LOS ANGELES — In a study that used computerized pill bottles to track medication adherence, HIV-infected patients with cognitive problems were far more likely to miss doses when they had to take pills three times a day, compared to once or twice per day.
Reporting in the December 24 issue of Neurology, researchers at the Veterans Affairs Greater Los Angeles Health Care System and the University of California, Los Angeles, suggest simpler drug therapies may be critical in managing HIV, which often requires complex drug regimens of up to 20 to 30 pills per day.
The study of 137 of adults with HIV found that 34 percent had problems with memory, attention or decision-making–common symptoms of HIV infection. On average, these patients followed their drug regimen only 70 percent of the time over the one-month study period, compared to 82 percent for patients with no cognitive trouble.
Among the cognitively impaired group, medication adherence dropped to 52 percent when patients had to take three daily doses of their main HIV drug, compared to 78 percent for those who needed only one or two doses.
According to lead author Charles H. Hinkin, PhD, there is likely a two-way relationship between missed doses and disease progression, resulting in a downward spiral for HIV patients. Drugs that fight the spread of HIV in the body also protect the mind. Those who miss doses are likely to suffer more effects of the infection, including memory and attention problems, resulting in poorer adherence to the drug regimen.
“Those who fail to take their medications are more likely to develop cognitive problems that in turn further compromise their adherence,” said Hinkin, a neuropsychologist with VA and UCLA.
Patients in the study were all on highly active antiretroviral therapy (HAART), which can involve “cocktails” of up to four or five medications. The therapy can fail when patients do not take all their prescribed doses, resulting in worse symptoms and the development of drug-resistant strains of the virus, which can then be transmitted to others.
A study at the VA Pittsburgh Health Care System, published in the Annals of Internal Medicine in 2000, showed that HAART failed to suppress the virus in only 1 of 5 patients who took their medications 95 percent of the time. The figure climbed to 4 of 5 patients for those with poorer than 80 percent adherence. Patients with poorer adherence had more opportunistic infections and spent more days in the hospital.
Hinkin’s study used pill bottles with computer chips that recorded when the bottle was opened. He said this posed an advantage over previous studies of HAART adherence that relied on pill counts by medical staff or self-reports from patients. Both those methods are thought to underestimate non-adherence. Another strength of the study, said Hinkin, is that it used extensive neuropsychological tests, rather than patients’ own reports of their cognitive ability.
One surprising finding in the study: Participants over age 50 were nearly three more likely than younger patients to stick to their medication schedule. Hinkin explained that older adults may be more accustomed to taking medications, or their daily routines may be better suited to it. Also, none of the patients in the study were age 70 or older, when cognitive decline becomes more of an issue. However, in a related study, the VA/UCLA team found that older HIV patients who were cognitively impaired had the greatest degree of difficulty with medication adherence.
Hinkin’s group is conducting further research on the relationship between cognitive status and HAART adherence, as well as exploring other factors known to disrupt drug regimens, such as alcoholism, drug abuse and depression.