Glaucoma Medication Adherence Clinical Trial
Official title:
The Impact of a Brief Educational Intervention on Glaucoma Adherence
OBJECTIVE Our objective was to determine whether two group educational sessions plus
one-on-one eye drop instillation training would improve adherence to glaucoma therapy as
measured by pharmacy claims data in a cohort of newly diagnosed patients. Our hypothesis was
that adherence would be improved in the intervention group and that patients would better
understand their disease and how to manage it.
METHODS Study Design and Population: A randomized controlled clinical trial was conducted in
newly diagnosed glaucoma patients at Maisonneuve-Rosemont Hospital in Montreal, Canada. Half
of the participants were randomized to receive the intervention and half were randomized to
receive a delayed intervention at the conclusion of the study. Inclusion criteria included a
diagnosis of glaucoma requiring intraocular pressure lowering eye drop therapy and
prescription drug insurance through the Régie de l'Assurance Maladie du Québec (RAMQ) (the
Quebec Health Insurance Program) throughout the course of the study. There were three
sources of data for this study: a questionnaire, the medical record, and RAMQ prescription
drug claims data. Follow-up was for one year.
Recruitment and Randomization: From July, 2007 until December, 2011, a researcher approached
eligible patients to determine their interest in participating in the study. Interested
participants signed the informed consent form and were randomized. Participants in the
intervention group were given an appointment to come back to the Hospital for the group
intervention. Participants in the control group were given an appointment to receive the
group intervention at the end of the study.
Intervention: Small groups of about 10 people were gathered for two 60-90 minute educational
sessions on glaucoma in a classroom at Maisonneuve-Rosemont Hospital. During a break, each
patient received one-on-one teaching on how to properly instill drops without touching the
eye or using unnecessary drops.
Questionnaire and Assessment of Eye Drop Technique: A single questionnaire was given at the
end of the study to all participants. The intervention group completed the questionnaire
after the intervention while the control group completed the questionnaire before the
intervention. Questions were included on demographics, systemic comorbidities, ocular
medications, eye drop practices and difficulties, and glaucoma knowledge.
The instructor rated the ability of the participant to put eye drops in the eye taking into
account the number of drops that were used and whether contact with the lid or conjunctiva
occurred (good, fair, bad).
We created a composite score on the perception of the importance of glaucoma eye drop
therapy using the following four questions: 1) do you think glaucoma is a serious disease,
2) do you believe that your treatment will be effective, 3) do you think your drops can
lower the pressure in your eyes, 4) do you think your drops can help to preserve vision.
Answers of no or do not know were given 0 points and answers of yes were given 1 point.
Scores were summed and the composite score ranged from 0 to 4.
Medical Chart Review: At the end of the follow-up period, information was obtained on: the
prescribed eye drop therapy for each patient per eye, whether the patient had undergone
glaucoma filtering surgery, whether the patient had died or was no longer being followed,
the most recent visual field mean deviation in the better eye using the Humphrey Visual
Field Analyzer 24-2 SITA Standard Program.
Pharmaceutical Claims and Calculation of Medication Possession Ratio: The Medication
Possession Ratio (MPR) was calculated as the sum of days of prescription supply divided by
the number of days in which a prescription was required. Each person gave consent to contact
the RAMQ to obtain pharmaceutical claims for all glaucoma medications. Data were collected
on the date of purchase, and the name, dose, and class of the medicine. Data on the number
of days of medication available per bottle were taken from the Rylander and Friedman studies
with the minimum value used. For the numerator of the MPR, we calculated how many days of
medication were available using RAMQ data. For the denominator of the MPR, we calculated the
number of days that medication was prescribed in the medical chart. We took into account
whether drops were needed for one or two eyes. If a participant was on multiple medications,
we calculated a single mean MPR for all medications. We then dichotomized the MPR so that
those having medication less than 75% of the days were defined as non-adherent, as we did
previously in Djafari et al.
SIGNIFICANCE Adherence can be a problem in glaucoma because patients must often take daily
eye drops despite not noticing any benefit to their vision and despite frequent side
effects. Low cost interventions that help to improve adherence are needed.
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