Rates of Undiagnosed Hypertension and Diagnosed Hypertension Without Anti-hypertensive Medication Following the Affordable Care Act

Abstract

Background: The Affordable Care Act (ACA) Medicaid expansion improved access to health insurance and health care services. This study assessed whether the rate of patients with undiagnosed hypertension and the rate of patients with hypertension without anti-hypertensive medication decreased post-ACA in community health center (CHC).

Methods: We analyzed electronic health record data from 2012 to 2017 for 126,699 CHC patients aged 19-64 years with ≥1 visit pre-ACA and ≥1 post-ACA in 14 Medicaid expansion states. We estimated the prevalence of patients with undiagnosed hypertension (high blood pressure reading without a diagnosis for ≥1 day) and the prevalence of patients with hypertension without anti-hypertensive medication by year and health insurance type (continuously uninsured, continuously insured, gained insurance, and discontinuously insured). We compared the time to diagnosis or to anti-hypertensive medication pre- vs. post-ACA.

Results: Overall, 37.3% of patients had undiagnosed hypertension and 27.0% of patients with diagnosed hypertension were without a prescribed anti-hypertensive medication for ≥1 day during the study period. The rate of undiagnosed hypertension decreased from 2012 through 2017. Those who gained insurance had the lowest rates of undiagnosed hypertension (2012: 14.8%; 2017: 6.1%). Patients with hypertension were also more likely to receive anti-hypertension medication during this period, especially uninsured patients who experienced the largest decline (from 47.0% to 8.1%). Post-ACA, among patients with undiagnosed hypertension, time to diagnosis was shorter for those who gained insurance than other insurance types.

Conclusions: Those who gained health insurance were appropriately diagnosed with hypertension faster and more frequently post-ACA than those with other insurance types.

Clinical trials registration: Trial Number NCT03545763.

Keywords: Affordable Care Act; Medicaid expansion; blood pressure; community health center; hypertension; medication.

© American Journal of Hypertension, Ltd 2021. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Figures

Graphical Abstract

Figure 1.

Operationalization of patients defined as having undiagnosed hypertension and those with diagnosed hypertension without anti-hypertensive medication.

Figure 2.

Trends in the proportions of patients with undiagnosed hypertension by insurance type, 2012–2017. Patients with diagnosed hypertension without anti-hypertensive medication were those with a diagnosis of hypertension that did not have a documented prescription for a hypertension medication for at least 1 day. Continuously insured patients had any type of health insurance (Medicaid or private insurance) at all visits during the time they had undiagnosed hypertension in the study period (2012–2017). Continuously uninsured patients had no health insurance at any visit during the time they had undiagnosed hypertension in the study period (2012–2017). Patients who gained insurance were uninsured at the first visit identifying them as having undiagnosed hypertension but gained insurance (Medicaid or private insurance) at a subsequent visit, and kept health insurance for the remainder of their visits during the study period (2012–2017). Discontinuously insured patients fluctuated on and off health insurance throughout the time they had undiagnosed hypertension.

Figure 3.

Trends in the proportions of patients with diagnosed hypertension without anti-hypertensive medication by insurance type, 2012–2017. Patients with diagnosed hypertension without anti-hypertensive medication had a diagnosis of hypertension any time during the study period and were without a documented prescription for an anti-hypertensive medication for at least 1 day after a documented diagnosis. Patients remained in this group until they received a prescription for an anti-hypertensive medication or their last visit during the study period. Continuously insured patients had any type of health insurance (Medicaid or private insurance) at all visits during the time they were diagnosed with hypertension and without anti-hypertensive medication in the study period (2012–2017). Continuously uninsured patients had no health insurance at any visit during the time they were diagnosed with hypertension and without anti-hypertensive medication in the study period (2012–2017). Patients who gained insurance were uninsured at the first visit identifying them as diagnosed with hypertension and without anti-hypertensive medication but gained insurance (Medicaid or private insurance) at a subsequent visit, and kept health insurance for the remainder of their visits during the study period (2012–2017). Discontinuously insured patients fluctuated on and off health insurance throughout the time they were diagnosed with hypertension and without anti-hypertensive medication.

Figure 4.

Adjusted time to diagnosis among undiagnosed hypertension and those with diagnosed hypertension without anti-hypertensive medication pre- and post-ACA by insurance type. Hazard ratios were adjusted for sex, ethnicity, race, age at the study starts, urban/rural location, number of visits, Charlson comorbidity index score, and federal poverty level. Error bars represent the 95% confidence intervals. Referent insurance type is gained insurance. Time to diagnosed hypertension was the time, in months, from the date of their elevated blood pressure to a documented diagnosis. For those who never had a documented diagnosis, it was the time until their last visit to a study clinic. Time to prescription among patients with diagnosed hypertension without anti-hypertensive medication was the time, in months, from the first documented hypertension diagnosis until the first documented prescription for an anti-hypertensive medication. For patients who never received a documented anti-hypertensive medication, it was the time until their last visit to a study clinic. Continuously insured (Cont. Ins) patients had any type of health insurance at all visits during the time they had undiagnosed hypertension or were diagnosed with hypertension and without anti-hypertensive medication in the study period (2012–2017). Continuously uninsured (Cont. Unins) patients had no health insurance at any visit during the time they had undiagnosed hypertension or were diagnosed with hypertension and without anti-hypertensive medication in the study period (2012–2017). Discontinuously insured (Discont. Ins) patients fluctuated on and off health insurance throughout the time they had undiagnosed hypertension or were diagnosed with hypertension and without anti-hypertensive medication. Abbreviation: ACA, Affordable Care Act.