3048 — Lower Health Literacy is Associated with Poorer Medication Knowledge, but Not Adverse Drug Events among Older Veterans
Kaboli PJ (Iowa City VAMC (CRIISP)) , McDonald K
(Touro University, San Francisco), Barnett MJ
(Iowa City VAMC (CRIISP) and Touro University, San Francisco), Arozullah A
(Jesse Brown VAMC, MCHSPR (Midwest Center for Health Services and Policy Research), and University of Illinois at Chicago)
Low health literacy is associated with misunderstanding medical instructions and lower medication-related knowledge, but little is known about associated clinical outcomes. Our objective was to study the association between health literacy and adverse drug events (ADEs) in an elderly veteran population.
Subjects were recruited from a VA primary care clinic who were >65 years of age, taking >5 scheduled medications, and cognitively intact. Medication knowledge and following label directions was assessed by clinical pharmacist interview. ADEs were determined by patient interview and chart review at 3 and 12 months. Health literacy was assessed using the Rapid Estimate of Adult Literacy in Medicine (REALM).
The 310 subjects recruited had a mean age of 74, 99% were white, 97% male, and were taking on average 12.1 medications. Subject REALM-based literacy levels were <6th grade (9%), 7th-8th grade (30%), and >8th grade (61%). Percentage of medication names known by the patient was lower for the <6th grade (29%) compared to the 7th-8th grade (49%) and >8th grade (56%) groups (P<.001) and percentage of medication purposes known was also lower in the lower literacy group (49% vs. 71% vs. 74%; P<.001). However, lower literacy was not associated with taking medications correctly by the label: <6th grade (84%), 7th-8th grade (80%), and >8th grade (77%) levels (P=.14) and was not associated with experiencing an ADE at one year (48% vs. 33% vs. 40%; P=.30). Results were similar when stratified by number of medications, however patients receiving <9 medications were taking a greater percentage of medications according to the label (83%) when compared to patients taking >13 medications (76%) (P=.02). In multivariable analyses, controlling for number of medications and demographics, lower health literacy was not associated with ADEs.
Similar to prior studies, we found that patients with lower health literacy have less medication knowledge. However, our results suggest that poorer knowledge did not result in lower adherence or higher ADEs.
Although health literacy may directly impact patient medication knowledge, other factors may mitigate the effect on health outcomes such as ADEs. Systems in VHA, such as electronic medical records or pharmacist support, may overcome lower medication knowledge.