Instantaneous Preference was a Stronger Instrumental Variable than Three- and Six-Month Prescribing Preference For NSAIDs

摘要

ObjectivePrescriber preference has been used as an instrumental variable (IV) in a prior study of nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) versus selective cyclooxygenase-2 (COX-2) inhibitors, with preference expressed as the drug constituting the immediately preceding prescription by the same prescriber (instantaneous preference). We sought to compare the correlations between different IV measures with exposure.