Marko Kavcic

Dexrazoxane exposure and risk of secondary acute myeloid leukemia in pediatric oncology patients

Dexrazoxane may reduce anthracycline‐associated cardiotoxicity in pediatric cancer patients. However, concerns of secondary acute myeloid leukemia (AML) have led to restrictions on pediatric dexrazoxane use in Europe. Published data about dexrazoxane‐associated secondary AML are limited and conflicting. We sought to estimate the secondary AML risk in children receiving dexrazoxane after anthracycline exposure.

Outcome of pediatric acute myeloid leukemia patients receiving intensive care in the United States.

Objective: Children with acute myeloid leukemia are at risk for sepsis and organ failure. Outcomes associated with intensive care support have not been studied in a large pediatric acute myeloid leukemia population. Our objective was to determine hospital mortality of pediatric acute myeloid leukemia patients requiring intensive care. Design: Retrospective cohort study of children hospitalized between 1999 and 2010. Use of intensive care was defined by utilization of specific procedures and resources. The primary endpoint was hospital mortality. Setting: Forty-three children’s hospitals contributing data to the Pediatric Health Information System database. Patients: Patients who are newly diagnosed with acute myeloid leukemia and who are 28 days through 18 years old (n = 1,673) hospitalized any time from initial diagnosis through 9 months following diagnosis or until stem cell transplant. A reference cohort of all nononcology pediatric admissions using the same intensive care resources in the same time period (n = 242,192 admissions) was also studied. Interventions: None. Measurements and Main Results: One-third of pediatric patients with acute myeloid leukemia (553 of 1,673) required intensive care during a hospitalization within 9 months of diagnosis. Among intensive care admissions, mortality was higher in the acute myeloid leukemia cohort compared with the nononcology cohort (18.6% vs 6.5%; odds ratio, 3.23; 95% CI, 2.64–3.94). However, when sepsis was present, mortality was not significantly different between cohorts (21.9% vs 19.5%; odds ratio, 1.17; 95% CI, 0.89–1.53). Mortality was consistently higher for each type of organ failure in the acute myeloid leukemia cohort versus the nononcology cohort; however, mortality did not exceed 40% unless there were four or more organ failures in the admission. Mortality for admissions requiring intensive care decreased over time for both cohorts (23.7% in 1999–2003 vs 16.4% in 2004–2010 in the acute myeloid leukemia cohort, p = 0.0367; and 7.5% in 1999–2003 vs 6.5% in 2004–2010 in the nononcology cohort, p < 0.0001). Conclusions: Pediatric patients with acute myeloid leukemia frequently required intensive care resources, with mortality rates substantially lower than previously reported. Mortality also decreased over the time studied. Pediatric acute myeloid leukemia patients with sepsis who required intensive care had a mortality comparable to children without oncologic diagnoses; however, overall mortality and mortality for each category of organ failure studied was higher for the acute myeloid leukemia cohort compared with the nononcology cohort.

Leveraging Administrative Data to Monitor Rituximab Use in 2875 Patients at 42 Freestanding Children's Hospitals across the United States

OBJECTIVE To describe the pharmacoepidemiology of rituximab use in children and to estimate the frequency of infectious events within a 1-year period after rituximab exposure. STUDY DESIGN This is a retrospective cohort study of patients who received rituximab at 1 of 42 childrens hospitals contributing data to the Pediatric Health Information System between January 1999 and June 2011. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge diagnosis codes were analyzed to categorize underlying diseases (hematologic malignancies, primary immunodeficiencies, autoimmune diseases, and transplant recipients) and to estimate inpatient infectious complication rates within each category. RESULTS A total of 2875 patients with 4639 rituximab admissions were identified. The median age at index admission was 11 years (IQR, 5-15 years). The rate of rituximab admissions increased from 3 to 185 per 100,000 admissions per year over the study interval. During the 1-year follow-up period, 463 patients (16%) died. Infectious events were assessed in 2246 of the rituximab-exposed patients; 6.1% were diagnosed with sepsis and 2.0% with septic shock. The frequency of sepsis ranged from 2.4% in patients with autoimmune diseases to 12.2% in those with primary immunodeficiencies. Three patients were assigned an ICD-9-CM discharge diagnosis code for Pneumocystis joroveci pneumonia, 1 patient was assigned an ICD-9-CM discharge diagnosis code for hepatitis B, and 1 patient was assigned an ICD-9-CM discharge diagnosis code for progressive multifocal leukoencephalopathy. CONCLUSION The use of rituximab has increased significantly in children with a variety of underlying diseases. Based on ICD-9-CM code data, the rates of sepsis and other life-threatening infections after rituximab exposure vary depending on the underlying condition. Based on surveillance of infection using ICD-9-CM diagnosis codes, the rates of opportunistic infections appear to be low.

Induction mortality and resource utilization in children treated for acute myeloid leukemia at free-standing pediatric hospitals in the United States

Clinical trials in pediatric acute myeloid leukemia (AML) determine induction regimen standards. However, these studies lack the data necessary to evaluate mortality trends over time and differences in resource utilization between induction regimens. Moreover, these trials likely underreport the clinical toxicities experienced by patients.

Assembly of a cohort of children treated for acute myeloid leukemia at free-standing children's hospitals in the United States using an administrative database.

Pediatric Health Information System data were used to establish a multi‐center cohort of 1,686 children treated for newly diagnosed acute myeloid leukemia (AML). The cohort assembly process, which included myeloid leukemia ICD‐9 discharge diagnosis codes and manual review of induction chemotherapy, was validated by chart review at a single institution. The use of ICD‐9 codes alone resulted in a poor positive predictive value (PPV; 31%). Inclusion of the results from the chemotherapy review improved the PPV to 100% without compromising sensitivity (95.7%). This cohort provides a reliable source for future comparative effectiveness and clinical epidemiology studies in pediatric AML. Pediatr Blood Cancer 2013; 60: 508–511.

Accuracy of Adverse Event Ascertainment in Clinical Trials for Pediatric Acute Myeloid Leukemia

PURPOSE Reporting of adverse events (AEs) in clinical trials is critical to understanding treatment safety, but data on AE accuracy are limited. This study sought to determine the accuracy of AE reporting for pediatric acute myeloid leukemia clinical trials and to test whether an external electronic data source can improve reporting. METHODS Reported AEs were evaluated on two trials, Childrens Oncology Group AAML03P1 and AAML0531 arm B, with identical chemotherapy regimens but with different toxicity reporting requirements. Chart review for 12 AEs for patients enrolled in AAML0531 at 14 hospitals was the gold standard. The sensitivity and positive predictive values (PPV) of the AAML0531 AE report and AEs detected by review of Pediatric Health Information System (PHIS) billing and microbiology data were compared with chart data. RESULTS Select AE rates from AAML03P1 and AAML0531 arm B differed significantly and correlated with the targeted toxicities of each trial. Chart abstraction was performed on 204 patients (758 courses) on AAML0531. AE report sensitivity was < 50% for eight AEs, but PPV was > 75% for six AEs. AE reports for viridans group streptococcal bacteremia, a targeted toxicity on AAML0531, had a sensitivity of 78.3% and PPV of 98.1%. PHIS billing data had higher sensitivity (> 50% for nine AEs), but lower PPV (< 75% for 10 AEs). Viridans group streptococcal detection using PHIS microbiology data had high sensitivity (92.3%) and PPV (97.3%). CONCLUSION The current system of AE reporting for cooperative oncology group clinical trials in pediatric acute myeloid leukemia underestimates AE rates. The high sensitivity and PPV of PHIS microbiology data suggest that using external data sources may improve the accuracy of AE reporting.

Variation in Risk of Hospital-Onset Clostridium difficile Infection Across β-Lactam Antibiotics in Children With New-Onset Acute Lymphoblastic Leukemia

BACKGROUND Antibiotic exposure is common among children with leukemia. However, limited data exist regarding the risk of Clostridium difficile infection (CDI) across anti-pseudomonal β-lactam antibiotics commonly used for fever and neutropenia. METHODS A multicenter cohort of children with newly diagnosed acute lymphoblastic leukemia (ALL) was established from 43 freestanding childrens hospitals from 1999 to 2009. Patients were followed until their index CDI event, defined by the CDI ICD-9 code plus a C difficile test charge, or until 180 days from ALL diagnosis. Cox proportional hazards models were performed to identify the hazards of CDI after exposure to anti-pseudomonal β-lactams, adjusting for demographics, other antibiotic exposures, severity of illness, antacids, gastrointestinal manipulation, and confounding by hospital. RESULTS A cohort of 8268 ALL patients was assembled; median age was 5.5 years (interquartile range, 3.26-10.58). Two-hundred sixty-eight (3.2%) patients developed CDI within 180 days of ALL diagnosis. Each 1-day increase in exposure to an anti-pseudomonal β-lactam within the prior 30 days was associated with a significantly increased risk for CDI (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.01, 1.09). Ceftazidime (HR, 1.05; 95% CI, 1.02, 1.08) and cefepime (HR, 1.07; 95% CI, 1.02, 1.12) were each independently associated with CDI. CONCLUSIONS Efforts to reduce total exposure to anti-pseudomonal β-lactam agents may help to reduce the risk of CDI in children with newly diagnosed ALL. Cefepime and ceftazidime were independently associated with CDI, whereas anti-pseudomonal penicillins and carbapenems were not. These findings, if confirmed, have potential implications for antibiotic choice during periods of fever and neutropenia.

Establishing a high‐risk neuroblastoma cohort using the pediatric health information system database

International Classification of Diseases, 9th Revision (ICD‐9) code(s) for neuroblastoma do not exist, preventing identification of these patients in administrative databases. To overcome this challenge, a three‐step algorithm, using ICD‐9 codes, exclusion criteria, and manual review of chemotherapy billing data, was utilized to assemble a high‐risk neuroblastoma cohort (n = 952) from the Pediatric Health Information System (PHIS) Database and validated at a single institution [sensitivity 89.1%; positive predictive value (PPV) 96.1%]. This cohort provides a data source for future comparative effectiveness and clinical epidemiology studies in high‐risk neuroblastoma patients. Pediatr Blood Cancer 2014;61:1129–1131.

Induction mortality, ATRA administration, and resource utilization in a nationally representative cohort of children with acute promyelocytic leukemia in the United States from 1999 to 2009

Limited data exist on induction mortality of pediatric patients with acute promyelocytic leukemia in the United States, usage of all‐trans retinoic acid (ATRA) during acute promyelocytic leukemia induction, and the resources needed to deliver induction therapy.

Antifungal Prophylaxis Associated With Decreased Induction Mortality Rates and Resources Utilized in Children With New-Onset Acute Myeloid Leukemia

BACKGROUND Invasive fungal infections cause significant morbidity and mortality for children with acute myeloid leukemia (AML). Data on the comparative effectiveness of antifungal prophylaxis in this population are limited. METHODS A pediatric AML cohort was assembled from the Pediatric Health Information System database using ICD-9 codes and pharmacy data. Antifungal prophylaxis status was determined by pharmaceutical data review within 21 days of starting induction chemotherapy. Patients were followed until end of induction, death, or loss to follow-up. Cox regression analyses compared induction mortality and resources utilized between patients receiving and not receiving antifungal prophylaxis. A propensity score accounted for variation in demographic factors, location of care, and severity of illness at presentation. RESULTS Eight hundred seventy-one AML patients were identified; the induction case fatality rate was 3.7%. In the adjusted Cox regression model, patients receiving antifungal prophylaxis (57%) had a decreased hazard for induction mortality (hazard ratio [HR], 0.42; 95% confidence interval [CI], .19-.90). Children receiving prophylaxis were less frequently exposed to broad-spectrum gram-positive (incidence rate ratio [IRR], 0.87; 95% CI, .79-.97) and antipseudomonal β-lactam agents (HR, 0.91; 95% CI, .85-.96), had fewer blood cultures (IRR, 0.78; 95% CI, .71-.86), and had fewer chest CT scans (IRR, 0.73; 95% CI, .60-.88). CONCLUSIONS Antifungal prophylaxis in pediatric AML patients was associated with reduced induction mortality rates and supportive care resources. Further investigation is necessary to determine whether antifungal prophylaxis should include antimold activity.