Evaluation of Patient Outcome Benefits and Resource Utilization Associated with a Hematopathologist-Directed Workflow for Diagnosis of Hematological Malignancies

Traditionally, the appropriate selection of diagnostic tests is determined solely by the ordering clinician. This can be quite challenging in the case of hematological malignancies, where guidelines require detailed correlation between molecular, morphologic and immunologic results for accurate classification. We have undertaken a study to determine the impact of including a hematopathologist in the initial test selection and case management. Our working hypothesis is that this should improve the timeliness and accuracy of diagnoses. Therefore, an analytical framework based on measuring patient outcomes and resource utilization is feasible to compare diagnostic workflows. We compared outcomes and resource utilization between cohorts of patients in which diagnosis was obtained using the traditional or hematopathologist supplemented workflows. Two studies were performed: the first utilized a smaller regional electronic health record (EHR) database from a Southeast US practice, affording a higher degree of practice and demographics uniformity, the second utilized a more heterogeneous national US claims database. Patients were matched by ultimate diagnosis and demographics and all studies were retrospective.

In the first regional cohort, we studied 791 patients collected between 2007 and 2009 and required a minimum of one year of data post bone marrow biopsy to be available. The patients had a diagnostic evaluation by a hematopathologist-managed workflow (Test, n=640) or by laboratories that follow a traditional diagnostic workflow (Control, n=151). Patients were matched by gender, age, ethnicity, ECOG status and diagnosis. Outcomes were assessed as overall survival and transfusion dependence. Resource utilization (lab tests and supportive therapeutics) was also evaluated. As a sensitivity analysis, outcomes of 19, 416 patients from the national cohort were evaluated using patients collected between 2006 and 2008. These patients had a diagnostic evaluation by a hematopathologist-managed workflow (Test, n=3, 236) or by laboratories that follow a traditional diagnostic workflow (Control, n=16, 180). Patients were matched by gender, age, ethnicity, geography, payer type, Charlson co-morbidities and diagnosis.

Overall survival benefit for the regional EHR-based study was not observed beyond statistical significance (p=0.564, HR=0.530; 95%CI=0.233–1.205) although a strong trend favoring the Test cohort could be observed. In the national study, where claims data over one year was available for a greater proportion of patients, improved overall survival (p=0.050, HR=0.634; 95%CI=0.402–1.001) for Test cohort patients could be discerned. Test cohort patients exhibited improved transfusion dependence (p=0.009; HR=0.455, 95% CI=0.252–0.824) in the regional study, but this effect was not observed in the national study set (p=0.644; HR=0.959, 95% CI=0.803–1.145). Resource utilization was assessed in the regional study and Test cohort patients appear associated with significantly reduced resource utilization: lab tests (p<0.0001), ancillary procedures (p<0.0001), therapeutics (p<0.0001) and erythropoietin stimulating agents (p<0.0001).

We present an analytical framework by which the impact on patient outcomes can be evaluated as a function of adding a hematopathologist in the selection of diagnostic tests and case management. Our initial results using EHR records from a multi-site single practice, and claims data from a national database, suggest that differences in outcomes and resource utilization can be discerned as a function of diagnostic workflow. Though we have done our best to reduce the possibility of distortion by confounding variables and unidentified bias, we hope that this study will provide the impetus for further replication across multiple cohorts, labs and prospective trials in the future.

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