Medication data collection and coding in a home-based survey of older adults.

OBJECTIVES: To describe the collection, coding, and validity of medication data from the National Social Life, Health and Aging Project (NSHAP)-a survey of a national probability sample of adults aged 57-85 years.
METHODS: Medication data were collected during an in-home interview by direct observation using a computer-based log and included prescription, over-the-counter, and nutritional supplements. The Multum drug database was used for coding drug names and for mapping those names to therapeutic categories. Drugs not included in Multum were assigned to medication classes by extending Multum's typology. Internal and external validity of the medication data are examined and analytic use of the medication data is discussed.
RESULTS: Only 0.9% of respondents refused to participate in the medication log. Ninety-nine percent of all entries were identified and mapped to a medication class. Use of medication classes correlated highly with the presence of corresponding health conditions and related biological measures. The prevalence of use of common therapeutic classes of medications in NSHAP is comparable to that found in other national studies. DISCUSSION: Nearly all NSHAP respondents cooperated with the medication use data collection protocol. Medication data obtained by the in-home, direct observation medication log method were found to be internally and externally valid.