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
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
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
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
"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.
For Further Information: Dave Lavallee 401-874-2116