Adverse Drug Events After Hospital Discharge in Older Adults:Types, Severity, and Involvement of Beers Criteria Medications

Abir O. Kanaan, PharmD,*†‡ Jennifer L. Donovan, PharmD,*†‡ Nerissa P. Duchin, BS,†‡

Terry S. Field, DSc,†‡ Jennifer Tjia, MD, MSCE,†‡ Sarah L. Cutrona, MD, MPH,†‡

Shawn J. Gagne, BA,† Lawrence Garber, MD,† Peggy Preusse, RN,† Leslie R. Harrold, MD, MPH,†‡

and Jerry H. Gurwitz, MD†‡

OBJECTIVES: To characterize adverse drug events(ADEs) occurring within the high-risk 45-day period afterhospitalization in older adults.

DESIGN: Clinical pharmacists reviewed the ambulatoryrecords of 1,000 consecutive discharges.

SETTING: A large multispecialty group practice closelyaligned with a Massachusetts-based health plan.

PARTICIPANTS: Hospitalized individuals aged 65 andolder discharged home.

MEASUREMENTS: Possible drug-related incidents occur-ring during the 45-day period after hospitalization wereidentified and presented to a pair of physician-reviewerswho classified incidents as to whether an ADE was pres-ent, whether the event was preventable, and the severity ofthe event. Medications implicated in ADEs were furthercharacterized according to their inclusion in the 2012Beers Criteria for Potentially Inappropriate MedicationUse in Older Adults.

RESULTS: At least one ADE was identified during the45-day period in 18.7% (n = 187) of the 1,000 discharges.Of the 242 ADEs identified, 35% (n = 84) were deemedpreventable, of which 32% (n = 27) were characterized asserious, and 5% (n = 4) as life threatening. More than halfof all ADEs occurred within the first 14 days after hospi-talization. The percentage of ADEs in which Beers Criteriamedications were implicated was 16.5% (n = 40). Beerscriteria medications with both a high quality of evidenceand strong strength of recommendation were implicated in6.6% (n = 16) of the ADEs.

CONCLUSION: ADEs are common and often preventablein older adults after hospital discharge, underscoring theneed to address medication safety during this high-risk per-iod in this vulnerable population. Beers criteria medications

played a small role in these events, suggesting that efforts toimprove the quality and safety of medication use during thiscritical transition period must extend beyond a singularfocus on Beers criteria medications. J Am Geriatr Soc61:1894–1899, 2013.

Key words: adverse drug events; Beers medications;ambulatory care setting; older adults

Adverse drug events (ADEs), especially those that may bepreventable, pose a serious concern in older adults dur-

ing the immediate posthospitalization period. This is a high-risk time for older adults, when multiple medication changesoccur that can lead to confusion regarding medication man-agement for patients and providers.1–3 One study of olderhospitalized adults found that 40% of all admission medica-tions were discontinued by discharge and that 5% of all dis-charge medications had been newly started during thehospitalization.4 It has been estimated that 12% to 17% ofgeneral medical patients experience ADEs after hospital dis-charge, a large percentage of which may be preventable.2,3

Multiple factors may contribute to suboptimal medica-tion management after hospital discharge, including poorphysician–patient communication and inadequate educa-tion regarding medication use,5 poor therapeutic monitor-ing,6,7 and incomplete or inaccurate information transferbetween clinicians.8 During the immediate posthospitaldischarge period, individuals may receive medications fromdifferent prescribers, who may lack access to comprehen-sive reconciled medication information.9 In addition, lackof prompt follow-up care after a hospitalization may exac-erbate problems during this particularly high-risk period.

The purpose of this study was to characterize the fre-quency, preventability, and severity of ADEs occurringduring the 45-day posthospitalization period in olderadults discharged from hospital to home. Medicationsimplicated in ADEs were further characterized according

From the*MCPHS University, †Meyers Primary Care Institute, and‡University of Massachusetts Medical School, Worcester, Massachusetts.

Address correspondence to Abir O. Kanaan, 19 Foster Street, Worcester,MA 01608. E-mail: abir.kanaan@mcphs.edu

DOI: 10.1111/jgs.12504

JAGS 61:1894–1899, 2013

© 2013, Copyright the Authors

Journal compilation © 2013, The American Geriatrics Society 0002-8614/13/$15.00

to their inclusion in the 2012 Beers Criteria for PotentiallyInappropriate Medication Use in Older Adults.10

METHODS

Study Setting and Population

This study was conducted in the setting of a large multispe-cialty group practice closely aligned with a Massachusetts-based health plan. Hospitalists employed by the medicalgroup deliver hospital care. The group practice uses an elec-tronic health record system. The study population wasderived from the health plan’s senior plan membership, themajority of whom the multispecialty group cares for.

One thousand consecutive discharges from the hospi-tal between August 26, 2010, and December 27, 2010, ofindividuals aged 65 and older at time of discharge whowere discharged from the primary inpatient facility servingthe medical group for a nonpsychiatric condition, had noplans to enroll in hospice upon discharge, and were dis-charged to the community (not a skilled nursing facility orlong-term care setting) were studied. The observation per-iod included days 1 to 45 after hospital discharge.

The institutional review board of the University ofMassachusetts Medical School and the institutional reviewboard of the group practice and health plan approved theproject.

Definitions and Classification of Events

Three trained clinical pharmacists performed comprehen-sive medical record reviews to identify possible drug-related incidents during the 45-day posthospital dischargeperiod. Comprehensive medical record reviews consisted ofreview of hospital discharge summaries and emergencydepartment visits; office visit notes; and telephone encoun-ters and communications that occurred between the indi-vidual and providers and between providers. If a hospitaladmission or an emergency department visit occurredwithin the observation period of interest, notes werereviewed for evidence of a drug-related incident that mayhave led to that hospital admission or emergency depart-ment visit, but any drug-related incidents that occurredduring a hospitalization or an emergency department visitwere not considered in the context of this study. A com-puter-generated list with signals of possible adverse eventswas produced for each discharged individual, includinghigh drug concentrations, abnormal laboratory data,administration of antidotes that might relate to an ADE,and International Classification of Diseases, Ninth Revi-sion, codes suggesting potential adverse effects of drugs.11

The clinical pharmacist–reviewers used these reports tofocus and enhance their reviews to identify possible drug-related incidents.

Preparation of Event Summaries

An event summary was prepared whenever the clinicalpharmacist identified a possible drug-related incident. Theevent summary incorporated data obtained from a compre-hensive review including medical and medication history,physical examination findings, laboratory data, and

provider assessments. The event summary also capturedinformation to assess the probability of the adverse eventbeing attributable to the drug, including timing, severity,and resolution. Drug references and literature were alsoreviewed to estimate the incidence of ADEs associatedwith the use of specific drug therapies.12

Outcome Measures

An ADE was defined as an injury resulting from a drug,rather than from an underlying disease. An ADE can berelated to an error or an adverse drug reaction without anerror.6,7,13–15 The clinical pharmacists (AOK, JLD) pre-sented all possible drug-related incidents to pairs of physi-cian-reviewers (JG, JT, LH, SC). These physician-reviewersindependently classified incidents using a structured implicitreview process, which has been used in numerous prior stud-ies of ADEs in various clinical settings.6,7,14–18 Briefly, thereview assessed whether an ADE occurred, the preventabil-ity and severity of the event, and the effects of the event onthe individual. In determining whether an ADE hadoccurred, the physician-reviewers considered the sequentialrelation between the drug exposure and the event andwhether the event reflected a known effect of the drug.

ADEs were considered preventable if they were due toan error and were preventable by any means available.7 Pre-ventability was categorized as preventable, probably pre-ventable, probably not preventable, or definitely notpreventable; results were collapsed into the categories ofpreventable (preventable and probably preventable) andnonpreventable (probably not preventable and definitely notpreventable). Severity of ADEs was categorized as less seri-ous, serious, life-threatening, or fatal.7,14 ADEs categorizedas less serious included rashes, bruising, and constipation.Examples of serious events included falls, dizziness withorthostasis, and gastrointestinal bleeding not requiringhospitalization. Examples of life-threatening events includedacute kidney injury with hyperkalemia and thromboembolicevents. The effects of ADEs on participants were categorizedas laboratory abnormalities requiring only a change in ther-apy, symptoms of less than 1 day in duration, symptoms of1 day and longer in duration, disability, and death. Thestages of pharmaceutical care during which an error leadingto a preventable ADE occurred (prescribing, dispensing,adherence, monitoring) were also characterized. For a singleADE, it may have been possible to identify errors at morethan one stage of pharmaceutical care or to identify morethan one error within a single stage of care.

Medications implicated in ADEs were further character-ized according to whether they were included in the 2012Beers Criteria for Potentially Inappropriate Medication Usein Older Adults.10 An interdisciplinary panel developed themost recent revision of the criteria, employing an evidence-based approach to rate the strength of recommendations foreach medication and the strength of the evidence that indi-cated that each medication was potentially inappropriate.The 2012 Beers criteria encompass 53 medications or medi-cation classes divided into three categories: potentially inap-propriate medications to avoid in older adults, potentiallyinappropriate medications to avoid in older adults with cer-tain diseases and syndromes that the drugs can exacerbate,and medications to be used with caution in older adults. For

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the purpose of the present study, Beers criteria medicationsincluded medications that had high quality of evidence and astrong recommendation to avoid their use and that wereclassified as potentially inappropriate medications and medi-cations to be used with caution according to the 2012 Beerscriteria. Dosing, sex, age, route, and drug form as outlinedin the Beers criteria tables were considered when classifyingmedications.

When the physician-reviewers disagreed on the classifi-cation of an ADE, its preventability, or its severity, theymet and reached consensus; consensus was reached in allinstances in which there was initial disagreement. All ini-tial assessments of the physician-reviewers were compared,and interrater reliability was calculated using the kappastatistic. The kappa was 0.63 (95% confidence interval(CI) = 0.53–0.72) for judgment regarding the presence ofan ADE, 0.62 (95% CI = 0.51–0.73) for preventability,and 0.47 (95% CI = 0.34–0.60) for severity. A kappascore between 0.6 and 0.8 reflects substantial agreement,and a score between 0.41 and 0.6 is considered moder-ate.19 The relative risk of preventability for serious versusless-than-serious events was calculated with 95% CIs usingthe epitab function in of Stata version 11 (Stata Corp.,College Station, TX).

RESULTS

The 1,000 consecutive discharges involved 850 differentparticipants; 731 had one discharge, and 119 had morethan one discharge. The mean � standard deviation age ofparticipants at the time of discharge was 78.8 � 7.1;51.6% were female.

The clinical pharmacists identified 330 possible drug-related incidents occurring during the 1- to 45-day periodafter hospital discharge, 242 (73%) of which the

physician-reviewers deemed to be ADEs. There was atleast one ADE identified in 18.7% (n = 187) of hospitaldischarges, and 44 discharges had more than one ADE.More than half of ADEs occurred within 14 days afterhospital discharge (Figure 1).

Twenty-four percent of ADEs were categorized as seri-ous or life threatening (Table 1). There were no fatal events.Abnormal laboratory results requiring only a change in ther-apy accounted for 18% of all ADEs. Nearly 60% (n = 141)resulted in symptom duration of 1 or more days. Two eventsresulted in nonpermanent disability and included a fall withan associated injury related to the use of cardiovascular andsedative or hypnotic medications and a cardiovascular eventrelated to the inappropriate discontinuation of drug therapy.

Of the 242 ADEs, 35% (n = 84) were considered to bepreventable, 32% (n = 27) of which were serious and 5%(n = 4) life threatening (Table 2). More-severe ADEs (seri-ous and life threatening) were significantly more likely to bedeemed preventable (relative risk = 1.9, 95%CI = 1.4–2.6).

ADEs According to Type and Drug Class

Gastrointestinal events (e.g., diarrhea, constipation,abdominal pain) were the most common type of prevent-able ADEs (Table 3); other common preventable ADEswere cardiovascular and renal- or electrolyte-related events(hyperkalemia, hypokalemia, renal insufficiency). Cardio-vascular medications, diuretics, opioids, and anticoagulantsor antiplatelets were most commonly involved in prevent-able events (Table 4).

Errors Associated with ADEs

In the 84 preventable ADEs, errors occurred most often atthe prescribing (n = 65, 54%) or monitoring (n = 44,

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45

Tota

l eve

nts

Number of days post hospital discharge

Figure 1. Days after discharge to first event.

1896 KANAAN ET AL. NOVEMBER 2013–VOL. 61, NO. 11 JAGS

36%) stage of pharmaceutical care. Errors accounting forpreventable ADEs were less commonly identified at thedispensing (n = 1, 1%) and administration or adherence(n = 11, 9%) stages. More than 40% (n = 34) of thepreventable ADEs were associated with an error at two ormore stages of pharmaceutical care.

Of prescribing errors, the most common were wrongdrug choice and wrong dose. Monitoring stage errors gen-erally referred to inadequate laboratory monitoring of drugtherapies or to a delayed response or failure to respond tosigns or symptoms of drug toxicity or laboratory evidenceof toxicity.

ADEs Associated with Beers Criteria

Of the 242 ADEs identified, 16.5% (n = 40) involved oneor more drugs included in the Beers criteria medications;specifically, 14.9% (n = 36) had one or more potentiallyinappropriate drugs, and 2.5% (n = 6) had one or moreuse-with-caution drugs. Non-cyclooxygenase-selective non-steroidal anti-inflammatory drugs were the most commontypes of Beers criteria medications implicated in ADEs(n = 7). Beers criteria medications with both a high qualityof evidence and strong strength of recommendation wereimplicated in 6.6% (n = 16) of the ADEs.

DISCUSSION

The posthospital syndrome has recently been described as acondition of generalized high risk.20 The findings of the cur-rent study serve to reinforce the importance of medicationsafety as a critically important concern during this period ofhigh vulnerability for older adults. It was determined thatADEs occurred frequently in older adults discharged home

Table 1. Characteristics of Adverse Drug Events withina 45-Day Period After Hospitalization

Characteristic

Overall,

n = 242

Preventable,

n = 84

n (%)

SeverityLess serious 185 (76.4) 53 (63.1)Serious 51 (21.1) 27 (32.1)Life threatening 6 (2.5) 4 (4.8)

Abnormal laboratoryresults without symptoms

44 (18.2) 12 (14.3)

Duration of symptoms, days<1 55 (22.7) 21 (25.0)≥1 141 (58.3) 50 (59.5)

Nonpermanent disability 2 (0.8) 1 (1.2)

Table 2. Selected Examples of Preventable More-SevereAdverse Drug Events

An individual taking an angiotensin-converting enzyme inhibitor (newmedication started in hospital and continued at discharge), a beta-blocker (dose increased at discharge), a thiazide diuretic, and a loopdiuretic developed hypotension (systolic blood pressure in the 50 s, asreported by a visiting nurse) and required emergency transport andhospitalizationAn individual taking an opioid (started in hospital and continued atdischarge) without an appropriate bowel regimen required evaluation inthe emergency department for severe constipationAn individual taking a sulfonylurea (glipizide) developed hypoglycemia(blood glucose in the 30 s) requiring emergency medical services.Individual’s glycosylated hemoglobin was less than 7% and as low as5.5% over the 2 years preceding the event; the individual was alsotaking the drug inappropriately with respect to meal times

Table 3. Frequency of Types of Adverse Drug Events(ADEs)

Core Components

of ADEs

Overall,

n = 242

Preventable,

n = 84

n (%)

Cardiovascular 54 (22.3) 21 (25.0)Renal or electrolyte 53 (21.9) 24 (28.6)Gastrointestinal tract 43 (17.8) 23 (27.4)Hemorrhagic 26 (10.7) 7 (8.3)Syncope or dizziness 23 (9.5) 11 (13.1)Metabolic or endocrine 18 (7.4) 6 (7.1)Neuropsychiatric 18 (7.4) 7 (8.3)Fatigue 15 (6.2) 1 (1.2)Dermatologic or allergic 11 (4.5) 0 (0)Infection 7 (2.9) 2 (2.4)Falls without injury 6 (2.5) 3 (3.6)Respiratory tract 2 (0.8) 2 (2.4)Hematologic 3 (1.2) 0 (0)Ataxia or difficulty with gait 1 (0.4) 0 (0)Anticholinergic 2 (0.8) 0 (0)Fall with injury 2 (0.8) 2 (2.4)Chills 2 (0.8) 1 (1.2)

ADEs could manifest as more than one type.

Table 4. Frequency of Adverse Drug Events Accordingto Drug Class

Prescription

Drug Class

Overall,

N = 242

Preventable,

n = 84

n (%)

Cardiovascular 86 (35.5) 34 (40.5)Diuretics 49 (20.2) 20 (23.8)Opioids 23 (9.5) 14 (16.7)Antibiotics or anti-infectives 19 (7.9) 2 (2.4)Anticoagulants 18 (7.4) 5 (6.0)Antiplatelets 18 (7.4) 4 (4.8)Aspirin 16 (6.6) 5 (6.0)Steroids 13 (5.4) 3 (3.6)Antineoplastics 12 (5.0) 0 (0)Nonsteroidal anti-inflammatory drugs 11 (4.5) 7 (8.3)Nutrients or supplements 10 (4.1) 4 (4.8)Hypoglycemics 8 (3.3) 3 (3.6)Gastrointestinal tract 7 (2.9) 3 (3.6)Sedatives or hypnotics 7 (2.9) 4 (4.8)Antidepressants 5 (2.1) 5 (6.0)Antihyperlipidemics 4 (1.7) 0 (0)Muscle relaxants 4 (1.7) 4 (4.8)Antipsychotics 4 (1.7) 2 (2.4)Other 10 (4.1) 3 (3.6)

Drugs in more than one category were associated with some events. Fre-

quencies in each column sum to greater than the total number of events.

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during the 45-day period after hospitalization, with an eventidentified in nearly one in five discharges. More thanone-third of ADEs were considered preventable, and more-severe events were more likely to be deemed preventable.More than half of ADEs happened within 14 days afterhospitalization, and most errors associated with preventableevents occurred at the prescribing and monitoring stages ofpharmaceutical care. Other studies that have examinedADEs after hospitalization have found that they occurcommonly and are often preventable.2,3,21

Only a small proportion of the identified ADEs wererelated to medications found on the Beers list. Althoughthe current study employed the most recently updatedBeers criteria, studies of ADEs conducted in other clinicalsettings have suggested that Beers list medications areassociated with few adverse events.22–24 For example, ananalysis of emergency hospitalizations for ADEs in olderadults reported that only 6.6% of all hospitalizations wereassociated with Beers criteria medications.22 Similarly,another study found that only 3.6% of emergency depart-ment visits for ADEs were associated with Beers criteriamedications.23 The somewhat higher percentage of ADEsassociated with Beers criteria in the current study mayreflect that ADEs that lead to an emergency departmentvisit are generally severe, and Beers criteria medicationsmay lead to less-severe events not requiring an emergencydepartment visit or hospitalization.

The findings of this study can be directly applied toimprove the quality of care of older adults discharged fromthe hospital. The results suggest that errors in medicationprescribing and monitoring are most commonly associatedwith the occurrence of ADEs during this high-risk posthos-pitalization period. Enhanced monitoring involving ateam-based approach to care that includes the physicianworking together with other health disciplines, includingnursing and pharmacy, seems an essential component ofany initiative designed to reduce risk for older adults afterhospital discharge.25–27 Clinical decision support incorpo-rated into electronic health records that provides promptsfor follow-up office visits, notification of medicationchanges that occurred during the hospitalization, and rec-ommendations for laboratory monitoring may hold prom-ise for reducing medication error rates and preventableADEs in the posthospital discharge period.28 Educationalefforts relating to the optimal use of medications in olderadults should target all health professionals providing careto older adults. In addition, enhanced surveillance andreporting systems for ADEs in the ambulatory setting,especially those relating to medication errors, are essentialto inform the design of new system-based approaches toreducing risk of ADEs.

This study benefitted from the availability of informa-tion contained in the electronic health records, includingprescription medications, laboratory results, clinic notes,and telephone communications. The clinical pharmacistsperformed a comprehensive medical record review using allof these sources of medical information. Nevertheless, thestudy had some limitations. There is inherently a level ofsubjectivity in the process of classifying ADEs. Although the2012 Beers criteria were used, this version of the criteria didnot exist during the period of the research. The findings mayhave been somewhat different if the 2012 Beers criteria had

been available and widely publicized at that time. Medica-tions are only one facet of an analysis of medication safety.Errors of omission (missed opportunities to prescribe appro-priate medications) and individual behaviors leading toADEs are also important aspects of pharmaceutical care butwere not the focus of the present study.

In summary, it was determined that ADEs are com-mon in older adults during the immediate posthospitaliza-tion period. Beers criteria medications play only a smallrole in these events. Efforts to improve the quality andsafety of medication use during this critical transition per-iod for older adults are necessary, but it is essential thatthese efforts extend beyond a singular focus on Beers crite-ria medications.

ACKNOWLEDGMENTS

We thank Kevin Swearengin, PharmD, for his assistancewith the data abstraction and Mary Ellen Stansky forassistance with technical aspects of this study. The authorspresented this research abstract at the American College ofClinical Pharmacy Annual Meeting, October 21–24, 2012,Hollywood, Florida; the Annual HMO Research NetworkConference, April 16–18, 2013, Burlingame, California;and Annual Scientific Meeting of the American GeriatricsSociety, May 3–5, 2013, Grapevine, Texas.

Conflict of Interest: Nerissa Duchin was supported bya Medical Student Training in Aging Research Awardfrom the American Federation for Aging Research.

The editor in chief has reviewed the conflict of interestchecklist provided by the authors and has determined thatthe authors have no financial or any other kind of personalconflicts with this paper.

This study was funded by Grant R18 HS017203 fromthe Agency for Healthcare Research and Quality. Dr. Cut-rona is supported by Award KL2RR031981 from theNational Center for Research Resources.

Author Contributions: Kanaan, Donovan: conceptionand design, acquisition of data, analysis and interpretationof data, drafting, revising the article critically for impor-tant intellectual content. Duchin, Field, Tjia, Garber,Gurwitz: conception and design, acquisition of data, analy-sis and interpretation of data, revising the article criticallyfor important intellectual content. Cutrona, Gagne,Preusse, Harrold: acquisition of data, analysis and inter-pretation of data, revising the article critically for impor-tant intellectual content. All authors reviewed andapproved the submitted version of the article.

Sponsor’s Role: The sponsor was not involved in thestudy design, methods, subject recruitment, data collec-tions, analysis, or preparation of the paper. The content issolely the responsibility of the authors and does not neces-sarily represent the official views of the funders.

REFERENCES

1. Beers MH, Sliwkowski J, Brooks J. Compliance with medication orders

among the elderly after hospital discharge. Hosp Formul 1992;27:720–724.2. Forster AJ, Clark HD, Menard A et al. Adverse events among medical

patients after discharge from hospital. Can Med Assoc J 2004;170:345–349.3. Forster AJ, Murff HJ, Peterson JF et al. The incidence and severity of

adverse events affecting patients after discharge from the hospital. Ann

Intern Med 2003;138:161–167.

1898 KANAAN ET AL. NOVEMBER 2013–VOL. 61, NO. 11 JAGS

4. Beers MH, Dang J, Hasegawa J et al. Influence of hospitalization on drug

therapy in the elderly. J Am Geriatr Soc 1989;37:679–683.5. Calkins DR, Davis RB, Reiley P et al. Patient-physician communication at

hospital discharge and patients’ understanding of the postdischarge treat-

ment plan. Arch Intern Med 1997;157:1026–1030.6. Gurwitz JH, Field TS, Harrold LR et al. Incidence and preventability of

adverse drug events among older persons in the ambulatory setting. JAMA

2003;289:1107–1116.7. Bates DW, Cullen DJ, Laird N et al. Incidence of adverse drug events and

potential adverse drug events. Implications for prevention. ADE Prevention

Study Group. JAMA 1995;274:29–34.8. van Walraven C, Seth R, Laupacis A. Dissemination of discharge summaries.

Not reaching follow-up physicians. Can Fam Physician 2002;48:737–742.9. Coleman EA. Falling through the cracks: Challenges and opportunities for

improving transitional care for persons with continuous complex care

needs. J Am Geriatr Soc 2003;51:549–555.10. American Geriatrics Society. Beers Criteria Update Expert Panel. American

Geriatrics Society Updated Beers Criteria for Potentially Inappropriate

Medication Use in Older Adults. J Am Geriatr Soc 2012;2012(60):616–631.

11. Field TS, Gurwitz JH, Harrold LR et al. Strategies for detecting adverse

drug events among older persons in the ambulatory setting. J Am Med

Inform Assoc 2004;11:492–498.12. Micromedex� Healthcare Series [on-line]. Greenwood Village, CO: Thom-

son Healthcare. Available at http://www.micromedex.com Accessed Decem-

ber 15, 2011.

13. Leape LL, Bates DW, Cullen DJ et al. Systems analysis of adverse drug

events. JAMA 1995;274:35–43.14. Gurwitz JH, Field TS, Avorn J et al. Incidence and preventability of

adverse drug events in nursing homes. Am J Med 2000;109:87–94.15. Leape LL, Cullen DJ, Clapp MD et al. Pharmacist participation of physi-

cian rounds and adverse drug events in the intensive care unit. JAMA

1999;282:267–270.16. Kaushal R, Bates DW, Landrigan C et al. Medication errors and adverse

drug events in pediatric inpatients. JAMA 2001;285:2114–2120.

17. Bates DW, Leape LL, Cullen DJ et al. Effect of computerized physician

order entry and a team intervention on prevention on serious medication

errors. JAMA 1998;280:1311–1316.18. Bates DW, Spell N, Cullen DJ et al. The costs of adverse drug events in

hospitalized patients. JAMA 1997;277:307–311.19. Sackett DL, Haynes RB, Guyatt GH et al. Clinical Epidemiology: A Basic

Science for Clinical Medicine, 2nd Ed. Boston, MA: Little Brown and Co.,

1991.

20. Krumholz HM. Post-hospital syndrome-an acquired, transient condition of

generalized risk. N Engl J Med 2013;368:100–102.21. Forster AJ, Murff HJ, Petereson JF et al. Adverse drug events occurring fol-

lowing hospital discharge. J Gen Intern Med 2005;20:317–323.22. Budnitz DS, Lovegrove MC, Shehab N et al. Emergency hospitalizations

for adverse drug events in older Americans. N Engl J Med 2011;365:

2002–2012.23. Budnitz DS, Shehab N, Kegler SR et al. Medication use leading to emer-

gency department visits for adverse drug events in older adults. Ann Intern

Med 2007;147:755–765.24. Page RL II, Ruscin JM. The risk of adverse drug events and hospital-

related morbidity and mortality among older adults with potentially inap-

propriate medication use. Am J Geriatr Pharmacother 2006;4:297–305.25. Makowsky MJ, Schindel TJ, Rosenthal M et al. Collaboration between

pharmacists, physicians and nurse practitioners: A qualitative investigation

of working relationships in the inpatient medical setting. J Interprof Care

2009;23:169–184.26. Jain M, Miller L, Belt D et al. Decline in ICU adverse events, nosocomial

infections and cost through a quality improvement initiative focusing on

teamwork and culture change. Qual Saf Health Care 2006;15:235–239.27. Isetts BJ, Brown LM, Schondelmeyer SW et al. Quality assessment of a col-

laborative approach for decreasing drug-related morbidity and achieving

therapeutic goals. Arch Intern Med 2003;163:1813–1820.28. Field TS, Garber L, Gagne SJ et al. Technological resources and personnel

costs required to implement an automated alert system for ambulatory phy-

sicians when patients are discharged from hospitals to home. Inform Prim

Care 2012;20:87–93.

JAGS NOVEMBER 2013–VOL. 61, NO. 11 ADEs AFTER HOSPITALIZATION IN OLDER ADULTS 1899