using information technology to detect ambulatory adverse events related to antidiabetic drug...
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Using Information Technology to Using Information Technology to Detect Ambulatory Adverse Events Detect Ambulatory Adverse Events
Related to Antidiabetic Drug TherapyRelated to Antidiabetic Drug Therapy
Judy Wu, PharmDDuke University Hospital
Co-Investigators: Heidi Cozart, RPh; Julie Whitehurst, PharmD;
Philip Rodgers, PharmD; Jennifer Mando, PharmD
Adverse Drug Events (ADEs)Adverse Drug Events (ADEs) Research primarily in the inpatient setting
3 – 6 ADEs per 100 admissions1-3
27% – 50% of ADEs are preventable1-3
Estimated cost: $ 3.5 billion (2006 dollars)4
ADE detection methods Chart review, patient surveys, computer event
monitoring, text scanning, voluntary reporting Multiple methods = more ADEs
Not well understood in other care settings
1. Bates DW et al. JAMA 1995;274(1):29-34.2. Classen DC et al. JAMA. 1997;277(4):301-6.3. Jha AK et al. J Am Med Inform Assoc 1998;5(3):305-14.4. Aspden P, IOM (U.S.). Preventing medication errors. Washington, DC: National Academies Press, 2007.
““Most data on medication error incidence rates Most data on medication error incidence rates come from the inpatient setting, butcome from the inpatient setting, but
- Institute of Medicine
the magnitude of the problem is likely to the magnitude of the problem is likely to be greater outside the hospital.”be greater outside the hospital.”
Aspden P, IOM (U.S.). Preventing medication errors. Washington, DC: National Academies Press, 2007.
MedicationMedicationErrorsErrors
Adverse Adverse Drug Drug
EventsEvents(ADEs)(ADEs)
DefinitionsDefinitions
Gandhi TK et al. International Journal for Quality in Health Care. 2000; 12:69–76.
Patient injury resulting from medical intervention
related to a drug
Bates DW et al. JAMA. 1995; 274:29–34.
Any error in any stage of the medication use process
(ordering, transcribing, dispensing, administering, or monitoring)
Bates DW et al. J Gen Intern Med 1995;10: 199-205.
Scope of the ProblemScope of the Problem Limited research in ambulatory care1,2
Baseline ADE incidence rate Identify strategies to decrease ADEs
Barriers to ambulatory care ADE research Inefficient Lack of accessible data Large patient population Most common medications resulting in ED
visits Insulin and warfarin3,4
1. Thomsen LA et al. Ann Pharmacother 2007;41(9):1411-26.2. Field T et al. Med Care 2005; 43: 1171-1176.3. Hafner J et al. Annals of Emergency Medicine. 2002; 30: 258-267.4. Budnitz DS et al. JAMA 2006;296(15):1858-66.
Research ObjectivesResearch Objectives Quantify hypoglycemia ambulatory ADEs Quantify hypoglycemia ambulatory ADEs
resulting in emergency department visits or resulting in emergency department visits or hospitalizationhospitalization
Characterize the population of subjects Characterize the population of subjects experiencing ADEs experiencing ADEs
Evaluate the utility of three different electronic Evaluate the utility of three different electronic adverse event detection methodsadverse event detection methods
Design a catalog of trigger words to detect Design a catalog of trigger words to detect possible ADEs through free-text searchingpossible ADEs through free-text searching
Study DesignStudy Design Retrospective, electronic chart review
Approved by Duke University Institutional Review Board Study site: Duke University Hospital Study period: January 1, 2007 to September 30, 2007
Inclusion criteria Subjects >18 years old experiencing possible antidiabetic
drug-induced hypoglycemia resulting in an emergency department visit or hospitalization
Exclusion criteria Subjects experiencing hypoglycemia not associated with
medication use Lack of objective evidence
Hypoglycemic ADE Blood glucose < 50 mg/dL while on antidiabetic
therapy ADE scoring
ADE = causality score ≥ 5 and a severity score ≥ 3 Causality - Naranjo algorithm1
Severity - Duke 7 point ADE severity score2
ADE group Comprehensive list of ADEs detected from any of the
3 tools
MeasurementsMeasurements
1. Naranjo CA et al. Clin Pharmacol Ther. 1981;30:239-245.2. Kilbridge PM et al. J Am Med Inform Assoc 2006; 13: 372-377.
Detection MethodsDetection Methods
Computerized ADE Surveillance (ADE-S)Computerized ADE Surveillance (ADE-S)
Diagnosis (ICD-9) codesDiagnosis (ICD-9) codes
Free-text searchingFree-text searching
Detection Methods:Detection Methods:Computerized ADE Surveillance
Logic based rules Screens demographic and laboratory data,
medications, and other clinical results Alerts pharmacist about possible ADEs Review and scoring process Acute care setting vs emergency department Hypoglycemia rule
Dextrose 50% when BG < 50 mg/dL
Detection Methods:Detection Methods:Diagnosis (ICD-9) codes
Administrative dataAdministrative data International Classification of Diseases, 9International Classification of Diseases, 9thth edition edition Codes for diagnoses and proceduresCodes for diagnoses and procedures
E900 codes specific to adverse events due to E900 codes specific to adverse events due to drugs drugs E932.3 Adverse effect insulin/antidiabeticsE932.3 Adverse effect insulin/antidiabetics
Detection Methods:Detection Methods:Free-text searching
Electronic medical records Emergency department visits
Refinement of searching tool Identification of trigger words Elimination of negative and ambiguous terms
Final search strategy Include {DM or diabetes} AND {hypoglycemia or
hypoglycemic or low blood glucose or low BG or low glucose} AND exclude {(-)DM}
Results: Hypoglycemia Alerts DetectedResults: Hypoglycemia Alerts Detected
n = 138
n = 72
n = 212
# of unique alerts = 364
8 666626
12112
168
32
Results: Hypoglycemia ADEs DetectedResults: Hypoglycemia ADEs Detected
ComputerComputerSurveillanceSurveillance
ADEs = 154 (42%)ADEs = 154 (42%)
91 91 55 55
5757
6666
ADE PopulationADE PopulationCharacteristics
Number of events 154
Age in years (mean ± SD) 59 ± 16.6
GenderMale (%) 45
Number of comorbidities (mean ± SD) 6.8 ± 3.7
Number of medications (mean ± SD)
AntidiabeticTotal
1.7 ± 0.69.8 ± 5.0
Hospitalization (%) 49
ADE Distribution By RaceADE Distribution By Race
n = 154
ADE Distribution By AgeADE Distribution By Agen = 154
Number of Events
ADEs With Insulin InvolvementADEs With Insulin Involvementn = 154
Mean blood glucose value at time of hypoglycemic event:
32 mg/dL
Mean blood glucose value at time of hypoglycemic event:
32 mg/dL
Insulin +Insulin +SulfonylureaSulfonylurea
4.5%4.5%
Positive Predictive Value (PPV) of Positive Predictive Value (PPV) of ADE Detection ToolsADE Detection Tools
ComputerComputerSurveillanceSurveillance
43%43%40%40%
79%79% Overestimation
100%100%
91 ADEs 91 ADEs 55 ADEs 55 ADEs
57 ADEs57 ADEs
Sensitivity of ADE Detection ToolsSensitivity of ADE Detection Tools
0%
20%
40%
60%
80%
100%
ADE-S ICD-9 Free-text
36% 37%59%
n = 154
LimitationsLimitations Retrospective, chart reviewRetrospective, chart review Not generalizable to other ambulatory ADEsNot generalizable to other ambulatory ADEs Subjectivity in scoring ADEsSubjectivity in scoring ADEs Underestimation of hypoglycemic incidence rateUnderestimation of hypoglycemic incidence rate
Specific population Specific population Exclusion of symptomatic hypoglycemia with BG > 50Exclusion of symptomatic hypoglycemia with BG > 50 Undetected hypoglycemic ADEs?Undetected hypoglycemic ADEs?
Detection tool limitationsDetection tool limitations ADE-S, ICD-9, free-text searchADE-S, ICD-9, free-text search
ConclusionConclusion 17 hypoglycemia ADEs per month were 17 hypoglycemia ADEs per month were
detecteddetected 49% require hospitalization49% require hospitalization 71% of ADEs involved insulin use71% of ADEs involved insulin use
African American and older age present more African American and older age present more frequently with hypoglycemia ADEs frequently with hypoglycemia ADEs
Highest yield & sensitivity Highest yield & sensitivity free text search tool free text search tool Greatest PPV Greatest PPV ICD-9 coding ICD-9 coding Minimal overlap among toolsMinimal overlap among tools Combining methods increases ADE yieldCombining methods increases ADE yield
““The primary focus of research on medication errors in the The primary focus of research on medication errors in the next decade should be prevention strategies, recognizing next decade should be prevention strategies, recognizing that to plan an error prevention study, it is essential to be that to plan an error prevention study, it is essential to be
able to measure the baseline rate of errors.”able to measure the baseline rate of errors.”- - Institute of MedicineInstitute of Medicine
Future research:Future research: Expand into other populations and other Expand into other populations and other
ambulatory ADE areasambulatory ADE areas Tool refinementTool refinement Use of detection methods in outpatient clinicsUse of detection methods in outpatient clinics Prevention strategiesPrevention strategies
AcknowledgementsAcknowledgements
Heidi CozartHeidi Cozart Julie WhitehurstJulie Whitehurst DHTSDHTS Department of PharmacyDepartment of Pharmacy Residency Research CommitteeResidency Research Committee
QuestionsQuestions
Race DistributionRace Distribution
http://quickfacts.census.gov/qfd/states/37/37063.html
North Carolina Durham County
Duke
Race DistributionRace Distribution
http://quickfacts.census.gov/qfd/states/37/37063.html
Predicted Actual