BACKGROUND: The use of Medicaid data to study @entity5 -related outcomes would be highly desirable. However, the accuracy of Medicaid claims data in the identification of incident cases of @entity0 is unknown. OBJECTIVES: (1) To estimate the sensitivity of Medicaid claims data for case ascertainment of @entity0 , and (2) to determine the positive predictive value ( @entity2286 ) of diagnostic and procedure codes retrieved from Medicaid claims, using the Ohio Cancer Incidence Surveillance System (OCISS) as the gold standard. METHODS: The study used the linked OCISS and Medicaid enrollment files, 1997-1998 (n = 1,648). The claims search yielded 2,635 incident cases, of which 1,132 were also identified through the OCISS-Medicaid files. Sensitivity and @entity2286 of Medicaid data were calculated in subgroups of the population. RESULTS: The overall sensitivity was 68.7 percent, but varied greatly across the subgroups of the population. It was lower among @entity1 enrolled in Medicaid only for part of the study year than those enrolled in Medicaid for 12 months of the study year (56.7 percent and 78.0 percent respectively, p < 0.0001), and lower among those who are dual Medicare-Medicaid eligible compared to those not participating in the Medicare program (63.1 percent and 78.6 percent respectively, p < 0.0001). The overall @entity2286 was 43.0 percent, increasing up to 86.6 percent in the presence of procedure codes indicating the presence of mastectomy and lumpectomy, in addition to that of @entity0 . CONCLUSIONS: The sensitivity of Medicaid claims for case ascertainment of @entity0 is somewhat low, but improves considerably when accounting for @entity1 enrolled in Medicaid for the entire duration of the study year. The @entity2286 is poor due to a high rate of false positives. The higher @entity2286 obtained in the presence of procedure codes, in addition to diagnosis codes, will help researchers to correctly identify incident cases of @entity0 using Medicaid claims data.

Ability of Medicaid claims data to identify incident cases of XXXX in the Ohio Medicaid population.

@entity5 :: ('MESH:D009369', 'Disease') :: ['cancer'] @entity1 :: ('9606', 'Species') :: ['women'] @entity2286 :: ('12211', 'Species') :: ['PPV'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast cancer diagnosis', 'breast cancer']
@entity0 :: (MESH:D001943,Disease) :: ['breast cancer']
