Objective To evaluate the quality of a multiyear linkage between the Colorado all‐payer claims database (APCD) and the Colorado Central Cancer Registry. Data sources Secondary 2012–2017 data from the APCD and the Colorado Cancer Registry. Study design Descriptive analysis of the proportion of cases captured by the linkage in relation to the cases reported by the registry. Data collection/extraction methods We used probabilistic linkage to combine records from both data sources for all patients diagnosed with cancer. Results We successfully linked 93% of the 146,884 patients in the registry. Approximately 63% of linked patients were perfect matches on five identifiers. Of partial matches, 81.6% were matched on four identifiers with missing or partial Social Security Numbers. The linkage rate was lower for uninsured patients at diagnosis (74.7%) or patients with private plans (89.4%) but close to 100% for Medicare and Medicaid enrollees. Most of the 29% of patients who did not have claims at the time of diagnosis were covered by private plans that may not submit claims. Conclusions APCD‐registry linkages are a promising source of data to conduct population‐based research from multiple payers. However, not all payers submit claims, and the quality of the data may vary by state.

Background: We evaluated treatment concordance between the Colorado All Payer Claims Database (APCD) and the Colorado Central Cancer Registry (CCCR) to explore whether APCDs can augment registry data. We compare treatment concordance for breast cancer, an extensively studied site with an inpatient reporting source and select leukemias that are often diagnosed outpatient. Methods: We analyzed concordance by cancer type and treatment, patient demographics, reporting source, and health insurance, calculating the sensitivity, specificity, positive predictive values (PPV) and Kappa statistics. We estimated an adjusted logistic regression model to assess whether the APCD statistically significantly reports additional cancer-directed treatments. Results: Among women with breast cancer, 14% had chemotherapy treatments that were absent from the CCCR. Missing treatments were more common among women younger than age 50 (15%) and patients aged 75 and older (19%), rural residents (17%), and when the reporting source was outpatient (22%). Similar and more pronounced patterns for people with leukemia were observed. Concordance for oral treatments was lower for each cancer. Sensitivity and PPVs were high, with moderate Kappa statistics. The APCD was 5.3 percentage points less likely to identify additional treatments for breast cancer patients and 10 percentage points more likely to identify additional treatments when the reporting source was an outpatient facility. Conclusion: A robust data infrastructure is needed to investigate research questions that require population-level analyses, particularly for questions seeking to reduce health inequity and comparisons across payers, including Medicare Advantage and fee-for-service. APCD data are a step toward creating an infrastructure for cancer, particularly for patients who reside in rural areas and/or receive care from outpatient centers.

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ImportancePrior research has reported undertreatment among patients with cancer who are insured by Medicaid, but this finding may be due, in part, to incomplete data in cancer registries.ObjectiveTo compare disparities in radiation and hormone therapy between women with breast cancer covered by Medicaid and those with private insurance using the Colorado Central Cancer Registry (CCCR) and CCCR data supplemented with All Payer Claims Data (APCD).Design, Setting, and ParticipantsThis observational cohort study included women aged 21 to 63 years who received breast cancer surgery. We linked the CCCR and Colorado APCD to identify Medicaid and privately insured women who were newly diagnosed with invasive, nonmetastatic breast cancer between January 1, 2012, and December 31, 2017. In the radiation treatment analysis, we narrowed the sample to women who received breast-conserving surgery (Medicaid, n = 1408; private, n = 1984) and in the hormone therapy analysis, we selected women who were hormone-receptor positive (Medicaid, n = 1156; private, n = 1667).Main Outcomes and MeasuresWe used logistic regression to estimate the likelihood of treatment within 12 months to assess whether the results varied between data sources.ResultsThere were 3392 and 2823 participants in the radiation and hormone therapy cohorts, respectively. The mean (SD) age was 51.71 (8.30) years in the radiation therapy cohort, and 52.00 (8.16) years in the hormone therapy cohort. Among the participants, there were 140 (4%) and 105 (4%) who were Black non-Hispanic, 499 (15%) and 406 (14%) who were Hispanic, 2602 (77%) and 2190 (78%) were White, and 151 (4%) and 122 (4%) were other/unknown in the radiation and hormone therapy cohorts, respectively. A higher percentage of women were aged 50 years or younger in the Medicaid samples (40% vs 34% in the privately insured sample) and identified as non-Hispanic Black (about 7%) or Hispanic (approximately 24%). Treatment was underreported in both sources, but to a lesser extent in the APCD (2.5% and 2.0% for Medicaid and private insurance, respectively) compared with CCCR (19.5% and 13.3% for Medicaid and private insurance, respectively). Using CCCR data, Women with Medicaid insurance were 4 (95% CI, −8 to −1; P = .02) and 10 (95% CI, −14 to −6; P < .001) percentage points less likely to have a record of radiation and hormone therapy compared with privately insured women, respectively. Using combined CCCR and APCD, no statistically significant disparity was observed in radiation or hormone therapy between Medicaid-insured and privately insured women.Conclusions and RelevanceAmong women with breast cancer covered by Medicaid vs private insurance, cancer treatment disparities may be overestimated if based solely on cancer registry data.