Therapeutic adherence to osteoporosis treatment

Adherence of patients to therapy is a major determinant of therapeutic success, which is not included in most clinical studies. This is especially true for chronic diseases with few subjective symptoms, such as osteoporosis. The aim of our study was to describe and to analyze the therapeutic adherence to several widely used anti-osteoporotic medications in real-world medicine in Slovakia.

Using a retrospective approach, data about drug prescriptions for 8,223 patients from 3 consecutive years were analyzed regarding compliance and persistence. Compliance was measured as medication possession ratio-ratio between the supply of the drugs in the treatment time according to the prescriptions and the time of observation. Persistence was assessed as the percentage of patients who used the drug without a gap for the given time period.

The average compliance was 70%, 59%, and 4% for 6, 12, and 24 months, respectively. Average persistence was very low with 54%, 42%, and 22% for 6, 12, and 24 months, respectively. Total average persistence was only 9.8 months. Medications with lower frequency of application tended to be associated with higher adherence.

In conclusion, the therapeutic adherence to anti-osteoporotic treatments varies between the available drugs and drug regimens. In general, the adherence is very low but comparable to previously published studies from other countries. This variability of adherence should be considered in clinical decision making together with the variability of therapeutic efficiency found in clinical studies.