Hospitalizations due to preventable adverse reactions—a systematic review

To determine the prevalence of hospital admissions associated with ADRs and examine differences in prevalence rates between population groups and methods of ADR detection. Studies were identified through electronic searches of Cumulative Index to Nursing and Allied Health Literature, EMBASE, and MEDLINE to August 2007. There were no language restrictions. A systematic review was conducted of prospective observational studies that used the World Health Organization ADR definition. Subgroup analysis examined the influence of patient age groups and methods of ADR detection on reported ADR admission rates. All statistical analyses were performed using STATA v 9.0. Twenty-five studies were identified including 106,586 patients who were hospitalized; 2143 of these patients had experienced ADRs. The prevalence rates of ADRs ranged from 0.16% to 15.7%, with an overall median of 5.3% (interquartile range [IQR] 2.7-9.0%). Median ADR prevalence rates varied between age groups; for children, the ADR admission rate was 4.1% (IQR 0.16-5.3%), while the corresponding rates for adults and elderly patients were 6.3% (IQR 3.9-9.0%) and 10.7% (IQR 9.6-13.3%), respectively. ADR rates also varied depending on the methods of ADR detection employed in the different studies. Studies that employed multiple ADR detection methods, such as medical record review and patient interview, reported higher ADR admission rates compared with studies that used medical record review alone. Anti-infective drugs were most often associated with ADR admissions in children; cardiovascular drugs were most often associated with ADR admissions in adults and elderly patients. Approximately 5.3% of hospital admissions were associated with ADRs. Higher rates were found in elderly patients who are likely to be receiving multiple medications for long-term illnesses. The methods used to detect ADRs are also likely to explain much of the variation in the reported ADR prevalence rates between different studies.

Background Adverse drug reactions in children are an important public health problem. We have undertaken a systematic review of observational studies in children in three settings: causing admission to hospital, occurring during hospital stay and occurring in the community. We were particularly interested in understanding how ADRs might be better detected, assessed and avoided. Methods and Findings We searched nineteen electronic databases using a comprehensive search strategy. In total, 102 studies were included. The primary outcome was any clinical event described as an adverse drug reaction to one or more drugs. Additional information relating to the ADR was collected: associated drug classification; clinical presentation; associated risk factors; methods used for assessing causality, severity, and avoidability. Seventy one percent (72/102) of studies assessed causality, and thirty four percent (34/102) performed a severity assessment. Only nineteen studies (19%) assessed avoidability. Incidence rates for ADRs causing hospital admission ranged from 0.4% to 10.3% of all children (pooled estimate of 2.9% (2.6%, 3.1%)) and from 0.6% to 16.8% of all children exposed to a drug during hospital stay. Anti-infectives and anti-epileptics were the most frequently reported therapeutic class associated with ADRs in children admitted to hospital (17 studies; 12 studies respectively) and children in hospital (24 studies; 14 studies respectively), while anti-infectives and non-steroidal anti-inflammatory drugs (NSAIDs) were frequently reported as associated with ADRs in outpatient children (13 studies; 6 studies respectively). Fourteen studies reported rates ranging from 7%–98% of ADRs being either definitely/possibly avoidable. Conclusions There is extensive literature which investigates ADRs in children. Although these studies provide estimates of incidence in different settings and some indication of the therapeutic classes most frequently associated with ADRs, further work is needed to address how such ADRs may be prevented.

* Although drugs generally are safe and effective therapies for numerous diseases, adverse drug reactions do occur and may even be fatal. * The incidence of fatal adverse drug reactions in hospitalized patients has been estimated to be approximately 5%. * In previous studies the incidence of fatal adverse drug reactions in hospitalized patients has been reported, but the incidence of fatal adverse drug reactions in the general population is largely unknown. * Fatal adverse drug reactions account for approximately 3% of all deaths in the general population. * Haemorrhages amount to almost two-thirds of the fatal adverse drug reactions and antithrombotic agents are implicated in more than half of the suspected fatal adverse drug reactions. * Fatal adverse drug reactions are estimated to be the seventh most common cause of death in Sweden. To determine the incidence of fatal adverse drug reactions (FADRs) in a Swedish population. Every seventh randomly selected deceased in three counties in South-east Sweden during 1 January 2001-31 December 2001 was identified in the Cause of Death Register. Relevant case records (hospitals and/or primary care centres and medicolegal files) were reviewed to identify suspected drug-related fatalities. Of 1574 deceased study subjects, 49 (3.1%; 95% CI 2.2%, 4.0%) were suspected to have died from FADRs. The most common suspected FADRs were gastrointestinal haemorrhages (n = 18; 37%), central nervous system haemorrhages (n = 14; 29%), cardiovascular disorders (n = 5; 10%), other haemorrhages (n = 4; 8%) and renal dysfunction (n = 3; 6%). The drugs most commonly implicated in FADRs were antithrombotic drugs (n = 31; 63%), followed by nonsteroidal anti-inflammatory drugs (NSAIDs) (n = 9; 18%), antidepressants (n = 7; 14%) and cardiovascular drugs (n = 4; 8%). Of all the 639 fatalities in hospital 41 (6.4%; 95% CI 4.5%, 8.3%) were suspected to be due to FADRs. The medical burden of FADRs is significant. Haemorrhages were seen in a majority of the FADRs; antithrombotic agents or NSAIDs were implicated in most of these events. These results suggest that preventive measures should be taken to reduce the number of deaths caused by drugs.