Factors affect in patient adherence to medication regimen

he medication regimen of the chronic diseases demands long term drugs administration and following up. It is well known that the treatment failure caused by poor medication adherence leads to frequent re-hospitalizations, poor outcome of the disease and increased health care costs. According to the World Health Organization (WHO), non-adherence to the medical regimen consists a major clinical problem in the management of patients with chronic illness. Rates of nonadherence with any medication treatment may vary from 15% to 93%, with an average estimated rate of 50%. Adherence with medication usage is defined as the proportion of prescribed doses of medication actually taken by a patient over a specified period of time. Compliance, a synonymous term which was commonly used in the past, implies a passive role and simply following the demands of a prescriber, and non-compliance has been regarded as associated with deviant or irrational behavior. The term “Adherence”, implies an active role in collaboration with a prescriber, and “non-adherence” encompasses the diverse reasons for patients not following a treatment recommendation. Adherence is a multidimensional phenomenon determined by the interaction of five sets of factors, termed "dimensions" by the WHO. These dimensions are: