Epidemiology of adverse drug events in the nursing home setting

Evidence of oxidative injury during aging of the liver in a mouse model

The aim of the present study was to determine whether oxidative stress contributes to aging of the liver in a mouse model. Liver was obtained from young (3-5 months old) and aged (18-24 months old) mice. No age-induced gross changes in liver morphology were detected by light microscopy. Apoptosis was measured using the fragment end labeling of DNA for the immunohistochemical identification of the apoptotic nuclei. The total apoptotic cells represented 1% of the total cells in livers of young mice and 8% in those of aged mice. Among the total apoptotic cells in livers of aged animals, 15% were hepatocytes, 40% sinusoidal endothelial cells, and 45% bile duct cells. Hepatic lipid peroxidation, expressed as malonaldehyde levels, protein oxidation, measured by protein carbonyl content, and DNA oxidation, measured as 8-hydroxy-2'-deoxyguanosine (oxo(8)dG), were significantly increased in the livers of aged animals as compared to younger mice. The apoptotic cells presented elevated levels of oxidized DNA, detected by immunohistochemistry using an antibody directed against oxo(8)dG in serial sections. These results suggest that livers of aged animals presents evidence of increased oxidative injury and apoptosis. Because the apoptotic cells in the aged livers are mostly bile duct cells and sinusoidal endothelial cells, the cells most sensitive to oxidative stress injury, it can be hypothesized that reactive oxygen species-induced apoptosis in these cells contributes to the aging of the liver.

Occurrence of potential drug-drug interactions in nursing home residents

Objective

It has been suggested that elderly people are at increased risk of drug-related problems such as drug-induced adverse effects, drug-drug interactions and drug-disease interactions. This is particularly the case for nursing home residents because of the often complicated and multiple co-morbidity that occurs in these people. The aim of this study was to develop prescribing indicators to assess systematically the occurrence and nature of potential drug-drug interactions (DDIs) in a cohort of Dutch nursing home residents.

Method

The study was conducted in residents aged 65 years and over in six nursing homes (n=2,355, two-year study period). Computerised medication data for the residents were evaluated with respect to co-prescribing of potentially interacting drugs. All DDIs that were classified as clinically relevant according to the Dutch National Drug Interaction Database were studied. DDIs were classified into three categories according to their pharmacological mechanism: 1 — pharmacokinetic interactions at the level of gastrointestinal (GI) absorption; 2 — pharmacokinetic interactions at the level of metabolism and excretion; and 3 — pharmacodynamic interactions.

Key findings

Thirty-two per cent (n=748) of all residents were exposed to one or more combinations of drugs that could lead to clinically adverse outcomes. The numbers of residents who received drug combinations with a mechanism of interaction from category 1, 2 or 3 were 73 (3 per cent), 164 (7 per cent) and 612 (26 per cent) respectively. The number of medications prescribed was significantly associated with the occurrence of a potential DDI (P<0.05). Drugs most frequently involved were oral anticoagulants, antibiotics and theophylline.

Conclusion

During the two-year study period, about one-third of the residents were exposed to at least one drug interaction considered clinically relevant. Adequate surveillance systems are needed to enable better identification of these interactions with a view to preventing potential clinical problems. Using the prescribing indicators developed in this study, such surveillance could focus on detection and clinical aspects of potential DDIs and possible alternative treatments.

The elderly as a sensitive population in environmental exposures: making the case

The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.

Assessing multiple medication use with probabilities of benefits and harms

OBJECTIVE

A quantitative framework to assess harms and benefits of candidate medications in the context of drugs that a patient is already taking is proposed.

METHOD

Probabilities of harms and benefits of a given medication are averaged to yield a utility value. The utility values of all medications under consideration are combined as a geometric mean to yield an overall measure of favorability. The grouping of medications yielding the highest favorability value is chosen.

RESULTS

Five examples of choosing between widely used candidate medications demonstrate the feasibility of the proposed framework.

DISCUSSION

The framework proposed provides a simple method for considering the trade-offs involved in prescribing multiple medications. It can be adapted to include additional parameters representing severity of condition, prioritization of outcomes, patient preferences, dosages, and medication interactions. Inconsistent reporting in the medical literature of data about benefits and harms of medications, dosages, and interactions constitutes its primary limitation.

Is dementia special care really special? A new look at an old question

OBJECTIVES

To quantify differences in care provided to nursing home (NH) residents with dementia living on and off dementia special care units (SCUs).

DESIGN

Cross-sectional study using propensity score adjustment for resident and NH characteristics.

SETTING

Free-standing NHs in nonrural U.S. counties that had an SCU in 2004 (N=1,896).

PARTICIPANTS

Long-stay (> or = 90 days) NH residents with a diagnosis of Alzheimer's disease or dementia and at least moderate cognitive impairment (N=69,131).

MEASUREMENTS

Resident-level NH care processes such as physical restraints, bed rails, feeding tubes, psychotropic medications, and incontinence care.

RESULTS

There was no difference in the use of physical restraints (adjusted odds ratio (AOR)=0.94, 95% confidence interval (CI)=0.79-1.11), but SCU residents were less likely to have had bed rails (AOR=0.55, 95% CI=0.46-0.64) and to have been tube fed (AOR=0.36, 95% CI=0.30-0.43). SCU residents were more likely to be on toileting plans (AOR=1.23, 95% CI=1.08-1.39) and less likely to use pads or briefs in the absence of a toileting plan (AOR=0.73, 95% CI=0.61-0.88). SCU residents were more likely to have received psychotropic medications (AOR=1.23, 95% CI=1.05-1.44), primarily antipsychotics (SCU=44.9% vs non-SCU=30.0%).

CONCLUSION

SCU residents received different care than comparable non-SCU residents. Most strikingly, SCU residents had greater use of antipsychotic medications.

Prävention unerwünschter Arzneimittelwirkungen bei älteren Patienten

Adverse drug reactions are among the most common adverse events and a significant cause of preventable morbidity and mortality. As multimorbidity and polypharmacy are frequent in this population, the elderly are at special risk for adverse drug events, although the calendar age has not been proved as independent risk factor in this context. In particular falls and delirium are clinically significant and typical adverse drug events in the elderly. In this review mechanisms and factors which determine adverse drug re actions are described, and possible strategies for an effective prevention are given. This covers pharmacokinetic, pharmacogenetic and pharmacodynamic aspects as well as factors influencing individual adherence to drug therapy. A significant portion of adverse drug reaction may be prevented by a thorough indication and prudent monitoring of pharmacotherapy. Also adherence to pharmacotherapy may be improved by tailored and individual means referring to the patient's needs and expectancies. In the elderly functional limitations such as reduced cognitive abilities, reduced visual acuity and impaired dexterity determine an ineffective pharmacotherapy and medication errors. Hereby these functional limitations are significant predictors of adverse drug events in the context of self-management of pharmacotherapy. Testing of functional abilities as provided in the geriatric assessment is helpful to identify these factors. Among altered pharmacokinetic factors in the elderly, reduced renal function is most important to avoid overdosage. Although a precise measurement of renal function is not possible in a bed-side manner, an estimation of actual renal function utilizing estimation-formulas should always take place.

Adverse drug events in cognitively impaired elderly patients

BACKGROUND/AIMS

Adverse drug events (ADEs) are a frequent problem encountered in the elderly. The aim of this study was to elucidate the factors that influence ADEs in an elderly population with cognitive impairment.

METHODS

242 patients were recruited from dementia clinics and assessed after 6 months for ADEs. The use of natural health products (NHPs) was also documented.

RESULTS

Backward logistic regression found that higher age (OR = 1.06; 95% CI 1.01-1.12), and greater cognitive impairment (OR = 0.94; 95% CI 0.90-0.98) were associated with an increased risk of developing an ADE while the use of NHPs (OR = 0.32; 95% CI 0.13-0.79) was associated with a decreased risk (chi(2) = 27.6, p < 0.001).

CONCLUSION

Risk of ADEs increased with greater age and cognitive impairment but decreased with the use of NHPs.

Epidemiology of medication-related adverse events in nursing homes

BACKGROUND

Nursing home residents are prescribed more medications than patients in any other clinical setting. Although pharmacotherapy for older nursing home residents is usually safe and effective, it can lead to medication-related adverse events such as adverse drug reactions (ADRs), adverse drug withdrawal events (ADWEs), and therapeutic failures (TFs).

OBJECTIVE

This article reviews the descriptive (incidence) and analytic (risk factor) epidemiology of medication-related adverse events occurring in nursing home residents as reported in the literature during the last 2 decades.

METHODS

A search of MEDLINE and International Pharmaceutical Abstracts was conducted for articles published in English between January 1986 and July 2006 using the following terms: adverse drug events, adverse drug reactions, adverse drug withdrawal events, aged, drug therapy, drug-related problems, medication-related problems, nursing homes, therapeutic failures, and treatment failures. The reference lists of identified articles, recent review articles, book chapters, and the authors' reference library were also searched manually.

RESULTS

Seven studies met the inclusion and exclusion criteria and were included in this review. Five studies described ADRs, 1 described ADWEs, and 1 described TFs. The studies of ADRs used different methods of detecting ADRs, resulting in incidence rates ranging from 1.19 to 7.26 per 100 resident-months. The single study of ADWEs reported an incidence of 2.60 per 100 resident-months. An incidence rate for the single study describing TFs could not be calculated.

CONCLUSIONS

Medication-related adverse events are common in the nursing home setting. Additional studies are needed to enhance the detection and prevention of medication-related adverse events and to reduce their impact on residents' outcomes and health care costs.

Prevalence of insomnia and its associated factors in elderly long-term care residents

Insomnia is a significant problem that may jeopardize elderly residents' quality of life in long-term care settings. However, there are only a few studies dealing with sleeping disturbances among nursing home residents. The goal of this study was to determine the prevalence of insomnia and its associated factors in nursing home residents. A cross-sectional study (n=2332) was conducted among seniors living in long-term care facilities. The findings indicate that 144 (6.2%) participants had an insomnia disorder according to DSM-IV criteria, 17% displayed at least one symptom of insomnia, and more that half of the subjects were benzodiazepine users. According to multivariate analysis, psychological distress (adjusted odds ratio=1.51) and disruptive behaviors (adjusted odds ratio=2.10) were the only factors associated with an insomnia disorder among this population. In conclusion, insomnia is a fairly important problem, as a symptom or a syndrome, among elderly people and deserves attention from caregivers. Alternative interventions to benzodiazepine drugs, which are suited to long-term care residents while tailored to these specific care settings, should be developed.

Ambulatory Care Visits for Treating Adverse Drug Effects in the United States, 1995–2001

BACKGROUND

Adverse d[rug events (ADEs) are a well-recognized patient safety 4concern, but their magnitude is unknown. Ambulatory viisits for treating adverse drug effects (VADEs) as recordeed in national surveys offer an alternative way to estimatte the national prevalence of ADEs because each VA]DE indicates that an ADE occurred and was seriousenough to require care.

METHODS

A nationallyrepresentative sample of visits to physician offices, hospital outpatient departments, and emergency departments was analyzed. VADEs were identified as tthe first-listed cause of injury.

RESULTS

In 2001, there Awere 4.3 million VADEs in the United States, averaging 15 visits per 1,000 population. VADE rates at physicianoffices, hospital outpatient departments, and hospittal emergency departments were at 3.7, 3.4, and 7.3 lper 1,000 visits, respectively. There was an upward tr'end in the total number of VADEs from 1995 to 2001 ((p < .05), but the increases in VADEs per 1000 visits an.d per 1,000 population were not statistically significant. VADEs were lower in children younger than 15 and higher in the elderly aged 65-74 than in adults aged 225-44 (p < .01) and were more frequent in females than irn males (p < .05).

DISCUSSION

Although methodologically conservative, the study suggests that ADEs are a significant threat to patient safety in the United States.

Aging biology and geriatric clinical pharmacology

Population aging evokes doomsday economic and sociological prognostication, despite a minority of older people suffering significant dependency and the potential for advances in therapeutics of age-related disease and primary aging. Biological aging processes are linked mechanistically to altered drug handling, altered physiological reserve, and pharmacodynamic responses. Parenteral loading doses need only be adjusted for body weight as volumes of distribution are little changed, whereas oral loading doses in some cases may require reduction to account for age-related increases in bioavailability. Age-related reduction of hepatic blood flow and hepatocyte mass and primary aging changes in hepatic sinusoidal endothelium with effects on drug transfer and oxygen delivery reduce hepatic drug clearance. Primary renal aging is evident, although renal clearance reduction in older people is predominantly disease-related and is poorly estimated by standard methods. The geriatric dosing axiom, "start low and go slow" is based on pharmacokinetic considerations and concern for adverse drug reactions, not from clinical trial data. In the absence of generalizable dosage guidelines, individualization via effect titration is required. Altered pharmacodynamics are well documented in the cardiovascular system, with changes in the autonomic system, autacoid receptors, drug receptors, and endothelial function to modify baseline cardiovascular tone and responses to stimuli such as postural change and feeding. Adverse drug reactions and polypharmacy represent major linkages to avoidable morbidity and mortality. This, combined with a deficient therapeutic evidence base, suggests that extrapolation of risk-benefit ratios from younger adults to geriatric populations is not necessarily valid. Even so, therapeutic advances generally may convert healthy longevity from an asset of fortunate individuals into a general social benefit.

What do we know about medication errors in inpatient psychiatry?

BACKGROUND

Adverse drug events (ADEs) have been implicated as a cause of substantial morbidity and mortality. Psychiatrists have successfully characterized one category of ADE--adverse drug reactions (ADRs), which have been studied from a medication-specific psychopharmacology frame of reference. The literature on ADEs, both preventable and nonpreventable, was reviewed within the broader patient safety framework.

METHODS

English-language studies involving ADEs and medication errors in psychiatry for 1996 through 2003 were identified on MEDLINE and by using a hand search of bibliographies.

RESULTS

Few reports on the incidence and characteristics of medication errors in psychiatric hospitals could be found. Psychiatrists may not be sufficiently aware of the harm caused by errors, methodological issues regarding error detection, the validity of reported medication error rates, and the challenge of creating a nonpunitive error-reporting culture. PREVENTION STRATEGIES: Application of a systems-oriented approach to ADE reduction and the promotion of a nonpunitive culture are essential. Clinical and pharmacy staff could monitor the literature for published reports of preventable adverse events and review those reports in multidisciplinary team meetings.

CONCLUSIONS

Psychiatry would benefit from learning about the terminology used in describing medication errors and ADEs. Relatively few data are available regarding the frequency and consequences of medication errors in psychiatry; more research is needed.

The appropriateness of drug use in an older nondemented and demented population

OBJECTIVE

To assess the extent of inappropriateness of drug use in an older nondemented and demented population.

DESIGN

Descriptive analysis based on data from a sample of older subjects age 81 years and older. Data were collected from the second follow-up conducted in 1994-1996.

SETTING

A population-based study of the Kungsholmen project in Stockholm, Sweden.

PARTICIPANTS

Drug information was obtained from 681 subjects with a mean age of 86.9 years. The subjects were predominantly women (78%). Thirteen percent resided in institutions and 27.6% were diagnosed with dementia.

MEASUREMENTS

Dementia diagnosis based on DSM III-R. Criteria for inappropriateness of drug use: use of drugs with potent anticholinergic properties, drug duplication, potential drug-drug and drug-disease interactions, and inappropriate drug dosage.

RESULTS

The mean number of drugs used was 4.6: 4.5 drugs for nondemented and 4.8 for demented subjects. Nondemented subjects more commonly used cardiovascular-system drugs and demented subjects used nervous-system drugs. Demented subjects were more commonly exposed to drug duplication and to drugs with potent anticholinergic properties, both involving the use of psychotropic drugs. Nondemented subjects were more commonly exposed to potential drug-disease interactions, mostly with the use of cardiovascular drugs. The most common drug combination leading to a potential interaction was the use of digoxin with furosemide, occurring more frequently among nondemented subjects. The most common drug-disease interaction was the use of beta-blockers and calcium antagonists in subjects with congestive heart failure. The doses of drugs taken by both nondemented and demented subjects were mostly lower than the defined daily dose.

CONCLUSION

There was substantial exposure to presumptive inappropriateness of drug use in this very old nondemented and demented population. The exposure of demented subjects to psychotropic drugs and nondemented subjects to cardiovascular drugs reflect the high frequency of prescribing these drugs in this population.

Determinants for the use of psychotropics among nursing home residents

PURPOSE

To characterise the prescription pattern of psychotropics in Danish nursing homes and to identify diagnostic, behavioural, cognitive and performance characteristics associated with prevalent psychotropic drug use.

METHODS

Prescribed daily medication was recorded from nurses' files. Based on the Anatomical Therapeutical Chemical (ATC) classification index, psychotropics were categorised into neuroleptics, benzodiazepines and antidepressants. Two hundred and eighty-eight residents were diagnosed using the GMS-AGECAT. One hundred and eighteen staff members were interviewed about the residents's Activities of Daily Living (ADL), behavioural problems (Nursing Home Behavior Problem Scale), orientation, communication skills and if the resident had any psychiatric disorder. Multiple logistic regression was used to select the items that determined the use of psychotropics.

RESULTS

Fifty-six percent of the residents received a psychotropic, 21% received neuroleptics, 38% received benzodiazepines and 24% received antidepressants. In the multivariate analysis, staff assessment of the resident's mental health was a determinant for the use of all types of specific psychotropics, whereas a GMS-AGECAT diagnosis only determined the use of neuroleptics. Behavioural problems were a determinant for the use of neuroleptics and the use of benzodiazepines irrespective of the psychiatric diagnosis of the resident. Use of antidepressants was associated with male gender and increasing age.

CONCLUSIONS

Staff perceptions of psychiatric morbidity and norms have a greater impact on the prescription of psychotropics than standardised clinical criteria.

Monotherapy trials with gabapentin for partial epilepsy

The efficacy and safety of gabapentin as monotherapy for treatment of partial onset seizures were evaluated in three large multicenter, double-blind, parallel-group, dose-controlled trials. In the first trial, 275 outpatients with refractory partial epilepsy maintained on stable doses of one or two antiepileptic drugs (AEDs) were switched to gabapentin (GBP) monotherapy at 600 mg, 1200 mg, or 2400 mg daily. Patients were required to exit the 26-week double-blind phase of the study if they experienced worsening of seizure frequency. With respect to time to exit, there was no statistically significant difference among the three groups; only 3% of patients withdrew from the trial because of adverse events. In the second study, 82 hospitalized patients with medically refractory epilepsy were tapered off baseline AEDs and randomly assigned to GBP monotherapy at 300 mg/day or 3600 mg/day. Patients remained in the trial for a maximum of 8 days but had to exit the trial if they experienced one or more exit events. Time to exit was significantly longer in patients in the 3600-mg group (151 h) compared with those in the 300-mg group (85 h) (p = 0.0001). None of the patients withdrew from the trial because of side effects. In the third study, 292 patients with newly diagnosed partial seizures were randomized to GBP 300, 900, or 1800 mg/day or to carbamazepine (CBZ) 600 mg/day. Patients remained in the trial for up to 6 months or until they experienced an exit event. Mean time to exit was significantly longer for patients who received GBP 900 mg/day (p = 0.02) or 1800 mg/day (p = 0.04) compared with those who received 300 mg/day. The completion rate for the CBZ group (37%) was similar to that of the GBP 900-mg (39%) and 1800-mg (38%) groups. Patients receiving CBZ had a higher withdrawal rate because of adverse events compared with the GBP 900-mg and 1800-mg groups. The results of these trials provide good evidence of the efficacy and safety of GBP as monotherapy for the treatment of partial-onset seizures.

Important drug-drug interactions in the elderly

Although drug-drug interactions constitute only a small proportion of adverse drug reactions, they are important because they are often predictable and therefore avoidable or manageable. Their frequency is related to the age of the patient, the number of drugs prescribed, the number of physicians involved in the patient's care and the presence of increasing frailty. The most important mechanisms for drug-drug interactions are the inhibition or induction of drug metabolism, and pharmacodynamic potentiation or antagonism. Interactions involving a loss of action of one of the drugs are at least as frequent as those involving an increased effect. It is likely that only about 10% of potential interactions result in clinically significant events and, while death or serious clinical consequences are rare, low-grade, clinically unspectacular morbidity in the elderly may be much more common. Nonspecific complaints (e.g. confusion, lethargy, weakness, dizziness, incontinence, depression, falling) should all prompt a closer look at the patient's drug list. There are a number of strategies that can be adopted to decrease the risk of potential clinical problems. The number of drugs prescribed for each individual should be limited to as few as is necessary. The use of drugs should be reviewed regularly and unnecessary agents withdrawn if possible, with subsequent monitoring. Patients should be encouraged to engage in a 'prescribing partnership' by alerting physicians, pharmacists and other healthcare professionals to symptoms that occur when new drugs are introduced. Physicians with a responsibility for elderly people in an institutional setting should develop a strategy for monitoring their drug treatment. For those interactions that have come to clinical attention, it is important to review why they happened and to plan for future prevention. Clinicians should also report, via the appropriate postmarketing surveillance scheme, any drug-drug interactions they have encountered. Finally, multidisciplinary education about the nature of physiological aging and its effect on drug handling, and the possible presentations of drug-related disease in older patients, is an important element in reducing interactions in the elderly.

The aging liver. Drug clearance and an oxygen diffusion barrier hypothesis

A change in drug clearance with age is considered an important factor in determining the high prevalence of adverse drug reactions associated with prescribing medications for the elderly. Despite this, no general principles have been available to guide drug administration in the elderly, although a substantial body of clearance and metabolism data has been generated in humans and experimental animals. A review of age-related change in drug clearances established that patterns of change are not simply explained in terms of hepatic blood flow, hepatic mass and protein binding changes. In particular, the maintained clearance of drugs subject to conjugation processes while oxygen-dependent metabolism declines, and all in vitro tests of enzyme function have been normal, requires new explanations. Reduction in hepatic oxygen diffusion as part of a general change in hepatocyte surface membrane permeability and conformation does provide one explanation for the paradoxical patterns of drug metabolism, and increased hepatocyte volume would also modify oxygen diffusion path lengths (the 'oxygen diffusion barrier' hypothesis). The reduction in clearances of high extraction drugs does correlate with observed reduction in hepatic perfusion. Dosage guidelines emerge from these considerations. The dosage of high clearance drugs should be reduced by approximately 40% in the elderly while the dosage of low clearance drugs should be reduced by approximately 30%, unless the compound is principally subject to conjugation mechanisms. If the hepatocyte diffusion barrier hypothesis is substantiated, this concept may lead to therapeutic (preventative and/or restorative) approaches to increased hepatocyte oxygenation in the elderly. This may lead to approaches for modification of the aging process in the liver.