IMT and cardiovascular risk

Modest increases in carotid intima media thickness (IMT) were reported in a new French study by Mercie and colleagues. [14] IMT increases are a marker for atherosclerosis and a recognised risk factor for cardiovascular disease, but at the 2003 Retrovirus Conference two separate studies reported contradictory results on whether this was occurring.

In this study, 346 patients had IMT measured by ultrasonography at baseline and again at 12 months. They reported a significant increase from 0.57 to 0.59mm but that this also was within the normal range, and that conventional cardiovascular risk factors were associated with the increase (age, gender and smoking). Although antiretroviral treatment was not an associated factor in multivariate analysis, a maximum increase in the general population over this period would be expected to only be 0.01mm.

The Retrovirus study that reported markedly increased IMT (5-fold compared to the previous study) was also presented as a poster at the lipodystrophy workshop. [15]

Hsue and colleagues from San Francisco General Hospital reported higher baselines IMT in 147 HIV-positive patients on HAART (122 male, 25 female) compared to their HIV-negative control group (0.9±0.2 versus 0.7±0.2).

A rate of progression in 87 HIV-positive patients after one year was 0.10mm (±0.1) compared to 0.01mm in published reports of HIV-negative populations. Traditional risk factors but also HIV were predictive in a multivariate analysis of IMT at baseline and age, Latino race and CD4-nadir were predictive of IMT progression.

comment

Previously reported increases in IMT in HIV-postive individuals compared to HIV-negative controls was linked to traditional risk factors rather than HIV or HAART (eg Depairon et al AIDS 2001; 15:329-334). The progression of IMT in this study is again out of proportion to any other study so far or other reports using IMT as a surrogate marker.

	HIV Treatment Bulletin Vol 4 No7 August / September 2003