A Steady State? Assessing Trends in Black-White Disparities in Hypertension Hospitalization Rates in Texas, 2006-2011 **

BACKGROUND: Black-white disparities in all-cause mortality narrowed in the mid- to late-20^th century when cardiovascular disease mortality declined most significantly among blacks, a proposed result of improved hypertension control. How black-white disparities in hypertension control have changed over time remains unclear. To better understand current trends in black-white disparities in hypertension control, we examined differences in hypertension hospitalization rates between blacks and whites, against a backdrop of mortality trends, in Texas from 2006-2011.

METHODS: We calculated point and interval estimates (α=0.05) of the relative incidence of hypertension hospitalizations and deaths due to hypertension and from all-causes between non-Hispanic blacks and whites using two datasets. We used hospital data from Texas Hospital Inpatient Discharge Data Files to estimate age-adjusted hypertension hospitalization rate ratios (RR) from 2006-2011, using hospital records with ICD-9 codes for hypertension (401-405) listed as principal diagnosis. We also used this data to calculate the population attributable risk fraction to quantify the proportional reduction in hospitalizations that would occur if blacks experienced the same rate as whites in 2011. We used Texas mortality data from 2006-2011 to estimate linear trends in age-adjusted mortality rates using least squares analyses and calculate mortality RR, using ICD-10 codes for hypertension mortality (I10-I15) and all-cause mortality (A00-Y89). We performed analyses in SAS 9.3, Microsoft Excel 2010, and VitalPro for DOS.

RESULTS: A statistically significant downward trend in all-cause mortality (ACM) among blacks decreased the RR to 1.2 by 2011. Neither blacks nor whites experienced statistically significant changes in hypertension mortality (HM) over time, keeping the RR constant at about 2.2. Similarly, the RR for hypertension hospitalizations (HH) remained constant over time—blacks were 4 times as likely to be hospitalized for hypertension as whites every year (2006-2011 RR: 4.5, 4.4, 4.6, 4.5, 4.6, and 4.4, respectively). In 2011, hospitalizations for hypertension would be reduced by over 36% if blacks experienced the same rate as whites.

CONCLUSIONS: From 2006-2011—a period marked by declines in ACM among blacks and the narrowing of racial disparities in ACM in Texas—the racial gap in HM remained steady, mirroring trends in HH. The constant racial gap in HM suggests changes in other causes of death must be responsible for the narrowing racial gap in ACM. And the constant excess burden of HH indicates uncontrolled hypertension remains a significant problem among blacks, highlighting the need for policies and programs aimed at minimizing racial disparities in disease detection and management.