In a recent Penn State study, when adults age 65 to 91 were asked to bring in all of their prescription medications in a brown paper bag, the resulting list was more complete than their official pharmacy records. 

Dr. Grace Caskie, research associate, Penn State Gerontology Center, who conducted the analysis, says, "Because people use multiple doctors, third party payers and pharmacies; often receive samples from their physicians; and sometimes even use other people's medicines, there is usually no single independent source of information on what medications they are taking." 

For example, in the Penn State study, pharmacy records showed that 20 percent of the participants had no current prescriptions, but only 10 percent of the people actually reported no current prescriptions. 

"Using the brown bag method of self-reporting could help doctors more accurately monitor medication compliance, guard against polypharmacy and prevent drug interactions," Caskie notes. 

The study is detailed in a paper, "Congruence of Self-Reported Medications with Pharmacy Prescription Records in Low-Income Older Adults," published in the current issue of the journal, The Gerontologist. Caskie's co-author is Dr. Sherry L. Willis, professor of human development. 

The participants included 294 predominantly White, female (87.8 percent), low-income individuals whose average age was 74.5. They were part of another study, Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE). The participants were also members of PACE, Pennsylvania's Pharmaceutical Assistance Contract for the Elderly. So, their brown bags could be checked against PACE records. 

In general, the researchers found a high level of agreement between the contents of the brown bags and the PACE pharmacy records. Caskie says, "Mismatches between the brown bags and the pharmacy records were most often explained by the pharmacy records not including a drug that the participant had reported in the brown bag, rather than the participant omitting a drug found in their pharmacy records." 

If the patient was taking less of the medicine than the physician prescribed in order to extend the supply, medications might be included in the brown bag beyond their prescribed dosing window, the Penn State researchers' note. 

Such behavior may explain why 10 percent of the participants had no current pharmacy records for prescription refills but reported taking medications. 

The researchers also found that individuals with worse health consistently had poorer matches between the brown bags and the PACE records. Married participants and those in better health were less likely to omit drugs included in the pharmacy records. Medications for more serious conditions or those that are taken on a long-term basis were more likely to be reported than medication taken on an as needed basis, for a short time or for less serious conditions. 

Drugs taken in forms other than by mouth, for example via a patch, were more likely to be omitted from brown bags. 

The researchers write, "Although self-report measures are widely used, few studies have examined the congruence of prescription records and self report measures." They conclude, "We believe the brown bag method provides a reasonable substitute for pharmacy records as a measure of current medications." 

The study was supported by grants from the National Institute on Aging and the National Institute on Nursing Research.