Modelling drug-related morbidity in Sweden using an expert panel of physicians
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In modelling studies using pharmacists’ opinions, drug-related morbidity (DRM) and preventable DRM have been more common than in observational studies, and the resulting costs are extensive. Modelling studies’ estimates may vary depending on informants’ profession. The purpose of this modelling study was to estimate the proportion of patients with DRM and preventable DRM and the cost of illness (COI) of DRM in Sweden based on physicians’ expert opinions.
A conceptual model of DRM was modified from previous studies. Using a modified Delphi technique, a panel of physicians (n = 19) estimated the probabilities of DRM, preventable DRM, and clinical outcomes of DRM separately for outpatients and inpatients. DRM included new medical problems (adverse drug reactions, drug dependence, and intoxications by overdose) and therapeutic failure (insufficient effects of medicines, and morbidity due to untreated indication). A COI analysis included the direct costs of DRM.
Physicians estimated that 51 ± 22% [mean ± standard deviation (SD)] of outpatients experience DRM and 12 ± 8% preventable DRM. Of inpatients, 54 ± 17% was estimated to experience DRM and 16 ± 7% preventable DRM. Of outpatients with DRM, 24 ± 11% was estimated to experience preventable DRM, whereas this proportion for inpatients was 31 ± 15%. The estimated COI was 376 euros per outpatient and 838 euros per inpatient.
Swedish physicians estimated that every other outpatient and inpatient experiences DRM, which is often preventable and costly. As physicians’ estimates on the proportion of patients with DRM were higher than in observational studies in restricted subpopulations, DRM may be more common in the general population than observational studies suggest.
KeywordsDrug-related morbidity Cost of illness Preventability Decision trees Pharmacoepidemiology
We acknowledge Professor Lyle Bootman and colleagues in the College of Pharmacy, University of Arizona, for access to material on their conceptual model. We also thank the physician panelists and the participants in the pilot. The study was conducted as part of the project Drug-Related Morbidity in Sweden (DRUMS). The authors thank Karolina Andersson Sundell, Anna K Jönsson, and Clas Rehnberg in the DRUMS research group for their contribution to study design. The study was funded by an unrestricted grant from The National Corporation of Swedish Pharmacies (Apoteket AB).
Conflicts of interest
The authors’ work was independent of the sponsor, The National Corporation of Swedish Pharmacies (Apoteket AB), who had no role in study design; data collection, analysis, and interpretation; writing the manuscript, or the decision to submit the manuscript for publication. The authors declare that they have no conflicts of interest.
The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Medical Products Agency.
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