Low literacy predicts nonadherence to medication regimens

March 18, 2011

Many patients, especially those with limited literacy, do not consolidate prescription medication regimens efficiently, which could lead to nonadherence, according to a recent study in the Archives of Internal Medicine.

Many patients, especially those with limited literacy, do not consolidate prescription medication regimens efficiently, which could lead to nonadherence, according to a recent study in the Archives of Internal Medicine.

Investigators conducted structured interviews with 464 participants, aged 55 to 74 years, who were receiving care either at an academic general practice or at 1 of 3 federally qualified health centers in Chicago. Participants were asked to demonstrate how they would take a hypothetical, 7-drug medication regimen over a 24-hour period, which could be consolidated into 4 dosing episodes per day. The number of dosing episodes per day was the study's primary outcome, and what caused participants to complicate the regimen by taking medication more than 4 times per day.

Participants were found to have 6 dosing episodes on average in 24 hours (range 3–14).  One-third of the participants (29.3%) dosed their medications 7 or more times per day, while only 14.9% organized the regimen into 4 or fewer times per day.

Low literacy independently predicted dosing more times per day. Although instructions for 2 of the drugs were identical, 31.0% of participants did not take these medications at the same time.  Adding an extra instruction to one drug-"take with food and water"-in a set of drugs with similar instructions resulted in 49.5% of participants taking the medications at different times. When the instructions for the medications stated the dose frequency differently (eg, "every 12 hours" vs "twice daily"), 79.0% did not consolidate the medications.

"We offer compelling, preliminary evidence of the need to help all patients more clearly understand, organize, and simplify their medication regimens," concluded the investigators.  They suggested that standard, explicit instructions are 1 possible response to improving adherence to medication regimens. However, other task-centered strategies also may be necessary to help patients.