Background Acute lymphoblastic leukemia (ALL) accounts for almost one quarter of pediatric cancer in the United States. Despite cooperative group therapeutic trials, there remains a paucity of large cohort data on which to conduct epidemiology and comparative effectiveness research studies. Research Design We designed a three-step process utilizing ICD-9 discharge diagnoses codes and chemotherapy exposure data contained in the Pediatric Health Information System administrative database to establish a cohort of children with de novo ALL. This process was validated by chart review at one of the pediatric centers. Results An ALL cohort of 8,733 patients was identified with a sensitivity of 88% (95% CI: 83–92%) and a positive predictive value of 93% (95% CI: 89–96%). The 30-day all cause inpatient case fatality rate using this three-step process was 0.80% (95% CI: 0.63–1.01%), which was significantly different than the case fatality rate of 1.40% (95% CI: 1.23–1.60%) when ICD-9 codes alone were used. Conclusions This is the first report of assembly and validation of a cohort of de novo ALL patients from a database representative of free standing children's hospitals across the United States. Our data demonstrate that the use of ICD-9 codes alone to establish cohorts will lead to substantial patient misclassification and result in biased outcome estimates. Systematic methods beyond the use of just ICD-9 codes must be employed prior to analysis to establish accurate cohorts of patients with malignancy. A similar approach should be followed when establishing future cohorts from administrative data.

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.

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.

Background 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. Procedure A retrospective cohort of children with newly identified malignancies (excluding AML) receiving anthracyclines between January 1, 1999 and March 31, 2011 was established using the Pediatric Health Information System (PHIS). Patients were followed for all subsequent admissions to identify dexrazoxane exposures and secondary AML, defined by AML ICD-9 codes and AML induction chemotherapy. Logistic regression was used to model the association of dexrazoxane and secondary AML risk. A propensity score was used to adjust for measurable confounding. Results Of 15,532 patients in the cohort exposed to anthracyclines, 1,406 received dexrazoxane. The secondary AML rate was 0.21% (3 of 1,046) in dexrazoxane-exposed and 0.55% (77 of 14,126) in unexposed patients. In a propensity score-adjusted multivariate analysis, dexrazoxane exposure was not associated with an increased risk of secondary AML, OR =0.38, 95% CI 0.11–1.26. Conclusions Dexrazoxane was not associated with an increased risk of secondary AML in a large cohort of pediatric cancer patients receiving anthracyclines in US hospitals. While these data support dexrazoxane’s safety in the general pediatric oncology population, additional studies are needed to confirm these findings and to quantify dexrazoxane’s long-term cardioprotective effects. Pediatr Blood Cancer

Background 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. Methods The Pediatric Health Information System database was used to identify children treated for presumed de novo AML between 1999 and 2010. Induction mortality, risk factors for induction mortality, and resource utilization by induction regimen were estimated using standard frequentist statistics, logistic regression and Poisson regression, respectively. Results A total of 1686 patients were identified with an overall induction case fatality rate of 5.4% that decreased from 9.8% in 2003 to 2.1% in 2009 (p= 0.0023). The case fatality rate was 9.0% in the intensively-timed DCTER induction and 3.8% for ADE induction (adjusted OR=2.2, 95% CI 1.1-4.5). Patients treated with intensively-timed DCTER regimens had significantly greater antibiotic, red cell/platelet transfusion, analgesic, vasopressor, renal replacement therapy, and radiographic resource utilization than patients treated with ADE regimens. Resource utilization was substantially higher than reported in published pediatric AML clinical trials. Conclusions Induction mortality for children with AML decreased significantly as ADE use increased. In addition to higher associated mortality, intensively-timed DCTER regimens had a correspondingly higher use of health care resources. Using resource utilization data as a proxy for adverse events, adverse event rates reported on clinical trials substantially underestimated the clinical toxicities of all pediatric AML induction regimens.