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Framingham Risk Score Linked to Other Heart Risk Factors in HIV Cohort
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16th Conference on Retroviruses and Opportunistic Infections, February 8-11, 2009, Montreal
Mark Mascolini
An intermediate or high Framingham heart risk score predicted high internal carotid intima media thickness (IMT), high common carotid IMT, and detectable coronary artery calcium in 334 HIV-infected adults in the Nutrition for Healthy Living (NFHL) cohort [1]. Liana Falcone and Tufts University colleagues proposed that the Framingham score is a useful "predictive instrument for cardiovascular risk stratification in the HIV-infected population." Meanwhile, other researchers are trying to devise a heart disease equation specifically for people with HIV.
This cross-sectional study involved 334 NFHL cohort members who had ultrasonography for internal and common carotid IMT, recognized predictors of atherosclerosis, and CT scans for coronary artery calcium. A quality control analysis of IMT readings in 32 people yielded intraclass correlation coefficients of 0.911 for common carotid IMT and 0.883 for internal carotid IMT. Falcone and colleagues collected clinical and demographic data on cohort members within 12 months of IMT and coronary artery calcium readings. They classified 10-year Framingham cardiovascular risk scores below 6% as low and at or above 6% as intermediate/high.
Three quarters of cohort members (74.3%) were men, 52.7% were white, and 49.5% were smokers. Almost three quarters of the group (73.7%) were taking antiretrovirals, including 45.2% taking a protease inhibitor and 32.6% taking a nonnucleoside.
The low Framingham score group included 180 people, and the high group had 154. People with an intermediate/high score were significantly older (average 47.8 +/- 6.7 vs 41.3 +/- 6.4 years, P < 0.001), and a significantly greater proportion were men (90.3% vs 60.6%, P < 0.001). High-sensitivity C-reactive protein (hsCRP) was significantly higher in the intermediate/high group (3.6 +/- 6.5 vs 2.4 +/- 2.9, P = 0.03), as were apolipoprotein A1, B, and E levels (P < 0.001 for all three). QUICKI scores for insulin sensitivity were significantly worse in the intermediate/high group (P = 0.02), as were "good" high-density lipoprotein cholesterol levels (P < 0.001). Total cholesterol and "bad" low-density lipoprotein cholesterol were significantly higher in the high/intermediate group (P < 0.001).
People with an intermediate/high Framingham score had been infected with HIV significantly longer than those with a low score (average 10.4 +/- 4.7 vs 9.2 +/- 4.8 years, P = 0.02). Antiretroviral treatment duration was also significantly longer in the intermediate/high group (34.6 +/- 25.8 vs 28.9 +/- 25.0 months, P = 0.05).
The investigators found four other significant differences between the low and intermediate/high Framingham score groups:
· Waist circumference: average 91.0 cm low vs 94 cm intermediate/high, P = 0.03
· Systolic blood pressure: 113.2 mm Hg low vs 124.2 mm Hg intermediate/high, P < 0.001
· Diastolic blood pressure: 72.8 mm Hg low vs 78.9 mm Hg intermediate/high, P < 0.001
· Ever had hypertension: 28% low vs 43% high, P = 0.006
Common carotid IMT was significantly higher in the intermediate/high Framingham group (median 0.61 mm, interquartile range [IQR] 0.54-0.70 vs 0.54 mm, IQR 0.48-0.60, P < 0.001), as was internal carotid IMT (0.65 mm, IQR 0.58-0.95 vs 0.55 mm, IQR 0.49 vs 0.64, P < 0.001). While 71% with an intermediate/high Framingham score had a coronary artery calcium score above 0, 42% in the low Framingham group had a calcium score above 0 (P < 0.001).
Multivariate analysis correlated an intermediate/high Framingham score with a 7 times higher risk of common carotid IMT at or above 0.8 mm vs below 0.8 mm (adjusted odds ratio [AOR] 7.067, 95% confidence interval [CI] 2.332-21.421, P = 0.001). An intermediate/high Framingham doubled the risk of an internal carotid IMT at or above 1.0 mm vs below 1.0 mm (AOR 2.222, 95% CI 1.116-4.426, P = 0.023). And an intermediate/high Framingham score predicted a tripled risk of a coronary calcium score above 0 (AOR 3.444, 95% CI 2.105-5.635, P < 0.001).
Three years ago D:A:D investigators reported a higher number of myocardial infarctions (MIs) among antiretroviral-treated cohort members than the Framingham score predicted: 9 observed MIs in 10 years vs 5.5 predicted [2]. The D:A:D group is trying to improve the Framingham equation by factoring in HIV-specific variables to predict coronary heart disease (CHD) [3]. Comparing this tool with the Framingham model, D:A:D researchers reported that the Framingham equation tended to overestimate absolute CHD risk in the D:A:D population, while slightly underpredicting MI risk. Whether an HIV-specific risk calculator substantially improves on the Framingham score awaits confirmation.
References
1. Falcone L, Mangili A, Skinner S, Polak J, Wanke C. Framingham risk score and markers of early atherosclerosis in a cohort of HIV-infected subjects. 16th Conference on Retroviruses and Opportunistic Infections. February 8-11, 2009. Montreal. Abstract 726.
(This poster is online at http://www.retroconference.org/2009/PDFs/726.pdf.)
2. Law MG, Friis-Moller N, El-Sadr WM, et al. The use of the Framingham equation to predict myocardial infarctions in HIV-infected patients: comparison with observed events in the D:A:D study. HIV Med. 2006;7;218-230.
3. Friis-Moller N, Thiebaut R, Reiss P, et al. Predicting the risk of coronary heart disease (CHD) in HIV-infected patients: the D:A:D CHD risk equation. 14th Conference on Retroviruses and Opportunistic Infections. February 2007. Los Angeles. Abstract 808.
(This poster is online at http://www.cphiv.dk/Portals/0/Files/CROI07_808_NFM.pdf.)
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