This Week in HIV Research: The Science of Risk

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Thanks for joining us for another brief exploration of notable recently published research with relevance to the HIV care community. This week's highlighted studies are all about risk factors for complications among people living with HIV: Which factors we're paying too much attention to, which factors we should be paying more attention to, and which factors we're still not altogether certain about.

Specifically, this week we learn:

  • Our clinical eye should be cast more closely on traditional factors than HIV-specific factors when gauging a person's risk of developing non-communicable complications.
  • Frailty appears to be a particularly reliable indicator of future fracture risk among women with HIV.
  • We need to be careful about the extent to which we lean exclusively on traditional lipid measurements when gauging coronary risks among people with HIV.
  • New data extend the debate over the extent to which efavirenz (Sustiva, Stocrin) use during pregnancy is associated with birth defects.

Come along as we glance more deeply at each of these findings. To beat HIV, you have to follow the science!

Barbara Jungwirth is a freelance writer and translator based in New York. Follow Barbara on Twitter: @reliabletran. Myles Helfand is the executive editor and general manager of TheBody and TheBodyPRO. Follow Myles on Twitter: @MylesatTheBody.

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HIV and Comorbidities: Traditional Risk Factors Often Matter Most

Among people living with HIV, traditional risk factors outweigh HIV-related risks as a cause of many health complications, an analysis published in The Lancet found.

Researchers calculated population attributable fractions (PAFs) among participants living with HIV who developed non-AIDS-defining cancers, end-stage liver or kidney diseases, or myocardial infarctions (MIs). PAFs quantify the proportional reduction in an illness, if the associated risk factor was eliminated (e.g., nobody smoked).

They found that addressing non-HIV risks could curb a significant proportion of these conditions: Smoking prevention, for instance, could avoid 24% of non-AIDS-defining cancers and 37% of MIs, while hypercholesterolemia prevention could avoid 44% of MIs. By contrast, the effect of CD4 count and viral load management was more muted: Keeping a person's CD4 count at or above 200 could avoid 3% of non-AIDS-defining-cancers and 6% of MIs, while maintaining a viral load below 400 copies/mL could avoid 2% of non-AIDS-defining cancers and 5% of MIs, the authors calculated.

Study authors recommended screening people living with HIV for such traditional risks. However, researchers Line D. Rasmussen and Niels Obel wondered in a related commentary whether increased screenings might rekindle stigma.

Both the study authors and commentators did appear to agree that limited resources needed to be allocated in a way that most effectively maintains the health of an aging population living with HIV.

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Frailty Increases Risk of Fracture in Women With HIV

Frailty greatly speeds up the occurrence of fractures in women, and HIV enhances the risk, a study published in AIDS showed.

Researchers followed 1,332 women living with HIV and 534 not living with the virus for a median of 10 years. At study start, those in the HIV group were slightly older (median age 42 years) and had a somewhat lower body mass index than the control group.

Frailty was defined as having three of the following five problems: slow gait, reduced grip strength, exhaustion, unintentional weight loss, and low physical activity. The study focused on the extent to which frailty affected the amount of time it took for a woman to experience her first and second bone fractures.

During the study period, 20% of those living with HIV sustained fractures (including 6% who broke a bone more than once), compared to 15% in the control group (5% more than once). Frail women had a roughly 70% greater risk of fracture independent of HIV status; within the HIV-positive group, that risk increased to about 90%.

Early frailty screening of women living with HIV can identify those at risk and develop strategies to prevent fractures, study authors concluded.

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Typical Lipid Parameters May Miss HIV-Specific Coronary Atherosclerosis Risk

Traditional markers for subclinical coronary artery disease may underestimate its risk among people living with HIV, a study published in AIDS showed. The serum lipid parameters used to determine heart disease risk in the general population do not take into account HIV-specific factors, such as inflammation and antiretroviral treatment, study authors said.

They analyzed data on coronary artery calcium, stenosis, and plaque, as well as lipid parameters, among 429 men living with HIV and 303 controls. Total cholesterol and other lipid measurements were associated with mixed plaque, greater than 50% stenosis, and coronary artery calcium independent of HIV status, but that association was less pronounced in the HIV group than in the control group.

Because of this weaker association, some people living with HIV who are at increased risk of heart disease may not be identified, study authors concluded. They called for further research into the relationship between traditional lipid parameters and cardiovascular disease among those living with HIV.

Analysis Questions Prior Findings on Birth Defects Following Efavirenz Exposure

An analysis of data on 24,963 infants born to women living with HIV that was published in the Journal of Acquired Immune Deficiency Syndromes found no greater risk of birth defects, including neurological problems, in babies born to women who took efavirenz before or during the first trimester of pregnancy.

In line with some European countries where guidelines suggest pregnant women avoid efavirenz altogether, only 14% of infants had been exposed to efavirenz. However, the antiretroviral is used more extensively across the globe. Some previous studies, including one reported at IDWeek 2018, had shown higher rates of neurological problems in children born to women who were on efavirenz-containing antiretroviral regimens. The current study was intended to prove that the drug does not increase the risk of birth defects.

In the IDWeek study, it took an average of two years for the children to be diagnosed with neurological issues. By contrast, most studies included in the new analysis provided data for six months after birth. The authors of the current analysis acknowledge potential underreporting as a result, but believe few birth defects were missed. They favor reconsideration of European recommendations against the use of efavirenz.