Model Says Replacing Abacavir Is Single Best MI-Preventing Strategy With HIV
Compared with three traditional myocardial infarction (MI)-thwarting strategies, switching from the nucleoside abacavir prevented more MIs over 10 years in a decision-tree model . Priscilla Hsue (University of California, San Francisco) and colleagues from other centers suggested their findings "highlight the role that abacavir substitution can have on MI risk over time compared to antismoking, hypertension and lipid-lowering interventions."
HIV clinicians are more aware than most providers of the importance and difficulty of MI prevention in an aging population. Getting people to quit smoking remains challenging, and controlling hypertension and abnormal lipids takes more than writing prescriptions. But one MI-prevention tactic, replacing abacavir with another drug, could not be simpler. Hsue and colleagues stressed that other antiretrovirals are also associated with MI risk, but they chose to focus on abacavir as an MI-preventing switch strategy.
Aiming to help clinicians prioritize MI-reducing interventions, they created a decision-tree model to estimate the impact of different interventions on predicted MI rates. The model considered four strategies:smoking cessation counseling, replacing abacavir with another drug, prescribing antihypertensives, and prescribing lipid-lowering drugs. The model adjusted for age, sex, and the four risk factors and aimed to predict the 10-year impact on a 50-year old man with HIV who smokes and has hypertension and dyslipidemia. The model considered both the probability of successfully changing the risk factor (100% with abacavir switching) and the impact of the change when successful. The researchers based assumptions about intervention effectiveness on research involving people with HIV or the general population.
Hsue and coworkers figured a baseline MI rate of 14 per 1000 person-years for the 50-year-old hypertensive hyperlipidemic smoker. Compared with doing nothing, smoking-cessation counseling eased the MI rate by 11% to 12.7 MIs per 1000 person-years. Prescribing an antihypertensive trimmed the MI rate by 19% to 11.6 per 1000. Prescribing a lipid-lower drug cut the MI rate by 31% to 9.8 per 1000. Switching from abacavir outdid them all, slicing the MI rate by 45% to 7.7 per 1000.
"By incorporating the impact of cardiovascular risk factor modification based on real-world data," the researchers concluded, "this model suggests that replacing abacavir, which can be accomplished in most patients, has a greater impact on MI risk than interventions solely based on modifying each of three traditional risk factors, one at a time."
They added that the model may overestimate the impact of prescribing antihypertensives or antilipid agents because complete success with those strategies is tough in practice. They believe that interventions addressing all cardiovascular risk factors are warranted "and are at least additive when successful."
1. Hsue P, McComsey GA, Cohen C, Sola A, Beaubrun AC. Comparing strategies for reducing myocardial infarction rates in HIV patients. 25th Conference on Retroviruses and Opportunistic Infections (CROI). March 4-7, 2018. Boston. Abstract 692.