Title: Explanation of the importance of medication adherence in antiretroviral therapy by using random numbers
Authors: Shinobu Tatsunami - St. Marianna University School of Medicine (Japan) [presenting]
Takahiko Ueno - St Marianna University School of Medicine (Japan)
Abstract: Even after remarkable developments in an antiretroviral therapy, almost perfect adherence to medication intake is needed in patients. Incomplete adherence may result in the failure of a therapy. However, the frequency of failure is extremely low under good control by medical experts. Therefore, there is little statistical data that can make patients realize the potential risk of incomplete adherence. In this context, a simple dynamic model that expresses the failure of therapy by using random numbers has been developed. This model contains three main variables of viral concentration $v(t)$, strength of the immune activity $L(v)$, and the concentration of a drug $c(t)$. The most fundamental assumption is that the probability of the appearance of a drug-resistant virus depends on the time-derivative of viral concentration, dv(t)/dt. An additional assumption is that the viral concentration v(t) does not reach zero but maintains a small value such as the attainable limit. Under this assumption, the dynamic equation could describe the divergence of viral concentration with a low frequency. The frequency of viral divergence depended on the various patterns of incompleteness in medication adherence. However, it showed non-sensitive dependence on the attainable limit of viral concentration.