New Swiss research has shown the benefits of treating hypertension in HIV-positive people. The investigators calculated that the reduction in blood pressure achieved by their patients would “significantly reduce cardiovascular endpoints”. Traditional, rather than HIV-associated, risk factors were associated with increases in blood pressure.
The research was published in the online edition of the Journal of Acquired Immune Deficiency Syndromes.
Cardiovascular disease is now an important cause of serious illness and death in people with HIV. Hypertension can increase the risk of cardiovascular events, and its incidence among people with HIV is growing. The reasons for this are unclear, but appear to include the natural effects of ageing, traditional factors such as smoking, the inflammatory effects of HIV and the side-effects of some antiretroviral drugs.
Regardless of the exact cause, appropriate treatment for high blood pressure could reduce the risk of cardiovascular disease in HIV-positive people. However, only limited information is available on the extent of hypertension control in this population.
Investigators from the Swiss HIV Cohort therefore followed patients with baseline hypertension for ten years, monitoring the use of hypertensive medication and the risk of cardiovascular events.
The period of analysis was 2000 to 2011. Blood pressure was monitored every six months. Participants were diagnosed with hypertension if they had systolic blood pressure above 139 mmHG or diastolic blood pressure above 89 mmHg at two consecutive visits.
A total of 10,361 participants were included in the investigators’ analysis. None had experienced a major cardiovascular event or were taking blood pressure medication.
Hypertension was diagnosed in 2595 people. All these individuals had at least one other cardiovascular risk factor, such as smoking, dyslipidemia, family history, diabetes or chronic kidney disease. Their median age was 49 years, 84% were men, median CD4 cell count was 467 cells/mm3 and 71% had a viral load below 50 copies/ml.
The median period of follow-up was 3.7 years. Overall, 869 participants started treatment for hypertension, an incidence of 79 people per 1000 patient-years. The investigators were concerned by this finding, commenting “many patients remain untreated or insufficiently treated for hypertension”.
Treatment achieved a mean decrease in systolic blood pressure of -0.28 mmHg per year and a mean reduction in diastolic blood pressure of -0.89 per year. This reduction in systolic blood pressure was low “but clinically relevant, and would correspond to a mean decrease of -2.5 mmHg over a median observation period of 3.7 years”, write the investigators. They believe this reduction would significantly reduce the risk of cardiovascular disease.
Risk factors for an increase in blood pressure included older age, male sex, injecting drug use, abnormal lipid levels, higher body mass index (BMI) and hip-to-waist ratio. These factors are similar to those seen in the general population. However, a HIV viral load above 400 copies/ml was also associated with blood pressure increases.
A total of 118 participants with confirmed hypertension experienced a cardiovascular event. These included 54 heart attacks, 32 strokes and ten sudden cardiac deaths.
Each 10mmHg increase in systolic blood pressure was associated with an 18% increase in the relative risk of a cardiovascular event (HR = 1.18; 95% CI, 1.0-6-1.32). Other factors associated with cardiovascular events included older age, higher total cholesterol, smoking, longer exposure to a protease inhibitor and use of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen.
Participants were more likely to be offered therapy for hypertension if they had experienced a cardiovascular event (HR = 7.03; 95% CI, 3.89-10.1), had chronic kidney disease (HR = 2.42; 95% CI, 1.54-3.80) or were diabetic (HR = 1.54; 95% CI, 1.28-1.84).
“Clinicians caring for HIV-infected patients seem to be more inclined to treat hypertensive patients at very high cardiovascular risk for preventing relapsing cardiovascular events,” suggest the researchers. “Surveillance data from HIV-negative hypertensive patients indicate similar trends of higher treatment rates in individuals with higher cardiovascular risk.”
The investigators highlight research from the United States showing that “better control of cardiovascular risk factors may be achieved and is associated with decreased cardiovascular mortality”. They therefore conclude, “more aggressive treatment and better management of hypertension are urgently needed in HIV-infected patients.”
Nüesch R et al. Risk of cardiovascular events and blood pressure control in hypertensive HIV-infected patients: Swiss HIV Cohort Study (SHCS). J Acquir Immune Defic Syndr, online edition, DOI: 10.1097/QAI.0b013e3182847cd0, 2013.