Results
A total of 434,288 patients from all 50 states and the District of Columbia met our criteria for newly identified diabetes. Demographic features (age and sex distributions) of patients remained stable between the control and study periods (Table 1). The mean (SD) age of Medicaid patients was similar between expansion and nonexpansion states: 48.2 (11.2) vs. 48.0 (11.4), respectively. Non-Medicaid (hereafter referred to as "other") patients were older than Medicaid patients in expansion (51.3 [10.0] vs. 48.2 [11.2] years) and nonexpansion (52.1 [9.5] vs. 48.0 [11.4] years) states.
Overall, we observed a 1.6% increase in newly identified diabetes from the control period to the study period (Table 2). In our analysis, we focused on patients who were enrolled in Medicaid at least once during the control or study periods and for whom data were available establishing the absence of diabetes (by ICD-9 code or hemoglobin A1c test result) in the preceding calendar year. A total of 26,237 Medicaid-enrolled patients were newly identified with diabetes in the control period vs. 29,673 Medicaid-enrolled patients in the study period: an increase of 13% (Table 2). We examined the data for other (non-Medicaid) patients in both periods as well to have a comparison group with which to contrast the observations in Medicaid patients. The number of patients with newly identified diabetes among other patients increased by only 0.03% from the control (n = 189,161) to the study (n = 189,217) periods (Table 2).
The Medicaid patients were then analyzed after assignment into the two categories (expansion states versus nonexpansion states) (Table 2). Within the expansion states, 14,625 patients were classified as having newly identified diabetes in the control period vs. 18,020 patients in the study period: an increase of 23%. In the nonexpansion states, by contrast, 11,612 patients were classified as having newly identified diabetes in the control period vs. 11,653 patients in the study period: an increase of 0.4% (Fig. 1).
Figure 1.
Patients with newly identified diabetes in expansion (blue) and nonexpansion (red) states.
The number of other patients with newly identified diabetes decreased by 2.2% within the expansion states between the control (106,524) and study (104,133) periods but increased by 3.0% (82,637 in the control period to 85,084 in the study period) in the nonexpansion states (Fig. 1). The overall increase in newly identified patients with diabetes was about the same magnitude in the expansion states (0.8%) and nonexpansion states (2.6%) (Table 2).
Patients were also categorized by sex (Table 3) and by age range (younger, ages 19–49 years, and older, ages 50–64 years) (Table 4). The surge in newly identified Medicaid patients with diabetes in the expansion states was observed for each category of sex or age-group (P < 0.0001).
A potential explanation for the increase in the number of newly identified patients with diabetes is that diabetes is being diagnosed at an earlier stage of disease. Among Medicaid patients with newly identified diabetes, the mean (SD) hemoglobin A1c was 8.03% (1.92) (64 mmol/mol). Mean hemoglobin A1c levels among Medicaid patients were significantly lower in the expansion states (7.96% [1.88]) (63 mmol/mol) than in the nonexpansion states (8.14% [1.97]) (65 mmol/mol) (P < 0.0001). Consistent with this, the percentage of Medicaid patients with hemoglobin A1c results of 6.5–6.9% (48–52 mmol/mol) was higher in the expansion states (44.1%) than in the nonexpansion states (39.3%) (P < 0.0001).
For other patients with newly identified diabetes, we observed no difference in the mean hemoglobin A1c or percentage of patients with hemoglobin A1c results between 6.5 and 6.9% (48–52 mmol/mol). The mean (SD) hemoglobin A1c was similar in the expansion states (7.78% [1.72] [62 mmol/mol]) and the nonexpansion states (7.79% [1.73] [62 mmol/mol]), as was the percent of patients with hemoglobin A1c results in the 6.5–6.9% (48–52 mmol/mol) range: 47.5% in the expansion states and 47.1% in the nonexpansion states.
The mean (SD) hemoglobin A1c was 8.03% (1.92) (64 mmol/mol) in the Medicaid patients and 7.78% (1.73) (62 mmol/mol) in other patients. The percent of hemoglobin A1c results of 6.5–6.9% (48–52 mmol/mol) was 42.4% in the Medicaid patients and 47.3% in other patients.
Diabetes Care. 2015;38(5):833-837. © 2015 American Diabetes Association, Inc.
