Effect of Competition Bias in Safety Signal Generation: Analysis of a Research Database of Spontaneous Reports in France

• Published in: Drug safety 2012-10, Vol.35 (10), p.855-864
• Main Authors: Pariente, Antoine, Avillach, Paul, Salvo, Francesco, Thiessard, Frantz, Miremont-Salamé, Ghada, Fourrier-Reglat, Annie, Haramburu, Françoise, Bégaud, Bernard, Moore, Nicholas
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Clinical trial. Drug monitoring; Drug Safety and Pharmacovigilance; General pharmacology; Human immunodeficiency virus; Medical sciences; Medicine; Medicine & Public Health; Original Research Article; Pharmacology. Drug treatments; Pharmacology/Toxicology
• ISSN: 0114-5916; 1179-1942
• DOI: 10.1007/BF03261981

Background: Automated disproportionality analysis of spontaneous reporting is increasingly used routinely. It can theoretically be influenced by a competition bias for signal detection owing to the presence of reports related to well-established drug-event associations. Objective: The aim of the study was to explore the effects of competition bias on safety signals generated from a large spontaneous reporting research database. Methods: Using the case/non-case approach in the French spontaneous reporting research database, which includes data of reporting in France from January 1986 to December 2001, the effects of the competition bias were explored by generating safety signals associated with six events of interest (gastric and oesophageal haemorrhages, central nervous system haemorrhage and cerebrovascular accidents, ischaemic coronary disorders, migraine headaches, muscle pains, and hepatic enzymes and function abnormalities) before and after removing from the database reports relating to drugs known to be strongly associated with these events, whether they constituted cases or non-cases. As this study was performed on a closed database (last data entered 31 December 2001), potential signals unmasked by removal were considered as real signals if no or only incomplete knowledge about the association was available from the literature before 1 January 2002. Results: For gastric and oesophageal haemorrhages, after removing reports involving antithrombotic agents or NSAIDs, three potential signals were unmasked (prednisone, rivastigmine and isotretinoin). For central nervous system haemorrhage and cerebrovascular accidents, after removing reports involving antithrombotic agents, three potential signals were unmasked (ethinylestradiol, interferon-α-2B and methylprednisolone). For ischaemic coronary disorders, after removing reports involving anthracyclines, bleomycine, anti-HIV drugs or triptans, one potential signal was unmasked (ondansetron). For migraine headaches, after removing reports involving nitrates, calcium channel blockers, opioid analgesics or intravenous immunoglobulins, six potential signals were unmasked (ammonium chloride, leflunomide, milnacipran, montelukast, proguanil and pyridostigmine). For muscle pains, after removing reports involving statins or fibrates, seven potential signals were unmasked (hydroxychloroquine, lactulose, levodopa in combination with dopadecarboxylase inhibitor, nevirapine, nomegestrol, ritonavir and stavudine). Fina