Detection of adverse drug reactions in a neurological department: comparison between intensified surveillance and a computer-assisted approach

Machine-learning-based adverse drug event prediction from observational health data: A review

Adverse drug events (ADEs) are responsible for a significant number of hospital admissions and fatalities. Machine learning models have been developed to assess the individual patient risk of having an ADE. In this article, we have reviewed studies addressing the prediction of ADEs in observational health data with machine learning. The field of individualised ADE prediction is rapidly emerging through the increasing availability of additional data modalities (e.g., genetic data, screening data, wearables data) and advanced deep learning models such as transformers. Consequently, personalised adverse drug event predictions are becoming more feasible and tangible.

Categorization and association analysis of risk factors for adverse drug events

PURPOSE

Adverse drug events (ADE) are among the leading causes of morbidity and hospitalization. This review analyzes risk factors for ADE, particularly their categorizations and association patterns, the prevalence, severity, and preventability of ADE, and method characteristics of reviewed studies.

METHODS

Literature search was conducted via PubMed, Science Direct, CINAHL, and MEDLINE. A review was conducted of research articles that reported original data about specific risk factors for ADE since 2000. Data analyses were performed using Excel and R.

RESULTS

We summarized 211 risk factors for ADE, and grouped them into five main categories: patient-, disease-, medication-, health service-, and genetics-related. Among them, medication- and disease-related risk factors were most frequently studied. We further classified risk factors within each main category into subtypes. Among them, polypharmacy, age, gender, central nervous system agents, comorbidity, service utilization, inappropriate use/change use of drugs, cardiovascular agents, and anti-infectives were most studied subtypes. An association analysis of risk factors uncovered many interesting patterns. The median prevalence, preventability, and severity rate of reported ADE was 19.5% (0.29%~86.2%), 36.2% (2.63%~91%), and 16% (0.01%~47.4%), respectively.

CONCLUSIONS

This review introduced new categories and subtypes of risk factors for ADE. The broad and in-depth coverage of risk factors and their association patterns elucidate the complexity of risk factor analysis. Managing risk factors for ADE is crucial for improving patient safety, particularly for the elderly, comorbid, and polypharmacy patients. Some under-explored risk factors such as genetics, mental health and wellness, education, lifestyle, and physical environment invite future research.

Data Requirements for the Correct Identification of Medication Errors and Adverse Drug Events in Patients Presenting at an Emergency Department

BACKGROUND

Adverse drug events (ADE) involving or not involving medication errors (ME) are common, but frequently remain undetected as such. Presently, the majority of available clinical decision support systems (CDSS) relies mostly on coded medication data for the generation of drug alerts. It was the aim of our study to identify the key types of data required for the adequate detection and classification of adverse drug events (ADE) and medication errors (ME) in patients presenting at an emergency department (ED).

METHODS

As part of a prospective study, ADE and ME were identified in 1510 patients presenting at the ED of an university teaching hospital by an interdisciplinary panel of specialists in emergency medicine, clinical pharmacology and pharmacy. For each ADE and ME the required different clinical data sources (i.e. information items such as acute clinical symptoms, underlying diseases, laboratory values or ECG) for the detection and correct classification were evaluated.

RESULTS

Of all 739 ADE identified 387 (52.4%), 298 (40.3%), 54 (7.3%), respectively, required one, two, or three, more information items to be detected and correctly classified. Only 68 (10.2%) of the ME were simple drug-drug interactions that could be identified based on medication data alone while 381 (57.5%), 181 (27.3%) and 33 (5.0%) of the ME required one, two or three additional information items, respectively, for detection and clinical classification.

CONCLUSIONS

Only 10% of all ME observed in emergency patients could be identified on the basis of medication data alone. Focusing electronic decisions support on more easily available drug data alone may lead to an under-detection of clinically relevant ADE and ME.

Comorbidity, Polytherapy, and Drug Interactions in a Neurological Context: An Example of a Multidisciplinary Approach to Promote the Rational Use of Drugs

Purpose:

A high number of adverse drug reactions (ADRs), mainly caused by drug–drug interactions (DDIs), occur in neurological wards and few data are available about incidence and prevalence of DDIs in this context. This study investigated—(1) the prevalence of drug–drug and drug–disease interactions in patients admitted to a neurological unit in Italy, (2) the risk factors for DDIs, and (3) the diseases and the drug classes mostly involved in drug–drug and drug–disease interactions.

Methods:

For 2 months, we performed a retrospective, observational study in the neurological unit of St Bassiano Hospital, enrolling 79 patients who received a drug prescription at discharge.

Results:

About half of the patients were discharged with 5 or more prescribed drugs, and 72% of patients showed potential, clinically relevant DDIs. Linear correlations were observed between age and number of prescribed drugs ( P < .01) and between age and number of interactions ( P < .01). The number of prescribed drugs was associated with the number of detected DDIs ( P < .01). The application of drug interaction alerts and the use of medication inappropriateness criteria (ie, Beers criteria) were not satisfactory in choosing the best therapy for each patient. Therefore, multidisciplinary discussions of each clinical case was required.

Conclusion:

The study demonstrated that the neurological patient, especially if elderly, has a high risk of DDI and ADRs and that many of these can be avoided by case discussion in multidisciplinary team meetings, in which the presence of a dedicated clinical pharmacist is crucial.

Incidence, risk factors and risk prediction of hospital-acquired suspected adverse drug reactions: a prospective cohort of Ugandan inpatients

OBJECTIVES

To determine the incidence and risk factors of hospital-acquired suspected adverse drug reactions (ADRs) among Ugandan inpatients. We also constructed risk scores to predict and qualitatively assess for peculiarities between low-risk and high-risk ADR patients.

METHODS

Prospective cohort of consented adults admitted on medical and gynaecological wards of the 1790-bed Mulago National Referral Hospital. Hospital-acquired suspected ADRs were dichotomised as possible (possible/probable/definite) or not and probable (probable/definite) or not, using the Naranjo scale. Risk scores were generated from coefficients of ADR risk-factor logistic regression models.

RESULTS

The incidence of possible hospital-acquired suspected ADRs was 25% (194/762, 95% CI: 22% to 29%): 44% (85/194) experienced serious possible ADRs. The risk of probable ADRs was 11% (87/762, 95% CI 9% to 14%): 46% (40/87) had serious probable ADRs. Antibacterials-only (51/194), uterotonics-only (21/194), cardiovascular drugs-only (16/194), antimalarials-only (12/194) and analgesics-only (10/194) were the most frequently implicated. Treatment with six or more conventional medicines during hospitalisation (OR=2.31, 95% CI 1.29 to 4.15) and self-reported herbal medicine use during the 4 weeks preadmission (OR=1.96, 95% CI 1.22 to 3.13) were the risk factors for probable hospital-acquired ADRs. Risk factors for possible hospital-acquired ADRs were: treatment with six or more conventional medicines (OR=2.72, 95% CI 1.79 to 4.13), herbal medicine use during the 4 weeks preadmission (OR=1.68, 95% CI 1.16 to 2.43), prior 3 months hospitalisation (OR=1.57, 95% CI 1.09 to 2.26) and being on gynaecological ward (OR=2.16, 95% CI 1.36 to 3.44). More drug classes were implicated among high-risk ADR-patients, with cardiovascular drugs being the most frequently linked to possible ADRs.

CONCLUSIONS

The risk of hospital-acquired suspected ADRs was higher with preadmission herbal medicine use and treatment with six or more conventional medicines during hospitalisation. Our risk scores should be validated in large-scale studies and tested in routine clinical care.

Evaluation of a Computer Application for Retrospective Detection of Vitamin K Antagonist Treatment Imbalance

OBJECTIVE

Management of vitamin K antagonists (VKAs) is difficult, and overdoses can have dramatic hemorrhagic consequences. The adverse drug event (ADE) scorecards is a tool intended for the detection and description of adverse drug reaction/ADE developed during a European computerized medical data processing project. It is used in a quality assurance process. Our objective was to evaluate the performance of the ADE scorecards in the detection of the contributing factors for VKA overdoses, among the cases where a VKA overdose is observed.

METHODS

Twenty-eight rules allow the detection of VKA treatment overdose related to drug or a clinical situation. They were applied on 14,748 electronic medical records from a community hospital. Among 582 records including a VKA prescription, 59 cases of VKA overdoses (international normalized ratio ≥ 5) during the hospital stay have been identified. The ADE scorecards detected 49 of them. We evaluated the positive predictive value and sensitivity of these rules, by an expert review of the cases.

RESULTS

The expert review confirmed the contribution of a detected risk factor to the VKA overdose in 11 cases. Therefore, the precision of the rules is 22.4%. The sensitivity is 84.6%. The risk factors were mainly infection and amiodarone introduction. The 4 cases of clinical injury related to a drug were properly designated by the rules.

CONCLUSIONS

Our study shows the great potential of the ADE scorecards for detecting cofactors of VKA overdoses and gives an argument to include complex rules in the knowledge bases used for the detection and identification of ADEs in large medical databases.

Epidemiology of adverse drug reactions in Europe: a review of recent observational studies

Adverse drug reactions (ADRs) cause considerable mortality and morbidity but no recent reviews are currently available for the European region. Therefore, we performed a review of all epidemiological studies quantifying ADRs in a European setting that were published between 1 January 2000 and 3 September 2014. Included studies assessed the number of patients who were admitted to hospital due to an ADR, studies that assessed the number of patients who developed an ADR during hospitalization, and studies that measured ADRs in the outpatient setting. In total, 47 articles were included in the final review. The median percentage of hospital admissions due to an ADR was 3.5 %, based on 22 studies, and the median percentage of patients who experienced an ADR during hospitalization was 10.1 %, based on 13 studies. Only five studies were found that assessed ADRs occurring in the outpatient setting. These results indicate that the occurrence of ADRs in the European hospital setting—both ADRs that result in hospitalization and ADRs that occur during the hospital stay—is significant. Furthermore, the limited number of studies that were performed in the outpatient setting identify a lack of information regarding the epidemiology of ADRs in this setting.

Detection of medication-related problems in hospital practice: a review

This review examines the effectiveness of detection methods in terms of their ability to identify and accurately determine medication-related problems in hospitals. A search was conducted of databases from inception to June 2012. The following keywords were used in combination: medication error or adverse drug event or adverse drug reaction, comparison, detection, hospital and method. Seven detection methods were considered: chart review, claims data review, computer monitoring, direct care observation, interviews, prospective data collection and incident reporting. Forty relevant studies were located. Detection methods that were better able to identify medication-related problems compared with other methods tested in the same study included chart review, computer monitoring, direct care observation and prospective data collection. However, only small numbers of studies were involved in comparisons with direct care observation (n = 5) and prospective data collection (n = 6). There was little focus on detecting medication-related problems during various stages of the medication process, and comparisons associated with the seriousness of medication-related problems were examined in 19 studies. Only 17 studies involved appropriate comparisons with a gold standard, which provided details about sensitivities and specificities. In view of the relatively low identification of medication-related problems with incident reporting, use of this method in tracking trends over time should be met with some scepticism. Greater attention should be placed on combining methods, such as chart review and computer monitoring in examining trends. More research is needed on the use of claims data, direct care observation, interviews and prospective data collection as detection methods.

Adverse drug reactions in hospitalised children in Germany are decreasing: results of a nine year cohort-based comparison

BACKGROUND

In recent years, efforts have been made to improve paediatric drug therapy. The aim of this research was to investigate any changes regarding the frequency and nature of adverse drug reactions (ADRs) in hospitalized children in one paediatric general medical ward over a 9-year period.

METHODOLOGY

Two prospective observational cohort studies were conducted at a large University hospital in Germany in 1999 and 2008, respectively. Children aged 0-18 years admitted to the study ward during the study periods were included. ADRs were identified using intensive chart review. Uni- and multivariable regression has been used for data analysis.

RESULTS

A total of 520 patients (574 admissions) were included [1999: n = 144 (167); 2008: n = 376 (407)]. Patients received a total of 2053 drugs [median 3, interquartile range (IQR) 2-5]. 19% of patients did not receive any medication. Median length of stay was 4 days (IQR 3-7; range 1-190 days) with a significantly longer length of stay in 1999. The overall ADR incidence was 13.1% (95% CI, 9.8-16.3) varying significantly between the two study cohorts [1999: 21.9%, 95% CI, 14.7-29.0; 2008: 9.2%, 95% CI, 5.9-12.5 (p<0.001)]. Antibacterials and corticosteroids for systemic use caused most of the ADRs in both cohorts (1999; 2008). Exposure to systemic antibacterials decreased from 62.9% to 43.5% whereas exposure to analgesics and anti-inflammatory drugs increased from 17.4% to 45.2%, respectively. The use of high risk drugs decreased from 75% to 62.2%. In 1999, 45.7% and in 2008 96.2% of ADRs were identified by treating clinicians (p<0.001).

CONCLUSIONS

Between 1999 and 2008, the incidence of ADRs decreased significantly. Improved treatment strategies and an increased awareness of ADRs by physicians are most likely to be the cause for this positive development. Nevertheless further research on ADRs particularly in primary care and the establishment of prospective pharmacovigilance systems are still needed.

Use of an abnormal laboratory value-drug combination alert to detect drug-induced thrombocytopenia in critically Ill patients

PURPOSE

The aim of this study was to assess the performance of a commercially available clinical decision support system (CDSS) drug-laboratory result alert in detecting drug-induced thrombocytopenia in critically ill patients.

MATERIALS AND METHODS

Adult patients admitted to the medical and cardiac intensive care unit during an 8-week period and identified by 1 of 3 signals in the CDSS, TheraDoc, were eligible. Alerts were generated when the patient had a low platelet count and was ordered a potentially causal drug. Patients were evaluated in real time for the occurrence of an adverse drug reaction using 3 causality instruments. Positive predictive values were calculated for the alert.

RESULTS

Sixty-four patients with a mean age of 54 years met the inclusion criteria, generating 350 alerts. Positive predictive values were 0.36, 0.83, and 0.40 for signals 1, 2, and 3, respectively. Overall, there were 137 adverse drug reactions identified in the 350 alerts, with heparin, vancomycin, and famotidine as the 3 most common potential causes.

CONCLUSIONS

A commercial CDSS drug-laboratory alert is effective at identifying drug-induced thrombocytopenia in the intensive care unit and may improve patient safety. Compared with previous studies, the combination alert performs better than alerts based exclusively on laboratory values and should be considered to reduce alert fatigue.

A systematic review to evaluate the accuracy of electronic adverse drug event detection

OBJECTIVE

Adverse drug events (ADEs), defined as adverse patient outcomes caused by medications, are common and difficult to detect. Electronic detection of ADEs is a promising method to identify ADEs. We performed this systematic review to characterize established electronic detection systems and their accuracy.

METHODS

We identified studies evaluating electronic ADE detection from the MEDLINE and EMBASE databases. We included studies if they contained original data and involved detection of electronic triggers using information systems. We abstracted data regarding rule characteristics including type, accuracy, and rationale.

RESULTS

Forty-eight studies met our inclusion criteria. Twenty-four (50%) studies reported rule accuracy but only 9 (18.8%) utilized a proper gold standard (chart review in all patients). Rule accuracy was variable and often poor (range of sensitivity: 40%-94%; specificity: 1.4%-89.8%; positive predictive value: 0.9%-64%). 5 (10.4%) studies derived or used detection rules that were defined by clinical need or the underlying ADE prevalence. Detection rules in 8 (16.7%) studies detected specific types of ADEs.

CONCLUSION

Several factors led to inaccurate ADE detection algorithms, including immature underlying information systems, non-standard event definitions, and variable methods for detection rule validation. Few ADE detection algorithms considered clinical priorities. To enhance the utility of electronic detection systems, there is a need to systematically address these factors.

Risk factors associated with adverse drug reactions in hospitalised children: international multicentre study

BACKGROUND

Understanding the epidemiology and risk factors of adverse drug reactions (ADRs) is important in order to develop appropriate prevention strategies. This study aimed to identify risk factors associated with ADRs in hospitalised children and recommend strategies to minimise ADRs.

METHODS

A prospective multicentre cohort study was conducted on paediatric general medical wards in five European and non-European hospitals. ADRs were identified by intensive chart review. Multivariable logistic regression was used to investigate risk factors associated with ADRs. For the risk factor analysis, prescribed drugs were divided into high-risk and low-risk drug groups. Analgesics, anti-epileptics, antibacterials and antimycotics for systemic use, corticosteroids for systemic use and immunosuppressant agents were considered as high-risk groups whereas the remaining drug classes were defined as low-risk drug groups.

RESULTS

A total of 1,253 paediatric patients were identified [Australia (n = 145), Germany (n = 372), Hong Kong (n = 138), Malaysia (n = 291), UK (n = 307)]. A total of 328 ADRs were observed in 16.7% of patients (186/1,115). Use of five or more low-risk drugs per patient or three or more high-risk drugs was a strong predictor for ADRs (OR 4.7, 95% CI 2.4-9.3; OR 6.5, 95% CI 2.7-16.0 respectively; p < 0.001). Older children were more likely to experience ADRs; gender was not significantly associated.

CONCLUSION

To reduce the risk of ADRs in children, clinicians and pharmacists should aim to minimise polypharmacy and be aware of higher ADR risks associated with some drug groups.

[Pharmacologically-induced neurocatastrophes]

Drug-induced adverse reactions represent a significant health problem in developed countries. These events cause 5% of hospital admissions and are one of the main causes of mortality. Neurological manifestations are among the most frequent. This article reviews catastrophic cerebrovascular situations and confusional syndromes, as well as epilepsy, structural encephalopathy, neuromuscular disorders, catastrophic movement disorders and infections, all of which can be drug-induced.

Testing a trigger tool as a method of detecting harm from medication errors in a UK hospital: a pilot study

Objectives

The aim was to adapt a US adverse drug event (ADE) trigger tool for UK use, and to establish its positive predictive value (PPV) and sensitivity in comparison to retrospective health record review for the identification of preventable ADEs, in a pilot study on one hospital ward.

Methods

An established US trigger tool was adapted for UK use. We applied it retrospectively to 207 patients' health records, following up positive triggers to identify any ADEs (both preventable and non-preventable). We compared the preventable ADEs to those identified using full health record review.

Key findings

We identified 168 positive triggers in 127 (61%) of 207 patients. Seven ADEs were identified, representing an ADE in 3.4% of patients or 0.7 ADEs per 100 patient days. Five were non-preventable adverse drug reactions and two were due to preventable errors. The prevalence of preventable ADEs was 1.0% of patients, or 0.2 per 100 patient days. The overall PPV was 0.04 for all ADEs, and 0.01 for preventable ADEs. PPVs for individual triggers varied widely. Five preventable ADEs were identified using health record review. The sensitivity of the trigger tool for identifying preventable ADEs was 0.40, when compared to health record review.

Conclusions

Although we identified some ADEs using the trigger tool, more work is needed to further refine the trigger tool to reduce the false positives and increase sensitivity. To comprehensively identify preventable ADEs, retrospective health record review remains the gold standard and we found no efficiency gain in using the trigger tool.

Hospital Admissions Associated with Adverse Drug Reactions: A Systematic Review of Prospective Observational Studies

Objective:

To determine the prevalence of hospital admissions associated with ADRs and examine differences in prevalence rates between population groups and methods of ADR detection.

Data Sources:

Studies were identified through electronic searches of Cumulative Index to Nursing and Allied Hearth Literature. EMBASE, and MEDLINE to August 2007. There were no language restrictions.

Study Selection and Data Extraction:

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.

Data Synthesis:

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. Antiinfective drugs were most often associated with ADR admissions in children; cardiovascular drugs were most often associated with ADR admissions in adults and elderly patients.

Conclusions:

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.

A systematic review of the performance characteristics of clinical event monitor signals used to detect adverse drug events in the hospital setting

OBJECTIVE

Despite demonstrated benefits, few healthcare organizations have implemented clinical event monitors to detect adverse drug events (ADEs). The objective of this study was to conduct a systematic review of pharmacy and laboratory signals used by clinical event monitors to detect ADEs in hospitalized adults.

DESIGN

We performed a comprehensive search of MEDLINE, CINHAL and EMBASE to identify studies published between 1985 through 2006. Studies were included if they: described a clinical event monitor to detect ADEs in an adult hospital setting; described laboratory or pharmacy ADE signals; and, provided positive predictive values (PPVs) or information to allow the calculation of PPVs for individual ADE signals.

MEASUREMENTS

We calculated overall estimates of PPVs and 95% confidence intervals (CIs) for signals reported in 2 or more studies and contained no evidence heterogeneity. Results were examined by signal category: medication levels, laboratory tests, or antidotes.

RESULTS

We identified 12 observational studies describing 36 unique ADE signals. Fifteen signals (3 antidotes, 4 medication levels, and 8 laboratory values) contained no evidence of heterogeneity. The pooled PPVs for these individual signals ranged from 0.03 [CI=0.03-0.03] for hypokalemia, to 0.50 [CI=0.39-0.61] for supratherapeutic quinidine level. In general, antidotes (range=0.09-0.11) had the lowest PPVs, followed by laboratory values (0.03-0.27), and medication levels (0.03-0.50).

CONCLUSION

Results from this study should help clinical information system and computerized decision support producers develop or improve existing clinical event monitors to detect ADEs in their own hospitals by prioritizing those signals with the highest PPVs [corrected]

Drug-Related Problems in Hospitals

Problems associated with pharmacotherapy (in particular, medication errors and adverse drug events) are frequent and are associated with increased costs for treatment. Analysis of original publications published between 1990 and 2005 on the topics of medication errors and/or adverse drug events in hospitalised patients, focusing on the frequency of, risk factors for and avoidance of such problems associated with pharmacotherapy, indicated that medication errors occurred in a mean of 5.7% of all episodes of drug administration, but with a high variability among the 35 studies retrieved. This variability was explained by the methods by which medication errors were detected (systematic screening of patients versus chart review or spontaneous reporting) and by the way drugs were administered (intravenously administered drugs are associated with the highest error frequencies). Errors occurred throughout the whole medication process, with administration errors accounting for more than half of all errors. Important risk factors included insufficient pharmacological knowledge of health professionals, errors in the patient charts or documentation by nurses and inadequate pharmacy services.Adverse events or reactions, on the other hand, affected 6.1 patients per 100 hospitalised and also showed a high variability among the 46 studies retrieved. This variability could also be explained by the different methods of assessment of the frequency of adverse drug events or reactions, as well as by the different wards on which the studies were performed. Important risk factors for adverse drug events or reactions included polypharmacy, female sex, drugs with a narrow therapeutic range, renal elimination of drugs, age >65 years and use of anticoagulants or diuretics. Since medication errors are strong risk factors for preventable adverse drug events or reactions, strategies have to be put in place for their reduction. Such strategies include ensuring that all persons involved in the medication process (nurses, pharmacists and physicians) have good pharmacological knowledge, computerisation of the entire medication process, and the engagement of a sufficient number of clinical pharmacists on the wards.

Unerwünschte Arzneimittelwirkungen

Adverse drug reactions (ADR) occur in about 5% of all pharmacologically treated patients. Between 2% and 20% of all hospital admissions are caused by ADR, and approximately 10% of all hospitalized patients experience ADR during their hospital stay. Several thousand patients die due to ADR in Germany each year. ADR-associated drugs come predominantly from the class of non-steroidal antiinflammatory drugs, anticoagulants, acetylsalicylic acid and cardiovascular drugs. Most ADR cases present as gastrointestinal bleeding and adverse cardiovascular effects. Apart from this, one or more drugs are withdrawn from the market each year because of unwanted but mostly rare side effects. In recent years the most prominent cases were rofecoxib, cisapride and cerivastatin. Physicians in Germany are obliged to report ADR. A substantial proportion of ADR, however, is not reported because it is deemed to be either too well known or the association between the drug and the adverse effect is too doubtful. In some cases, histopathological findings are needed to determine the diagnosis of ADR. Accordingly, physicians should inform the pathologist whether an ADR is suspected and which drugs may be responsible.

Incidence of drug-induced liver injury in medical inpatients

OBJECTIVES

Drug-induced liver injury (DILI) is a common concern. However, data on DILI epidemiology in inpatients are sparse.

METHODS

To investigate the incidence of DILI, we screened all patients in the pharmacoepidemiological inpatient database according to the CIOMS (Council for International Organisation of Medical Science) criteria, which consist of the evaluation of some clinical chemistry laboratory liver parameters (CIOMS laboratory criteria) and the exclusion of any disease-related causes for the liver injury. Thus, only cases with probable or certain causality according to the World Health Organization criteria were included.

RESULTS

Among a total of 6383 patients, liver parameters were determined in 4610, and 489 among them fulfilled the CIOMS laboratory criteria. However, 401 patients had to be excluded because of disease-related liver injury and, thus, the study cohort consisted of 4209 patients at risk for DILI. Among a total of 88 DILI cases, 31 had no documented normal baseline liver parameters and, thus, represented prevalent cases. The remaining 57 represented incident DILI cases. Thus, the incidence of DILI was 1.4% (95% CI 1.0, 1.7). The drug classes most frequently causing DILI were heparins, antibacterials, tuberculostatics and antineoplastic agents. Among those, antineoplastic agents and tuberculostatics showed the highest incidence. Liver injury was not mentioned among the diagnoses or in the physician's discharge letter in about 52-68% of all cases.

CONCLUSION

Approximately 1 in 100 patients develops DILI during hospitalisation in a department of medicine. Incidences of DILI were highest for antineoplastic agents and tuberculostatics. DILI is frequently missed and, therefore, DILI detection by diagnoses will result in misleadingly low incidence rates.

Detecting Adverse Drug Reactions on Paediatric Wards

BACKGROUND

Adverse drug reactions (ADRs) contribute significantly to patient morbidity and mortality, as well as to costs for healthcare systems. Our aim was to evaluate the type and incidence of ADRs in a paediatric hospital population, comparatively ascertained by two different methodological approaches.

METHODS

Our prospective study enrolled all patients admitted to two of the general children wards (46 beds) and the paediatric intensive care unit (6 beds) at the HELIOS Klinikum Wuppertal teaching hospital in Germany, over the study period of 3 months. We used two methods to detect ADRs. The intensified surveillance system relied on a trained physician conducting ward rounds and assessing patient charts. The computer-assisted screening of pathological laboratory parameters used values slightly below or above the age-specific normal range as a trigger signal for a potential ADR, which was subsequently assessed by trained personnel.

RESULTS

By applying both methods simultaneously we observed that 14.1% of children experienced an ADR while they were hospitalised and 2.7% of children were admitted to hospital because of the ADR. Intensified surveillance resulted in the detection of 101 ADRs in 11.9% of patients, predominantly presenting with gastrointestinal symptoms, skin and CNS disorders; computer-assisted screening identified 45 ADRs in 5.7% of patients, mainly with drug-induced blood dyscrasia and liver damage. Furthermore, the ADRs detected by the intensified method were more severe, affected younger children and showed a closer causal attributability to the reaction than the ADRs observed by the computerised method. The spectra of drugs involved were similar, with the anti-infectives being suspected most frequently. The sensitivities of the intensified surveillance system and the computerised surveillance screening came to 67.2% and 44.8%, respectively, with computer-assisted screening having a specificity of 72.8%. The mean positive predictive value of the pathological laboratory values under surveillance by computer-assisted screening was 18.6%. Approximately 25% of ADR-related drugs administered were used for off-label indications.

CONCLUSION

Using the published literature for comparison, we found that ADRs occur as frequently in paediatric patients as in adult patients. Intensified surveillance and computerised surveillance applied in the paediatric setting show substantial differences in their detection specificities. A higher number of and more severe ADRs can be detected by intensified surveillance than by computerised surveillance, but require higher personnel resources.

Detection of drug-related adverse events in hospitals

Adverse drug events (ADEs) contribute significantly to patient morbidity and mortality as well as to cost for healthcare providers and society. Since only serious ADEs will result in hospitalisation, the evaluation of ADEs leading to hospitalisation reflects safety and appropriateness of ambulatory prescribing. ADEs occurring during hospitalisation may result from the special clinical situation of hospitalised patients; high degree of severity of diseases (e.g., renal failure, necessity of intensive care) and specific drugs administered only in hospitals. Moreover, the number of diagnostic and therapeutic procedures carried out daily puts the hospitalised patient at an extremely high risk for ADEs.