TY - BOOK

T1 - Quality indicators of preventable adverse drug events in patients with type 2 diabetes

T2 - application of a new register-based model

AU - Thomsen, Linda Aagaard

PY - 2009

Y1 - 2009

N2 - SummaryBackground: Preventable adverse drug events are caused by errors in the medication usePreventable adverse drug events are caused by errors in the medication use process, and are of particular interest when designing interventions to improve the qualityof medication therapy. Type 2 diabetes became the case because a large proportion ofpatients are undertreated and not monitored as recommended; yet, the epidemiology ofpreventable adverse drug events in type 2 diabetes is largely unknown. The aims of thestudies were to develop quality indicators for preventable adverse drug events in patientswith type 2 diabetes, and apply a new register-based model with the ability to assess theepidemiology and economic impact of preventable adverse drug events in patients withtype 2 diabetes, in order to give health care decision makers a clinical and health economicrationale for prioritizing interventions against medication errors.Methods: A systematic literature review of the available literature on preventable adverseA systematic literature review of the available literature on preventable adverse drug events was conducted to describe the incidence and characteristics of preventableadverse drug events in the primary care setting (Article 1).Construction of the preventable adverse drug events assessment model required four steps.The first step consisted of the development, validation, and feasibility of preventableadverse drug event indicators for type 2 diabetes (Articles 2 and 3). Preventable adversedrug event scenarios were identified through a literature review. Face, content and constructvalidity was assessed using a Delphi consensus study. The feasibility of a computerisedsearch for indicator positives within Danish health care registers was determined byassessing the operationalisability of the indicators, and the availability of the required data.The second step in the model consisted of the identification of preventable adverse drugevents. To identify the most frequent preventable adverse drug events, a databasecontaining health care data for a random 10% of the Danish population receiving oralantihyperglycaemic treatment (9,791 persons) was set up, and indicator positives identified(Articles no. 2 and 3). The third step in the model consisted of a risk assessment ofpreventable adverse drug events, including an assessment of clinical areas that need qualityimprovement. One study concerned the four indicators on inadequate preventive treatmentafter acute myocardial infarction (AMI) (Article 4), and another study concerned the fourindicators on inadequate monitoring of HbA1c resulting in admission with hyper- oriiihypoglycemia (Article 5). In the AMI study, a register-based study of the total Danishpopulation (8,275 persons) receiving oral antihyperglycaemic treatment and surviving anAMI was conducted. The study period was 1 January 2001 to 31 December 2004. Patientswere followed until their first recurrent AMI. The proportion of patients in inadequatetreatment, and the risk of recurrent AMI associated with inadequate treatment weredetermined. Statistical analysis was performed using a Cox regression model and a casecrossoverdesign. In the HbA1c study, a register-based study of the total population in theDanish county of Århus receiving oral antihyperglycaemic treatment (18,922 persons) wasconducted. The study period was 1 January 2000 to 31 December 2004. The rate ofindicator positives; the status of HbA1c monitoring; stratification between treatmentsettings; and high risk patient groups were assessed. The risk of diabetes-related hospitaladmission associated with HbA1c monitoring and treatment was determined using logisticregression.The fourth step in the model was a health economic evaluation of the cost-effectiveness ofshifting patients from inadequate to adequate medical treatment. The database used for theAMI indicator study formed the database for this study. Five post AMI treatment scenarioswere analysed, and incremental cost-effectiveness ratios calculated.Results: The systematic literature review (Article 1) revealed that preventable adverse drugThe systematic literature review (Article 1) revealed that preventable adverse drug events are common in primary care, with many resulting in hospitalisation. Projected to aDanish setting, 216,000 patients will experience a preventable adverse drug event eachyear, and 162,000 of these patients will need hospital admission. Quality improvementinterventions should target errors in prescribing and monitoring, especially for patientsusing cardiovascular drugs, analgesics and antihyperglycaemic agents.The indicator development study resulted in 27 preliminary preventable adverse drugevents indicators for type 2 diabetes, of which 18 (67%) achieved consensus (Article 2). Allindicators were operationalisable, but incomplete information on laboratory data and overthe-counter medicine caused inaccurate incidence estimates. Therefore, the two riskassessment studies relied on indicators where laboratory data were not required, or relied ona diabetes specific database containing the necessary laboratory data.ivThe screening study (Article 3) revealed that most cases of preventable adverse drug eventsconcern admissions with hyperglycemia, reduced renal function and recurrent AMI, relatedto inadequate treatment or monitoring.The AMI indicator study (Article 4) revealed that 77% of type 2 diabetes patients do notreceive recommended treatment after an AMI and 19% experience a recurrent AMI after amedian follow-up time of only 1.75 years. Inadequate preventive treatment increases therisk of recurrent AMI up to five times. Even though underdosed or absent antiplatelettreatment doubles the risk of recurrent AMI, 29% do not receive such treatment. Also, therisk of recurrent AMI decreases as the number of recommended medications or the dosesincrease; yet, beta-blockers and lipid-lowering agents were underdosed.The economic evaluation based on the AMI study (Article 6) revealed, that from a publichealth care systems' point of view, providing intensive cardioprotective treatmentaccording to already accepted guidelines to type 2 diabetes patients is cost-effective.The HbA1c study demonstrated how diabetes-related hospital admissions are frequent, andhow preventable adverse drug events are particularly frequent in insulin users. Importanttarget groups for future quality improvement initiatives are the small group of unmonitoredpatients (3.3 %); the 20 % of the population being hyperglycaemic, particularly those whodo not receive antihyperglycaemic treatment; patients receiving cardiovascular but noantihyperglycaemic treatment.Implications: The developed model for assessment of the epidemiology of preventableThe developed model for assessment of the epidemiology of preventable adverse drug events may be used at the system level, health care practitioner level, andpatient level. At the system level, the model may assist the tailoring of interventions aimedat preventing the most frequent medication errors and such which may have seriousconsequences, and eventually assist in restructuring the medication use system to achieve asystem less sensitive to errors and safer for patients.At the health care practitioner level, patient databases may be screened for indicatorpositives to provide an assessment of the quality of provided health care. At the patientlevel, the indicators may be used to identify medication errors in order to prospectivelyavoid the manifestation of adverse outcomes.

AB - SummaryBackground: Preventable adverse drug events are caused by errors in the medication usePreventable adverse drug events are caused by errors in the medication use process, and are of particular interest when designing interventions to improve the qualityof medication therapy. Type 2 diabetes became the case because a large proportion ofpatients are undertreated and not monitored as recommended; yet, the epidemiology ofpreventable adverse drug events in type 2 diabetes is largely unknown. The aims of thestudies were to develop quality indicators for preventable adverse drug events in patientswith type 2 diabetes, and apply a new register-based model with the ability to assess theepidemiology and economic impact of preventable adverse drug events in patients withtype 2 diabetes, in order to give health care decision makers a clinical and health economicrationale for prioritizing interventions against medication errors.Methods: A systematic literature review of the available literature on preventable adverseA systematic literature review of the available literature on preventable adverse drug events was conducted to describe the incidence and characteristics of preventableadverse drug events in the primary care setting (Article 1).Construction of the preventable adverse drug events assessment model required four steps.The first step consisted of the development, validation, and feasibility of preventableadverse drug event indicators for type 2 diabetes (Articles 2 and 3). Preventable adversedrug event scenarios were identified through a literature review. Face, content and constructvalidity was assessed using a Delphi consensus study. The feasibility of a computerisedsearch for indicator positives within Danish health care registers was determined byassessing the operationalisability of the indicators, and the availability of the required data.The second step in the model consisted of the identification of preventable adverse drugevents. To identify the most frequent preventable adverse drug events, a databasecontaining health care data for a random 10% of the Danish population receiving oralantihyperglycaemic treatment (9,791 persons) was set up, and indicator positives identified(Articles no. 2 and 3). The third step in the model consisted of a risk assessment ofpreventable adverse drug events, including an assessment of clinical areas that need qualityimprovement. One study concerned the four indicators on inadequate preventive treatmentafter acute myocardial infarction (AMI) (Article 4), and another study concerned the fourindicators on inadequate monitoring of HbA1c resulting in admission with hyper- oriiihypoglycemia (Article 5). In the AMI study, a register-based study of the total Danishpopulation (8,275 persons) receiving oral antihyperglycaemic treatment and surviving anAMI was conducted. The study period was 1 January 2001 to 31 December 2004. Patientswere followed until their first recurrent AMI. The proportion of patients in inadequatetreatment, and the risk of recurrent AMI associated with inadequate treatment weredetermined. Statistical analysis was performed using a Cox regression model and a casecrossoverdesign. In the HbA1c study, a register-based study of the total population in theDanish county of Århus receiving oral antihyperglycaemic treatment (18,922 persons) wasconducted. The study period was 1 January 2000 to 31 December 2004. The rate ofindicator positives; the status of HbA1c monitoring; stratification between treatmentsettings; and high risk patient groups were assessed. The risk of diabetes-related hospitaladmission associated with HbA1c monitoring and treatment was determined using logisticregression.The fourth step in the model was a health economic evaluation of the cost-effectiveness ofshifting patients from inadequate to adequate medical treatment. The database used for theAMI indicator study formed the database for this study. Five post AMI treatment scenarioswere analysed, and incremental cost-effectiveness ratios calculated.Results: The systematic literature review (Article 1) revealed that preventable adverse drugThe systematic literature review (Article 1) revealed that preventable adverse drug events are common in primary care, with many resulting in hospitalisation. Projected to aDanish setting, 216,000 patients will experience a preventable adverse drug event eachyear, and 162,000 of these patients will need hospital admission. Quality improvementinterventions should target errors in prescribing and monitoring, especially for patientsusing cardiovascular drugs, analgesics and antihyperglycaemic agents.The indicator development study resulted in 27 preliminary preventable adverse drugevents indicators for type 2 diabetes, of which 18 (67%) achieved consensus (Article 2). Allindicators were operationalisable, but incomplete information on laboratory data and overthe-counter medicine caused inaccurate incidence estimates. Therefore, the two riskassessment studies relied on indicators where laboratory data were not required, or relied ona diabetes specific database containing the necessary laboratory data.ivThe screening study (Article 3) revealed that most cases of preventable adverse drug eventsconcern admissions with hyperglycemia, reduced renal function and recurrent AMI, relatedto inadequate treatment or monitoring.The AMI indicator study (Article 4) revealed that 77% of type 2 diabetes patients do notreceive recommended treatment after an AMI and 19% experience a recurrent AMI after amedian follow-up time of only 1.75 years. Inadequate preventive treatment increases therisk of recurrent AMI up to five times. Even though underdosed or absent antiplatelettreatment doubles the risk of recurrent AMI, 29% do not receive such treatment. Also, therisk of recurrent AMI decreases as the number of recommended medications or the dosesincrease; yet, beta-blockers and lipid-lowering agents were underdosed.The economic evaluation based on the AMI study (Article 6) revealed, that from a publichealth care systems' point of view, providing intensive cardioprotective treatmentaccording to already accepted guidelines to type 2 diabetes patients is cost-effective.The HbA1c study demonstrated how diabetes-related hospital admissions are frequent, andhow preventable adverse drug events are particularly frequent in insulin users. Importanttarget groups for future quality improvement initiatives are the small group of unmonitoredpatients (3.3 %); the 20 % of the population being hyperglycaemic, particularly those whodo not receive antihyperglycaemic treatment; patients receiving cardiovascular but noantihyperglycaemic treatment.Implications: The developed model for assessment of the epidemiology of preventableThe developed model for assessment of the epidemiology of preventable adverse drug events may be used at the system level, health care practitioner level, andpatient level. At the system level, the model may assist the tailoring of interventions aimedat preventing the most frequent medication errors and such which may have seriousconsequences, and eventually assist in restructuring the medication use system to achieve asystem less sensitive to errors and safer for patients.At the health care practitioner level, patient databases may be screened for indicatorpositives to provide an assessment of the quality of provided health care. At the patientlevel, the indicators may be used to identify medication errors in order to prospectivelyavoid the manifestation of adverse outcomes.

KW - Former Faculty of Pharmaceutical Sciences

M3 - Ph.D. thesis

SN - 987-87-02199-56-0

BT - Quality indicators of preventable adverse drug events in patients with type 2 diabetes

PB - Museum Tusculanum

CY - København

ER -