Elderly/Long-term Care

Changes in cost to patients reduce new use of antidepressants among the elderly, but have less impact on continued use

Greater cost-sharing requirements reduce the likelihood that elderly adults with depression will begin using needed antidepressant medications, but has little effect on those who are already taking such medications, according to a new study. The researchers used two closely timed changes in costs to elderly patients in the Canadian Province of British Columbia to shed light on the likely impact of changes in prescription drug coverage in the United States as persons go from private insurance copayments (fixed payment per prescription) for medications to Medicare coinsurance (fixed percentage of the cost per prescription) with deductibles.

In January 2002, the British Columbia Government switched from paying the full cost of prescriptions for seniors to requiring a copay of $25 Canadian ($10 for low-income seniors). In May 2003, the program began requiring patients to pay a 25 percent coinsurance once an income-based deductible was met. This "natural experiment" allowed the researchers to study the effect of the cost changes on the starting, usage, and stopping of antidepressant therapy by British Columbian seniors from January 1997 through December 2005.

They found that, as the British Columbia health plan moved from complete coverage of prescriptions to requiring a copayment and, later, to coinsurance after meeting a deductible, the rate of initiation of antidepressant therapy slowed significantly. The level of antidepressant initiation increased from 4.3 starts per 1,000 seniors per month in 1997 to 5.0 starts per 1,000 in December 2001. Implementation of the copay policy in January 2002 reduced the antidepressant therapy start level by 0.38 per 1,000 seniors per month without changing the rate of increase over time. Introduction of coinsurance in May 2003 reduced the rate of increase per month by 0.03 per 1,000 seniors.

Depression is thought to be undertreated among seniors in the United States, and programs have been developed to increase the use of antidepressants in this population. To be effective, these programs may need to take into account (and perhaps intervene) to counter the effects of patient cost sharing on antidepressant use, the researchers concluded.

The study was funded in part by the Agency for Healthcare Research and Quality (HS10881). More details are in "The impact of cost sharing on antidepressant use among older adults in British Columbia," by Philip S. Wang, M.D., Dr.P.H., Amanda R. Patrick, M.S., Colin R. Dormuth, Sc.D., and others, in the April 2008 Psychiatric Services 59(4), pp. 377–383.

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