Surge in Newly Identified Diabetes Among Medicaid Patients in 2014 Within Medicaid Expansion States Under the Affordable Care Act

Harvey W. Kaufman; Zhen Chen; Vivian A. Fonseca; Michael J. McPhaul


Diabetes Care. 2015;38(5):833-837. 

In This Article

Abstract and Introduction


Objective Twenty-six states and the District of Columbia expanded Medicaid in January 2014 pursuant to the Affordable Care Act (ACA); 24 states did not. This created an opportunity to examine the impact of Medicaid expansion on the number of Medicaid patients with newly identified diabetes among enrollees (19–64 years of age) who had laboratory testing through Quest Diagnostics.

Research Design and Methods Newly identified diabetes was defined as an ICD-9 diagnosis code of 250.x (diabetes) or hemoglobin A1c of >6.4% (46 mmol/mol) within the first 6 months of a calendar year and the absence of both in the preceding calendar year within our data repository.

Results We identified 215,398 and 218,890 patients who met our definition of newly diagnosed diabetes within the first 6 months of 2013 (control period) and 2014 (study period), respectively (a 1.6% increase). We identified 26,237 Medicaid-enrolled patients with new diabetes in the control period vs. 29,673 in the study period: an increase of 13%. The number of Medicaid-enrolled patients with newly identified diabetes increased by 23% (14,625 vs. 18,020 patients) in the 26 states (and District of Columbia) that expanded Medicaid compared with an increase of 0.4% (11,612 vs. 11,653 patients) in the 24 states that did not expand Medicaid during this period. Similar differences were observed in younger and older adults and for both men and women.

Conclusions This study suggests that in the states that expanded Medicaid under the ACA, an increased number of Medicaid patients with diabetes are being diagnosed and treated earlier. This could be anticipated to lead to better long-term outcomes.


The Affordable Care Act (ACA) refers to both the Patient Protection and Affordable Care Act (public law 111–148) and the Health Care and Education Reconciliation Act (public 111–152) of 2010. Together, the ACA expanded Medicaid eligibility to reach nearly all nonelderly adults with incomes ≤138% of the federal poverty level (FPL)—about 16,105 USD for an individual in 2014. Effective 1 January 2014, this expansion established a new coverage pathway for millions of uninsured adults who were previously excluded from the program. After a U.S. Supreme Court decision, states could decide whether they would accept the conditions to expand Medicaid.[1] Twenty-six states and the District of Columbia ("expansion states") agreed to expand Medicaid; 24 states did not.[2]

This division of states created an opportunity to examine the impact of Medicaid expansion on specific health metrics, such as detection of disease, using the Quest Diagnostics database. In this Quest Diagnostics Health Trends study, we used deidentified patient data to assess changes in identification of newly identified laboratory-defined diabetes after implementation of Medicaid expansion.

We selected diabetes as an indicator because it is a common medical condition affecting ~28–29 million Americans and has a much larger population at risk.[3] In addition, aggressive prevention and treatment programs have been shown to improve outcomes.[4] Clear definitions have been established that are amenable to analysis using laboratory measurements in a large database-centered epidemiological study.[5] Finally, any observations derived from such an analysis are likely to be applicable to other common chronic medical conditions.