Quantifying the costs of serious adverse drug reactions to antiepileptic drugs

Direct costs of severe cutaneous adverse reactions in a tertiary hospital in Korea

BACKGROUND/AIMS

There are only a few reports on the direct costs of severe cutaneous adverse reactions (SCARs), including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN), despite the tremendous negative impact these reactions can have on patients. We estimated the direct costs of treating SCARs.

METHODS

Patients admitted to a tertiary teaching hospital for the treatment of SCARs from January 1, 2005 to December 31, 2010 were included. Patients who had experienced SCARs during their admission for other medical conditions were excluded. The direct costs of hospitalization and outpatient department visits were collected. Inpatient and outpatient care costs were calculated, and factors affecting inpatient care costs were analyzed.

RESULTS

The total healthcare cost for the management of 73 SCAR patients (36 with DRESS, 21 with SJS, and 16 with TEN) was 752,067 US dollars (USD). Most of the costs were spent on inpatient care (703,832 USD). The median inpatient care cost per person was 3,720 (range, 1,133 to 107,490) USD for DRESS, 4,457 (range, 1,224 to 21,428) USD for SJS, and 8,061 (range, 1,127 to 52,220) USD for TEN. Longer hospitalization significantly increased the inpatient care costs of the patients with DRESS (by 428 USD [range, 395 to 461] per day). Longer hospitalization and death significantly increased the inpatient care costs of the patients with SJS/TEN (179 USD [range, 148 to 210] per day and an additional 14,425 USD [range, 9,513 to 19,337] for the deceased).

CONCLUSION

The management of SCARs required considerable direct medical costs. SCARs are not only a health problem but also a significant financial burden for the affected individuals.

Severe Cutaneous Adverse Reactions to Antiepileptic Drugs: A Nationwide Registry-Based Study in Korea

PURPOSE

Severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms (DRESS) to antiepileptic drug (AED), are rare, but result in significant morbidity and mortality. We investigated the major culprit drugs, clinical characteristics, and clinical course and outcomes of AED-induced SCARs using a nationwide registry in Korea.

METHODS

A total of 161 patients with AED-induced SCARs from 28 referral hospitals were analyzed. The causative AEDs, clinical characteristics, organ involvements, details of treatment, and outcomes were evaluated. We compared the clinical and laboratory parameters between SJS/TEN and DRESS according to the leading causative drugs. We further determined risk factors for prolonged hospitalization in AED-induced SCARs.

RESULTS

Carbamazepine and lamotrigine were the most common culprit drugs causing SCARs. Valproic acid and levetiracetam also emerged as the major causative agents. The disease duration and hospital stay in carbamazepine-induced SJS/TEN were shorter than those in other AEDs (P< 0.05, respectively). In younger patients, lamotrigine caused higher incidences of DRESS than other drugs (P= 0.045). Carbamazepine, the most common culprit drug for SCARs, was associated with a favorable outcome related with prolonged hospitalization in SJS (odds ratio, 0.12; 95% confidence interval, 0.02-0.63, P= 0.12), and thrombocytopenia was found to be a risk factor for prolonged hospitalization in DRESS.

CONCLUSION

This was the first large-scale epidemiological study of AED-induced SCARs in Korea. Valproic acid and levetiracetam were the significant emerging AEDs causing SCARs in addition to the well-known offending AEDs such as carbamazepine and lamotrigine. Carbamazepine was associated with reduced hospitalization, but thrombocytopenia was a risk factor for prolonged hospitalization. Our results suggest that the clinical characteristics and clinical courses of AED-induced SCARs might vary according to the individual AEDs.

Patient reported adverse events among epileptic patients taking antiepileptic drugs

Objective:

The aim of this study was to assess patient reported adverse events and associated factors among epileptic patients taking antiepileptic drugs on follow-up at University of Gondar Referral Hospital.

Methods:

Cross-sectional study was done on 354 adult epileptic patients. Patients who were on antiepileptic drugs for epilepsy treatment for less than a year, those who were below 18 years old, patients with incomplete information on the chart and those who were involuntary or uncooperative were excluded from the study. Data were entered in to SPSS version 20.0 for analysis. Bivariate and multivariate binary logistic regression analysis was done to see factors associated with antiepileptic drugs adverse effect. Level of statistical significance was declared at p ≤ 0.05.

Result:

Generalized tonic clonic seizure was the most common (86.2%) type of epilepsy. A total of 79 adverse events were reported. The most frequently encountered adverse events were fatigue (5.08%), gastrointestinal disturbance (4.24%) and sedation/depression (4.24%). Adverse drug effect of antiepileptic drugs was significantly associated with illiterate educational status, increased number of antiepileptic drugs, no seizure during last follow-up and last year, and 1–5 seizures for the last year.

Conclusion:

About one-sixth of epileptic patients reported adverse drug effects. Adverse drug effects were more commonly seen in patients with low educational status, increased number of antiepileptic drugs, absence of seizure during last follow-up and last year, and 1–5 seizures for the last year. So clinicians should give emphasis for patients with these characteristics to counsel on how to minimize or prevent adverse drug events from antiepileptic drugs or giving reassurance about it if it is minor.

Clinical coding of prospectively identified paediatric adverse drug reactions--a retrospective review of patient records

BACKGROUND

National Health Service (NHS) hospitals in the UK use a system of coding for patient episodes. The coding system used is the International Classification of Disease (ICD-10). There are ICD-10 codes which may be associated with adverse drug reactions (ADRs) and there is a possibility of using these codes for ADR surveillance. This study aimed to determine whether ADRs prospectively identified in children admitted to a paediatric hospital were coded appropriately using ICD-10.

METHODS

The electronic admission abstract for each patient with at least one ADR was reviewed. A record was made of whether the ADR(s) had been coded using ICD-10.

RESULTS

Of 241 ADRs, 76 (31.5%) were coded using at least one ICD-10 ADR code. Of the oncology ADRs, 70/115 (61%) were coded using an ICD-10 ADR code compared with 6/126 (4.8%) non-oncology ADRs (difference in proportions 56%, 95% CI 46.2% to 65.8%; p < 0.001).

CONCLUSIONS

The majority of ADRs detected in a prospective study at a paediatric centre would not have been identified if the study had relied on ICD-10 codes as a single means of detection. Data derived from administrative healthcare databases are not reliable for identifying ADRs by themselves, but may complement other methods of detection.

The direct medical costs associated with suspected heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is an adverse drug reaction associated with heparin exposure. Sunnybrook Health Sciences Centre, a tertiary-care adult academic hospital, has cared for an average of 100 cases of suspected HIT per year. Although the management of suspected HIT is resource intensive, few studies have assessed the cost burden associated with HIT, and none have assessed the costs of suspected HIT.

OBJECTIVE

The objective of this study was to identify and quantify the direct medical costs associated with suspected (confirmed and negative) HIT at a hospital in Canada.

METHODS

A cost-of-illness analysis was conducted in patients with suspected HIT during 2005. Resource utilization variables included (i) laboratory tests to investigate HIT; (ii) HIT-safe anticoagulant use; (iii) diagnostic imaging related to HIT or its treatment; and (iv) additional hospital days attributed to HIT. The average costs per case of confirmed HIT, confirmed HIT with thrombosis (HITT) and negative HIT were calculated in $Can, year 2007 values.

RESULTS

Confirmed HITT cases incurred substantially greater costs ($Can34 155, range 358-202 069; n = 12) than confirmed HIT cases without thrombosis ($Can4575, range 39-16 373; n = 8). The average cost of care for a negative HIT case was $Can119 (range 39-4181; n = 88).

CONCLUSIONS

This is the first study to quantify the costs associated with suspected HIT cases. These cases increase the costs of hospital care and provide further justification for HIT prevention strategies.

Update on pharmacogenetics in epilepsy: a brief review

Recent developments in the pharmacogenetics of antiepileptic drugs provide new prospects for predicting the efficacy of treatment and potential side-effects. Epilepsy is a common, serious, and treatable neurological disorder, yet current treatment is limited by high rates of adverse drug reactions and lack of complete seizure control in a significant proportion of patients. The disorder is especially suitable for pharmacogenetic investigation because treatment response can be quantified and side-effects can be assessed with validated measures. Additionally, there is substantial knowledge of the pharmacodynamics and kinetics of antiepileptic drugs, and some candidate genes implicated in the disorder have been identified. However, recent studies of the association of particular genes and their genetic variants with seizure control and adverse drug reactions have not provided unifying conclusions. This article reviews the published work and summarises the state of research in this area. Future directions for research and the application of this technology to the clinical practice of individualising treatment for epilepsy are discussed.

The economic cost of epilepsy: a review of the literature

Economic concerns are increasingly important in health system design, provider payment, and research funding decisions. Cost estimates are needed to provide insight into where the potential opportunities for cost-savings lie and to lay the groundwork for research to determine how to treat the disorder more effectively. The methods used by economists to estimate the direct and indirect costs of epilepsy are reviewed and results from studies in different countries are discussed. General patterns across patients with different types of conditions are reported. Gaps in the literature are identified and future research needs are assessed.

Economic evaluation of antiepileptic drug therapy: a methodologic review

PURPOSE

The increasing number of antiepileptic drugs (AEDs) fostered the development of economic studies in epilepsy. We reviewed this literature to identify and discuss methodologic issues.

METHODS

We included all studies devoted to cost-based evaluation in epilepsy, published in English from 1989 to 2001, and identified via a Medline search.

RESULTS

We identified a series of methodologic problems. First, we reconsidered heterogeneity of concepts and estimating methods, often cited as the most critical problem, as they do not necessarily result from a failure to apply standard methods. One must distinguish "natural" sources of heterogeneity arising from the many unconstrained choices left open in the implementation of economic evaluation on the one hand, and imperfect information and observation-based sources of heterogeneity leading to constrained choices on the other hand. By their very nature, cost-of-illness studies are subject to this variety of choices and were used to illustrate our purpose. Second, cost-minimization studies were reviewed, as they raise additional problems related to study design and choice of an outcome measure. Finally, deficiencies were also identified in cost-effectiveness and cost-utility studies concerning attempts to incorporate patient's point of view in outcome measurement.

CONCLUSIONS

We agreed with previous reviews on the difficulty of compare results from economic studies in epilepsy due to heterogeneity in methods and concepts used. This is partly due to imperfect information and limits in observation as sources for data collection, as well as to unavailability of refined outcome measures. Therefore, improvements are possible in this field.

Experience with an adverse drug reaction reporting program in a neurology specialty clinic

OBJECTIVE

To describe an adverse drug reaction (ADR) reporting program that was developed in a university-affiliated neurology specialty clinic.

METHODS

Reportable ADRs were identified through 3 mechanisms: by clinicians through routine visits, by patients who were encouraged to follow up with the pharmacist in the clinic, and by the pharmacist who contacted high-risk patients. Patient demographics, the suspected drug(s), elements to define probability, and outcomes were documented, collated, and analyzed for trends and opportunities for continuous quality-improvement efforts. Information was shared with clinic administrators and clinicians. Serious ADRs were reported to the Food and Drug Administration.

RESULTS

The experience during a 1-year period, during which 40 ADRs were reported, is described. Medications by frequency of report and types of reactions are reported. None of the ADRs required admission to the hospital. Pharmacy personnel reported the majority of ADRs (92.5%).

CONCLUSIONS

This program is successfully incorporated within daily practice and is an integral part of quality-improvement efforts.

Adverse effects of antiepileptic drugs

Because the efficacies of antiepileptic drugs (AEDs) are often equivalent, selection of an AED is often determined by adverse effects. Differences in methods for labeling adverse effects and in the adverse effect terms themselves, variations in the populations studied, and inconsistent classifications of adverse effects make it difficult to know how to use information on adverse effects to choose an AED. Effort is underway to develop more extensive and internationally acceptable descriptive terms for adverse effects. Comparison of adverse effects in patients taking AEDs with adverse events in control groups is helpful; however, data from controlled studies are often lacking for most AEDs. Because of these limitations, the clinician must adopt a preventative and early detection approach based on some general principles. This review outlines factors to consider for avoiding and detecting AED adverse effects. The occurrence of weight change with AEDs is reviewed extensively, serving to illustrate how the principle factors can be used to avoid and manage adverse effects and where there is need for better studies of the short- and long-term adverse effects of AEDs.