Weaknesses of Yellow Cards

WEAKNESSES OF YELLOW CARDS

As mentioned previously, all spontaneous reporting Schemes have a number of limitations; these have been documented previously (e.g. Rawlins, Fracchia and Rodriguez-Farre, 1992; Meyboom et al., 1997a, b). The limitation of most concern is under-reporting: it is clear from a number of studies that only a small proportion of ADRs are ever reported to the regulatory authorities, both in the United Kingdom (e.g. Smith et al., 1996; Sweis and Wong, 2000) and in other countries (e.g. Chan and Critchley, 1994; Moride et al., 1997; Alvarez-Requejo et al., 1998).

Under-reporting of ADRs is clearly of concern, since it may lead to under-estimation of the signifi-cance of a particular reaction. This is compounded by the fact that the magnitude of under-reporting is vari-able; studies have suggested that levels of reporting are influenced by factors such as the seriousness of the reaction, whether the reaction is labelled, the length of time a drug has been on the market, and promotion or publicity about the medicine or the reaction (Rawlins, 1988a; Griffin and Weber, 1992; Smith et al., 1996; Haramburu, Begaud and Moride, 1997; Moride et al., 1997; Alvarez-Requejo et al., 1998). There is also evidence to suggest that levels of reporting may vary between different groups of doctors, with hospital doctors reporting less frequently than general practi-tioners (GPs) (Bateman, Sanders and Rawlins, 1992; Eland et al., 1999).

Various studies have attempted to establish the reasons for under-reporting; recent surveys of atti-tudes to reporting of ADRs suggest that lack of time and uncertainty as to whether the reaction was caused by a drug are among the most common factors in deterring reporting (Belton et al., 1995; Eland et al., 1999; Sweis and Wong, 2000). Another factor iden-tified by some groups was concern about breaching patient confidentiality (Bateman, Sanders and Rawl-ins, 1992; Sweis and Wong, 2000).

Average ADR reporting rates for the Yellow Card Scheme (e.g. reports per million inhabitants per year) are among the highest in the world (e.g. Edwards, 1997), especially when compared with other countries with a large population (Griffin, 1986). However, a survey in 1984 (Speirs et al., 1984) found that only 16% of doctors who were eligible to report suspected ADRs to the Scheme had actually submitted a Yellow Card between 1972 and 1980. More recent figures are more encouraging; an analysis of the reporters of Yellow Cards submitted between 1992 and 1995 showed that around one-third of practising doctors submitted a report during this 4-year period. However, it is clear that many doctors do not contribute to the Yellow Card Scheme; this is unlikely to be simply because these doctors do not see patients who have experienced an adverse reaction.