Adverse drug events among children presenting to a hospital emergency department in Newfoundland and Labrador, Canada

The epidemiology of drug-related hospital admissions in paediatrics - a systematic review

BACKGROUND

Despite previous efforts, medication safety in paediatrics remains a major concern. To inform improvement strategies and further research especially in outpatient care, we systematically reviewed the literature on the frequency and nature of drug-related hospital admissions in children.

METHODS

Searches covered Embase, Medline, Web of Science, grey literature sources and relevant article citations. Studies reporting epidemiological data on paediatric drug-related hospital admissions published between 01/2000 and 01/2024 were eligible. Study identification, data extraction, and critical appraisal were conducted independently in duplicate using templates based on the 'Joanna Briggs Institute' recommendations.

RESULTS

The review included data from 45 studies reporting > 24,000 hospitalisations for adverse drug events (ADEs) or adverse drug reactions (ADRs). Due to different reference groups, a total of 52 relative frequency values were provided. We stratified these results by study characteristics. As a percentage of inpatients, the highest frequency of drug-related hospitalisation was found with 'intensive ADE monitoring', ranging from 3.1% to 5.8% (5 values), whereas with 'routine ADE monitoring', it ranged from 0.2% to 1.0% (3 values). The relative frequencies of 'ADR-related hospitalisations' ranged from 0.2% to 6.9% for 'intensive monitoring' (23 values) and from 0.04% to 3.8% for 'routine monitoring' (8 values). Per emergency department visits, five relative frequency values ranged from 0.1% to 3.8% in studies with 'intensive ADE monitoring', while all other eight values were ≤ 0.1%. Heterogeneity prevented pooled estimates. Studies rarely reported on the nature of the problems, or studies with broader objectives lacked disaggregated data. Limited data indicated that one in three (median) drug-related admissions could have been prevented, especially by more attentive prescribing. Besides polypharmacy and oncological therapy, no other risk factors could be clearly identified. Insufficient information and a high risk of bias, especially in retrospective and routine observational studies, hampered the assessment.

CONCLUSION

Given the high frequency of drug-related hospitalisations, medication safety in paediatrics needs to be further improved. As routine identification appears unreliable, clinical awareness needs to be raised. To gain more profound insights especially for generating improvement strategies, we have to address under-reporting and methodological issues in future research.

TRIAL REGISTRATION

PROSPERO (CRD42021296986).

Medication Errors in Pediatric Emergency Departments: A Systematic Review and Recommendations for Enhancing Medication Safety

OBJECTIVE

This systematic review aims to investigate the prevalence, preventability, and severity of medication errors in pediatric emergency departments (P-EDs). It also aims to identify common types of medication errors, implicated medications, risk factors, and evaluate the effectiveness of interventions in preventing these errors.

METHODS

A systematic review analyzed 6 primary studies with sample sizes ranging from 96 to 5000 pediatric patients in P-EDs. The review followed Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and included observational studies and randomized controlled trials involving patients aged 18 years and younger. Comprehensive searches in biomedical databases were conducted, and conflicts in record screening were resolved by a third reviewer using systematic review software.

RESULTS

Medication errors in P-EDs are prevalent, ranging from 10% to 15%, with dosing errors being the most common, accounting for 39% to 49% of reported errors. These errors primarily stem from inaccurate weight estimations or dosage miscalculations. Inadequate dosing frequency and documentation also contribute significantly to medication errors. Commonly implicated medications include acetaminophen, analgesics, corticosteroids, antibiotics, bronchodilators, and intravenous fluids. Most errors are categorized as insignificant/mild (51.7% to 94.5%) or moderate (47.5%). Risk factors associated with medication errors in P-EDs include less experienced physicians, severely ill patients, and weekend/specific-hour ordering. Human factors such as noncompliance with procedures and communication failures further contribute to medication errors. Interventions such as health information technology solutions like ParentLink and electronic medical alert systems, as well as structured ordering systems, have shown promise in reducing these errors, although their effectiveness varies.

CONCLUSIONS

Overall, this systematic review provides valuable insights into the complexity of medication errors in the P-ED, emphasizes the need for targeted interventions, and offers recommendations to enhance medication safety and reduce preventable errors in this critical health care setting.

Medication errors in children visiting pediatric emergency departments

OBJECTIVES

Medication safety represents an important challenge in children. There are limited studies on medication errors in pediatric patients visiting emergency departments. To help bridge this gap, we characterized the medication errors detected in these patients, determining their severity, the stages of the medication process in which they occurred, the drugs involved, and the types and causes associated with the errors.

METHODS

We conducted a multicenter prospective observational study in the pediatric emergency departments of 8 Spanish public hospitals over a 4-month period. Medication errors detected by emergency pediatricians in patients between 0 and 16 years of age were evaluated by a clinical pharmacist and a pediatrician. Each medication error was analyzed according to the updated Spanish Taxonomy of Medication Errors.

RESULTS

In 99,797 visits to pediatric emergency departments, 218 (0.2%) medication errors were detected, of which 74 (33.9%) resulted in harm (adverse drug events). Preschoolers were the age group with the most medication errors (126/218). Errors originated mainly in the prescribing stage (66.1%), and also by self-medication (16.5%) and due to wrong administration of the medication by family members (15.6%). Dosing errors (51.4%) and wrong/improper drugs (46.8%) were the most frequent error types. Anti-infective drugs (63.5%) were the most common drugs implicated in medication errors with harm. Underlying causes associated with a higher proportion of medication errors were "medication knowledge deficit" (63.8%), "deviation from procedures/guidelines" (48.6%) and "lack of patient information" (30.3%).

CONCLUSIONS

Medication errors presented by children attending emergency departments arise from prescriptions, self-medicationand administration, and lead to patient harm in one third of cases. Developing effective interventions based on the types of errors and the underlying causes identified will improve patient safety.

Medication errors in children visiting pediatric emergency departments

OBJECTIVES

Medication safety represents an important challenge in children. There are limited studies on medication errors in pediatric patients visiting emergency departments. To help bridge this gap, we characterized the medication errors detected in these patients, determining their severity, the stages of the medication process in which they occurred, the drugs involved, and the types and causes associated with the errors.

METHODS

We conducted a multicenter prospective observational study in the pediatric emergency departments of 8 Spanish public hospitals over a 4-month period. Medication errors detected by emergency pediatricians in patients between 0 and 16 years of age were evaluated by a clinical pharmacist and a pediatrician. Each medication error was analyzed according to the updated Spanish Taxonomy of Medication Errors.

RESULTS

In 99,797 visits to pediatric emergency departments, 218 (0.2%) medication errors were detected, of which 74 (33.9%) resulted in harm (adverse drug events). Preschoolers were the age group with the most medication errors (126/218). Errors originated mainly in the prescribing stage (66.1%), and also by self-medication (16.5%) and due to wrong administration of the medication by family members (15.6%). Dosing errors (51.4%) and wrong/improper drugs (46.8%) were the most frequent error types. Anti-infective drugs (63.5%) were the most common drugs implicated in medication errors with harm. Underlying causes associated with a higher proportion of medication errors were "medication knowledge deficit" (63.8%), "deviation from procedures/guidelines" (48.6%) and "lack of patient information" (30.3%).

CONCLUSIONS

Medication errors presented by children attending emergency departments arise from prescriptions, self-medication, and administration, and lead to patient harm in one third of cases. Developing effective interventions based on the types of errors and the underlying causes identified will improve patient safety.

Development and Adjustment of an Algorithm for Identifying Drug-Related Hospital Admissions in Pediatrics

OBJECTIVE

Adverse drug events (ADEs) in the outpatient pediatric pharmacotherapy can be serious and lead to inpatient admissions. Recent research only focused on ADE identification during hospitalization. The aim of the present study was to develop an algorithm to identify drug-related hospital admissions in pediatrics.

METHODS

A systematic literature research was performed, and a pediatric trigger tool for identifying drug-related inpatient admissions was built. The initial version was tested in a sample of 292 patients admitted to a German university children's hospital. Subsequently, the tool was further improved by combining different modules as a novel approach.

RESULTS

The obtained algorithm with 39 triggers in 5 modules identified drug-related inpatient admissions at a sensitivity of 95.5% (95% confidence interval [CI], 89.3%-100%) and a specificity of 16.5% (95% CI, 11.9%-21.2%), respectively. After modifications including trigger activation requiring a combination of different modules, specificity increased to 56.9% (95% CI, 50.7%-63.0%). Identifying 36 of 44 ADEs leading to admission, sensitivity remained high (81.8% [95% CI, 70.4%-93.2%]). The overall positive predictive value was 25.2% (95% CI, 18.1%-32.3%).

CONCLUSIONS

The algorithm is the first trigger tool to identify ambulant acquired ADEs leading to hospital admission in pediatrics. However, the underlying patient sample is small.Using a larger population for refinement will allow further specifications and reduction in the total amount of triggers and thus signals.

Adverse Drug Events Related to Common Asthma Medications in US Hospitalized Children, 2000-2016

BACKGROUND

The reduction in adverse drug events is a priority in healthcare. Medications are frequently prescribed for asthmatic children, but epidemiological trends of adverse drug events related to anti-asthmatic medications have not been described in hospitalized children.

OBJECTIVE

The objective of this study was to report incidence trends, risk factors, and healthcare utilization of adverse drug events related to anti-asthmatic medications by major drug classes in hospitalized children in the USA from 2000 to 2016.

METHODS

A population-based temporal analysis included those aged 0-20 years who were hospitalized with asthma from the 2000 to 2016 Kids Inpatient Database. Age-stratified weighted temporal trends of the inpatient incidence of adverse drug events related to anti-asthmatic medications (i.e., corticosteroids and bronchodilators) were estimated. Stepwise multivariate logistic regression models generated risk factors for adverse drug events.

RESULTS

From 2000 to 2016, 12,640 out of 698,501 pediatric asthma discharges (1.7%) were associated with adverse drug events from anti-asthmatic medications. 0.83% were adverse drug events from corticosteroids, resulting in a 1.14-fold increase in the length of stay (days) and a 1.42-fold increase in hospitalization charges (dollars). The overall incidence (per 1000 discharges) of anti-asthmatic medication adverse drug events increased from 5.3 (95% confidence interval [CI] 4.6-6.1) in 2000 to 21.6 (95% CI 18.7-24.6) in 2016 (p-trend = 0.024). Children aged 0-4 years had the most dramatic increase in the incidence of bronchodilator adverse drug events from 0.2 (95% CI 0.1-0.4) to 19.3 (95% CI 15.2-23.4) [p-trend ≤ 0.001]. In general, discharges among asthmatic children with some comorbidities were associated with an approximately two to five times higher odds of adverse drug events.

CONCLUSIONS

The incidence of adverse drug events from common anti-asthmatic medications quadrupled over the past decade, particularly among preschool-age children who used bronchodilators, resulting in substantial increased healthcare costs. Those asthmatic children with complex medical conditions may benefit the most from adverse drug event monitoring.

Adverse Drug Event-Related Admissions to a Pediatric Emergency Unit

OBJECTIVES

The objectives of this study were to analyze adverse drug events (ADEs) related to admissions to a pediatric emergency unit and to identify the associated risk factors.

METHODS

This was a prospective study. Demographic data and details of medications were collected for each patient admitted. Case studies were performed by clinical pharmacists and the clinical team to discuss whether the admission was due to an ADE and to characterize the ADE. Multivariate logistic regression was used for statistical analysis.

RESULTS

In total, 1708 pediatric patients were included in this study. Adverse drug events were the cause of hospital admission in 12.3% of the studied population. The majority of patients presenting with an ADE were in the age group of 0 to 5 years (61.6%), had a mean ± SD age of 4.9 ± 3.9 years, were female (51.2%), were Caucasian (72.0%), and had infectious disorders (49.3%). High frequencies of medication errors (68.8%), use of drugs to treat respiratory disorders (27.7%), and ADEs of mild severity (75.3%) were reported. The risk of being admitted to the pediatric emergency unit for any ADE increased in cases of neurological (odds ratio [OR], 4.63; 95% confidence interval [CI], 2.38-8.99), dermatological (OR, 3.16; 95% CI, 1.93-5.18), and respiratory (OR, 3.02; 95% CI, 1.89-4.83) disorders.

CONCLUSIONS

A high frequency of ADE-related admissions to the pediatric emergency unit was observed. The risk of being admitted to the pediatric emergency unit for any ADE increased in cases of neurological, dermatological, and respiratory disorders. Clinical pharmacists play an important role in the identification of ADEs and the education of child caregivers and health care providers concerning pediatric medication.

Variability in Antibiotic Prescribing for Upper Respiratory Illnesses by Provider Specialty

OBJECTIVE

To evaluate variation in antibiotic prescribing between pediatric and nonpediatric providers for common upper respiratory illnesses.

STUDY DESIGN

Patient encounters for children aged <18 years from a regional health care system were identified. Electronic medical records from 2011 to 2016 were extracted for diagnoses of upper respiratory infection, pharyngitis, acute otitis media, and sinusitis. Encounters with competing medical diagnoses, recent hospitalization, and antibiotic prescriptions within 30 days were excluded. Adherence to antibiotic guidelines was assessed by provider training (pediatric, nonpediatric physicians, and advance practice providers). Additional factors assessed were calendar year, and patient's age, sex, insurance status, and number of sick visits in the prior year.

RESULTS

Across 6 years, 141 361 visits were examined: 43 914 for upper respiratory infection, 43 701 for pharyngitis, 43 925 for acute otitis media, and 9821 for sinusitis. Pediatricians were more likely than Advanced practice providers (APP) and nonpediatric providers to have guideline-concordant prescribing for pharyngitis (pediatricians, 66.7% [95% CI, 54.5-77.0]; nonpediatricians, 49.1% [95% CI, 36.3-62.0], APPs, 52.2% [95% CI, 39.4-64.7]; P < .0001) and sinusitis (pediatricians, 70.8% [95% CI, 53.8-83.4], nonpediatricians, 63.3% [95% CI, 46.8-77.2], APPs, 62.1% [95% CI, 45.1-76.5]; P = .48) and to withhold antibiotics for upper respiratory infection than APPs and nonpediatric providers (pediatricians, 86.6% [95% CI, 81.2-90.6], nonpediatricians, 80.8% [95% CI, 73.0-86.8], APPs, 76.8% [95% CI, 68.4-83.5]; P < .0001). Pediatricians were less likely to prescribe antibiotics for pharyngitis without a positive test for group A Streptococcus than APPs and nonpediatric providers (pediatricians, 15.1% [95% CI, 10.4-21.6], nonpediatricians, 29.4% [95% CI, 20.8-39.6], APPs, 27.2% [95% CI, 19.3-36.9]; P < .0001). First-line antibiotic prescribing for acute otitis media did not differ between provider specialties. A trend toward more guideline-concordant prescribing was seen for pharyngitis and sinusitis over the study period.

CONCLUSIONS

Pediatricians were more likely to adhere to guidelines for management of pediatric acute respiratory infections. Pediatric antibiotic stewardship efforts should also target nonpediatricians.

Medication-related visits in a pediatric emergency department: an 8-years retrospective analysis

Background

There are limited data on the characterization of medication-related visits (MRVs) to the emergency department (ED) in pediatric patients in Italy. We have estimated the frequency, severity, and classification of MRVs to the ED in pediatric patients.

Methods

We retrospectively analyzed data for children seeking medical evaluation for a MRV over an 8 years period. A medication-related ED visit was identified by using a random pharmacist assessment, emergency physician assessment, and in case of conflicting events, by a third investigators random assessment.

Results

In this study, regarding a single tertiary center in Italy, on a total of 147,643 patients from 0 to 14 years old, 497 medication-related visits were found, 54% of which occurred in children from 0 to 2 years of age. Severity was classified as mild in 21.6% of cases, moderate in 67.2% of cases, and severe in 11.2% of cases. The most common events were related to drug use without indication (51%), adverse drug reactions (30.3%), supratherapeutic dosage (13.2%) and improper drug selection (4.5%).

The medication classes most frequently implicated in an ADE were anti-infective drugs for systemic use (28.9%), central nervous system agents (22.3%) and respiratory system drugs (10.8%).

The most common symptom manifestations were dermatologic conditions (46.1%), general disorder and administration site conditions (29.7%) and gastrointestinal symptoms (16.0%).

Conclusions

To our knowledge, this is the first study in Italy evaluating the epidemiologic characteristics of MRVs confirming a significant cause of healthcare contact resulting in ED visits and hospital admissions with associated resource utilization. Our results suggests further future prospective, large-sample sized, and multicenter research is necessary to better understand the impact of MRVs and to develop strategies to provide care plans and monitor patients to prevent medication-related visits.

Trial registration

Not applicable.

Risk of Hospital-Acquired Complications in Patients with Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

Unintended injuries or complications in hospitalized patients are common, potentially preventable, and associated with adverse consequences, including greater mortality and health care costs. Patients with CKD may be at higher risk of hospital-acquired complications (HACs).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Adults from a population-based cohort (Alberta Kidney Disease Network) who were hospitalized from April 1, 2003, to March 31, 2008, made up the study cohort. Kidney function was defined using outpatient eGFR and proteinuria (protein-to-creatinine ratio or dipstick) in the year before index hospitalization. Comorbid conditions were identified using validated algorithms applied to administrative data. A specific diagnostic indicator was used to identify HACs. Complications were classified into clinically homogeneous groups and subclassified as potentially preventable (p-HACs) or always preventable (a-HACs). Multivariable logistic regressions models were used to examine the association of CKD with HACs, accounting for confounders.

RESULTS

Of 536,549 patients, 8.5% had CKD; those with CKD were older and more likely to be admitted for circulatory system diseases than those without CKD. In fully adjusted models, the odds ratio (OR) of any hospital complication in patients with CKD (reference: no CKD) was 1.19 (95% confidence interval [95% CI], 1.18 to 1.26); there was a graded relation between the risk of HACs and CKD severity, with an OR of 1.81 (95% CI, 1.51 to 2.17) in those with the most severe CKD (eGFR, 15-29 ml/min per 1.73 m(2) and proteinuria, >30 mg/mmol). Findings were similar for p-HACs (OR, 1.20 [95% CI, 1.16 to 1.24] and 1.78 [95% CI, 1.43 to 2.11], respectively). The a-HACs had similar point estimates.

CONCLUSIONS

The presence of CKD and its severity are associated with a higher risk of HACs, including those considered preventable. Targeted strategies to reduce complications in patients with CKD admitted to the hospital should be considered.

Medication-related emergency department visits in pediatrics: a prospective observational study

BACKGROUND AND OBJECTIVE

There are few data on the rate and characterization of medication-related visits (MRVs) to the emergency department (ED) in pediatric patients. We sought to evaluate the frequency, severity, preventability, and classification of MRVs to the ED in pediatric patients.

METHODS

We performed a prospective observational study of pediatric patients presenting to the ED over a 12-month period. A medication-related ED visit was identified by using pharmacist assessment, emergency physician assessment, and an independent adjudication committee.

RESULTS

In this study, 2028 patients were enrolled (mean age, 6.1 ± 5.0 years; girls, 47.4%). An MRV was found in 163 patients (8.0%; 95% confidence interval [CI]: 7.0%-9.3%) of which 106 (65.0%; 95% CI: 57.2%-72.3%) were deemed preventable. Severity was classified as mild in 14 cases (8.6%; 95% CI: 4.8%-14.0%), moderate in 140 cases (85.9%; 95% CI: 79.6%-90.8%), and severe in 9 cases (5.5%; 95% CI: 2.6%-10.2%). The most common events were related to adverse drug reactions 26.4% (95% CI: 19.8%-33.8%), subtherapeutic dosage 19.0% (95% CI: 13.3%-25.9%), and nonadherence 17.2% (95% CI: 11.7%-23.9%). The probability of hospital admission was significantly higher among patients with an MRV compared with those without an MRV (odds ratio, 6.5; 95% CI: 4.3-9.6) and, if admitted, the median (interquartile range) length of stay was longer (3.0 [5.0] days vs 1.5 [2.5] days, P = .02).

CONCLUSIONS

A medication-related cause was found in ∼1 of every 12 ED visits by pediatric patients, of which two-thirds were deemed preventable. Pediatric patients who present to the ED with an MRV are more likely to be admitted to hospital and when admitted have a longer length of stay.

Medication-related emergency department visits and hospital admissions in pediatric patients: a qualitative systematic review

OBJECTIVE

To review and describe the current literature pertaining to the incidence, classification, severity, preventability, and impact of medication-related emergency department (ED) and hospital admissions in pediatric patients.

STUDY DESIGN

A systematic search of PubMED, Embase, and Web of Science was performed using the following terms: drug toxicity, adverse drug event, medication error, emergency department, ambulatory care, and outpatient clinic. Additional articles were identified by a manual search of cited references. English language, full-reports of pediatric (≤18 years) patients that required an ED visit or hospital admission secondary to an adverse drug event (ADE) were included.

RESULTS

We included 11 studies that reported medication-related ED visit or hospital admission in pediatric patients. Incidence of medication-related ED visits and hospital admissions ranged from 0.5%-3.3% and 0.16%-4.3%, respectively, of which 20.3%-66.7% were deemed preventable. Among ED visits, 5.1%-22.1% of patients were admitted to hospital, with a length of stay of 24-72 hours. The majority of ADEs were deemed moderate in severity. Types of ADEs included adverse drug reactions, allergic reactions, overdose, medication use with no indication, wrong drug prescribed, and patient not receiving a drug for an indication. Common causative agents included respiratory drugs, antimicrobials, central nervous system drugs, analgesics, hormones, cardiovascular drugs, and vaccines.

CONCLUSION

Medication-related ED visits and hospital admissions are common in pediatric patients, many of which are preventable. These ADEs result in significant healthcare utilization.

Reações adversas a medicamentos levando crianças a atendimento na emergência hospitalar

Determinou-se incidência de reações adversas a medicamentos (RAM) que levaram crianças a atendimento de emergência em um hospital universitário de São Paulo, SP. Foram analisadas, retrospectivamente, 23.286 fichas de atendimento (FA) em emergência pediátrica, a partir de código CID que indicasse possível RAM. Observaram-se 83 (0,36%) RAMs. A maioria ocorreu na faixa etária entre 1 a 5 anos com leve predominância no sexo masculino (51,8%). Os medicamentos mais implicados foram antibacterianos para uso sistêmico (53,0%), vacinas (9,6%) e analgésicos (7,2%). A maior parte das RAMs foram manifestações dérmicas (54,2%) ou gastrointestinais (22,9%). Duas RAMs foram consideradas graves (2,4%) e levaram a internação; enquanto 61,4% foram leves e 36,1% foram moderadas. A incidência foi inferior à literatura, provavelmente por ser estudo retrospectivo, utilizando-se o CID para seleção das FA. Observou-se que, no Brasil, as RAMs levam crianças a atendimento de emergência, com características semelhantes às de outros países. Intervenções são necessárias para melhorar o diagnóstico e a utilização de antimicrobianos, uma vez que foram os medicamentos mais implicados nas RAMs observadas. A pesquisa no setor de emergência hospitalar é importante para se conhecer as RAMs que ocorrem fora do contexto hospitalar, podendo contribuir para identificar aquelas de maior gravidade. A metodologia utilizada, apesar das limitações, requer poucos recursos humanos e materiais, sendo uma boa alternativa para um diagnóstico inicial, que deve ser sucedido por estudos mais elaborados e de maior sensibilidade para detectar essas reações e propor medidas dirigidas à sua prevenção.

Prevalence of adverse drug events in ambulatory care: a systematic review

OBJECTIVE

Most medications are prescribed, dispensed, and administered in ambulatory care settings, yet little information exists on the adverse effects of drugs in this setting. This review was conducted to estimate the prevalence of adverse drug events (ADEs) and the proportion of preventable ADEs in ambulatory care settings; compare data for different age groups including children, adults, and elderly patients; and review drug classes most commonly associated with ADEs.

DATA SOURCES

Four electronic databases-PubMed (1966-March 2011), International Pharmaceutical Abstracts (1970-March 2011), EMBASE (1980-March 2011), and the Cochrane Database of Systematic Reviews (1993-March 2011)-were systematically searched for published data. Bibliographies of retrieved articles were searched individually for additional relevant studies.

STUDY SELECTION

A standardized definition of an ADE was used to select studies in populations living in the community, with medical visits to primary care facilities, nonspecialty ambulatory care facilities, and/or admissions to a hospital for medication-related adverse events.

DATA EXTRACTION

Data were extracted using a standardized table. Forty-three studies met our inclusion criteria.

DATA SYNTHESIS

The median ADE prevalence rate for retrospective studies was 3.3% (interquartile range [IQR] 2.3-7.1%) vs 9.65% (IQR 3.3-17.35%) for prospective studies. Median preventable ADE rates in ambulatory care-based studies were 16.5%, and 52.9% for hospital-based studies. Median prevalence rates by age group ranged from 2.45% for children to 5.27% for adults, 16.1% for elderly patients, and 3.45% for studies including all ages.

CONCLUSIONS

Despite a recent increase in publications on ADEs in the ambulatory care setting, most studies remain hospital based. Notable differences in prevalence rates by age groups and by responsible drug categories provide guidance on how to direct attention toward effective targets for improvement of medication safety in ambulatory care settings.