Does prior authorization of sibutramine improve medication compliance or weight loss?

Nutrition Research Newsletter, April, 2005

Medication compliance is notoriously poor in all conditions. The long-term management of obesity is particularly beset by medication noncompliance. The risk for weight regain is even greater than the risk for those with major organ cancer to succumb to the cancer. Long-term medication use could become an increasingly necessary proposition. Understanding medication compliance in the treatment of obesity is, thus, a fundamental concern. One might speculate that cost drives medication compliance where the prior authorization process is concerned. However, when the effect of cost on compliance was actually measured, a modest 10% increase in compliance was derived from a 50% decrease in copayment. Prior authorization (PAR) typically requires that a letter or form be submitted to an insurer by the prescribing provider.

In a review of the literature, no published study has evaluated the relative effect on compliance or outcomes by comparing subjects with prior authorization approval to those taking the same medication without reimbursement. The working hypothesis of this retrospective analysis is that the PAR process denotes a level of physician commitment not required of the other levels of cost/reimbursement. This may be perceived by the patient as supportive endorsement by the physician and, therefore, effect a greater commitment on the patient's part to adhere to the medication regimen. This study was designed to examine whether PAR for insurer reimbursement of weight loss medication affects compliance with taking sibutramine or adherence to a medical weight control program.

A retrospective review was conducted of 22 subjects who had received a prescription for sibutramine that was reimbursed through their health insurer by prior authorization (PAR) and compared them with 47 randomly selected subjects who were also prescribed sibutramine but did not receive reimbursement (non-PAR). Outcome measures included the percentage weight lost, visits to the clinic, and number of prescriptions received at 3 months, 6 months, 9 months, and 12 months.

The proportion of subjects remaining in the clinic program, the number of clinic visits made, the number of prescriptions received, and the amount of weight lost were all significantly greater among PAR subjects than among non-PAR subjects. PAR subjects used the medication 37% longer by month 6 (2.43 vs. 1.52 prescriptions), visited the clinic 44% more often (72.5 vs. 40.5 visits in 12 months), and achieved 38% better maximal weight loss (16% vs. 9.9% at 6 months) than non-PAR subjects.

In this study, subjects who received prior authorization for sibutramine were more compliant with taking their medication, and they used the recommended dietary counseling visits more frequently. Three key findings of this study were 1) the proportion of subjects dropping out of the clinic program was much higher among non-PAR subjects from the very start of the program. As expected, the relative difference in attrition between groups decreased over time, although it remained highly statistically significant throughout the 12 months; 2) a related variable, the number of clinic visits, was 40% higher among PAR subjects throughout the 12 months; and 3) weight loss was 40% greater among PAR subjects than non-PAR subjects by month 6. This study suggests that, when those medications are not included on a health insurer's formulary, the use of the prior authorization process may improve both medication and behavioral compliance.

J. Risser, P. Vash, L. Nieto. Does prior authorization of sibutramine improve medication compliance or weight loss? Obes Res 13:86-92 (January 2005) [Correspondence: Joseph A. Risser, Lindora Medical Clinics, 3505 Cadillac Avenue, Suite N-2, Costa Mesa, CA 92626. E-mail: jrisser@attglobal.net]