The Framingham function overestimates the risk of ischemic heart disease in HIV-infected patients from Barcelona

Abstract

Background: Cardiovascular risk (CVR) assessment helps to identify patients at high CVR. The Framingham CVR score (FRS) is the most widely used methods but may overestimate risk in regions with low incidence of cardiovascular disease. The objective was to compare the 10-year performance of the original and the adapted REGICOR - Framingham CVR functions in HIV-infected individuals.

Methods: We carried out a longitudinal study of HIV-infected patients with CVR evaluation in a hospital in Barcelona between 2003 and 2013.

Statistics: Risk probability was calculated using the FRAMINGHAM function and REGICOR adaptation to the Spanish population, and individuals were categorized in three groups (low, 0 < 5%; moderate, 5-10%; and high, >10%). For each risk group, the number of events over 10 years was calculated using the Kaplan-Meier method, and the expected number of events was calculated by multiplying the frequency of participants in the group by the mean of the probabilities from the risk function. We used the X(2) goodness-of-fit test to assess agreement between observed and expected.

Results: Six hundred and forty-one patients were followed up for a median of 10.2 years, and 20 ischemic heart events (IHE) were observed. The mean (95% CI) number of IHEs per 1000 person-years was 3.7 (2.06-5.27). The estimates from the Framingham and REGICOR functions were 40 and 14 IHEs, respectively. The estimate from the original Framingham function differed significantly from the observed incidence (p < 0.001), whereas that from the REGICOR-adapted function did not (p = 0.15). In terms of the number of cardiovascular events (38 events observed), the REGICOR function significantly underestimated risk (p = 0.01), whereas the estimate from the Framingham function was similar to observed (p:0.93).

Conclusions: The FRS significantly overestimates risk of IHE events in our HIV-infected patients, while the REGICOR function is a better predictor of these events. In terms of cardiovascular events, the REGICOR function significantly underestimates risk, whereas the FRS is a better estimator. We recommend using CVR scales and adjusting them to the origin of the population being studied.

Keywords: Cardiovascular risk; Framingham; HIV; REGICOR.