Tradeoffs of using administrative claims and medical records to identify the use of personalized medicine for patients with breast cancer.

BACKGROUND: Administrative claims and medical records are important data sources to examine healthcare utilization and outcomes. Little is known about identifying personalized medicine technologies in these sources.
OBJECTIVES: To describe agreement, sensitivity, and specificity of administrative claims compared with medical records for 2 pairs of targeted tests and treatments for breast cancer. RESEARCH
DESIGN: Retrospective analysis of medical records linked to administrative claims from a large health plan. We examined whether agreement varied by factors that facilitate tracking in claims (coding and cost) and that enhance medical record completeness (records from multiple providers).
SUBJECTS: Women (35 to 65 y of age) with incident breast cancer diagnosed in 2006 to 2007 (n=775). MEASURES: Use of human epidermal growth factor receptor 2 (HER2) and gene expression profiling (GEP) testing, trastuzumab, and adjuvant chemotherapy in claims and medical records.
RESULTS: Agreement between claims and records was substantial for GEP, trastuzumab, and chemotherapy, and lowest for HER2 tests. GEP, an expensive test with unique billing codes, had higher agreement (91.6% vs. 75.2%), sensitivity (94.9% vs. 76.7%), and specificity (90.1% vs. 29.2%) than HER2, a test without unique billing codes. Trastuzumab, a treatment with unique billing codes, had slightly higher agreement (95.1% vs. 90%) and sensitivity (98.1% vs. 87.9%) than adjuvant chemotherapy.
CONCLUSIONS: Higher agreement and specificity were associated with services that had unique billing codes and high cost. Administrative claims may be sufficient for examining services with unique billing codes. Medical records provide better data for identifying tests lacking specific codes and for research requiring detailed clinical information.