Trends in Mail-Order Prescription Use among U.S. Adults from 1996 to 2018: A Nationally Representative Repeated Cross-Sectional Study

BACKGROUND. Mail-order prescriptions are popular in the U.S., but the recent mail delays due to operational changes at the United States Postal Services (USPS) may postpone the delivery of vital medications. Despite growing recognition of the health and economic effects of a postal crisis on mail-order pharmacy consumers, little is known about the extent of mail-order prescription use, and – most importantly – the population groups and types of medications that will likely be most affected by these postal delays. METHODS. The prevalence of mail-order prescription use was assessed using a nationally representative repeated cross-sectional survey (the Medical Expenditure Panel Survey) carried out among adults aged 18 and older in each year from 1996 to 2018. We stratified use of mail-order prescription by socio-demographic and health characteristics. Additionally, we calculated which prescription medications were most prevalent among all mailed medications, and for which medications users were most likely to opt for mail-order prescription. FINDINGS. 500,217 adults participated in the survey. Between 1996 and 2018, the prevalence of using at least one mail-order prescription in a year among U.S. adults was 9·8% (95% CI, 9·5%-10·0%). Each user purchased a mean of 19.4 (95% CI, 19·0-19·8) mail-order prescriptions annually. The prevalence of use increased from 6·9% (95% CI, 6·4%-7·5%) in 1996 to 10·3% (95% CI, 9·7%-10·9%) in 2018, and the mean annual number of mail-order prescriptions per user increased from 10·7 (95% CI, 9·8-11·7) to 20·5 (95% CI, 19·3-21·7) over the same period. Use of mail-order prescription in 2018 was common among adults aged 65 and older (23·9% [95% CI, 22·3%-25·4%]), non-Hispanic whites (13·6% [95% CI, 12·8%-14·5%]), married adults (12·7% [95% CI, 11·8%-13·6%]), college graduates (12·2% [95% CI, 11·3%-13·1%]), high-income adults (12·6%, [95% CI, 11·6%-13·6%]), disabled adults (19·3% [95% CI, 17·9%-20·7%]), adults with poor health status (15·6% [95% CI, 11·6%-19·6%]), adults with three or more chronic conditions (24·2% [95% CI, 22·2%-26·2%]), Medicare beneficiaries (22·8% [95% CI, 21·4%-24·3%]), and military-insured adults (13·9% [95% CI, 10·8%-17·1%]). Mail-order prescriptions were commonly filled for analgesics, levothyroxine, cardiovascular agents, antibiotics, and diabetes medications. INTERPRETATION. The use of mail-order prescription, including for critical medications such as insulin, is increasingly common among U.S. adults and displays substantial variation between population groups. A national slowdown of mail delivery could have important health consequences for a considerable proportion of the U.S. population, particularly during the current Coronavirus disease 2019 epidemic.