It clearly measures a different dimension of adherence to the MPR, with which it is poorly correlated, but also is complementary to the MMAS, providing additional information on patient perceptions, as indicated by the only moderate correlation between the MMAS EPZ-6438 ic50 score and the ADEOS-12 score.

In addition, this disease-specific index is complementary to general adherences measures, which are useful to compare adherence across different diseases, but are often relatively insensitive. Finally, psychometric analyses identified two pragmatic score thresholds (16 and 20) which provide a good basis to guide interpretation of the score in daily practice. A patient with an ADEOS index ≥ 20 is expected to be unlikely to discontinue while a patient with an index ≥ 16 is at risk for treatment discontinuation. Given that many of the attributes of medication adherence, for example patient–physician relationships and patient empowerment, are likely to be culturally dependent, it will be important to validate the psychometric properties of the ADEOS-12 questionnaire and its score thresholds in other countries. To this end,

a validated translation of the ADEOS-12 questionnaire into English is provided in the Electronic Supplementary Material. Our study has certain limitations. Firstly, the response rate was only moderate, with 62.5% of patients returning a completed ADEOS questionnaire. In order to limit potential Birinapant clinical trial social pressure on patients to “conform” [46] and in order to match as closely as possible naturalistic conditions of use of the questionnaire, no attempts were made to contact patients who had not returned

their questionnaires spontaneously to remind them to do so. However, even if non-adherent patients are under-represented in our sample, they still make up a significant proportion of the sample, with 26% having an MPR <0.80 for their most recent treatment and 35% scoring less than four on the MMAS. Another potential source of non-representativity relates to patients who did not return to see their GP after the initial prescription of osteoporosis treatment, who were not accessible for the study. These patients are likely to be non-persistent and the adherence rates estimated in our study may in consequence be somewhat over-estimated. Another limitation is that women receiving injectable antiresorptive treatments were excluded nearly from the study, since it was considered that their adherence behaviour would be governed by quite different principles. The validity and performance of the ADEOS questionnaire in other populations, such as women receiving injectable treatments, remain to be confirmed. In conclusion, the ADEOS-12 provides the physician with a simple patient-reported measure to determine adherence to osteoporosis treatments. This is the first disease-specific adherence measure to have been developed for osteoporosis, a disease in which poor treatment adherence is a major issue.