Health economics in osteoporosis : construction and application of a new state-transition microsimulation model
Creators: name: Si, L
Publisher: name: University Of Tasmania
Year: 2023

description: Osteoporosis is a chronic disease causing a huge disease and economic burden to the society. Many screening and treatment interventions are effective at preventing osteoporotic fractures, while implementation of such interventions incur substantial costs. Health economics modelling plays a critical role in evaluations that aim at identifying interventions representing the best value for money. This thesis presents the construction and validation of a new state of the art osteoporosis health economics model, and key important examples of its application in the health economic evaluation of screening for osteoporosis and fracture prevention. Chapter 1 presents a general introduction to osteoporosis and health economics. Chapter 2 presents a systematic review of all osteoporosis health economic models and the evolution of modelling in the field of osteoporosis over the past decades. Osteoporosis health economic models have improved with the development of more sophisticated modelling techniques. In addition, medication persistence and adherence have become increasingly recognized as important factors influencing the long-term cost-effectiveness of osteoporosis treatments and have been increasingly incorporated in recent models. This review then guided the development of a state of the art model that built on the strengths and overcame the deficiencies identified. One of the key issues in the cost-effectiveness analysis is to assign the health related-utility values (HSUVs) to different disease states. Chapter 3 presents the development of a standard set of HSUVs for osteoporosis-related conditions using a systematic review and meta-analysis approach. Fracture events have great impacts on HSUVs, particularly for patients with hip and clinical vertebral fractures, but multiple studies have produced a range of values for the impact of fractures on HSUVs. A systematic review and meta-analysis is performed in order to provide summary measures of HSUVs before and after fractures, to be used in future health economics models. HSUVs improve with time after fracture events, but still remain lower when compared with pre-fracture HSUVs. Chapter 4 is the key to this thesis, and documents the development and validation of a new state of the art osteoporosis health economics model. The model is a state-transition microsimulation model incorporating major clinical outcomes of osteoporosis. It is validated in the Chinese population but is flexible to be adapted to other populations, and demonstrates good face, internal and external validities. Chapter 5 to 7 are three key examples of the model application in cost-of-illness and cost effectiveness studies. Chapter 5 presents the first example of the application of the new osteoporosis health economics model to estimate the absolute risks of osteoporotic fractures in the Chinese population. More than 40% of Chinese women and approximately 10% of Chinese men aged 50 years are expected to have the first osteoporotic fracture in their remaining lifetimes. Compared to the rest of the world, Chinese women have higher age-matched risks of osteoporotic fractures. Chapter 6 presents the second example of the model's application: a cost-of-illness study, which quantifies the magnitude of the cost of osteoporosis fractures in China. Annual fracture numbers and costs are estimated for the entire Chinese population. Additionally, projections of the number and costs of fractures through to the year of 2050 are performed. Approximately 2.33 (95% CI: 2.08, 2.58) million osteoporotic fractures are estimated to occur in 2010, costing USD 9.45 (95% CI: 8.78, 10.11) billion. The number and costs of fracture are estimated to double by 2035 if no action is taken. Chapter 7 presents the third example of the model's application. While Chapter 6 informs us of the size of the problem, Chapter 7 identifies possible strategies to address the problem. A cost-effectiveness analysis of different osteoporosis screening and treatment strategies is conducted using the osteoporosis health economics model. Pre-screening with quantitative ultrasound (QUS) with subsequent dual energy X-ray absorptiometry (DXA) screening if the QUS T-score‚Äöv¢¬ß-0.5 with a 2-year rescreening interval in the Chinese women starting at age 55 is the most cost-effective. Moreover, screening and treatment strategies are cost saving if the screening initiation age is 65 years. This thesis presents a range of health economic modelling studies with its construction, validation and application in health economic evaluations. This work will be useful in the scientific community and healthcare decision making in osteoporosis. Further, the model will be adapted to other populations to support the pharmaceutical submissions and identifications of osteoporotic fracture preventions that present best value for money.