphatemia (≥ 6.5 mmol/L), and hypocalcemia (< 7 mmol/L) within 3 days before or 7 days after the initiation of chemotherapy according to the Cairo and Bishop criteria.17 Septic shock was defined as per international pediatric sepsis consensus guidelines.18