Poor adherence to the treatment for diabetes results in avoidable suffering for the patients and excess costs to the health system. The CODE-2 study (Cost of Diabetes in Europe - type 2) found that, in Europe, only 28% of patients treated for diabetes achieved good glycaemic control (3,4). The control of diabetes requires more than just taking medicine. Other aspects of self-management such as self-monitoring of blood glucose, dietary restrictions, regular foot care and ophthalmic examinations have all been shown to markedly reduce the incidence and progression of complications of diabetes. In the United States, less than 2% of adults with diabetes perform the full level of care that has been recommended by the American Diabetes Association (5). Poor adherence to recognized standards of care is the principal cause of development of complications of diabetes and their associated individual, societal and economic costs. The CODE-2 study was done in countries with nearly full access to medicines. The picture in developing countries, where many fewer patients have their diabetes well-controlled, is cause for even greater concern.
Patients with diabetes usually have co-morbidities that make their treatment regimens even more complex. In particular, other commonly associated diseases such as hypertension, obesity and depression are themselves known to be characterized by poor rates of adherence, and serve to further increase the likelihood of poor treatment outcomes (6,7).
The combined health and economic burden of diabetes is huge and increasing. The CODE-2 study showed that the total cost of treating more than 10 million patients with type 2 diabetes in the countries studied was approximately US 29 billion, which represents an average of 5% of the total health care expenditure in each country. The overall cost to the health care system of treating patients with type 2 diabetes is on average over 1.5 times higher than per capita health care expenditure, an excess cost-burden of 66% over the general population. Furthermore, that cost increases 2- to 3.5-fold once patients develop preventable microvascular and macrovascular complications. Hospitalization costs, which include the treatment of long-term complications such as heart disease, account for 30 - 65% of the overall costs of the disease - the largest proportion of costs.
The direct costs of complications attributable to poor control of diabetes are 3 - 4 times higher than those of good control. The indirect costs (production losses due to sick leave, early retirement and premature death) are of approximately the same magnitude as these direct costs. Similar findings have been reported in other studies (8-10). Clearly, if health systems could be more effective in promoting adherence to self-management of diabetes, the human, social and economic benefits would be substantial.