Objectives: The objective of the study was to critically assess references cited in support of claims in drug advertisements.
Methods: Drug advertising brochures were collected from privately practicing General Practitioners from different parts of Karachi. Three blinded reviewers then categorized each reference in the brochure according to the sources viz: journals (both Medline indexed and non-indexed), medical reference books, web addresses, personal communications or testimonials, abstracts presented at symposia/conferences, WHO and National Health Guidelines, 'data on file' and 'others' (which included a diverse set of references). Each reviewer then assessed and analyzed the references further into 2 broad categories: traceable and non-traceable. Traceable references were appraised and, depending upon the claim with which the reference was attached, were classified into justifiable, inaccurate/false, exaggerated and ambiguous.
Results: We collected a total of 175 different brochures. Thirty-nine (22.3%) brochures did not cite any references and were not subjected to further analysis. The remaining 136 (77.7%) contained a total of 559 references. 305 (54.6%) of these references were from Medline-indexed journals; 67 (12.0%) were from non-indexed journals; 55 (9.8%) references quoted medical reference books; 27 (4.8%) references cited web addresses; 12 (2.1%) references were personal communications/testimonials; 11 (2.0%) references referred to abstracts presented at symposia/conferences; 12 (2.1%) references were from WHO and National Health Guidelines; 8 (1.4%) references were listed as 'data on file', while the remainder that could not be defined were classified as 'others' (13.1%). Out of a total of 559 references, 249 (44.5%) could not be traced. After critically analyzing the 310 traceable references, 197 (63.5%) were adjudged justifiable, 30 (9.7%) inaccurate/false, 79 (25.5%) exaggerated and 15 (4.8%) ambiguous.
Conclusion: Results of this study show for the first time that the claims substantiated with references in the pharmaceutical advertisements in Pakistan are highly unreliable.