The growing gap in hypertension control between insured and uninsured adults: National Health and Nutrition Examination Survey 1988 to 2010

Abstract

Hypertension awareness, treatment, and control are lower among uninsured than insured adults. Time trends in differences and underlying modifiable factors are important for informing strategies to improve health equity. National Health and Nutrition Examination Surveys 1988 to 1994, 1999 to 2004, and 2005 to 2010 data in adults aged 18 to 64 years were analyzed to explore this opportunity. The proportion of adults with hypertension who were uninsured increased from 12.3% in 1988 to 1994 to 17.4% in 2005 to 2010. In 1988 to 1994, hypertension awareness, treatment, and control to <140/<90 mm Hg (30.1% versus 26.5%; P=0.27) were similar in insured and uninsured adults. By 2005 to 2010, the absolute gap in hypertension control between uninsured and insured adults of 21.9% (52.5% versus 30.6%; P<0.001) was explained approximately equally by lower awareness (65.2% versus 80.7%), fewer aware adults treated (75.2% versus 88.5%), and fewer treated adults controlled (63.1% versus 73.5%; all P<0.001). Publicly insured and uninsured adults had similar income. Yet, hypertension control was similar across time periods in publicly and privately insured adults, despite lower income and education in the former. In multivariable analysis, hypertension control in 2005 to 2010 was associated with visit frequency (odds ratio, 3.4 [95% confidence interval, 2.4-4.8]), statin therapy (1.8 [1.4-2.3]), and healthcare insurance (1.6 [1.2-2.2]) but not poverty index (1.04 [0.96-1.12]). Public or private insurance linked to more frequent healthcare, greater awareness and effective treatment of hypertension, and appropriate statin use could reverse a long-term trend of growing inequity in hypertension control between insured and uninsured adults.

Keywords: healthcare disparities; healthy people programs; hypertension; insurance, health; medically uninsured.

Figure 1

Hypertension control is shown for the three NHANES time periods in uninsured and insured patients (left) and for publicly and privately insured patients (right).P-values over time periods compare the two groups during that time interval. P-values to the right of 2005–2010, indicate a significant change for the group designated over the 3 NHANES time periods.

Figure 2

The prevalence of hypertension and the percentages of patients with hypertension that are aware, treated, aware adults treated, and treated adults controlled are shown. On the left hand side, comparative data are provided for uninsured and insured patients. On the right hand side, comparative data are provided for patients with private or public insurance. P-values over time periods indicate differences between the two groups during that time interval. P-values to the right of the group symbol for 2005–2010, indicate a significant change for the group designated over the 3 NHANES time periods.