Free drug samples may burden patients' pockets

They followed 5,709 patients from the national survey for up to two years. The mean age of patients was 48 years, 84 percent were white and 76 percent had private insurance. Fourteen percent of patients received at least one sample, with a total of 2,343 samples dispensed during the analysis period.

The authors found that there were important differences in the characteristics of patients who received samples and those who did not. The odds of sample receipt were lower among those who were older and also among those who had Medicaid as their source of insurance coverage.

The study was not designed to identify the exact reason that sample users have higher prescription costs after sample receipt. However, the authors hypothesize two main possibilities for this surprising finding.

First, those who received samples may have been more seriously ill than those who did not. But underlying health status, say the authors, explains only a part of the difference in out-of-pocket costs.

Equally important, they suggest, is that patients who receive free samples may end up paying for a prescription for the medicine initially begun as a free samples. The medicines that are given as free samples are often the newest and the most expensive.

"Regardless of the degree to which these different mechanisms account for our findings," Alexander said, "patients and physicians should consider complementary ways to reduce patients' burden from out-of-pocket prescription costs, such as using more generic medicines, stopping non-essential treatments, and using three-month rather than one-month supplies."

For policy-makers and researchers, their findings provide an opportunity to consider the complexity of issues raised by sample use.

"Further research is needed to examine patient-physician communication about samples," suggests Alexander, "as well as how physicians decide who needs samples and how samples are distributed across different types of physician practices."

They are also continuing studies that look the economic consequences of other common prescribing decisions that physicians and patients face.

The study was supported by the Robert Wood Johnson Foundation. Additional authors of the paper include James Zhang from Virginia Commonwealth University and Anirban Basu from the University of Chicago.