Quality of reporting of drug exposure in pharmacoepidemiological studies

Abstract

Purpose Exposure definitions vary across pharmacoepidemiological studies. Therefore, transparent reporting of exposure definitions is important for interpretation of published study results. We aimed to assess the quality of reporting of exposure to identify where improvement may be needed. Method We systematically reviewed observational pharmacoepidemiological studies that used routinely collected health data, published in 2017 in six pharmacoepidemiological journals. Reporting of exposure was scored using 11 items of the ISPE‐ISPOR guideline on reporting of pharmacoepidemiological studies. Results Of the 91 studies included, all studies reported the type of exposure (100%), while most reported the exposure risk window (85%) and the exposure assessment window (98%). Operationalization of the exposure window was described infrequently: 16% (14/90) of the studies explicitly reported the presence or absence of an induction period if applicable, 11% (5/47), and 35% (17/49) reported how stockpiling and gaps between exposure episodes were handled, respectively, and 35% (17/49) explicitly mentioned the exposure extension. Switching/add‐on was reported in 62% (50/81). How switching between drugs was dealt with and specific drug codes were reported in 52 (57%) and 24 (26%) studies, respectively. Conclusion Publications of pharmacoepidemiological studies frequently reported the type of exposure, the exposure risk window, and the exposure assessment window. However, more details on exposure assessment are needed, especially when it concerns the operationalization of the exposure risk window (eg, the presence or absence of an induction period or exposure extension, handling of stockpiling and gaps, and specific codes), to allow for correct interpretation, reproducibility, and assessment of validity.

A data‐informed approach using individualised dispensing patterns to estimate medicine exposure periods and dose from pharmaceutical claims data

“…Determining medicine exposure periods is critical in pharmacoepidemiological research for exposure‐outcome studies and in quantifying persistence and adherence to treatment. Pharmaceutical claims (i.e., dispensing) data are often used as a key information source for defining medicine exposure periods 1 . In many jurisdictions, including across Europe 2 and Australia, 3 however, pharmaceutical claims data do not record information on exact indications, directions for use, or the intended duration of medicine supply.…”

Bias in observational studies on the effectiveness of in hospital use of hydroxychloroquine in COVID‐19

“…We observed this most often in the assessment of bias due to missing data. This poor reporting is not specific to COVID‐19 research and has also been observed for pharmacoepidemiologic studies in general 30,31 . Understandably, due to word limits, authors are unable to elaborate on all methodological decisions in their manuscript.…”

“…This poor reporting is not specific to COVID-19 research and has also been observed for pharmacoepidemiologic studies in general. 30,31 Understandably, due to word limits, authors are unable to elaborate on all methodological decisions in their manuscript. However, in situations where methods deviate from generally accepted methods, substantiation of choices that were made is needed for correct interpretation of the results of a study as well as for assessment of its validity.…”

Medicine utilization studies in Australian individual‐level dispensing data: A blinded, multi‐center replicated analysis

“…24 While the implementation of these definitions will depend on the specific data source, the basic considerations are similar across Europe, Asia and North America. 24 Differences across sites in their definitions of these events are likely to have contributed to the large variation in study measures observed in our study. Although we provided detailed descriptions of these treatment events in the initial shared protocol, each site had a different approach to operationalization of these events (Table 1).…”