The causes and costs of outpatient medication waste are not known. We report the results of a cross-sectional pilot survey of medication waste in a convenience sample of 73 New Hampshire retirement community residents aged 65 years or older. We used questionnaires and in-home pill counts to determine the annual occurrence of medication waste, defined as no intention to take leftover medicines prescribed within the past year. Mean individual annual cost of wasted medication was $30.47 (range = $0-$131.56). Waste represented 2.3% of total medication costs. The main causes for waste included: resolution of the condition for which the medication was prescribed (37.4%), patient-perceived ineffectiveness (22.6%), prescription change by the physician (15.8%), and patient-perceived adverse effects (14.4%). Individual costs were modest, but if $30 per person represents a low estimate of average annual waste, the US national cost for adults older than 65 years would top $1 billion per year.
Despite its potential importance, the problem of wasted medication has been studied little. Some previous research has concerned inpatient hospital and nursing facility drug discards.1-5 However, a pharmacy-based initiative for collecting wasted medications in Alberta, Canada, accumulated 204 tons of medicines over a 7-year period, suggesting the need for further research on outpatient drug waste.6
The specific aim of our study was to assess the occurrence, costs, and reasons for medication waste in a population of older adults by doing in-home surveys and counts of leftover medications. We also sought to determine why patients do not always finish their full prescriptions.
Methods
Our study, conducted from May 1999 to November 1999, was a cross-sectional survey describing medication use and nonuse in older adults in a retirement community. To minimize recall bias, researchers both used questionnaires and visited participants’ homes to sort pills according to active use or waste. Any medication prescribed within the past year that the study participant did not intend to use before its expiration date was considered wasted. If subjects recalled medications that had been thrown away, these were recorded. Questionnaire data included name, date of birth, sex, length of time in the residence, current medications, type and amount of medication discarded in the past year, and reasons for nonuse of medications.
All community residents in the study population had full prescription drug benefits without co-payments. In general, residents of this community have relatively high levels of education (78% had a bachelor’s degree or higher) and yearly income (only 4% were receiving less than $20,000).7 Primary care was largely obtained from an academic family physician and an internist, both with certificates of added qualification in geriatrics, and 2 geriatric nurse practitioners. To promote full disclosure of waste, data were kept confidential from the providers who cared for the study subjects. As a result, no clinical consequences of waste could be determined. The criteria for entry were age 65 years or older, voluntary response to study recruitment advertisements, residence in the facility for at least 1 year, and contact with a licensed health care provider within the past year. No volunteer subject was found ineligible. The Committee for Protection of Human Subjects at Dartmouth Medical School approved the study protocol.
The researchers coded medications by pharmaceutical class and calculated totals for each drug, including the costs of current medication use and total annual costs due to waste, using 1999 Red Book8 median wholesale drug cost estimates for a 3 months’ supply when exact prescription quantities were unknown.
Results
A total of 73 subjects received in-home pharmacy evaluations and completed questionnaires. Of these, 49 were women (67%), and 24 were men (33%). All were white, and all were older than 65 years. The mean age was 81.2 ± 6.0 (standard deviation [SD]) years. The mean number of years in residence was 5.4 ± 2.5 (SD).
The sum of all costs of wasted medication was $2011 in the study group (n=66). Mean per-person annual cost of wasted medication was $30.47 (range = $0-$131.56) based on the 66 subjects for whom complete data on pill counts were available. Pill counts were missing or incomplete on 7 questionnaires, which were not counted. Median annual waste was only $12.32, because 32 of the subjects (48%) wasted no medications. A total of 2078 wasted pills were found for the 66 subjects, yielding a mean of 31.5 pills wasted per subject (range = 0 to 208).
Mean waste represented 2.3% of total annual medication costs, which were $1302.78 per subject (interquartile range = $584.61-$1773.90). Increasing age was correlated with a higher number of pills wasted (r=0.35; P=.03) and a higher total cost of waste (r=0.20; P=.10). Total waste did not represent a fixed percentage of total annual medication costs. As yearly medication costs rose, waste as a percentage of yearly costs (ie, inefficient medication use) decreased significantly (r = -0.32; P=.02).