Читать книгу Cobert's Manual Of Drug Safety And Pharmacovigilance (Third Edition) - William Gregory - Страница 53

Perhaps the biggest limitation of spontaneous and stimulated ADR reporting, inherent to its nature of surveillance, is incomplete data which prevent the accurate quantitative estimation of risk. Ideally, one would like to calculate the probability for the occurrence for a particular AE in the patients receiving a particular drug, or risk, where

Numerator data are almost always incomplete. The number of AE reported is less than the true number of AE occurrences, because not all AEs are reported nor do we know what percent of AEs that occur are not reported.

There are many publications from around the world on underreporting but few actually are able to measure the true rate of underreporting (“a known unknown”).

It was estimated that in the United Kingdom only 10% of serious ADRs and 2–4% of non-serious ADRs that occur are reported.⁸ In the United States, the FDA estimated that only 1% of serious suspected ADRs were reported.⁹ In France, it was estimated that “no more than 5% of serious ADRs” are actually reported.¹⁰

In 2006, a report in the UK, Hazell and Shakir looked at the phenomenon and noted that, “In total, 37 studies using a wide variety of surveillance methods were identified from 12 countries. These generated 43 numerical estimates of under-reporting. The median under-reporting rate across the 37 studies was 94% (interquartile range 82–98%).” They reported that, “Factors associated with under-reporting included ignorance, diffidence and lethargy.”¹¹

In a study in Swedish hospitals, an underreporting rate of 86% for 10 selected diagnoses was found in one study (Underreporting of serious adverse drug reactions in Sweden.)¹²

A more recent report from Canada (https://uottawa.scholarsportal.info/ojs/index.php/RISS-IJHS/article/download/1448/1422) contained a good review of the situation as of 2014 and estimates that only 5% of AEs in Canada are reported.