Does hepatotoxicity occur in everyone taking ARV drugs?
There have been a number of studies looking at the percentage of patients who develop hepatotoxicity, according to the different ARV medications they are taking. One study reported in 2006 looked back at 20 studies published between 1990 and 2005. The studies included both people infected only with HIV as well as those coinfected with both HIV and hepatitis C virus (HCV). The meta-analysis found that liver enzyme elevations occurred in roughly 15 percent of coinfected individuals and 12 percent of those infected only with HIV. The more severe liver enzyme elevations occurred most frequently in those taking non-nucleoside reverse transcriptase inhibitors (NNRTIs).
Another study, conducted by researchers at the National Institutes of Health, looked at rates of hepatotoxicity among 10,611 HIV-positive people participating in 21 government-funded clinical trials conducted between 1991 and 2000. Overall, 6.2% of the clinical trial participants experienced severe hepatotoxicity. Among the participants who took an NNRTI (either Viramune, Sustiva, or Rescriptor) in combination with two nucleoside analogues, severe hepatotoxicity occurred in 8.2%. Among the participants who took a protease inhibitor in combination with two nucleoside analogues, severe hepatotoxicity occurred in 5%.
Unfortunately, clinical trials do not always reflect what is going to happen in the real world. Many clinical trials only follow participants for a year—and we know that HIV-positive people will need to take these medications for many years, which can increase the risk of hepatotoxicity. What's more, most clinical trials enroll patients who don't have other conditions that can further increase the risk of hepatotoxicity. For example, it is believed that women and people over the age of 50 are at a higher risk of developing hepatotoxicity. Obesity and heavy alcohol use can also increase the chances of hepatotoxicity occurring. There is also a very real concern that HIV-positive people who are coinfected with hepatitis B or hepatitis C are more likely to experience hepatotoxicity than those who are only infected with HIV.