Study by URI pharmacy professors finds AIDS patients overestimate their adherence to drug programs

KINGSTON, R.I.-- September 26, 1998 -- Patients who are HIV positive overestimate their compliance with drug regimens, according to a new study by a University of Rhode Island pharmacy professor.

While the overall medication adherence was good during the study, the researchers involved with the project said patients and their doctors and pharmacists should be aiming for 100 percent compliance.

The three-month study involved Drs. Cynthia Willey, the principal investigator, Kathleen M. Melbourne, and Sandra Geletko, all URI professors of pharmacy.

Completed by the Medication Compliance Research Team of the URI President's Health Promotion Partnership, the project entitled, "Stages of Change for Adherence with HIV Related Medications," has recently received national attention.

The study, which also involved Coastal Medical, a primary care physicians' group based in Providence, was presented today, Sept. 26 at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Diego. Dr. Melbourne's paper was selected by the conference for release to the national and international medical press.

Melbourne is also Pharmaceutical Care coordinator for Coastal Medical. Melbourne said the findings are important because missed doses of medication in the treatment of human immunodeficiency virus (HIV), the virus that can lead to AIDS, can result in drug resistance, drug failure and a quicker progression to AIDS.

"Unlike anti-hypertensive (high blood pressure) medications, with which a person can miss one or two doses and still return to adequate blood pressure when resuming the medication, drugs for HIV must be taken correctly and consistently or they won't work anymore," said Dr. Melbourne.

In the study, Dr. Melbourne compared patients' own reporting records with records taken from special medication bottle caps, which were placed on patients' medications and were able to record electronically the time and date of every bottle opening.

Dr. Melbourne said most protease inhibitors (strong anti-HIV) medications need to be taken at high doses and taken within a certain time interval, such as 8 to 12 hours, to maintain adequate blood levels of the medication in the body. "If the patients fluctuate from dosing schedules, the amount of medication in their bodies may not be enough to work effectively against HIV," Dr. Melbourne said. She said the findings may partially explain the large variability in response to medication taken by HIV-infected individuals.

Dr. Melbourne began the study with the premise that measuring how many doses people miss over time is difficult. So she and investigators chose to compare patients' self-reporting with data from the electronic cap to see if the results would be similar.

Dr. Melbourne used technology called the Medication Event Monitoring Systems (MEMS) track cap. For each month the caps were on each of the patients' medication bottles, the investigators were able to measure how many times the bottle was opened (which was counted as the number of doses taken) and the amount of time that elapsed between doses. The patients were aware of the high-tech caps.

Self-reporting was recorded by asking patients at each monthly study visit to report honestly how many doses they missed in the previous month and the variation in dosing times.

The study enrolled 50 HIV positive men and women over the age of 18 who were on triple antiretroviral therapy (including protease inhibitors). Forty-four

Coastal patients completed the study. The average age of the group was 38 and most, 94 percent, were men. Her study population averaged nine different medications per day, which translated into up to 30 pills a day.

Dr. Melbourne said in general, patients' adherence was very good, but missed doses were still documented in 98 percent of the study group and many patients did not stick to their dosing times. Only one patient out of the total took 100 percent of the doses during the three-month period.

The average dose percent (number of doses taken divided by number of doses prescribed) was 97.5 percent by the self-report method and 90.3 percent by electronic method. With HIV, clinicians need to help patients attain 100 percent compliance, according to the three URI professors.

Forty-three percent of patients taking protease inhibitors were two or more hours off their stated dosing schedule. "The reasons self-report is higher is because patients don't want to be looked upon as bad patients to their doctors," Dr. Melbourne said. "People don't want to admit they miss doses of medication."

She said the study group tended to be well educated and employed. "With a more diverse group you might find much lower compliance rates," she added.

"Health care providers need to stress the health implications of taking all the doses in a timely manner," she said.

Also working on the team were: Dr. Susan Brown, a pharmacy resident at URI and Coastal Medical; Sarah Chase, research assistant from URI and Dr. Alvan Fisher, physician at Coastal Medical and associate director at the Brown University AIDS program.

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For Further Information: Dave Lavallee 401-874-2116