Differences in utilization rates between commercial and administrative databases: implications for future health-economic and cross-national studies

Comparative cross national (CNC) drug utilization studies are challenging. However, there can be concerns with the accuracy and robustness of the data collected with previous studies showing differences in utilisation rates between different databases. In addition, if utilisation rates vary appreciably between countries with no logical explanation. These studies have been carried out for the same class across countries. This has now been extended to compare utilisation rates between different databases among four high volume classes among administrative and commercial databases in one country (Lithuania) between 2004 and 2012 alongside health policies. There were appreciable differences in the utilisation of PPIs (5 to 7 fold) and statins (2 to 6 fold) between the different databases with limited differences for the other two classes. This could be explained by restricted reimbursement for the PPIs and statins, with similar utilisation of renin-angiotensin inhibitors in Lithuania between the databases and with Western European countries in the absence of prescribing restrictions. Low utilisation of anti-depressants in Lithuania versus Western European countries also explained by ongoing policies. Essential to always record the database content in CNC studies alongside health policies otherwise the findings could be misinterpreted. Joint reporting should become standard for future CNC studies.