Surge in Newly Identified Diabetes Among Medicaid Patients in 2014 Within Medicaid Expansion States Under the Affordable Care Act
Kaufman HW, Chen Z, Fonseca VA, McPhaul MJ.
Diabetes Care. 2015 Mar 15. [Epub ahead of print]
Does Covering More People Find More Cases of Diabetes?
As a result of the Affordable Care Act (ACA), each US state had the option of expanding Medicaid eligibility to reach nearly all nonelderly, low-income adults beginning January 1, 2014. Although 24 states chose not to, 26 states and the District of Columbia opted for the expansion, setting up a natural experiment of the effects of providing coverage to more individuals.
In the current study, Kaufman and colleagues used data from a very large clinical laboratory database that includes individuals from all states to identify new cases of diabetes in the first 6 months of 2013 (pre-ACA) and 2014 (post-ACA). Newly identified diabetes was defined as having an ICD-9 diagnosis code of 250.x (diabetes) or a glycated hemoglobin (A1c) level ≥ 6.5% within the control or study period, and the absence of both in the preceding calendar year (January–December 2012 for control period and January–December 2013 for the study period). Patients were required to have at least one test during the control period. Medicaid status was included on the test requisition, and state of residence was provided by the patient at the time of the test. In addition to the difference in the proportion of newly identified diabetes patients on Medicaid, the investigators compared mean A1c levels of patients from expansion vs nonexpansion states.
A Substantial Difference
Overall, there were 215,398 new cases of diabetes in the pre-ACA period and 218,890 in the post-ACA period, an increase of 1.6%. By contrast, the increase from pre- to post-ACA was 13.1% among Medicaid patients. However, the growth in new Medicaid diabetes cases was driven almost entirely by states that expanded Medicaid coverage. New cases increased 23.2% in expansion states but only 0.4% in nonexpansion states.
Mean A1c levels among Medicaid patients were significantly lower in the expansion states than in the nonexpansion states (7.96% vs 8.14%, P < .0001), and the percentage of Medicaid patients with A1c levels at 6.5%–6.9% was higher in the expansion states than in the nonexpansion states (44.1% vs 39.3%, P < .0001). For non-Medicaid patients with newly identified diabetes, there was no difference in the mean A1c or percentage of patients with levels between 6.5% and 6.9% when comparing expansion and nonexpansion states. In summary, the overall growth in new diabetes cases was relatively flat, but expansion states shifted many more of these cases to Medicaid coverage, and expansion states appeared to find them slightly earlier in the course of their diabetes.