The risk of cardiovascular disease is increased in the HIV population, potentially due to the additional burdens of infection, inflammation and antiretroviral treatment (ART). This trial aims to examine the effect of dietary intervention on cardiovascular risk (CVR) in HIV dyslipidaemia.
This pilot, parallel, randomized controlled trial (ISRCTN32090191) recruited adults with stable HIV infection on ART and LDL-cholesterol >3mmol/l from 3 UK centres. Randomization (1:1) compared the effect of dietary advice to reduce saturated fat (Diet1) versus MedDiet with additional cholesterol lowering foods e.g. plant stanols, soya, oats (Diet2). Measurements of CV risk factors, fasting blood lipids, food intake, body composition, and arterial stiffness were conducted at baseline, month 6 and month 12. Between-group changes of CVR factors were assessed using ANCOVA, with adjustments for baseline values of the dependent variables. Analysis was by intention to treat (ITT) and Complier Average Causal Effect.
60 eligible adults were randomized with mean age 42±7years, LDL-cholesterol 3.9±0.6mmol/l, 50% female, 65% non-smokers, 50% black African, 40% white European. Baseline characteristics were comparable between groups. At 6 months, Diet2 participants (n=29) showed a significantly greater reduction in LDL-cholesterol, total to HDL-cholesterol ratio, systolic blood pressure (BP) and increase in Mediterranean Diet Score, than those in Diet1 (n=31), see table. Intake of Mediterranean (olive oil, fish, legumes) and Portfolio foods (nuts, stanols) increased significantly in the Diet2 group (p<0.01). Individual adherence varied from 11 to 100% (mean 59±21%). Body composition, arterial stiffness, gut function, and levels of physical activity were not significantly different between the groups. As expected, the estimated treatment effect among compliers to MedDiet (LDL-cholesterol -0.87mmol/l, 95%CI -1.79 to 0.05) and Portfolio foods (-0.76mmol/l, 95%CI -1.54 to 0.01) appears larger than that for ITT analysis (-0.38mmol/l, 95%CI -0.68 to -0.09).
Dietetic advice to follow a Mediterranean diet containing nuts, plant stanols, soya protein, beans and oats produced a greater improvement in diet quality, blood pressure, and a 10% greater reduction in LDL-cholesterol than standard guidelines to reduce saturated fat intake. Analysis assuming full compliance and preserving randomisation suggests a possible doubling of this estimated treatment effect.