According to two new University of Washington studies, for people with human immunodeficiency virus, taking active antiretroviral medicines is much harder than it is believed.
One study looked at the effects of drinking alcohol on adherence and showed the risk for non-adherence was double among drinkers compared to abstainers.
The second study evaluated interventions using peers, electronic pagers or both, and showed that these tools promoted no lasting improvements in adherence rates.
"HIV is unique in the adherence levels needed to be effective. Typical adherence for people taking medication is 50 percent. But 50 or 60 percent adherence isn't going to work for HIV medications and will lead to resistance to the drugs. Taking drugs for HIV is a lifetime commitment; you are married to the pills," said Jane Simoni, a University of Washington psychology professor who specializes in studying adherence.
The alcohol paper analyzed data from 40 previous studies involving more than 25,000 people and established that drinking does have a consistent effect on adherence across studies.
"Drinking quantity, more than frequency of drinking, is associated with non-adherence. In general, people who drank alcohol had nearly twice the risk of non-adherence.
But the risk of non-adherence went up as the level of drinking went up," said Christian Hendershot, lead author of the alcohol study.
For the peer-pager study, researchers recruited 224 patients being treated at a Seattle clinic.
Patients were randomly assigned to one of four treatment groups - pager, peer, combined peer-pager and treatment as usual - for three months.
Simoni said patients who had peer support initially showed some increased adherence levels, but this didn't persist once the support ended.
The pagers did not successfully promote adherence at any point.
"We can change adherence a little, but it disappears when the intervention is taken away. Even though you are capable of doing something that doesn't mean you are motivated to do it all the time. Just ask anyone, 'Did you exercise yesterday?' 'Floss your teeth?' 'Avoid sweets?'" said Simoni.
"Add to this the complication that a person has to take these meds every day for a life-threatening disease.
There is a lot of emotional baggage surrounding the disease and the pills, and the medications have severe side effects," she added.