Effect of an intervention on the features of adverse drug reactions spontaneously reported in a hospital

Objectives A continuous intervention based on healthcare management agreements was associated in our hospital with an increase in the absolute number of spontaneous reporting of adverse drug reactions (ADRs), and also with an increase in the number of reports of serious or unexpected ADRs and ADRs associated with new drugs. The objective was to analyse the effect of this intervention on the features of ADRs spontaneously reported in a hospital, the drugs involved and the number of signals identified. Methods A longitudinal study with two periods, the 1st period without intervention from 1998 to 2002 and the 2nd period with intervention from 2003 to 2005, was carried out in a tertiary teaching hospital. Changes between the two periods with regard to the following variables were analysed: the patients’ characteristics, such as gender and age; the reported ADRs, and the medical assistance required; the suspected drugs involved in the ADRs; the main signals identified. Results Gender and age distribution of patients described in the spontaneous reports were no different in the two periods. During the second period, spontaneously reported cases requiring hospital admission and those occurring in hospital increased (236 from 2 in the first period and 277 from 99 in the first period respectively) and cases from outpatient hospital consultations began to be reported (13.9% of reports). The spontaneous reporting on all kinds of ADRs and drugs increased during the second period. Cutaneous reactions were the most frequently spontaneously reported ADRs in both periods followed by cardiovascular and neurological reactions in the first period, and haematological and gastrointestinal reactions in the second one. However, during the second period the higher increase was for endocrinological, urinary and hepatic reactions. Systemic antibiotics, anti-thrombotics and cardiac therapy drugs were the most common therapeutic subgroups reported to be suspected drugs in both periods, but in the second period the proportion of immunostimulants, beta blocking agents, immunosuppressants and psychoanaleptics increased. No signals were recognised during the first period; however, two signals and one additional safety concern were identified during the second. Conclusion An intervention based on healthcare management agreements, was associated with an important increase in spontaneous reporting of ADRs by hospital physicians and also with a change in terms of the type of ADRs identified affecting different organs or systems, and the therapeutic groups of drugs involved. Future studies should analyse the effect of different types of intervention on the spontaneous reporting of ADRs in hospitals.