Hospitalisations caused by adverse drug reactions (ADR): a meta-analysis of observational studies

A cluster-randomized educational intervention to reduce inappropriate prescription patterns for elderly patients in general practice--The Prescription Peer Academic Detailing (Rx-PAD) study [NCT00281450]

Background

Age-related alterations in metabolism and excretion of medications increase the risk of adverse drug events in the elderly. Inappropriate polypharmacy and prescription practice entails increased burdens of impaired quality of life and drug related morbidity and mortality. The main objective of this trial is to evaluate effects of a tailored educational intervention towards general practitioners (GPs) aimed at supporting the implementation of a safer drug prescribing practice for elderly patients ≥ 70 years.

Methods/design

Approximately 80 peer continuing medical education (CME) groups (about 600 GPs) in southern Norway will be recruited to a cluster randomized trial. Participating groups will be randomized either to an intervention- or a control group. The control group will not receive any intervention towards prescription patterns in elderly, but will be the target of an educational intervention for prescription of antibiotics for respiratory tract infections. A multifaceted intervention has been tailored, where key components are educational outreach visits to the CME-groups, work-shops, audit and feedback. Prescription Peer Academic Detailers (Rx-PADs), who are trained GPs, will conduct the educational outreach visits. During these visits, a set of quality indicators (QIs), i.e. explicit recommendations for safer prescribing for elderly patients, will be presented and discussed. Software will be handed out for installation in participants' practice computers to enable extraction of pre-defined prescription data. These data will subsequently be linked to corresponding data from the Norwegian Prescription Database (NorPD). Individual feedback reports will be sent all participating GPs during and one year after the intervention. Feedback reports will include QI-scores on individual- and group levels, before and after the intervention. The main outcome of this trial is the change in proportions of inappropriate prescriptions (QIs) for elderly patients ≥ 70 years following intervention, compared to baseline levels.

Discussion

Improvement of prescription patterns in medical practice is a challenging task. Evidence suggests that a thorough evaluation of diagnostic indications for drug treatment in the elderly and/or a reduction of potentially inappropriate drugs may impose significant clinical benefits. Our hypothesis is that an educational intervention program will be effective in improving prescribing patterns for elderly patients in GP settings.

Improper intake of medication by elders--insights on contributing factors: a review of the literature

Elders represent 6.4% of the world's populations, and 60% of them take medication. In one of six hospital admissions of elders, failures in medication intake are involved. Most of these admissions (88%) could be prevented if elders at risk can be identified (Beijer & Blaey, 2002). This review was conducted to identify and gain insight into which factors influence medication intake in elders. The factors are grouped into six categories: physiological factors, cognitive factors, polypharmacy and medication frequency, patient consent to the treatment and motivation for taking the medication, demographic variables, and family caregivers and social support. In order to identify elders at risk in an early stage, it is recommended that a risk-assessment instrument be developed.

Adverse drug reactions in an elderly hospitalised population: inappropriate prescription is a leading cause

OBJECTIVE

Adverse drug reactions (ADRs) represent a major public health problem in the aged. In order to better evaluate this problem in Brazil, this study was designed to assess the prevalence of ADRs in an elderly hospitalised population, identify the most common ADRs and the principal medications involved, evaluate the appropriateness of use of these drugs in elderly people and determine the risk factors implicated in the appearance of such ADRs.

METHODS

The study population was comprised of 186 elderly patients (> or =60 years of age) admitted to the internal medicine service of a teaching hospital. The patients were assessed by a single observer using an intensive drug surveillance method to identify and report ADRs. The degree of probability for each adverse reaction was determined using the Naranjo algorithm.

RESULTS

The mean (+/- SD) age of the patients studied was 73.6 +/- 9.1 years. Up to 115 patients (61.8%) of the study population presented at least one ADR. A total of 199 ADRs were found, at an average of 1.7 per patient. The ADRs appeared during hospitalisation in 46.2% of the study population, were present at the time of the admission but did not cause hospitalisation in 17.2% of patients, and were the cause of admission in 11.3% of patients. The most frequent ADR that caused hospitalisation was digitalis toxicity (22.7% of such ADRs). Hypokalaemia as a result of diuretics was the most prevalent ADR both during hospitalisation (11.8%) and at the time of admission without being the cause (12.1%). Captopril was the most frequently prescribed drug (138 prescriptions), and led to an ADR in 18.1% of patients who received the drug. Almost a quarter of the patients presenting an ADR were prescribed drugs considered inappropriate for the elderly. By means of a multiple logistic regression model, the following were considered to be significant risk factors for the appearance of ADRs: number of diagnoses (odds ratio [OR] 1.40; 95% CI 1.06, 1.86), number of drugs (OR 1.07; 95% CI 1.01, 1.13) and use of drug that is inappropriate for the elderly (OR 2.32; 95% CI 1.17, 4.59).

DISCUSSION

The main contribution of the present study was identification of use of drugs that are considered inappropriate for elderly populations as a major risk factor for presenting an ADR. This finding is useful for continuous education programmes, therapeutic committees and policy makers, because adverse effects complicate the course of diseases in aged patients, cause hospitalisation and/or require the prescription of additional drugs. In addition to contributing to a reduction in healthcare costs, continuous efforts to promote rational drug use could also benefit elderly patients by preventing some avoidable drug toxicity.

CONCLUSION

A significant prevalence of ADRs was found among hospitalised elderly people. The risk factors associated with ADRs in this population included use of drugs considered to be inappropriate for that population, number of previous diagnoses and number of administered drugs. More appropriate drug prescription could avoid part of this burden of disease by minimising preventable ADRs.

Adverse Drug Reaction-Related Hospitalisations

BACKGROUND

The incidence of adverse drug reaction (ADR)-related hospitalisations has usually been assessed within hospitals. Because of the variability in results and methodology, it is difficult to extrapolate these results to a national level.

OBJECTIVES

To evaluate the incidence and characteristics of ADR-related hospitalisations in The Netherlands in 2001.

METHODS

We conducted a nationwide study of all hospital admissions in 2001. Data were retrieved from a nationwide computer database for hospital discharge records. All acute, non-planned admissions to all Dutch academic and general hospitals in 2001 were included in the study (n = 668 714). From these admissions we selected all hospitalisations that were coded as drug-related, but intended forms of overdose, errors in administration and therapeutic failures were excluded. Hence, we extracted all ADR-related hospitalisations. We compared age, sex and the risk of a fatal outcome between patients admitted with ADRs and patients admitted for other reasons, as well as the most frequent main diagnoses in ADR-related hospitalisations and which drugs most frequently caused the ADRs. In addition, we evaluated to what extent these ADRs were reported to the Netherlands Pharmacovigilance Centre Lareb for spontaneous ADR reporting.

RESULTS

In 2001, 12 249 hospitalisations were coded as ADR related. This was 1.83% of all acute hospital admissions in The Netherlands (95% CI 1.80, 1.86). The proportion increased with age from 0.8% (95% CI 0.75, 0.85) in the <18 years group to 3.2% in the >/=80 years group (95% CI 3.08, 3.32). The most frequent ADR-related diagnoses of hospitalisations were bleeding (n = 1048), non-specified 'unintended effect of drug' (n = 438), hypoglycaemia (n = 375) and fever (n = 347). The drugs most commonly associated with ADR-related hospitalisations were anticoagulants (n = 2185), cytostatics and immunosuppressives (n = 1809) and diuretics (n = 979). Six percent of the ADR-related hospitalisations had a fatal outcome (n = 734). Older age and female gender were associated with ADR-related hospitalisations. Only approximately 1% of the coded ADRs causing hospitalisation were reported to our national centre for spontaneous ADR reporting.

CONCLUSION

The proportion of ADR-related hospitalisations is substantial, especially considering the fact that not all ADRs may be recognised or mentioned in discharge letters. Under-reporting of ADRs that result in hospital admission to our national centre for spontaneous ADR reporting was considerable.

Perception of potentially inappropriate medication in elderly patients by Slovak physicians

PURPOSE

The aim of the present study was to determine the risk perception of potentially inappropriate drug treatment of elderly patients by Slovak physicians. In Slovakia, a list of such drugs is not available.

METHODS

The study sample consisted of 600 patients aged > or =65 years hospitalized at the Department of Internal Medicine in a Slovak general hospital between 1 December 2003 and 31 March 2005. The use of potentially inappropriate drugs at the time of hospital admission and discharge was compared. Potentially inappropriate drug use was defined by Beers 2003 criteria. In addition, 206 physicians were asked to mark the drugs that they considered potentially inappropriate for elderly patients out of a list provided in a questionnaire analysis.

RESULTS

Out of 600 patients 20.2% and 20% were treated with at least one potentially inappropriate drug at the time of hospital admission and discharge, respectively. Hospitalization had no significant influence on the number of potentially inappropriate medicines used. The most frequently prescribed potentially inappropriate drugs were digoxin >0.125 mg/day and ticlopidine. Out of 206 responding physicians only 4.9% considered ticlopidine as potentially inappropriate for elderly patient. On the other hand, more than 20% of respondents were aware of the potential inappropriateness of amitriptyline, diazepam and chlordiazepoxide. Mentioned drugs were observed in less than 2% of study population (n = 600).

CONCLUSIONS

The results of the questionnaire analysis in physicians as well as the prevalence of potentially inappropriate medication demonstrate that Slovak clinicians are aware of the risk of certain treatments in elderly patients.

The Effect of Direct-to-Consumer Advertising on Prescription Drug Use by Older Adults

BACKGROUND AND OBJECTIVE

Although older adults are frequent consumers of prescription drugs and increasingly the intended audience of direct-to-consumer advertising (DTCA) marketing efforts, little is known about the effect of DTCA on older adults' prescription drug-seeking behaviour. In response, the objective of this study is to examine factors associated with requesting a prescription drug from a physician following exposure to DTCA among older adults, and whether the drug or other medical treatment was prescribed during the encounter.

METHODS

A secondary data analysis of the "Public Health Impact of Direct-to-Consumer Advertising of Prescription Drugs", a data set publicly available through the Inter-university Consortium for Political and Social Research (ICPSR 3687), was conducted. For the purposes of this study, only those respondents who indicated that they had been exposed to DTCA (n = 2601) were included in the study sample. Using a two-step weighted logistic regression approach, separate models were estimated to examine first, whether a request for the advertised drug was made following exposure to DTCA and secondly, the outcomes of any patient-physician encounters that occurred following exposure to DTCA.

RESULTS

Descriptive analysis of the outcome variables revealed that, among respondents exposed to DTCA, 31% (n = 801) requested a prescription drug from their physician. Approximately 5% of those who made a request were > or =75 years of age. Among respondents requesting a prescription drug, 69% (n = 556) received a prescription in response to their request, of whom, approximately 5% were > or =75 years of age. Multivariate findings suggest that although adults > or =75 years of age are less likely to request a prescription drug following exposure to DTCA (odds ratio [OR] = 0.58; p = 0.032), when they do approach their physicians, they are more likely to receive recommendations for further treatment, with ORs indicating a 250% (OR = 3.507; p = 0.002) increase in the odds of further referral among adults > or =75 years of age.

CONCLUSION

Overall, results from the study suggest that DTCA influences the patient-doctor relationship and prescription drug acquisition behaviour of patients; however, the nature of the effect of DTCA on older adults is complex. Because future cohorts of older adults may be more comfortable about requesting prescription drugs and the consumer-driven approach to obtaining medical care, understanding the impact of DTCA on older consumers represents an important area for further inquiry.

Mechanistic basis of adverse drugreactions: the perils of inappropriate dose schedules

Adverse drug reactions (ADRs) have long been recognised as a significant cause of morbidity and mortality. They account for a substantial number of clinical consultations, hospital admissions and extended duration of in-patient stay as well as mortality. By far the most common ADRs are the concentration-dependent pharmacological reactions, the majority of which ought to be preventable. As a result of high concentrations of the parent drug and/or its metabolite(s), there is an augmentation of primary pharmacological activity and/or appearance of new and undesirable secondary pharmacological activity. Typically, these high concentrations result from administration of high doses in an attempt to maximise efficacy and/or modulation of the pharmacokinetics of a drug by either genetic or non-genetic factors. High plasma concentrations of parent drug may result from inherited impairment or drug-induced inhibition of its pharmacokinetic disposition. Conversely, inherited overcapacity or drug-induced induction of the metabolism of a drug may result in low concentrations of parent drug and frequently, rapid accumulation of its metabolites. Environmental, dietary and phytochemical factors may also influence the activity of drug metabolising enzymes. As with inherited polymorphisms of acetylation and cytochrome P450-based drug metabolising enzymes, polymorphisms of other conjugation reactions, such as glucuronidation, increasingly appear to be associated with drug toxicity. Diseases of organs involved in elimination of a drug also alter its pharmacokinetics, plasma concentration and, therefore, the profile of its concentration-dependent ADRs. Inherited mutations, concurrently administered drugs or presence of certain diseases may also alter the sensitivity of some pharmacological targets, accounting for a substantial number of ADRs and interactions. When there is enhanced pharmacodynamic sensitivity, plasma drug concentrations that are apparently within the normal 'non-toxic' range give rise to ADRs. Recent advances have also provided important insights into the wider scope of drug-drug interactions. Interactions that occur at P-glycoproteins, drug transporters and efflux pumps, at various transmembrane interfaces such as the gastrointestinal wall, renal tubules, hepatobiliary border and blood-brain barrier, are beginning to explain many non-metabolic interactions. These alter the systemic exposure to drugs and have so far, begun to explain unexpected neurotoxicity and hepatotoxicity. The function of these transporters is also genetically modulated. These advances, together with continued increased awareness and education of prescribers and pharmacists, offer great opportunities for substantially minimising concentration-related ADRs.

Pharmaceutical care, European developments in concepts, implementation, teaching, and research: a review

This article discusses the concept of pharmaceutical care especially from the European perspective. It tries to clarify the current status of pharmaceutical care research and implementation, and if and how it can be part of the practice of pharmacy. Pharmaceutical care basically means improving the medication use process in order to improve outcomes, including the patients' quality of life, and that involves a focus change for pharmacy from product to patient. This change in focus also implies that the pharmacy curriculum should be adapted, in order for the pharmacist to be able to acquire new knowledge and skills. In most countries this change currently is taking place but not in very deliberate or structured manner. Some basic decisions have to be made, in order to guarantee that every patient receives pharmaceutical care when needed.

Drug-related problems in hospitalized patients on polypharmacy: the influence of age and gender

BACKGROUND

Drug-related problems (DRPs) have been shown to prevail in hospitalized patients, and polypharmacy and increasing age have been identified as two important risk factors.

OBJECTIVE

We investigated the occurrence of DRPs and adverse drug reactions (ADRs) amongst hospitalized patients prescribed polypharmacy, and the association of advanced age and female gender.

METHOD

A retrospective cross-sectional study was performed in an acute-care hospital in Singapore. Only patients prescribed polypharmacy were included. Mann-Whitney test was used to test for significant difference between the age and gender of patients and their risk of acquiring DRPs. The relative risks of developing DRP and ADR for geriatric patients and female patients were estimated.

RESULTS

Of 347 patients prescribed polypharmacy (43% female and 58.2% geriatrics), no statistical correlations were observed between age and gender with developing DRPs. An increased number of medications was associated with higher risk for patients with DRPs on admission (p = 0.001), but not for inpatients with DRPs (p = 0.119). Results from patients with ADRs showed that the relative risk (RR) of geriatrics prescribed polypharmacy and major polypharmacy (10 and more drugs) were 1.01 and 1.23, respectively. Female patients had a RR of 0.79 compared with male patients in developing ADRs.

CONCLUSION

Results showed that among patients with polypharmacy, age and gender may not be as important as number of drugs prescribed as predictors of experiencing a DRP. A similar trend was observed in the development of ADRs.

Patients’ role in reporting adverse drug reactions

This review discusses the involvement of patients in the reporting of adverse drug reactions (ADRs). Patients benefit from drugs but also experience their adverse effects. Since concerns about the safety of drugs are also patients' concerns, the patient could also play a part in decreasing the risks of drug therapy. Patient interest in the safety aspects of drugs is evident. At an international level, the merits of patient reports are being considered. To date, the literature does not yet provide any actual results in relation to the detection of ADRs by patients. Different considerations regarding ADR reporting by patients are discussed. The authors conclude that we should positively value patients' involvement in drug therapy and their concern regarding possible adverse effects. As a consequence, patients' reports on ADRs should be accepted.

Problemas de salud relacionados con los medicamentos en un servicio de urgencias hospitalario

BACKGROUND AND OBJECTIVE

Medication-related problems (MRPs) are health problems resulting from patient pharmacotherapy failure that interfere with the expected outcome in the patient's health status. The aim of this study was to discover the health problems associated with the appearance of MRPs.

PATIENTS AND METHOD

Patient interviews, together with the assessment of medical records were the sources of information used in the assessment and identification of MRPs. A validated questionnaire was used for the interviews; in order to classify the health problems found, the ICD-9 was used.

RESULTS

2,556 patients were interviewed over a period of one year at a hospital emergency department. 2,261 of these cases were valid. Osteoarticular diseases, poorly defined signs and symptoms of illness, injuries and intoxications were the disorders most commonly associated with the appearance of MRPs. MRPs of necessity and effectiveness had a similar profile. MRPs of safety were more commonly associated with poorly defined signs and symptoms of illness, injuries and intoxications, as well as nervous, digestive and blood problems.

CONCLUSIONS

Most frequent medication related health problems causing visits to hospital emergency departments were osteoarticular disorders, followed by poorly defined signs and symptoms of illness. Differences were observed in the diagnoses between the different dimensions and types of MRP.

Physicians??? Attitudes and Adverse Drug Reaction Reporting

OBJECTIVES

Voluntary adverse drug reaction (ADR) reporting is fundamental to medical drug safety surveillance; however, substantial under-reporting exists and is the main limitation of the system. This study sought to identify the knowledge- and attitude-related factors associated with ADR reporting by physicians in Northern Portugal.

METHODS

Case-control study covering a population of National Health Service medical practitioners. The 88 cases comprised physicians who had reported at least one ADR to the drug surveillance unit from the year 2000 to the date of enrolment in the study. The 771 controls were randomly selected from among the remaining physicians. All interviews were conducted using a self-administered questionnaire. Knowledge and attitudes regarding spontaneous ADR reporting were based on Inman's 'seven deadly sins'. Agreement with the questions included in the questionnaire was measured using a horizontal, continuous visual analogue scale, which was unnumbered. Recorded answers were read in a range from zero (total disagreement) to ten (total agreement). We used logistic regression to determine the ADR reporting adjusted odds ratio (ORadj) for a change in exposure corresponding to the interquartile range for each attitude.

RESULTS

A total of 397 questionnaires were received from 731 eligible practitioners (54.3%). Physicians who worked in primary versus hospital care (ORadj 7.74 [95% CI 1.85, 32.30]) and in general medicine (ORadj 1.05 [95% CI 0.30, 3.69]) versus medical specialities were more likely to report ADRs. In contrast, physicians working in the medical-surgical/surgical fields were significantly less likely to report ADRs compared with medical specialists (ORadj 0.10 [95% CI 0.02, 0.46]). Attitudes to ADRs were strongly associated with reporting probability. Hence, an interquartile decrease in any of the following attitudes increased the probability of reporting by: (i) 87% (p < 0.05) for complacency (the belief that really serious ADRs are well documented by the time a drug is marketed); (ii) 109% (p < 0.01) for insecurity (the belief that it is nearly impossible to determine whether a drug is responsible for a particular adverse reaction); (iii) 143% (p < 0.001) for diffidence (the belief that one would only report an ADR if one were sure that it was related to the use of a particular drug); (iv) 220% (p < 0.001) for indifference (the belief that the one case an individual doctor might see could not contribute to medical knowledge); and (v) 71% (p < 0.05) for ignorance (the belief that it is only necessary to report serious or unexpected ADRs).

CONCLUSION

This study shows that there are attitudes strongly associated with under-reporting. The implementation of purpose-designed educational interventions based on the attitudes identified in this study may serve to improve reporting substantially.

The Association of Inappropriate Drug Use with Hospitalisation and Mortality

BACKGROUND AND OBJECTIVE

Inappropriate prescribing is an important and possibly preventable risk factor for adverse drug reactions (ADRs) in the elderly, and hospital-based studies have shown that a large proportion of admissions is a result of ADRs. However, little is known about how inappropriate drug use (IDU) affects the elderly at the population level. The aim of this study was to explore possible associations of IDU with acute hospitalisation and mortality in an elderly population during 3 years of follow-up.

PATIENTS AND METHODS

Data from a rural, population-based, longitudinal cohort study within the Kungsholmen Project, Sweden, were used. 785 participants, > or=75 years of age, had complete data on drug use and selected covariates collected during baseline investigation from 1995 to 1998, and were included in the study. Hospitalisation and mortality data during 3 years after inclusion were collected. IDU was assessed at baseline using consensus-based criteria applicable to available data (derived from Beers' criteria, Canadian criteria and clinical indicators of drug-related morbidity in older adults) with the addition of potentially dangerous drug duplication and additional potentially hazardous drug-drug interactions. IDU was defined as presence of at least one inappropriate drug regimen according to the study criteria. Logistic regression and proportional hazard models were used, respectively, to study the association of IDU with hospitalisation and mortality.

RESULTS

Drugs were used on a regular or 'as needed' basis by 91.6% of the study population, with a mean of 4.4 drugs per person. IDU was common, with a prevalence of 18.6% and was associated with increased risk of at least one acute hospitalisation in community-living elderly, after adjustment for age, sex, education, comorbidity, dependency in activities of daily living (ADL) and smoking. The odds ratio was 2.72 (95% CI 1.64, 4.51). No association with mortality was found, after adjustment for age, sex, housing, education, comorbidity, ADL-dependency, smoking and body mass index.

CONCLUSION

Polypharmacy and IDU are common among the elderly and IDU is associated with acute hospitalisation in community-living elderly. Although causality cannot be established with this study design, the results are consistent with the high prevalence of drug-related hospital admissions found in hospital-based studies. Our results indicate that it is desirable with current knowledge, to reduce IDU through information to physicians and careful prescribing.

Frequency and risk factors of potentially inappropriate medication use in a community-dwelling elderly population: results from the 3C Study

OBJECTIVE

To estimate the frequency of potentially inappropriate medication use among community-dwelling elderly subjects and to identify socio-demographic factors associated with this use.

METHODS

Data were collected in the Three-City Study, a French longitudinal study on vascular factors and cognitive decline. The study population was composed of 9,294 subjects aged 65 years and older, living in the community. Inappropriate medication use was assessed using a list derived from the Beers criteria by a panel of French experts.

RESULTS

Nearly 40% of the participants used at least one potentially inappropriate medication: 23.4% used cerebral vasodilators, 9.2% long-acting benzodiazepines and 6.4% drugs with anticholinergic properties. Excluding cerebral vasodilators from the list, the frequency of potentially inappropriate medication use was 21.7%. This use was significantly more frequent among women, older subjects and poorly educated subjects. Adjusted analyses showed that these associations could not be explained by a confounding effect of medical factors. Compared with 13.0% of men with a high educational level, 27.9% of women with a low educational level used at least one potentially inappropriate medication (odds ratio=2.0; 95% confidence interval: 1.7-2.3).

CONCLUSION

This study is the first attempt to evaluate the frequency of potentially inappropriate medication use in the elderly French population. Female gender and low socio-economic characteristics reduced the chances of receiving optimal pharmacotherapy. The proportion of elderly subjects receiving potentially inappropriate medication was higher than shown in previous studies. This is mainly explained by differences in the use of cerebral vasodilators.

[When is expensive pharmacotherapy good value for the money?]

Expensive drugs are good value for money if they are effective and safe, and if they have a better cost-effectiveness ratio than the standard therapy. In this article, an overview of commonly used methods, sources and functions of health economic evaluation is presented and illustrated using clinical examples to facilitate interpretation of the health economic information.

Adverse drug reactions as cause of admission to hospital: prospective analysis of 18 820 patients

OBJECTIVE

To ascertain the current burden of adverse drug reactions (ADRs) through a prospective analysis of all admissions to hospital.

DESIGN

Prospective observational study.

SETTING

Two large general hospitals in Merseyside, England.

PARTICIPANTS

18 820 patients aged > 16 years admitted over six months and assessed for cause of admission.

MAIN OUTCOME MEASURES

Prevalence of admissions due to an ADR, length of stay, avoidability, and outcome.

RESULTS

There were 1225 admissions related to an ADR, giving a prevalence of 6.5%, with the ADR directly leading to the admission in 80% of cases. The median bed stay was eight days, accounting for 4% of the hospital bed capacity. The projected annual cost of such admissions to the NHS is 466m pounds sterling (706m Euros, 847m dollars). The overall fatality was 0.15%. Most reactions were either definitely or possibly avoidable. Drugs most commonly implicated in causing these admissions included low dose aspirin, diuretics, warfarin, and non-steroidal anti-inflammatory drugs other than aspirin, the most common reaction being gastrointestinal bleeding.

CONCLUSION

The burden of ADRs on the NHS is high, accounting for considerable morbidity, mortality, and extra costs. Although many of the implicated drugs have proved benefit, measures need to be put into place to reduce the burden of ADRs and thereby further improve the benefit:harm ratio of the drugs.

Comparison of Drug-Related Problems in Different Patient Groups

BACKGROUND:

There is a lack of knowledge concerning how drug-related problems (DRPs) vary in different patient groups. Possible dissimilarities need to be taken into consideration when guidelines for detecting and preventing DRPs are compiled.

OBJECTIVE:

To characterize and compare the frequency and categories of DRPs in different groups of hospitalized patients.

METHODS:

Patients admitted to 4 different types of departments at 5 hospitals in Norway were included consecutively. Medical records and information acquired at multidisciplinary morning meetings were sources for assessing the patients' DRPs.

RESULTS:

A total of 827 patients were included. Mean age was 70.8 years, 58.6% were female, and 81% had at least one DRP. An average of 1.9, 2.0, 2.1, and 2.3 DRPs per patient were found in the departments of cardiology, geriatrics, respiratory medicine, and rheumatology, respectively. Significant differences in the type of DRPs between the patient groups were found. The most frequent DRPs and the patient group in which they most often occurred were nonoptimal dose (cardiology, respiratory, geriatric) and need for additional drug (rheumatology).

CONCLUSIONS:

DRPs occurred in the majority of the patients in all departments. The type of DRP differed markedly between the patient groups. Knowledge of these differences is clinically valuable by enabling us to guide efforts toward prevention of DRPs. Antithrombotic agents, loop diuretics, angiotensin-converting enzyme inhibitors, penicillins, antiinflammatory drugs, and opioid analgesics commonly caused DRPs, even in departments where knowledge of these drugs is assumed to be extensive.

Adverse drug reactions in elderly patients

Many studies from around the world show a correlation between increasing age and adverse drug reaction (ADR) rate, at least for some medical conditions. More than 80% of ADRs causing admission or occurring in hospital are type A (dose-related) in nature, and thus predictable from the known pharmacology of the drug and therefore potentially avoidable. Frail elderly patients appear to be particularly at risk of ADRs and this group is also likely to be receiving several medicines. The toxicity of some drug combinations may sometimes be synergistic and be greater than the sum of the risks of toxicity of either agent used alone. In order to recognize and to prevent ADRs (including drug interactions), good communication is crucial, and prescribers should develop an effective therapeutic partnership with the patient and with fellow health professionals. Undergraduate and postgraduate education in evidence-based therapeutics is also vitally important. The use of computer-based decision support systems (CDSS) and electronic prescribing should be encouraged, and when problems do occur, health professionals need to be aware of their professional responsibility to report suspected adverse drug events (ADEs) and ADRs. "Rational" or "obligatory" polypharmacy is becoming a legitimate practice as increasing numbers of individuals live longer and the range of available therapeutic options for many medical conditions increases. The clear risk of ADRs in this situation should be considered in the context that dose-related failure of existing therapy to manage the condition adequately may be one of the most important reasons for admission of the elderly to hospital. Thus, age itself should not be used as a reason for withholding adequate doses of effective therapies.

Therapy related hospital admission in patients on polypharmacy in Singapore: a pilot study

OBJECTIVE

To estimate the incidence of drug-related problems (DRPs)-associated hospital admission, and its correlation to polypharmacy and age.

METHOD

A retrospective, cross-sectional study in in-patients on polypharmacy in Singapore. Significant differences (P < 0.05) between number of medications taken and age of patients were tested with the chi-square test.

RESULTS

The study population consisted of 347 patients (aged 16-97) on a mean of 7.4 +/- 2.1 medications. 10.8% of the study population had DRPs on admission: 71.9% of which were dominant reasons for admission, and DRPs contributed partly in the remaining cases. These DRPs were mostly avoidable, and can be broadly classified into non-compliance, adverse drug reactions, require synergistic therapy, inappropriate dose and untreated condition. 52% of these cases were made up of geriatric patients. No statistical difference was found between patients on polypharmacy and those on major polypharmacy (10 and more drugs) in having a DRP.

CONCLUSION

In this study, DRPs contributing to hospital admission appeared to be avoidable. Geriatrics were more susceptible to DRPs and future efforts are required in managing medications prescribed for these patients to reduce such incidences.

Investigation into the reasons for preventable drug related admissions to a medical admissions unit: observational study

OBJECTIVE

To describe the drugs and types of medicine management problems most frequently associated with preventable drug related admissions to an acute medical admissions unit.

DESIGN

Observation study.

SETTING

Medical admissions unit in a teaching hospital in Nottingham, UK.

PARTICIPANTS

4093 patients seen by pharmacists on the medical admissions unit between 1 January and 30 June 2001.

MAIN OUTCOME MEASURES

Proportion of admissions that were drug related and preventable, classification of the underlying causes of preventable drug related admissions, and identification of drugs most commonly associated with preventable drug related admissions.

RESULTS

Of the admissions seen by pharmacists, 265 (6.5%) were judged to be drug related and 178 (67%) of these were judged to be preventable. Preventable admissions were mainly due to problems with prescribing (63 cases (35%)), monitoring (46 cases (26%)), and adherence to medication (53 cases (30%)). The drugs most commonly implicated were NSAIDs, antiplatelets, antiepileptics, hypoglycaemics, diuretics, inhaled corticosteroids, cardiac glycosides, and beta-blockers.

CONCLUSIONS

Potentially preventable drug related morbidity was associated with 4.3% of admissions to a medical admissions unit. In 91% of cases these admissions were related to problems with either prescribing, monitoring, or adherence.