Establishment of an 11-Year Cohort of 8733 Pediatric Patients Hospitalized at United States Free-standing Children’s Hospitals With De Novo Acute Lymphoblastic Leukemia From Health Care Administrative Data

Abstract

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.

Volume–Outcome Relationships in Pediatric Acute Lymphoblastic Leukemia: Association Between Hospital Pediatric and Pediatric Oncology Volume With Mortality and Intensive Care Resources During Initial Therapy

“…14,15 Briefly, PHIS includes administrative and billing data from 46 free standing, non competing, not for profit tertiary children's hospitals across the United States (US). PHIS data include demographics, dates of service, discharge disposition, International Classification of Diseases, 9 th Revision (ICD-9) discharge diagnosis and procedure codes, and detailed billed resource utilization information.…”

“…14 A parallel cohort was constructed from Premier using the same steps applied to assemble the PHIS cohort. In brief, all patients younger than 19 years of age with a discharge ICD-9 code for ALL (204.xx) were identified.…”

Low rates of pregnancy screening in adolescents before teratogenic exposures in a national sample of children's hospitals

“…14,15 The hospitals included in this study were primarily urban, academic hospital centers affiliated with major medical centers. The PHIS hospital size varies from 100 to 500 beds.…”

“…Patients with ALL or AML were identified with a combination of International Classification of Diseases, Ninth Revision , diagnosis codes and a manual review of induction chemotherapy exposures, as previously validated. 14,15 …”

Use of patient registries and administrative datasets for the study of pediatric cancer

“…Despite the value of cooperative study groups, there are several limitations to use of their data for research, including a high administrative burden, lack of detailed cost data, and difficulty performing comparative effectiveness research beyond the primary clinical trial question [3]. Although COG operates the Children’s Cancer Research Network registry [4], data from cooperative groups have limited application to the study of population-based cancer incidence, as they tend to focus on patients from participating centers following enrollment in individual trials [5–8]. …”