Does first line antiretroviral therapy increase the prevalence of cardiovascular risk factors in Indian patients?: A cross sectional studyRAB Carey1, P Rupali1, OC Abraham1, D Kattula2
1 Department of Medicine, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Gastroenterological Sciences, Christian Medical College, Vellore, Tamil Nadu, India
Context: Antiretroviral therapy (ART) is associated with a myriad of metabolic complications which are potential cardiovascular risk factors. Early detection of these risk factors could help in alleviating morbidity and mortality in human immunodeficiency virus (HIV) infected patients on ART. Aims: To study the prevalence of cardiovascular risk factors in patients on a combination of nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs (NNRTIs) - the standard combination first line ART regimen used in tertiary referral center. Settings and Design: The prevalence of cardiovascular risk factors in HIV infected subjects with stage 1t disease on standard first line ART for at least 1 year, HIV infected subjects with stage 1 disease and not on ART and HIV negative subjects was assessed. The study was a cross-sectional study design. Materials and Methods: Basic demographic data was collected and patients were examined for anthropometric data and blood was collected for analysis of blood glucose, serum lipids, and fasting insulin levels. Statistical Analysis: Chi-square test was used to calculate significance. Statistical Package for Social Sciences (SPSS) software version 16.0 was used for data analysis. Results: The prevalence of hypercholesterolemia and hypertriglyceridemia was higher in the patients on ART when compared to patients not on ART (P<0.001). There was no difference in the prevalence of abnormal glycemic status, obesity, abdominal obesity, insulin resistance, and hyperinsulinemia between patients on ART and those not on ART. Conclusions: First line ART is associated with increased prevalence of dyslipidemia. Early detection and treatment of dyslipidemia should help in reducing the cardiovascular morbidity in patients on ART.
Keywords: Antiretroviral therapy, cardiovascular risk factors, human immunodeficiency virus infection
Antiretroviral therapy (ART) has led to a profound decrease in the mortality and morbidity related to the acquired immunodeficiency syndrome. It also has led, however, to an increase in the prevalence of cardiovascular risk factors in these patients. , The prevalence also seems to increase with the duration of therapy. With patients living longer, this could pose a danger in terms of increased morbidity and mortality due to cardiovascular diseases. In our study, we aimed to study the prevalence of cardiovascular risk factors in patients on a combination of nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs (NNRTIs) - the standard combination first line regimen used in developing countries.
Study setting and participants
The study was done in the human immunodeficiency virus (HIV) clinic of a tertiary care, teaching hospital in south India. The study had three arms with age and sex matched subjects - HIV infected subjects with stage 1t disease on standard, National AIDS Control Organization (NACO) recommended, first line ART completing at least 1 year, HIV infected subjects with stage 1 disease, and not on ART and HIV negative subjects. The HIV subjects were recruited from the weekly HIV clinic run by the institution. One of the investigators reported to the clinic and screened the patients. If the patients fulfilled the inclusion criteria, they were recruited for the study. The HIV negative subjects were recruited from among the attendants of the patients. The recruitment was stopped after 1 year.
We did a cross-sectional study looking at the prevalence of cardiovascular risk factors: Abnormal glycemic status, hypertension, dyslipidemia, obesity,  abdominal obesity,  hyperinsulinemia,  and insulin resistance. 
We collected basic demographic data and details of ART and adherence. Adherence was assessed by a 30 day recall. Height was measured using a standard height scale mounted on the wall. Weight was measured using a standardized spring balance. Waist circumference was measured at the level of umbilicus using a standard inch tape. Blood pressure was measured using a standard mercury sphygmomanometer. Fasting and post 75 g glucose load blood samples were collected along with fasting insulin and lipids levels and measured using an automated biochemical analyzer. We derived body mass index and insulin glucose ratio from measured values.
Abnormal glycemic status parameters included impaired glucose tolerance, impaired fasting glucose and diabetes, and were diagnosed based on 2006 World Health Organization (WHO) recommendations.  National Cholesterol Education Program (NCEP) guidelines were used for diagnosis of dyslipidemia.  Abnormal values include a total cholesterol (TC) of >200 mg/dl, low density lipoprotein (LDL) levels of >129 mg/dl, high density lipoprotein (HDL) level of <40 mg/dl and triglycerides level of >149 mg/dl. WHO Asia Pacific guidelines were used for the diagnosis of obesity and abdominal obesity. Body mass index (BMI) of >25 kg/m 2 was termed obesity and waist circumference of >90 cm in men and >80 cm in women was considered abdominal obesity.  Glucose insulin ratio of less than 4.5 was used to diagnose insulin resistance  and insulin levels more than 30 μIU/ml for a diagnosis of hyperinsulinemia.
The IRB approved the study and written informed consent was obtained from all study participants.
Taking the prevalence of a major cardiovascular risk factor - diabetes, in the general population to be 15.5%  and the prevalence of diabetes in patients on ART to be 35%, the required sample size to show a difference between the two groups with a power of 80% and at 5% level of significance was calculated as 75 in each group. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) software version 16.0. A P value of less than 5% was considered significant.
Characteristics of the study population
We recruited conveniently sampled 59 patients on ART, 66 ART naive patients, and 75 HIV negative individuals. The mean ages of the participants were 39.2, 33.1, and 37.7 years, respectively. Stage 1t had 42.37%, stage 1 had 65.15%, and the negative group had 30.67% of females. The mean duration since diagnosis of HIV infection was 66.1 months in the ART group and 25.58 months in the ART naive group. The median duration of ART was 31.9 months (range 12-131 months). The most common ART combination was stavudine, lamivudine, and nevirapine (47.27%) followed by zidovudine, lamivudine, and nevirapine (43.64%). The results of comparison of baseline demographic variables using analysis of variance (ANOVA) and post hoc analysis using Bonferroni's method are given in [Table 1] and [Table 2].
Prevalence of cardiovascular risk factors
The prevalence of cardiovascular risk factors was compared among the three groups (Chi-square test) [Table 3]. The difference in the prevalence of hypertension, hypercholestrolemia, high LDL, low HDL, and hypertriglyceridemia were found to be statistically significant. On group to group comparison [Table 3], the prevalence of hypercholesterolemia and hypertriglyceridemia was higher in the patients on ART when compared to patients not on ART (P<0.001). Low HDL was seen more often in HIV patients not on ART (P<0.001) compared to patients who had been on ART for a year. There was a trend towards increased prevalence of high LDL in patients on ART. However, this was not statistically significant. The difference in the prevalence of high cholesterol and high triglycerides is not seen when patients not on ART are compared with HIV negative subjects suggesting that ART is the factor that causes the elevated lipids in the patients on ART.
Patients with HIV on ART, when compared with HIV negative subjects, had lesser prevalence of hypertension (P=0.02) and low HDL status (P=0.06), and had a higher prevalence of high LDL status (P=0.006) and hypertriglyceridemia (P=0.002).
The prevalence of hypertension is lower in the HIV infected subjects not on ART when compared to HIV negative subjects. However, there is no difference in the prevalence of hypertension between the subjects on ART when compared to those not on ART.
On comparing the patients on stavudine with those on zidovudine, there is no statistically significant difference in the prevalence of risk factors. Those patients taking ART for more than 2 years had a statistically significant increase in the prevalence of abnormal glycemic status when compared with those on ART for less than 2 years (Chi-square 6.984; P<0.001). We also calculated TC and HDL ratio and the prevalence of higher ratio (males ≥6.4 and females ≥5.6) compared among the three groups was not statistically significant.
Overall, 88% of patients taking ART, 91.2% of patients not on ART and 90.8% of the HIV negative subjects had at least one cardiovascular risk factor. There is an increased prevalence of hypercholesterolemia, hypertriglyceridemia, and high HDL state in patients taking ART when compared with HIV positive patients not on ART. There is no significant difference in the prevalence of other risk factors.
For the analysis, age, gender, and all the risk factors that were studied except abdominal obesity and hyperinsulinemia, were included. Abdominal obesity was excluded as obesity, a related factor, was included and hyperinsulinemia was excluded as insulin resistance was included. After adjustment, the HIV patients on ART, when compared to the HIV negative group had lower prevalence of hypertension (P=0.037), higher prevalence of hypercholesterolemia (P=0.052), and higher prevalence of hypertriglyceridemia (P=0.003) [Table 4].
It is a well-established fact that the presence of multiple cardiovascular risk factors increases mortality and morbidity. Despite the fact that ART increases survival, the therapy has numerous adverse effects, and lipodystrophy and dyslipidemia are prominent among them. This has been established chiefly in patients on protease inhibitors.  There is limited data from the developing world where patients are predominantly on a combination of NRTIs and NNRTIs.  Available Indian data show that there is an increase in the prevalence of fasting hyperglycemia and dyslipidemia in patients who have been on first line antiretroviral agents. 
Our study shows a higher pevalence of hypercholesterolemia and hypertriglyceridemia and a decreased prevalence of low HDL status in patients on ART when compared to those not on ART. This difference was not seen when HIV infected patients are compared with HIV negative subjects indicating that ART is the likely reason for the increased prevalence of lipid adnormalities. HDL, however, seems to increase with ART. However, there was no increase in the prevalence of other cardiovascular risk factors like abnormal glycemic status, hypertension, insulin resistance, hyperinsulinemia, obesity, and abdominal obesity. Since high HDL levels are protective, this may offset to an extent the increased risk due to hypercholesterolemia and hypertriglyceridemia. Previous studies done in India as well as Ethiopia have demonstrated a similar high prevalence of dyslipidemia in patients on first line ART. ,
When compared with HIV negative subjects, those patients on ART have a lower prevalence of hypertension and low HDL status and a high prevalence of hypercholesterolemia and hypertriglyceridemia. After multivariate analysis, except for HDL, the same trend is maintained suggesting that first line ART in HIV patients is significantly associated with dyslipidemia. The low prevalence of hypertension in these patients, however, is a relief.
Our results become all the more significant in view of the fact that Indians are already at increased risk of cardiovascular disease. Moreover, HIV by itself, because of inflammation, increases cardiovascular risk by promoting atherosclerosis.  It is also known that stopping ART increases mortality.  In such a setting, where the effect of HIV is taken care of by the ART, it becomes necessary that the metabolic derangements due to ART be managed appropriately to mitigate the increased cardiovascular risk.
Cardiovascular risk in HIV infected patients on ART seems to be influenced by many factors. Current evidence supports early and continued use of ART with periodic monitoring and good control of the dyslipidemia with antilipidemic agents. Statins should be initiated in all patients with even the mildest form of dyslipidemia.  All other cardiovascular risk factors, like diabetes and hypertension, would require to be controlled optimally as well.
Though our study had limitations in terms of a small sample size and a cross-sectional study design, the results seem to point towards a definite increase in cardiovascular risk factors among Indian patients on first line ART. All conclusions drawn from our study require further confirmation by prospective studies looking at cardiovascular mortality as end point in an Indian setting.
[Table 1], [Table 2], [Table 3], [Table 4]