When Co-Payments Increase, Use Of Drugs Curtailed

As co-payments for pharmacy benefits climb, the use of medications decreases by as much as 45%, according to a four-year study conducted by Dana P. Goldman, Ph.D., and associates and published in the Journal of American Medical Association this past May.

The study found that the doubling of co-payments was associated with reduction in use of eight therapeutic classes of drugs. The largest decreases occurred for non-steroidal anti-inflammatory drugs (45%) and antihistamines (44%). Among patients diagnosed as having a chronic illness and receiving ongoing care, the study found use was less responsive to co-payment changes. For example, use of antidepressants declined by 8%, use of antihypertensives by 10%. However, larger reductions in use were observed for arthritis patients taking non-steroidal anti-inflammatory drugs (27%) and allergy patients taking antihistamines (31%). Patients with diabetes reduced their use of anti-diabetes drugs by 23%.

Data used in the study was compiled from pharmacy and medical claims submitted from 1997 to 2000 for 30 large employers and 52 health plans covering 528,969 beneficiaries, ages 18 to 64 years, continuously enrolled for up to four years.