Technical evaluation of methods for identifying chemotherapy-induced febrile neutropenia in healthcare claims databases

Abstract

BackgroundHealthcare claims databases have been used in several studies to characterize the risk and burden of chemotherapy-induced febrile neutropenia (FN) and effectiveness of colony-stimulating factors against FN. The accuracy of methods previously used to identify FN in such databases has not been formally evaluated.MethodsData comprised linked electronic medical records from Geisinger Health System and healthcare claims data from Geisinger Health Plan. Subjects were classified into subgroups based on whether or not they were hospitalized for FN per the presumptive “gold standard” (ANC <1.0×109/L, and body temperature ≥38.3°C or receipt of antibiotics) and claims-based definition (diagnosis codes for neutropenia, fever, and/or infection). Accuracy was evaluated principally based on positive predictive value (PPV) and sensitivity.ResultsAmong 357 study subjects, 82 (23%) met the gold standard for hospitalized FN. For the claims-based definition including diagnosis codes for neutropenia plus fever in any position (n=28), PPV was 100% and sensitivity was 34% (95% CI: 24–45). For the definition including neutropenia in the primary position (n=54), PPV was 87% (78–95) and sensitivity was 57% (46–68). For the definition including neutropenia in any position (n=71), PPV was 77% (68–87) and sensitivity was 67% (56–77).ConclusionsPatients hospitalized for chemotherapy-induced FN can be identified in healthcare claims databases--with an acceptable level of mis-classification--using diagnosis codes for neutropenia, or neutropenia plus fever.

Value of incorporating newly identified risk factors into risk prediction for chemotherapy‐induced febrile neutropenia

“…Only the first cycle was assessed to obtain the most unbiased FN risk, because FN risk in subsequent cycles might be affected by dose modification due to other complications. FN was defined by a combination of ICD‐9 codes, laboratory values, and health service utilization, using one of the following methods:10, 11, 12, 14 (1) neutropenia ICD‐9 code 288.0 and fever ICD‐9 code 780.6 (within 7 days); or (2) absolute neutrophil count (ANC) <1000/μL and fever ICD‐9 code 780.6 (within 7 days); or (3) hospitalization with neutropenia ICD‐9 code 288.0 as the primary diagnosis; or (4) neutropenia ICD‐9 code 288.0 or ANC <1000/μL within 7 days of hospitalization with ICD‐9 code of bacterial/fungal infection.…”

Use of prophylactic growth factors and antimicrobials in elderly patients with cancer: a review of the Medicare database

“…We compensated for this by using a sensitivity analysis to examine whether the drug combinations in the unclassified risk category included highly myelosuppressive agents. We employed a method previously described by Weycker et al [14]. By using this method, we found that in both breast and lung cancer, several patients in the unclassified risk category receiving GCSF were treated with one or more agents considered highly myelosuppressive (Supplementary Table S4), thus providing justification for the use of growth factor support.…”

“…Regimens not defined as high or intermediate FN risk were combined into an unclassified FN risk category. To further evaluate unclassified FN risk regimens, we identified the number of chemotherapeutic agents by level of myelosuppression (high, low, none) according to the definition from a prior study by Wecker and colleagues [14]. For each cycle, we categorized patients into one of the following four groups in descending hierarchical order: (1) two or more high myelosuppressive agents, (2) exactly one high myelosuppressive agent, (3) one or more low myelosuppressive agents in the absence of high myelosuppressive agents, and (4) none (mainly biologic agents, for example, rituximab).…”

A retrospective study of the clinical and economic burden during hospitalizations among cancer patients with febrile neutropenia

“…Furthermore, no single ICD-9 code exists for FN, which can contribute to errors of omission and commission during coding of the data. As an operational definition of FN, hospitalization with a diagnosis of neutropenia has a sensitivity of 67-80% and a specificity of 94% 31,32 when compared with the clinical definition of FN, which is fever (a single oral temperature !38.3 C or !38.0 C for at least 1 hour) with neutropenia (5500 neutrophils/mL or 51000 neutrophils/mL and a predicted decline to 5500 neutrophils/mL over the next 48 hours) 14 . To further validate the definition of FN, Premier records were linked to the OptumInsight database to determine the percentage of patients that had received chemotherapy before hospitalization for FN.…”