Karolina Andersson Sundell

Methods for assessing the preventability of adverse drug events : A systematic review

AbstractBackground: Preventable adverse drug events (ADEs) are common in both outpatient and inpatient settings. However, the proportion of preventable ADEs varies considerably in different studies, even when conducted in the same setting, and methods for assessing the preventability of ADEs are diverse. Objective: The aim of this article is to identify and systematically evaluate methods for assessing the preventability of ADEs. Data sources: Seven databases (Cochrane, CINAHL, EMBASE, IPA, MEDLINE, PsycINFO and Web of Science) were searched in September 2010 utilizing the databases’ index terms and other common terminology on preventable ADEs. No limits for the years of publication were set. Reference lists of included original articles and relevant review articles were also screened. Study selection: After applying predetermined inclusion and exclusion criteria on 4161 unique citations, 142 (3.4%) original research articles were included in the review. One additional article was included from reference lists. Outcome measures of included studies had to include the frequency of ADEs and the assessment of their preventability. Studies were excluded if they focused on individuals with one specific type of treatment, medical condition, medical procedure or ADE. Data extraction: Measurement instruments for determining the preventability of ADEs in each article were extracted and unique instruments were compared. The process of assessing the preventability of ADEs was described based on reported actions taken to standardize and conduct the assessment, and on information about the reliability and validity of the assessment. Data synthesis: Eighteen unique instruments for determining the preventability of ADEs were identified. They fell under the following four groups: (i) instruments using a definition of preventability only (n=3); (ii) instruments with a definition of preventability and an assessment scale for determining preventability (n=5); (iii) instruments with specific criteria for each preventability category (n=3); and (iv) instruments with an algorithm for determining preventability (n=7). Of actions to standardize the assessment process, performing a pilot study was reported in 21 (15%), and use of a standardized protocol was reported in 18 (13%), of the included 143 articles. Preventability was assessed by physicians in 86 (60%) articles and by pharmacists in 41 (29%) articles. In 29 (20%) articles, persons conducting the assessment were described as trained for or experienced in preventability assessment. In 94 (66%) articles, more than one person assessed the preventability of each case. Among these 94 articles, assessment was done independently in 73 (51%) articles. Procedures for managing conflicting assessments were diverse. The reliability of the preventability assessment was tested in 39 (27%) articles, and 16 (11%) articles referred to a previous reliability assessment. Reliability ranged from poor to excellent (kappa 0.19–0.98; overall agreement 26–97%). Four (3%) articles mentioned assessing validity, but no sensitivity or specificity analyses or negative or positive predictive values were presented. Conclusions: Instruments for assessing the preventability of ADEs vary from implicit instruments to explicit algorithms. There is limited evidence for the validity of the identified instruments, and instrument reliability varied significantly. The process of assessing the preventability of ADEs is also commonly imprecisely described, which hinders the interpretation and comparison of studies. For measuring the preventability of ADEs more accurately and precisely in future, we believe that existing instruments should be further studied and developed, or that one or more new instruments should be developed, and the validity and reliability of the existing and new instruments be established.

A comparison of two methods for estimating refill adherence to statins in Sweden: the RARE project.

To analyse and compare refill adherence to statins estimated with two different methods with a focus on sensitivity to definitions.

Prevalence and perceived preventability of self-reported adverse drug events--a population-based survey of 7099 adults.

Purpose Adverse drug events (ADEs) are common and often preventable among inpatients, but self-reported ADEs have not been investigated in a representative sample of the general public. The objectives of this study were to estimate the 1-month prevalence of self-reported ADEs among the adult general public, and the perceived preventability of 2 ADE categories: adverse drug reactions (ADRs) and sub-therapeutic effects (STEs). Methods In this cross-sectional study, a postal survey was sent in October 2010 to a random sample of 13 931 Swedish residents aged ≥18 years. Self-reported ADEs experienced during the past month included ADRs, STEs, drug dependence, drug intoxications and morbidity due to drug-related untreated indication. ADEs could be associated with prescription, non-prescription or herbal drugs. The respondents estimated whether ADRs and STEs could have been prevented. ADE prevalences in age groups (18–44, 45–64, or ≥65 years) were compared. Results Of 7099 respondents (response rate 51.0%), ADEs were reported by 19.4% (95% confidence interval, 18.5–20.3%), and the prevalence did not differ by age group (p>0.05). The prevalences of self-reported ADRs, STEs, and morbidities due to drug-related untreated indications were 7.8% (7.2–8.4%), 7.6% (7.0–8.2%) and 8.1% (7.5–8.7%), respectively. The prevalence of self-reported drug dependence was 2.2% (1.9–2.6%), and drug intoxications 0.2% (0.1–0.3%). The respondents considered 19.2% (14.8–23.6%) of ADRs and STEs preventable. Although reported drugs varied between ADE categories, most ADEs were attributable to commonly dispensed drugs. Drugs reported for all and preventable events were similar. Conclusions One-fifth of the adult general public across age groups reported ADEs during the past month, indicating a need for prevention strategies beyond hospitalised patients. For this, the underlying causes of ADEs should increasingly be investigated. The high burden of ADEs and preventable ADEs from widely used drugs across care settings supports redesigning a safer healthcare system to adequately tackle the problem.

Clinical Use and Effectiveness of Lipid Lowering Therapies in Diabetes Mellitus—An Observational Study from the Swedish National Diabetes Register

Objectives To describe the use and evaluate the effectiveness of different lipid lowering therapies in unselected patients with type 1 and type 2 diabetes in clinical practice. Design Observational population-based study using the personal identification number to link information from the National Diabetes Register, the Prescribed Drug Register and the Patient register in Sweden. All patients in the NDR aged 18–75 years with diabetes more than one year were eligible, but only patients starting any lipid lowering treatment with at least three prescriptions 1 July 2006–30 June 2007 were included (n = 37182). The mean blood lipid levels in 2008 and reductions in LDL cholesterol were examined. Results Blood lipid levels were similar in patients treated with simvastatin, atorvastatin and rosuvastatin, showing similar lipid lowering effect as currently used. Users of pravastatin, fluvastatin, ezetimib and fibrate more seldom reach treatment goals. Moderate daily doses of the statins were used, with 76% of simvastatin users taking 20 mg or less, 48% of atorvastatin users taking 10 mg, 55% of pravastatin users taking 20 mg, and 76% of rosuvastatin users taking 5 or 10 mg. Conclusions This observational study shows that the LDL-C levels in patients taking simvastatin, atorvastatin or rosuvastatin are very similar as currently used, as well as their LDL-C lowering abilities. There is potential to intensify lipid lowering treatment to reduce the remaining high residual risk and achieve better fulfilment of treatment goals, since the commonly used doses are only low to moderate.

Prevalence, nature and potential preventability of adverse drug events – a population-based medical record study of 4970 adults

Aims To estimate the 3 month prevalence of adverse drug events (ADEs), categories of ADEs and preventable ADEs, and the preventability of ADEs among adults in Sweden. Further, to identify drug classes and organ systems associated with ADEs and estimate their seriousness. Methods A random sample of 5025 adults in a Swedish county council in 2008 was drawn from the Total Population Register. All their medical records in 29 inpatient care departments in three hospitals, 110 specialized outpatient clinics and 51 primary care units were reviewed retrospectively in a stepwise manner, and complemented with register data on dispensed drugs. ADEs, including adverse drug reactions (ADRs), sub-therapeutic effects of drug therapy (STEs), drug dependence and abuse, drug intoxications from overdose, and morbidities due to drug-related untreated indication, were detected during a 3 month study period, and assessed for preventability. Results Among 4970 included individuals, the prevalence of ADEs was 12.0% (95% confidence interval (CI) 11.1, 12.9%), and preventable ADEs 5.6% (95% CI 5.0, 6.2%). ADRs (6.9%; 95% CI 6.2, 7.6%) and STEs (6.4%; 95% CI 5.8, 7.1%) were more prevalent than the other ADEs. Of the ADEs, 38.8% (95% CI 35.8–41.9%) was preventable, varying by ADE category and seriousness. ADEs were frequently associated with nervous system and cardiovascular drugs, but the associated drugs and affected organs varied by ADE category. Conclusions The considerable burden of ADEs and preventable ADEs from commonly used drugs across care settings warrants large-scale efforts to redesign safer, higher quality healthcare systems. The heterogeneous nature of the ADE categories should be considered in research and clinical practice for preventing, detecting and mitigating ADEs.

Cost of illness of patient-reported adverse drug events: a population-based cross-sectional survey.

Objectives To estimate the cost of illness (COI) of individuals with self-reported adverse drug events (ADEs) from a societal perspective and to compare these estimates with the COI for individuals without ADE. Furthermore, to estimate the direct costs resulting from two ADE categories, adverse drug reactions (ADRs) and subtherapeutic effects of medication therapy (STE). Design Cross-sectional study. Setting The adult Swedish general population. Participants The survey was distributed to a random sample of 14 000 Swedish residents aged 18 years and older, of which 7099 responded, 1377 reported at least one ADE and 943 reported an ADR or STE. Main outcome measures Societal COI, including direct and indirect costs, for individuals with at least one self-reported ADE, and the direct costs for prescription drugs and healthcare use resulting from self-reported ADRs and STEs were estimated during 30 days using a bottom-up approach. Results The economic burden for individuals with ADEs were (95% CI) 442.7 to 599.8 international dollars (Int

Socio-economic determinants of early discontinuation of anti-depressant treatment in young adults

), of which direct costs were Int

Durability of oral hypoglycemic agents in drug naïve patients with type 2 diabetes: report from the Swedish National Diabetes Register (NDR)

279.6 to 420.0 (67.1%) and indirect costs were Int

Effects of generic substitution on refill adherence to statin therapy: a nationwide population-based study

143.0 to 199.8 (32.9%). The average COI was higher among those reporting ADEs compared with other respondents (COI: Int

Refill adherence and self-reported adverse drug reactions and sub-therapeutic effects: a population-based study†

442.7 to 599.8 versus Int