Strengths
To our knowledge, this is the first systematic study of the effects of Portenoy and Foley’s seminal 1986 article. By analyzing 511 full-text citing articles, this study paints a detailed picture of the substantial and ongoing scientific impact of the index study. We analyzed all identified and retrievable articles regardless of country of origin or language of publication allowing us to establish a global, rather than only North American, understanding of the index study’s impact. Finally, this study uniquely combined bibliometrics, time-series analyses, relational content analysis, and qualitative analysis. These multiple analyses demonstrate strong concordance and thus strengthen our confidence in the findings, and provide a deeper and broader understanding of the evolution of opioid-related research between 1986 and 2019.