To the Editor:
French Guiana is the French overseas department where the human immunodeficiency virus (HIV) epidemic is most preoccupying. There are 38 new acquired immunodeficiency syndrome cases per 100,000 inhabitants per year and >1% of HIV-positive pregnant women. Approximately two thirds of the HIV patients are foreign citizens mostly from Haiti.1 The use of highly active antiretroviral therapy has led to remarkable gains in patient survival. However, HIV and the metabolic complications of highly active antiretroviral therapy seem to increase the risk of cardiovascular diseases, notably high blood pressure.2,3 To further improve survival, it is important to better understand these pathologies. The objective of the present study is to determine the risk factors for high blood pressure among patients followed in the hospital cohort of patients followed in the 3 hospitals of French Guiana.
HIV-positive patients followed in Cayenne, Kourou, and Saint Laurent du Maroni Hospitals between January 1, 1996, and December 31, 2006, were enrolled in the French Hospital Database for HIV. Time-independent variables such as sex, nationality, and mode of acquisition of HIV and time-dependent variables such as age, CD4 counts, HIV-1 viral loads, treatments, and clinical events recorded in the patient medical records by the physicians are routinely entered by trained clinical studies technicians. Diagnoses are coded according to the 10th international classification of diseases. Patients included in the French Hospital Database for HIV give informed consent for the use of their data. Their identity is encrypted before the data are sent to the Ministry of Health and the Institut National de la Recherche Médicale, which centralize data from Coordination Regionale VIH throughout France. This data collection is approved by the Commission Nationale Informatique et Libertés and does not include ethnic information. The data were analyzed with STATA 8.0.
In this retrospective cohort study, a single failure Cox proportional hazards model was used to evaluate the adjusted relation between failure and explanatory variables. The failure event was incidence of high blood pressure as reported by the physician. The main explanatory variables were as follows: age (categorized as younger than 30 years, 30-40 years, 40-60 years, and older than 60 years), gender, nationality (French citizens versus non-French citizens), CD4 count at the time of the visit (categorized as <50, 50-199, 200-499, and >500), presence or absence of different families of antiretrovirals (protease inhibitors, nonnucleoside reverse transcriptase inhibitors, and nucleoside reverse transcriptase inhibitors), and weight (height was not available for most patients, therefore the body mass index could not be calculated). The proportionality of the hazard functions was determined using Schoenfeld and scaled Schoenfeld residuals and the proportional hazards test. The model was stratified on variables that did not fulfill the proportional hazards assumption. Age, nationality, CD4 count category at the time of HIV diagnosis, and follow-up duration were transformed into dummy variables to compare different groups with a reference group.
A total of 1900 patients and 32,308 records were included, which represented 7456 person-years of follow-up. There were 113 reports of high blood pressure. Although blood pressure is frequently monitored by the physicians, it is not systematically measured. However, high blood pressure, being a chronic disease, is not likely to have escaped the physician's attention for long. Patients were right censored after the first failure event. Table 1 shows that, after adjustments for potential confounders, patients older than 40 years and patients with renal failure had a greater incidence of high blood pressure. A simple model including all specific antiretroviral molecules showed that only efavirenz [hazard ratio (HR) = 1.7, 95% confidence interval (CI) = 1.02 to 2.9, P = 0.04] and lopinavir + ritonavir (HR = 2, 95% CI = 1.04 to 3.9, P = 0.04) were independently associated with high blood pressure. After adjusting for potential confounders (notably age and weight), only efavirenz remained significantly associated with high blood pressure (HR = 1.8, 95% CI = 1.06 to 3, P = 0.03). To reduce the number of variables in the model, different antiretrovirals were pooled in homogeneous groups. In the ensuing models, both boosted protease inhibitors and nonnucleoside inhibitors were associated with increased blood pressure (Table 1).
Patients with CD4 counts <50 had a lower crude incidence of high blood pressure, but this association disappeared after adjusting for the confounding effect of the lower weight in these patients. The risk of high blood pressure increased with body weight [adjusted HR = 1.26 (95% CI = 1.09 to 1.46), P = 0.002 for a 10-kg increase in body weight]. Height was not systematically recorded; therefore, body weight was used instead of the body mass index. Haitians seemed at greater risk of high blood pressure after adjusting for the available potential confounders. Although patients from Guyana, Suriname, and French Guiana most often have African ancestry, Haitians had a greater risk of high blood pressure, perhaps because there is less mixing than in the 3 Guyanas (blacks are known to be more at risk of high blood pressure4,5); but there may also have been other unknown factors linked to Haitian origin. There are few studies on this matter, but a small study suggested a particular risk of high blood pressure among Haitians.6
As observed elsewhere,7 boosted protease inhibitors were associated with an increased risk of high blood pressure. Contrary to some other studies,4 but in accordance with others,8 we observed an association between high blood pressure and use of nonnucleoside reverse transcriptase inhibitors.
Although all HIV patients should be screened for cardiovascular risk factors, Haitians receiving highly active antiretroviral therapy, especially, if they are older than 40 years, overweight, and with other cardiovascular risk factors, seem particularly at risk of developing high blood pressure and should therefore be closely monitored.
Mathieu Nacher, MD, PhD*†‡
Celia Basurko, MD*
Vincent Vantilcke, MD†
Julie Dufour, MD§
Myriam El Guedj, MD†
Tania Vaz, MD†
Christian Magnien, MD†
Andry Randrianjohany, MD, MSc‖
Elodie Chauvet, MD‖
Fernand Alvarez, MD¶
*Coordiantion Régionale VIH de Guyane Centre Hospitalier Andrée Rosemon Rue des Flamboyants Cayenne, French Guiana
†Hôpital de Jour Adultes Centre Hospitalier Andrée Rosemon Rue des Flamboyants Cayenne, French Guiana Centre dInvestigations Cliniques Epidémiologie Clinique Antilles Guyane
§Service de Dermatologie Centre Hospitalier Andrée Rosemon Rue des Flamboyants Cayenne, French Guiana
‖Service de Médecine, Centre Hospitalier Frank Joly Saint Laurent du Maroni, French Guiana
¶Centre Médico Chirurgical de Kourou Kourou, French Guiana
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8. Chow DC, Souza SA, Chen R, et al. Elevated blood pressure in HIV-infected individuals receiving highly active antiretroviral therapy. HIV Clin Trials