Steven B. Leichter, MD, FACP, FACE, Sara Faulkner, and Joan Camp, RN

As diabetes care becomes more intensive and complex, the use of medications does as well. Patients with diabetes may often be on a mixture of diabetes medications, as well as other drugs for common associated conditions. These trends are encouraged by studies such as the United Kingdom Prospective Diabetes Study (UKPDS), which endorsed not only complex treatments for hyperglycemia, but also the aggressive addition of anti-hypertensive medications, when necessary, for diabetic patients.^1,2 Published guidelines for care also endorse such trends.³

Cost is an issue that has not been emphasized but is an inherent concern as medication use becomes more complex. How expensive are complex treatment regimens for patients? What percentage of patients in a region or area have a pharmacy benefits plan or insurance coverage for medications? To what degree does the cost of medications affect the prescribing physicians when patients do have insurance coverage for their drugs?

The Burden of Drug Costs
Overall, drug costs have become a substantial and rising part of total health care costs. For example, Medicaid recently announced that the cost of prescription drugs exceeded the cost of physician services.⁴ The same is true for commercial health plans.⁵

No doubt the same pattern is true for diabetes drugs; however, this issue has not been documented completely. The last available national estimate of drug and supply costs for diabetes care was by Huse and colleagues. They calculated that the average annual national patient expenditures in the late 1980s for insulin, syringes, and self-testing equipment and supplies for glucose measurements was $0.9 billion.⁶ However, this and other contemporaneous estimates did not account for medications for related conditions, such as hypertension and hyperlipidemia. In addition, the oral hypoglycemic medications available at that time cost much less than the drugs that have become available since. Therefore, similar estimates today may prove to be much higher, and the inclusion of medication for related disorders would substantially increase the costs.

Current Medication Use by Diabetic Patients
We surveyed medication use and cost of 128 patients (75 women, 53 men) seen in our program. The average patient took between 4 and 5 medications per day. Of these, 3–4 of the medications were for the treatment of diabetes, hypertension, or hyperlipidemia. The monthly cost of these drugs ranged from $80 to $115. These estimates did not include the cost of syringes or home glucose monitoring supplies. These two items increased monthly drug costs by at least $55. Thus, the total estimated monthly drug cost for these patients ranged between $115 and $170.

Stated Cost of Drugs
There is no reliable published standard of retail drug prices for physicians to use. Perhaps the closest listing is average wholesale price (AWP). This industry list of wholesale drug prices is supposed to be a reference for drug pricing. It has use in contract negotiations with various large health organizations and with managed care. In fact, many managed care contracts for drug pricing are quoted as a discount from AWP. However, this list is not readily available to practicing health professionals, and it is not a reliable guide to predict retail pricing of products.

In the absence of standard pricing guidelines, we survey five area pharmacies to gain an understanding of retail drug cost. As a policy, two of these are chain pharmacies, one is a pharmacy contained within a chain supermarket, and two are local independents. Prices for specific agents vary in all of our surveys by up to 30%. Usually, one of the chain pharmacies offers prices that are the least expensive or close to it, while another is always the most expensive. These prices rarely conform to the prices suggested to us by pharmaceutical representatives unless they have carried out similar surveys of local chains.

The Retail Cost of Diabetes Drugs
Retail prices for specific diabetes treatments may be confusing and, depending on how they are assessed, may vary widely. Pharmaceutical representatives often present drug costs on a per-dose basis or on the basis of 30 tablets. We prefer to consider drug costs on the basis of usual dosing for 30 days. When evaluated in that fashion, there are tangible differences in cost for drugs within a given class, and for one class of drugs versus another. Slight changes in treatment design may lead to substantial change in monthly cost. The same sort of situation exists for drugs for related disorders. Again, minor changes in the selection of drugs within a class may yield an important change in the daily cost of therapy.

Insurance Coverage
One of the arguments used to deflect physician concern about drug cost is that a drug is covered by health insurance programs common to the geographical area. Obviously, the prevalence of insurance coverage of prescription drugs varies from area to area. In our locality, only half of the patients we surveyed have such a benefit. Half of those had Medicaid. Half of the remainder had insurance reimbursement for prescription drugs but had to pay the initial cost out of their own pocket. Thus, claims that a high retail cost of a prescription drug will not affect patients may in reality be diluted by the percentage of patients who do not have such insurance.

A second issue occurs with patients who do have health insurance coverage for their prescription drugs. Many physicians and other providers do not realize that these plans cost profile provider drug use. Providers who have costly patterns of prescribing may eventually get sanctioned or at least cited by the plan. Thus, for many providers, the use of expensive medications may not be totally without its consequences, even when insurance covers a given drug for a patient.

Summary
The cost of prescription drugs for diabetic patients may be substantial, especially for those patients on multiple medications. In a survey of our patients, the majority take multiple medications, not only for diabetes, but also for related conditions. The cost of these agents may best be appreciated by representative surveys of local pharmacies, which assess the monthly cost of drugs as they are usually prescribed. Frequently, the monthly costs estimated by these methods will vary widely from information about monthly drug costs offered to physicians by pharmaceutical representatives.

We suggest that physicians and other providers be knowledgeable about drug costs. Drug costs may, in many instances, be a valid consideration in the design of therapy for people with diabetes. Discussing drug costs with patients may help physicians understand both the obstacles to drug use from the patient perspective and the potential negative effects on quality of life that drug costs may exert.

Steven B. Leichter, MD, FACP, FACE, is a clinical professor of medicine at Mercer University School of Medicine in Macon, Ga., and managing director of the Columbus Health Foundation in Columbus, Ga. Sara Faulkner is a student in the Magnet Program, Columbus High School, and Joan Camp, RN, is a nurse with the Columbus Health Education and Research Foundation, in Columbus, Ga.