Background Polypharmacy increases the risk of adverse drug reactions and possibly undertreatment.

Purpose To evaluate to what extent laboratory data, actual drug treatment, medical history and drug indications are interpreted in daily practice.

Materials and methods 46 health care professionals, including community pharmacists, nursing home physicians, and general practitioners in the Netherlands, were asked to participate in this review. The health care professionals were requested to perform medicines reviews for three different cases (A, B and C). Per case, the amount of information provided varied in three subsequent stages: in stage 1 only the medicines list was shown; in stage 2 the laboratory data and the reason for admission were added, and in stage 3 the medical history was also included. Following a Delphi method, a multidisciplinary expert panel established the gold standard for each case and stage, by performing the medicines review for each case and stage. For each case and each health care professional the number of remarks and their clinical relevance were retrospectively assessed in comparison to the corresponding case from the expert panel, i.e. with the same available information, in order to assess how the information was interpreted.

Results The average score for the three cases and the three stages was 36.85%. On one hand, medicines problems which were identified by few participants included the addition of new medicines and switching medicines according to clinical data and/or guidelines. On the other hand, dose reduction and/or drug stopping due to laboratory values or lack of indication were well identified.

Conclusions The large variation in the quality of medicines reviews, as well as a the low mean quality found in the present study, highlights that information might be incorrectly used or wrongly interpreted, irrespective of the available information.

No conflict of interest.