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Session 102 Poster Abstracts
Cardiovascular Complications: Risk Factors, Incidence, Prevalence, and Outcomes
Tuesday, 1:30 - 3:30 pm
Poster Hall


737    
Cardio- and Cerebrovascular Events and Predicted Rates of Myocardial Infarction in the D:A:D Study
M G Law*1, A D'Arminio Monforte2,4, N Friis-Moller2,3, R Weber3,4, W El-Sadr5, P Reiss6, F Dabis7, L Morfeldt8, S De Wit9, C Pradier 10, G Calvo11, O Kirk12, C Sabin13, A N Phillips13, and J D Lundgren2
1AHOD, Natl. Ctr. in HIV Epidemiology and Clin. Res., UNSW, Sydney, Australia; 2Copenhagen HIV Prgm., Hvidovre Univ. Hosp., Denmark; 3SHCS, Univ. Hosp. Zurich, Switzerland; 4ICONA, L Sacco Hosp., Univ. of Milan, Milan, Italy; 5CPCRA, Columbia Univ./Harlem Hosp., New York, NY, USA; 6ATHENA, HIV Monitoring Fndn., Academic Med. Ctr., Amsterdam, The Netherlands; 7Aquitaine, Bordeaux Univ. Hosp., INSERM U593, Bordeaux, France; 8HivBivus, Karolinska Hosp., Stockholm, Sweden; 9Saint-Pierre Cohort, CHU Saint-Pierre Hosp., Brussels, Belgium; 10Nice Cohort, CHU Nice Hosp. de l'Archet, France; 11BASS, Autonomous Univ. of Barcelona, Spain; 12EuroSIDA, CHIP, Hvidovre Univ. Hosp., Copenhagen, Denmark; and 13Royal Free Ctr. for HIV Med., Royal Free and Univ. Coll., London, UK

Background:  Recent results from the D:A:D Study, a prospective observational cohort of 23,468 HIV-patients, indicated that the incidence of myocardial infarction increased by 26% per year of exposure to combination antiretroviral treatment (CART). We investigated whether this risk was similar when including other cardiovascular events. We also compared the observed rate of myocardial infarctions to that predicted by conventional risk equations.

Methods:  Rates of first cardiovascular event (either myocardial infarction, cardiovascular death, invasive cardiovascular procedure, or stroke) were compared according to CART duration using Poisson regression methods. The Framingham equation was used to predict myocardial infarction rates by duration of CART (no CART, <1year, 1 to 2 years, 2 to 3 years, 3 to 4 years, and 4+ years) assuming a 5-fold increase in myocardial infarction risk in those with prior cardiovascular disease and adjusting for regional differences in myocardial infarction risk. Cardiovascular disease risk factors were time-updated for patients who contributed follow-up to more than 1 CART category. Sensitivity analyses were performed to assess the effect of model and data assumptions.

Results:  Over 36,151 person-years of follow-up, 199 patients experienced at least 1 cardiovascular event, an incidence of 5.5/1000 person-years. The incidence of first cardiovascular event increased with longer exposure to CART (RR per year of exposure: 1.26, 95%CI:  1.15 to 1.38). In patients receiving CART, the numbers of myocardial infarction observed during D:A:D follow-up were of similar magnitude and possibly somewhat higher than the  numbers predicted from Framingham:  9 observed vs 5.5 predicted, 14 vs 9.8, 22 vs 14.9, 31 vs 23.2 and 47 vs 37.0 in <1 year, 1 to 2 years, 2 to 3 years, 3 to 4 years, and 4+ years CART duration, respectively. In patients not receiving CART, the observed number of MIs was fewer than predicted (3 observed vs 7.6 predicted). Predicted myocardial infarction rates were within the 95% confidence interval of observed rates. Sensitivity analyses consistently showed that in patients receiving CART the observed and predicted rates of myocardial infarction increased in a parallel fashion with greater CART duration.

Conclusions:  The increased risk of cardiovascular event with longer exposure to CART is very similar to that found using myocardial infarction as the endpoint. The observed rate of myocardial infarction in the D:A:D Study was of a similar magnitude to, or somewhat higher than, that predicted by the Framingham cardiovascular disease risk equation. That observed and predicted rates of myocardial infarction increased in a parallel fashion with increased CART duration suggests that the observed increase in risk of myocardial infarction may largely be explained through CART-induced changes in conventional cardiovascular disease risk factors.

 

Keywords: cardiovascular; myocardial infarction; Framingham risk equation