Low Health Literacy Linked to Poor Medication Management

March 2, 2011

Patients with limited literacy may self-administer medications more times a day than is necessary, which can lead to missed or incorrectly administered dosing.

Many patients, especially those with limited literacy, may self-administer prescription medications more times a day than is necessary, which may lead to missed or incorrectly administered dosing, according to a report in the February 28 issue of Archives of Internal Medicine.

According to the Medical Expenditure Panel Survey, the average US adult fills nine prescriptions each year, while adults older than 65 years fill an average of 20 prescriptions a year, according to background information provided in the article. "Greater regimen complexity, based on multiple medications and/or multiple daily doses per drug, may lead to poorer adherence, which in turn will lead to worse health outcomes,” the authors wrote.

Michael S. Wolf, PhD, MPH, of the Feinberg School of Medicine, Northwestern University, Chicago, and colleagues interviewed 464 adults (average age 63.3 years) who were receiving care either at an academic general medicine practice or at one of three federally qualified health centers in Chicago. The goal of the study was to evaluate the accuracy and variability in the way patients would schedule a typical seven-drug regimen. Most participants (71.1%) were female and highly educated (61.4% were college graduates); however, nearly half were identified as having either low (20.7%) or marginal (22.8%) health literacy skills.

When dosing a seven-drug regimen, participants on average identified six times in 24 hours to take medicine, while dosing schedules ranged from as few as three times a day to as many as 14. One-third (29.3%) of participants dosed the regimen seven or more times within 24 hours, while 14.9% organized the medication four or fewer times a day.

For one set of medications, in which label instructions were identical, nearly one-third (30.8%) did not take the two pills at the same time. Another set had instructions to be taken at the same interval (three times daily) but one pill also had to be taken "with food and water." Half of the patients (49.5%) did not take these two medications at the same time of day. A third set compared drugs taken two times a day. One set of instructions noted frequency of "twice daily" and the other listed "every 12 hours." Four of five patients (79%) did not consolidate these and took the medications at two different times.

Low health literacy was found to be the only independent predictor of dosing the medication a greater number of times per day. Participants with low health literacy and no chronic conditions on average dosed the medications 8.4 times per day versus 5.6 to 6.3 times a day for other groups by literacy and chronic conditions.

"Many patients, especially those with limited literacy, do not consolidate prescription regimens in the most efficient manner, which could impede adherence," the authors wrote. "Standardized instructions proposed with the universal medication schedule and other task-centered strategies could potentially help patients routinely organize and take medication regimens."