In our prior work, we found that Hispanic patients were more likely to receive the JNC recommended antihypertensive drug class then Whites, however, Hispanics were also significantly less likely than Whites to have their therapy appropriately intensified in response to an uncontrolled BP [13
]. Furthermore, we found appropriate intensification of anti-hypertensive therapy was associated with subsequent BP control for all racial/ethnic groups, suggesting that the poorer rates of BP control among Hispanics in our prior study may have been due to significantly lower rates of antihypertensive medication intensification [13
]. In this study, we found that these previously noted racial/ethnic disparities in rates of antihypertensive therapy intensification may be due to differences in visit patterns among patients and in physicians' aggressiveness in managing BP in diabetic patients, suggesting that racial/ethnic differences in disease severity are likely determinants of unequal treatment of uncontrolled hypertension.
There is substantial literature, that suggests that racial/ethnic minority groups are less likely to have their antihypertensive therapy appropriately intensified [16
]. However, these studies were limited because the investigators were not able to assess practice patterns such as the frequency with which individual anti-hypertensive drugs were intensified in response to uncontrolled BP. We found that Hispanic patients in our cohort were also less likely to have their anti-hypertensive medications intensified at least once in response to repeatedly uncontrolled BP than were other racial/ethnic groups and our findings also expand beyond documenting racial/ethnic disparities in aggressiveness of therapy by determining the roles racial/ethnic differences in clinic utilization among patients and racial/ethnic differences in the prevalence of diabetes play in confounding differences in providers' aggressiveness in treating hypertension.
An important national priority in health care is the elimination of racial/ethnic disparities in healthcare; however, a better understanding of the determinants of disparities is needed to address this issue [20
]. Our finding that higher rates of diabetes among Hispanics in our cohort play a major role in the insufficient management of their uncontrolled BP is of particular concern given that Hispanics suffer a disproportionately larger burden from hypertension and diabetes compared to Whites; and that Hispanics are at a higher risk of having hypertension and diabetes, are less likely to be aware that they are hypertensive, are more likely to have target organ damage, and have significantly higher age-adjusted diabetes and hypertension-related mortality compared to whites in the U.S [5
]. Our findings are supported by several studies that have documented lower rates of BP control among diabetic patients [24
], and others showing that providers often do not attain adequate BP control for patients, even after multiple opportunities to do so [2
Our study has several limitations. We were unable to collect measures of patient adherence to prescribed therapy from the EMR. Providers may not want to intensify therapy at the same rate for patients they know are less compliant with therapy, although it is hard to identify these patients. We were also unable to determine English proficiency of each patient from the medical records. When a language barrier exists providers may be less likely to intensify therapy.
We examined disparities in quality of hypertension care, as measured by intensification of therapy, among a cohort of patients and physicians during 2001–2002 using the established guidelines available during that time period, the JNC VI, as the reference for our analyses. In comparison to JNC VI, the JNC VII guidelines recommend much more aggressive management of hypertension both in terms of the accepted level of BP control (130/80 for diabetic and renal failure patients and 140/90 for all others) and the recommendations to providers to intensify antihypertensive therapy more rapidly when BP is uncontrolled [14
]. However, since the JNC VII guidelines were not available until 2003, it would have been impossible for providers in our study sample to have been fully aware of them and it would have been misleading to assess the quality of hypertension care among our cohort using quality guidelines that were not in existence during that time. By using the less aggressive guidelines that were in existence during the study period, we may have underestimated the gap in rates of intensification between racial/ethnic groups and between patients with diabetes and those without.
Lastly, we examined patients who received their care at primary care practices affiliated with a single large urban teaching hospital, and although there was substantial socioeconomic diversity in our sample our results may not be generalizable to smaller, rural, or non-teaching hospitals.