Healthcare costs of adverse drug reactions and potentially inappropriate prescribing in older adults: a population-based study.

OBJECTIVES: To describe the distribution of costs based on potentially inappropriate prescribing (PIP) and adverse drug reaction (ADR) status in terms of total direct costs and costs caused by ADRs, among older adults. DESIGN: A retrospective cohort study was conducted among older adults, identified from a random sample of the general Swedish population. PIP was identified based on the Screening Tool of Older Persons' Prescriptions (STOPP) criteria and ADRs were identified using the Howard criteria. Causality between PIP and ADRs was evaluated using Hallas' criteria. Prevalence-based direct healthcare costs were calculated for the 3-month study period, including the total cost for healthcare and drugs, and the cost caused by ADRs. SETTING: All care levels, including primary care, other outpatient care and inpatient care. PARTICIPANTS: 813 adults ≥65 years. PRIMARY OUTCOME MEASURES: The prevalence and cost of PIP and ADRs. RESULTS: Total direct cost for persons with PIP was approximately twice the total cost of those without PIP (€1958 (€1428-€2616) vs €881 (€817-€1167), p=0.0020). The costs caused by ADRs was 10 times higher among persons with PIP, compared with those without PIP (€270 (€86-€545) vs €27 (€10-€61), p=0.047). For persons with ADRs caused by PIP, total direct costs were €4646 (€2617-€7931). This group represented 8% of the study population and used 25% of the costs. The main cost driver in all studied patient groups was healthcare contacts. CONCLUSIONS: Older persons with PIP and ADRs had high healthcare costs, particularly when ADRs were caused by PIP. Since these costs appear to be substantial, the potential savings by preventing their occurrence may, to a certain degree, cover the added cost of such activities. Further studies should be undertaken to provide further evidence on the costs of PIP, ADRs and ADRs caused by PIP.

Comparing Methods for Estimating Direct Costs of Adverse Drug Events.

OBJECTIVES: To estimate how direct health care costs resulting from adverse drug events (ADEs) and cost distribution are affected by methodological decisions regarding identification of ADEs, assigning relevant resource use to ADEs, and estimating costs for the assigned resources. METHODS: ADEs were identified from medical records and diagnostic codes for a random sample of 4970 Swedish adults during a 3-month study period in 2008 and were assessed for causality. Results were compared for five cost evaluation methods, including different methods for identifying ADEs, assigning resource use to ADEs, and for estimating costs for the assigned resources (resource use method, proportion of registered cost method, unit cost method, diagnostic code method, and main diagnosis method). Different levels of causality for ADEs and ADEs' contribution to health care resource use were considered. RESULTS: Using the five methods, the maximum estimated overall direct health care costs resulting from ADEs ranged from Sk10,000 (Sk = Swedish krona; ~€1,500 in 2016 values) using the diagnostic code method to more than Sk3,000,000 (~€414,000) using the unit cost method in our study population. The most conservative definitions for ADEs' contribution to health care resource use and the causality of ADEs resulted in average costs per patient ranging from Sk0 using the diagnostic code method to Sk4066 (~€500) using the unit cost method. CONCLUSIONS: The estimated costs resulting from ADEs varied considerably depending on the methodological choices. The results indicate that costs for ADEs need to be identified through medical record review and by using detailed unit cost data.

Direct and indirect costs for adverse drug events identified in medical records across care levels, and their distribution among payers.

BACKGROUND: Adverse drug events (ADEs) cause considerable costs in hospitals. However, little is known about costs caused by ADEs outside hospitals, effects on productivity, and how the costs are distributed among payers. OBJECTIVE: To describe the direct and indirect costs caused by ADEs, and their distribution among payers. Furthermore, to describe the distribution of patient out-of-pocket costs and lost productivity caused by ADEs according to socio-economic characteristics. METHOD: In a random sample of 5025 adults in a Swedish county, prevalence-based costs for ADEs were calculated. Two different methods were used: 1) based on resource use judged to be caused by ADEs, and 2) as costs attributable to ADEs by comparing costs among individuals with ADEs to costs among matched controls. Payers of costs caused by ADEs were identified in medical records among those with ADEs (n = 596), and costs caused to individual patients were described by socio-economic characteristics. RESULTS: Costs for resource use caused by ADEs were €505 per patient with ADEs (95% confidence interval €345-665), of which 38% were indirect costs. Compared to matched controls, the costs attributable to ADEs were €1631, of which €410 were indirect costs. The local health authorities paid 58% of the costs caused by ADEs. Women had higher productivity loss than men (€426 vs. €109, p = 0.018). Out-of-pocket costs displaced a larger proportion of the disposable income among low-income earners than higher income earners (0.7% vs. 0.2%-0.3%). CONCLUSION: We used two methods to identify costs for ADEs, both identifying indirect costs as an important component of the overall costs for ADEs. Although the largest payers of costs caused by ADEs were the local health authorities responsible for direct costs, employers and patients costs for lost productivity contributed substantially. Our results indicate inequalities in costs caused by ADEs, by sex and income.

Pharmacoepidemiology at Nordic School of Public Health NHV: Examples from 1999 to 2014.

BACKGROUND: Pharmacoepidemiology is a branch of public health and had a place at the Nordic School of Public Health. Courses, Master's theses and Doctorates of Public Health (DrPH) in Pharmacoepidemiology were a relatively minor, but still important part of the school's activities. METHODS: This paper gives a short background, followed by some snapshots of the activities at NHV, and then some illustrative case-studies. These case-studies list their own responsible co-authors and have separate reference lists. RESULTS: In the Nordic context, NHV was a unique provider of training and research in pharmacoepidemiology, with single courses to complete DrPH training, as well as implementation of externally-funded research projects. CONCLUSIONS: With the closure of NHV at the end of 2014, it is unclear if such a comprehensive approach towards pharmacoepidemiology will be found elsewhere in the Nordic countries.

Economic impact of adverse drug events--a retrospective population-based cohort study of 4970 adults.

BACKGROUND: The aim was to estimate the direct costs caused by ADEs, including costs for dispensed drugs, primary care, other outpatient care, and inpatient care, and to relate the direct costs caused by ADEs to the societal COI (direct and indirect costs), for patients with ADEs and for the entire study population. METHODS: We conducted a population-based observational retrospective cohort study of ADEs identified from medical records. From a random sample of 5025 adults in a Swedish county council, 4970 were included in the analyses. During a three-month study period in 2008, direct and indirect costs were estimated from resource use identified in the medical records and from register data on costs for resource use. RESULTS: Among 596 patients with ADEs, the average direct costs per patient caused by ADEs were USD 444.9 [95% CI: 264.4 to 625.3], corresponding to USD 21 million per 100 000 adult inhabitants per year. Inpatient care accounted for 53.9% of all direct costs caused by ADEs. For patients with ADEs, the average societal cost of illness was USD 6235.0 [5442.8 to 7027.2], of which direct costs were USD 2830.1 [2260.7 to 3399.4] (45%), and indirect costs USD 3404.9 [2899.3 to 3910.4] (55%). The societal cost of illness was higher for patients with ADEs compared to other patients. ADEs caused 9.5% of all direct healthcare costs in the study population. CONCLUSIONS: Healthcare costs for patients with ADEs are substantial across different settings; in primary care, other outpatient care and inpatient care. Hence the economic impact of ADEs will be underestimated in studies focusing on inpatient ADEs alone. Moreover, the high proportion of indirect costs in the societal COI for patients with ADEs suggests that the observed costs caused by ADEs would be even higher if including indirect costs. Additional studies are needed to identify interventions to prevent and manage ADEs.

Modelling drug-related morbidity in Sweden using an expert panel of pharmacists'.

BACKGROUND: Drug-related morbidity (DRM) is common and to some extent preventable, and associated with considerable costs in patients attending hospital. In outpatients and in the general public corresponding data are limited, but pharmacists' expert opinion has suggested high rates of DRM also in US ambulatory care. It is unknown if the results are applicable in Sweden today. OBJECTIVE: To estimate the proportions of patients with DRM and preventable DRM and the cost-of-illness (COI) of DRM in Sweden based on pharmacists' expert opinion. SETTING: Swedish healthcare. METHOD: The study applied a conceptual model of DRM based on a decision tree. An expert panel of pharmacists determined the probabilities of therapeutic outcomes of medication therapy. The COI analysis included direct costs from the healthcare perspective. Sensitivity analyses were performed for variations in probabilities and pathway costs. MAIN OUTCOME MEASURE: DRM included new medical problems (adverse drug reactions, drug dependence and intoxications) and therapeutic failures (insufficient effects of medicines and morbidity due to untreated indication). RESULTS: The expert panel estimated that 61 ± 14 % (mean ± SD) of all patients attending healthcare suffered from DRM, of which 29 ± 8 % suffered from new medical problems, 18 ± 6 % from therapeutic failures, and 15 ± 7 % from a combination of both. The DRM was considered preventable in 45 ± 15 % of the patients with DRM. The estimated COI was EUR 997 per patient attending healthcare, corresponding to an annual cost of EUR 6,600 million to the Swedish healthcare system. The COI ranged from EUR 490 to EUR 1,314 when varying the participants' probabilities of DRM and clinical outcomes from the first to the third quartile. Of the pathway costs, the COI was most sensitive to variation in the cost of prolonged hospital stay (COI range EUR 953-1,306). CONCLUSION: According to pharmacists' expert opinion, a large proportion of patients in Sweden experience DRM and preventable DRM, and the estimated COI of DRM is extensive. Since observational studies have not addressed the burden of DRM to the general public, this study adds the pharmacists' perception on DRM. Other healthcare professionals' perceptions on DRM need to be investigated in future studies.

Modelling drug-related morbidity in Sweden using an expert panel of physicians.

PURPOSE: In modelling studies using pharmacists' opinions, drug-related morbidity (DRM) and preventable DRM have been more common than in observational studies, and the resulting costs are extensive. Modelling studies' estimates may vary depending on informants' profession. The purpose of this modelling study was to estimate the proportion of patients with DRM and preventable DRM and the cost of illness (COI) of DRM in Sweden based on physicians' expert opinions. METHOD: A conceptual model of DRM was modified from previous studies. Using a modified Delphi technique, a panel of physicians (n = 19) estimated the probabilities of DRM, preventable DRM, and clinical outcomes of DRM separately for outpatients and inpatients. DRM included new medical problems (adverse drug reactions, drug dependence, and intoxications by overdose) and therapeutic failure (insufficient effects of medicines, and morbidity due to untreated indication). A COI analysis included the direct costs of DRM. RESULTS: Physicians estimated that 51 ± 22% [mean ± standard deviation (SD)] of outpatients experience DRM and 12 ± 8% preventable DRM. Of inpatients, 54 ± 17% was estimated to experience DRM and 16 ± 7% preventable DRM. Of outpatients with DRM, 24 ± 11% was estimated to experience preventable DRM, whereas this proportion for inpatients was 31 ± 15%. The estimated COI was 376 euros per outpatient and 838 euros per inpatient. CONCLUSIONS: Swedish physicians estimated that every other outpatient and inpatient experiences DRM, which is often preventable and costly. As physicians' estimates on the proportion of patients with DRM were higher than in observational studies in restricted subpopulations, DRM may be more common in the general population than observational studies suggest.