Effect of incentives for medication adherence on health care use and costs in methadone patients with HIV.
BACKGROUND
The potential benefits of anti-retroviral therapy for HIV is not fully realized because of difficulties in adherence with demanding treatment regimens, especially among injection drug users.


METHODS
HIV-positive methadone patients who were less than 80% adherent with their primary anti-retroviral therapy were randomized to a trial of incentives for on-time adherence. Adherence was rewarded with an escalating scale of vouchers redeemable for goods. Both intervention and control group visited a medication coach twice a month. The cost of the intervention was determined by micro-costing. Other costs were obtained from administrative data and patient report of out-of-system care.


RESULTS
During the 12-week intervention period, the incremental direct cost of the intervention, including treatment vouchers, was $942. The voucher group incurred $2572 in anti-retroviral drug cost, significantly more than the $1973 incurred by the comparison group (p<.01). Adherence, as measured by on-time openings of an electronically monitored vial, was 78% in the intervention group and 56% in the control group.


CONCLUSIONS
The incremental direct cost of voucher incentives was $292 per month. If the observed increase in adherence from voucher incentives can be sustained in the long-term, the literature suggests that disease progression will be slowed. Further research is needed to evaluate if the improvement can be sustained or achieved at lower cost. Mitigation of treatment resistance and reduction in HIV transmission are additional benefits that favor adoption.
Barnett
Paul G
PG
Veterans Affairs Health Economics Resource Center, 795 Willow Rd. (152 MPD), VA Palo Alto Health Care System, Menlo Park, CA 94025, USA. paul.barnett@va.gov
Sorensen
James L
JL
Wong
Wynnie
W
Haug
Nancy A
NA
Hall
Sharon M
SM
D000328:Adult; D044966:Anti-Retroviral Agents / Q000191:economics / Q000627:therapeutic use; D003695:Delivery of Health Care / Q000191:economics* / Q000706:statistics & numerical data; D016527:Drug Costs; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy / Q000191:economics*; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008691:Methadone / Q000191:economics* / Q000627:therapeutic use; D008875:Middle Aged; D009042:Motivation; D009293:Opioid-Related Disorders / Q000150:complications / Q000188:drug therapy / Q000191:economics
D044966:Anti-Retroviral Agents; D008691:Methadone