Control of Dyslipidemia and Hypertension in HIV Outpatients
Control of Dyslipidemia and Hypertension in HIV Outpatients
Previous studies have provided information on the prevalence of CVD risk factors in patients with HIV infection, but few have described results from clinical settings regarding how well these risk factors are treated and controlled. In this study, we show that in a population of outpatients infected with HIV, treatment rates for LDL-C dyslipidemia were high, but that a significant percentage of patients were not adequately controlled to the recommended target LDL-C goals. The treatment rate for hypertension was 75%, but control was poor, with 57% of the patients at goal blood pressure.
Unique to this study is that the population represents patients in a specialized HIV clinic and not patients recruited into a clinical trial, thus reflecting a real-world setting. Furthermore, the population is diverse, including approximately 25% women, an age range from 20 to 87 years, varied risk sources for HIV, and a diverse race/ethnicity reflective of a large urban population.
There is limited information from other populations of HIV-infected patients. In the HIV-HEART Study, an ongoing, prospective multi-center study of 803 patients (82% male, 88% White), 21% were hypertensive. Treatment rates for hypertension stratified by the Framingham risk score were 40% in low-risk group, 40% in intermediate-risk group, and 83% in high-risk groups. Dyslipidemia was prevalent among 24% (defined as elevated total cholesterol), and of those with known LDL-C values and of moderate or high risk, there were more than 50% and 30%, respectively, who were untreated. Not all patients had LDL-C measurement, and patients were enrolled from many centers in Germany and not one clinic where all patients received similar care. In a study of 542 patients in a Norwegian HIV clinic, 32% were hypertensive. Only 26 of these patients had been identified as having hypertension, and of these, 9 were on treatment and at goal.
Our results for LDL-C dyslipidemia showed good treatment compared with previous studies, except for those patients who were at higher risk for CVD according to the established guidelines. We used current population guidelines and a risk stratification algorithm to determine cutpoints for goal attainment. Recent primary care guidelines for HIV providers have endorsed this approach. It is unclear if traditional risk stratification and prediction formulas apply to patients with HIV and therefore accurately determine LDL-C goals. For example, Parra et al and Friis-Moller et al found that the Framingham risk score underestimated the presence of subclinical atherosclerosis and manifest disease in HIV-infected patients.
Despite the growing understanding that patients infected with HIV are at higher risk compared with non-HIV patients, current guidelines for LDL-C do not recommend more stringent goals for HIV patients. No validated CVD risk calculator exists specific to patients infected with HIV. Such a risk calculator should consider HIV-specific factors such as class(es) of ART as potential contributors of increased cardiovascular risk. For our study, we did not have information on specific ART medications and classes other than the category "PIs" that are known to exacerbate dyslipidemia. In our regression analysis, being on ART was not significantly associated with success to attain goal for LDL-C.
A lower goal for LDL-C would increase the prevalence of LDL-C dyslipidemia in our patient population and decrease the number attaining goal. In this study, the lowest attainment of goal (57% or 62%, respectively) were in those with CHD or CHD equivalents and those in the highest risk groups (56%), where the LDL-C goal was <100 mg/dL. The reasons for this include the more stringent target and limitations for use of lipid-lowering medications (eg, adverse effects, interaction with ART, and coverage by Medicaid).
Because there is scarce information on hypertension treatment and goal attainment in HIV-infected patients, comparisons with data from the general population may be informative. A report from the National Health and Nutrition Examination Survey of people in the United States aged 18 years of age and older from 2001 to 2010 showed that 77% of patients with hypertension were taking any antihypertensive drug and of those treated, 60% were controlled. Data from the New York City Health and Nutrition Examination Survey found that, among residents aged 20 years and older, 26% of subjects had hypertension, 73% were treated, and of those treated, 65% were at goal. A lack of routine place of medical care was most strongly associated with poor control. Among nonelderly adults with treated hypertension, Blacks had a 4-fold higher odds than Whites of having uncontrolled hypertension.
The treatment rates for hypertension in our study were relatively high. There are several reasons for this. There were 371 (8.7%) patients seen in the cardiology section of the clinic in addition to being followed by their PCP. The treatment rate was higher among those seen by a cardiologist (92%) compared with those who were only seen by their PCP (72%), whereas goal attainment was similar (56% vs. 57%). Because of the small number and interpretation confounded by indication, it is difficult to draw conclusions regarding the effect of provider status on dyslipidemia management. There could also be a heightened awareness among PCPs, as the clinic holds weekly conferences with several each year conducted by the cardiologist. Finally, we feel that the model of a specialized clinic for patients with HIV that includes co-located medical and support services may optimize treatment of CVD risk factors.
Although treatment rates for hypertension were relatively good, attainment of goal was low. A reason for this might be the influence of ART, in particular PI. In a study of all HIV-infected patients at 2 naval medical centers in the United States, hypertension was common (31%) among the 707 mostly male patients and did not differ between those receiving and those not receiving ART. However, in the Multicenter AIDS Cohort Study of 5578 participants, prolonged use of ART was significantly associated with a higher prevalence of systolic hypertension. In our study, 88% of patients were taking at least 1 ART medication and 66% of those on ART were on a regimen that included a PI. For hypertension, being on ART was associated with attaining blood pressure goal. Having a high viral load was also associated with not attaining blood pressure goal, whereas CD4 count did not show significant association. The significance and interpretation of these findings is unclear, as these analyses are exploratory, and the observed findings warrant further validation and elucidation.
Unlike many studies investigating CVD risk factors in patients infected with HIV, our study provided information on prevalence, treatment, and control of 2 important cardiovascular risk factors, dyslipidemia and hypertension. Our study population consisted of patients in a HIV clinic where all patients received standardized care and support without regard for ability to pay, which may minimize some confounding and heterogeneity issues in access to care. Also, the study sample is large and diverse in gender, age, race/ethnicity, and risk sources/status, which may make subgroups analyses meaningful.
There are several limitations to this study. Because of the cross-sectional design, results should be interpreted as prevalence (rather than risk or prospective event rate) and correlation (not causation or prospective association). Data abstraction from 2 of the 3 clinics was performed at a different calendar time than that from the third clinic. The proportion of missing data was varied but we addressed this issue by a standard statistical technique. Also, patients are from a single institution in an urban area; thus, representativeness or generalizability may be an issue. Although we did have information on the use of PIs, we did not have information on other classes of ART and specific PIs or on adherence to medical regimens. Finally, not all values of LDL-C were from fasting samples.
This study showed that control of LDL-C dyslipidemia among patients with HIV was good overall except for those at high risk, whereas control of high blood pressure was poor. It is still unclear if and how ART may influence CVD risk factors and make control more difficult or easier.
This report offers new information on management and goal attainment of CVD risk factors in patients living with HIV and insight into the HIV care model that includes expertise in the management of comorbidities, such as CVD risk factors, in addition to primary care for HIV. As CVD is becoming a leading cause of morbidity and mortality in these patients, our findings could provide a basis for further investigation regarding optimal treatment regimens and may support the development of guidelines specific to this population of patients.
Discussion
Previous studies have provided information on the prevalence of CVD risk factors in patients with HIV infection, but few have described results from clinical settings regarding how well these risk factors are treated and controlled. In this study, we show that in a population of outpatients infected with HIV, treatment rates for LDL-C dyslipidemia were high, but that a significant percentage of patients were not adequately controlled to the recommended target LDL-C goals. The treatment rate for hypertension was 75%, but control was poor, with 57% of the patients at goal blood pressure.
Unique to this study is that the population represents patients in a specialized HIV clinic and not patients recruited into a clinical trial, thus reflecting a real-world setting. Furthermore, the population is diverse, including approximately 25% women, an age range from 20 to 87 years, varied risk sources for HIV, and a diverse race/ethnicity reflective of a large urban population.
There is limited information from other populations of HIV-infected patients. In the HIV-HEART Study, an ongoing, prospective multi-center study of 803 patients (82% male, 88% White), 21% were hypertensive. Treatment rates for hypertension stratified by the Framingham risk score were 40% in low-risk group, 40% in intermediate-risk group, and 83% in high-risk groups. Dyslipidemia was prevalent among 24% (defined as elevated total cholesterol), and of those with known LDL-C values and of moderate or high risk, there were more than 50% and 30%, respectively, who were untreated. Not all patients had LDL-C measurement, and patients were enrolled from many centers in Germany and not one clinic where all patients received similar care. In a study of 542 patients in a Norwegian HIV clinic, 32% were hypertensive. Only 26 of these patients had been identified as having hypertension, and of these, 9 were on treatment and at goal.
Our results for LDL-C dyslipidemia showed good treatment compared with previous studies, except for those patients who were at higher risk for CVD according to the established guidelines. We used current population guidelines and a risk stratification algorithm to determine cutpoints for goal attainment. Recent primary care guidelines for HIV providers have endorsed this approach. It is unclear if traditional risk stratification and prediction formulas apply to patients with HIV and therefore accurately determine LDL-C goals. For example, Parra et al and Friis-Moller et al found that the Framingham risk score underestimated the presence of subclinical atherosclerosis and manifest disease in HIV-infected patients.
Despite the growing understanding that patients infected with HIV are at higher risk compared with non-HIV patients, current guidelines for LDL-C do not recommend more stringent goals for HIV patients. No validated CVD risk calculator exists specific to patients infected with HIV. Such a risk calculator should consider HIV-specific factors such as class(es) of ART as potential contributors of increased cardiovascular risk. For our study, we did not have information on specific ART medications and classes other than the category "PIs" that are known to exacerbate dyslipidemia. In our regression analysis, being on ART was not significantly associated with success to attain goal for LDL-C.
A lower goal for LDL-C would increase the prevalence of LDL-C dyslipidemia in our patient population and decrease the number attaining goal. In this study, the lowest attainment of goal (57% or 62%, respectively) were in those with CHD or CHD equivalents and those in the highest risk groups (56%), where the LDL-C goal was <100 mg/dL. The reasons for this include the more stringent target and limitations for use of lipid-lowering medications (eg, adverse effects, interaction with ART, and coverage by Medicaid).
Because there is scarce information on hypertension treatment and goal attainment in HIV-infected patients, comparisons with data from the general population may be informative. A report from the National Health and Nutrition Examination Survey of people in the United States aged 18 years of age and older from 2001 to 2010 showed that 77% of patients with hypertension were taking any antihypertensive drug and of those treated, 60% were controlled. Data from the New York City Health and Nutrition Examination Survey found that, among residents aged 20 years and older, 26% of subjects had hypertension, 73% were treated, and of those treated, 65% were at goal. A lack of routine place of medical care was most strongly associated with poor control. Among nonelderly adults with treated hypertension, Blacks had a 4-fold higher odds than Whites of having uncontrolled hypertension.
The treatment rates for hypertension in our study were relatively high. There are several reasons for this. There were 371 (8.7%) patients seen in the cardiology section of the clinic in addition to being followed by their PCP. The treatment rate was higher among those seen by a cardiologist (92%) compared with those who were only seen by their PCP (72%), whereas goal attainment was similar (56% vs. 57%). Because of the small number and interpretation confounded by indication, it is difficult to draw conclusions regarding the effect of provider status on dyslipidemia management. There could also be a heightened awareness among PCPs, as the clinic holds weekly conferences with several each year conducted by the cardiologist. Finally, we feel that the model of a specialized clinic for patients with HIV that includes co-located medical and support services may optimize treatment of CVD risk factors.
Although treatment rates for hypertension were relatively good, attainment of goal was low. A reason for this might be the influence of ART, in particular PI. In a study of all HIV-infected patients at 2 naval medical centers in the United States, hypertension was common (31%) among the 707 mostly male patients and did not differ between those receiving and those not receiving ART. However, in the Multicenter AIDS Cohort Study of 5578 participants, prolonged use of ART was significantly associated with a higher prevalence of systolic hypertension. In our study, 88% of patients were taking at least 1 ART medication and 66% of those on ART were on a regimen that included a PI. For hypertension, being on ART was associated with attaining blood pressure goal. Having a high viral load was also associated with not attaining blood pressure goal, whereas CD4 count did not show significant association. The significance and interpretation of these findings is unclear, as these analyses are exploratory, and the observed findings warrant further validation and elucidation.
Strengths
Unlike many studies investigating CVD risk factors in patients infected with HIV, our study provided information on prevalence, treatment, and control of 2 important cardiovascular risk factors, dyslipidemia and hypertension. Our study population consisted of patients in a HIV clinic where all patients received standardized care and support without regard for ability to pay, which may minimize some confounding and heterogeneity issues in access to care. Also, the study sample is large and diverse in gender, age, race/ethnicity, and risk sources/status, which may make subgroups analyses meaningful.
Limitations
There are several limitations to this study. Because of the cross-sectional design, results should be interpreted as prevalence (rather than risk or prospective event rate) and correlation (not causation or prospective association). Data abstraction from 2 of the 3 clinics was performed at a different calendar time than that from the third clinic. The proportion of missing data was varied but we addressed this issue by a standard statistical technique. Also, patients are from a single institution in an urban area; thus, representativeness or generalizability may be an issue. Although we did have information on the use of PIs, we did not have information on other classes of ART and specific PIs or on adherence to medical regimens. Finally, not all values of LDL-C were from fasting samples.
Conclusions
This study showed that control of LDL-C dyslipidemia among patients with HIV was good overall except for those at high risk, whereas control of high blood pressure was poor. It is still unclear if and how ART may influence CVD risk factors and make control more difficult or easier.
This report offers new information on management and goal attainment of CVD risk factors in patients living with HIV and insight into the HIV care model that includes expertise in the management of comorbidities, such as CVD risk factors, in addition to primary care for HIV. As CVD is becoming a leading cause of morbidity and mortality in these patients, our findings could provide a basis for further investigation regarding optimal treatment regimens and may support the development of guidelines specific to this population of patients.