Reporting of adherence to medication in recent randomized controlled trials of 6 chronic diseases: a systematic literature review.
BACKGROUND
International recommendations such as the CONSORT and International Conference on Harmonisation statements recognize patient adherence to prescribed treatment as an important aspect of a treatment's evaluation, but this issue is little assessed.


OBJECTIVE
To evaluate how medication adherence was assessed and reported in recently published randomized controlled trials (RCTs).


METHODS
All publications of RCTs assessing pharmacological treatments in 6 major chronic diseases published in high-impact-factor journals in 2003 and 2004 were selected from the Medline database. Two investigators analyzed how medication adherence was assessed and reported.


RESULTS
A total of 192 publications were analyzed: 71 in HIV infection, 48 diabetes mellitus, 24 rheumatoid arthritis, 23 asthma, 15 hypertension, 7 osteoporosis, and 4 about 2 of these diseases. The assessment of medication adherence was documented in 69 (35.9%) publications, by counting pill intake in half of these. Results of adherence were reported in 64 (33.3%) publications. Adherence was reported as a quantitative measure: Proportion of the treatment prescribed in 27 articles and as a qualitative measure (adherent patient, yes/no) in 41 (in 4 reports both techniques were used). When reported, the median intake of prescribed medication was 93%, and the median proportion of "nonadherent" patients was 6.2%.


CONCLUSIONS
There is important variability in the assessment and reporting of medication adherence in published RCTs of pharmacological treatments of selected chronic diseases, for a given disease and across diseases. Standardization is advisable to allow for comparisons among studies.
Gossec
Laure
L
AP-HP, Rheumatology B Department, Cochin Hospital, 27 rue du faubourg St Jacques, Paris 5 University, Paris, France. laure.gossec@cch.aphp.fr
Tubach
Florence
F
Dougados
Maxime
M
Ravaud
Philippe
P
D001172:Arthritis, Rheumatoid / Q000188:drug therapy; D001249:Asthma / Q000188:drug therapy; D003920:Diabetes Mellitus / Q000188:drug therapy; D015658:HIV Infections / Q000188:drug therapy; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D010024:Osteoporosis / Q000188:drug therapy; D010349:Patient Compliance; D010865:Pilot Projects; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D016312:Treatment Refusal