The objective of this article is to describe the unique challenges and present potential solutions and approaches for economic evaluations of precision medicine (PM) interventions using simulation modeling methods.Methods: Given the large and growing number of PM interventions and applications, methods are needed for economic evaluation of PM that can handle the complexity of cascading decisions and patient-specific heterogeneity reflected in the myriad testing and treatment pathways. Traditional approaches (eg, Markov models) have limitations, and other modeling techniques may be required to overcome these challenges. Dynamic simulation models, such as discrete event simulation and agent-based models, are used to design and develop mathematical representations of complex systems and intervention scenarios to evaluate the consequence of interventions over time from a systems perspective.Results: Some of the methodological challenges of modeling PM can be addressed using dynamic simulation models. For example, issues regarding companion diagnostics, combining and sequencing of tests, and diagnostic performance of tests can be addressed by capturing patient-specific pathways in the context of care delivery. Issues regarding patient heterogeneity can be addressed by using patient-level simulation models. Conclusion:The economic evaluation of PM interventions poses unique methodological challenges that might require new solutions. Simulation models are well suited for economic evaluation in PM because they enable patient-level analyses and can capture the dynamics of interventions in complex systems specific to the context of healthcare service delivery.

Background: This study aims to quantify medication costs in juvenile idiopathic arthritis (JIA), based on subtype. Research design and methods:This study is a single-center, retrospective analysis of prospective data from electronic medical records of JIA patients, aged 0-18 years between 1 April 2011 and 31 March 2019. Patient characteristics (age, gender, subtype) and medication use were extracted. Medication use and costs were reported as: 1) mean total annual costs; 2) between-patient heterogeneity in these costs; 3) duration of medication use; and, 4) costs over the treatment course. Results: The analysis included 691 patients. Mean total medication costs were €2,103/patient/year, including €1,930/patient/year (91.8%) spent on biologicals. Costs varied considerably between subtypes, with polyarticular rheumatoid-factor positive and systemic JIA patients having the highest mean costs (€5,020/patient/year and €4,790/patient/year, respectively). Mean annual medication costs over the patient's treatment course ranged from <€1,000/year (71.1% of patients) to >€11,000/year (2.5% of patients). Etanercept and adalimumab were the most commonly used biologicals. Cost fluctuations over the treatment course were primarily attributable to biological use. Conclusions: Polyarticular rheumatoid-factor positive and systemic JIA patients had the highest mean total annual medication costs, primarily attributable to biologicals. Costs varied considerably between subtypes, individuals, and over the treatment course.

Background This study aims to describe current practice in identifying and measuring health care resource use and unit costs in economic evaluations or costing studies of juvenile idiopathic arthritis (JIA). Methods A scoping review was conducted (in July 2018) in PubMed and Embase to identify economic evaluations, costing studies, or resource utilization studies focusing on patients with JIA. Only English language peer-reviewed articles reporting primary research were included. Data from all included full-text articles were extracted and analysed to identify the reported health care resource use items. In addition, the data sources used to obtain these resource use and unit costs were identified for all included articles. Results Of 1176 unique citations identified by the search, 20 full-text articles were included. These involved 4 full economic evaluations, 5 cost-outcome descriptions, 8 cost descriptions, and 3 articles reporting only resource use. The most commonly reported health care resource use items involved medication (80%), outpatient and inpatient hospital visits (80%), laboratory tests (70%), medical professional visits (70%) and other medical visits (65%). Productivity losses of caregivers were much more often incorporated than (future) productivity losses of patients (i.e. 55% vs. 15%). Family borne costs were not commonly captured (ranging from 15% for school costs to 50% for transportation costs). Resource use was mostly obtained from family self-reported questionnaires. Estimates of unit costs were mostly based on reimbursement claims, administrative data, or literature. Conclusions Despite some consistency in commonly included health care resource use items, variability remains in including productivity losses, missed school days and family borne costs. As these items likely substantially influence the full cost impact of JIA, the heterogeneity found between the items reported in the included studies limits the comparability of the results. Therefore, standardization of resource use items and unit costs to be collected is required. This standardization will provide guidance to future research and thereby improve the quality and comparability of economic evaluations or costing studies in JIA and potentially other childhood diseases. This would allow better understanding of the burden of JIA, and to estimate how it varies across health care systems. Electronic supplementary material The online version of this article (10.1186/s12969-019-0321-x) contains supplementary material, which is available to authorized users.

Objective Pharmacological treatment is a cornerstone of care for children with juvenile idiopathic arthritis (JIA). The objective of this study is to evaluate prescription patterns of conventional and biologic disease modifying anti-rheumatic drugs (c-DMARDs and b-DMARDs) for patients with JIA. Methods We conducted a retrospective cohort study of children diagnosed with JIA at a rheumatology pediatric clinic. Eligibility criteria were defined as children and youth newly diagnosed with enthesis-related arthritis, polyarticular, or oligoarticular JIA between 2011 and 2019, with at least one year of observation. Data on c-DMARDs and b-DMARDs prescriptions were obtained from electronic medical charts. We used descriptive statistics, Kaplan–Meier survival methods, and Sankey diagrams to describe treatment prescription patterns. Results A total of 325 patients with JIA were included, with a median observation time of 3.7 years. The most frequently prescribed c-DMARD and b-DMARD were methotrexate and etanercept, respectively. Within the first year of rheumatology care, 62% and 21% of patients had a c-DMARD and a b-DMARD prescribed, respectively. These proportions varied greatly by JIA subtype. Among the 147 (147/325, 45%) patients that had at least one b-DMARD prescribed, 24% were prescribed a second, and 7% a third-line of b-DMARD. A total of 112 unique treatment sequences were observed, with c-DMARD monotherapy followed by the addition of either a b-DMARD (56%) or another c-DMARD (30%) being the two most prevalent patterns in this cohort. Conclusion We observed a variety of treatment trajectories, with many patients experiencing multiple treatment lines, illustrating the complexity of the overall JIA treatment path.