list of 374 UK Primary Care Database Studies metadata and scores for transparency of clinical coding

A large component of total EMR research is made up by primary care database (PCD) studies and UK PCDs are among the most researched in the world. As one of the largest and most<br>important resources for EMR-based research, it seems reasonable to expect reporting of code lists in UK PCD-based studies to be at least as comprehensive as in other EMR studies. To<br>evaluate levels of transparency in the reporting of clinical code lists, we took a representative sample of UK PCD studies and assessed each study on its extent of reporting of the clinical codes used. We took a sample of 450 papers from the original 1359 identified from a PubMed search. Of these, 374 (83\%) had both the full text accessible to the University of Manchester library and were examples of primary PCD research. Only 5\% (19 of 392) studies published the entire set of clinical codes needed to reproduce the study (usually in an online<br>appendix), while only an additional 9\% (32 of 392) stated explicitly that the clinical codes were available upon request. In a subset of<br>articles published since 2008, 6.9\% (16 of 231) published the entire set of codes and 10.4\% (24 of 231 )stated that clinical codes were available upon request. See https://github.com/rOpenHealth/ClinicalCodes/tree/master/paper