Nearly 200 people with HIV who were on antiretroviral drugs and drank alcohol were followed for a year, and 51 percent stopped taking their medications while drinking - and those same patients tended to have higher viral loads, according to the new report.
Seth Kalichman, a professor at the University of Connecticut and lead author of the study, said patients need to be better educated about drinking and HIV treatments.
"The harms caused by missing their medications far outweigh the harms caused by mixing the two, if the person doesn't have liver disease. That's the reality of it," Kalichman told Reuters Health.
Drinking has been known to interfere with people's adherence to their medications, but "the consequences of inconsistent use of medications for HIV can be more severe in some ways," said Dr. Michael Ohl, a professor of medicine and infectious disease at the University of Iowa, who was not involved in the study.
Antiretroviral drugs suppress the HIV virus, and patients must take the medications continuously to prevent the virus from surging.
Additionally, going on and off the pills can lead to drug resistance, in which the antiretrovirals lose their potency.
To see how patients' beliefs about drinking and taking medication might contribute to poor adherence to the drugs, Kalichman and his colleagues surveyed 178 people - about four out of five of them men - who were currently using antiretroviral therapy and who reported that they drank alcohol.
At the beginning of the study, the researchers asked the participants about their alcohol-related beliefs, such as whether they thought their drugs wouldn't work as well if the two mixed. They also asked whether people would not take both at the same time - either by avoiding alcohol or the medicines.
Over the following year, the team checked in with patients every month to see how well they were sticking to their prescriptions through a pill count, and every other month they called to ask how often the patient had been drinking recently.
In addition, doctors' offices provided each patient's level of virus in the body and his or her CD4-cell counts, a measure of immune system health.
Kalichman's group found that 51 percent of the patients would avoid their medications at times when they drank, and half of the people in this group had poor adherence to their prescriptions.
In addition, half of the group that would skip pills also said they do not take their medications until alcohol is completely out of their system.
"It's pretty remarkable that about 50 percent of their patients reported doing this," said Catherine Grodensky, a researcher at the Center for AIDS Research at the University of North Carolina, who was not part of the study. "That's pretty surprising to me that it was such a high percentage."
In comparison, of the patients who reported not skipping their medications when they drank, 36 percent also did not adhere well to their prescriptions and 31 percent said they don't take the drugs until alcohol is out of their system.
"I think it's pretty well demonstrated that alcohol use is tied to poor adherence, and I think most people think it's because they're impaired in some way or they forget and it's an unintentional missing their medications, whereas here it shows they're (often) intentionally missing their medications," said Grodensky.
"And it looks like it's having some significant impacts on their treatment," she added.
People who skipped their medications while drinking were also more likely to have higher levels of HIV in their bodies and lower numbers of CD4 cells.
"People living with HIV who deliberately stop their medications when they are drinking are at risk for treatment failure," the authors write in the Journal of General Internal Medicine.
Ohl said the belief that antiretrovirals and alcohol are a toxic mix is something he hears frequently in his medical practice, but that there's no evidence that drinking should preclude taking HIV medication.
Andrea Sankar, a professor at Wayne State University, who did not participate in the study, said the belief likely comes from the advice that doctors typically give to patients, which is that they shouldn't drink when they are on therapy.
"When clinicians say, 'if you're taking antiretroviral therapy you shouldn't drink,' then what happens is rather than people stopping drinking, they stop taking their medications," she told Reuters Health.
Sankar said that doctors' offices are the best place to start changing behavior to make sure people continue to take their medication.
"We think it may be a pretty simple fix, just educating patients," said Kalichman.
SOURCE: http://bit.ly/SmCjg9 Journal of General Internal Medicine, online October 12, 2012.