Elsevier

Bone

Volume 142, January 2021, 115682
Bone

Cost-effectiveness of treatment of women aged 70 years and older with both osteopenia and microstructural deterioration

https://doi.org/10.1016/j.bone.2020.115682Get rights and content

Highlights

  • Women with osteopenia are the source of over 70% of fragility fractures.

  • Fractures are largely due to microstructural deterioration, which is quantifiable.

  • We modelled screening & treatment of women aged ≥70 yrs. with structural decay.

  • Treating would save 18.1 life-yrs & 14.6 QALYs/1000 women over 10 years.

  • This was cost effective; $4992/life year saved & $6135/QALY saved.

  • Women with osteopenia and microstructural decay should be identified and treated.

Abstract

Objective

Treatment is usually withheld from women with osteopenia even though they are the source of over 70% of all women having fragility fractures. As microstructural deterioration increases fracture risk and zoledronate reduces it, we aimed to determine whether identifying and treating women with osteopenia and severe microstructural deterioration is cost-effective. We also compared the health economic outcomes of ‘global’ versus ‘targeted’ treatment using SFS of women aged ≥70 years with osteopenia.

Design

We assessed the cost-effectiveness from using a Markov model that simulated 10-year follow up of women with osteopenia. Decision analysis compared measurement of distal radial microstructure using high resolution peripheral computed tomography (at a cost of USD $210) to target women with severe microstructural deterioration for zoledronate treatment, compared to standard care defined as measurement of bone mineral density (BMD) with treatment recommended when femoral neck BMD T score is ≤−2.5 SD with or without a prevalent fracture. In the ‘global’ treatment approach, high resolution peripheral quantitative tomography (HRpQCT) was not undertaken.

Setting

US healthcare system.

Participants

A hypothetical cohort of 1000 women aged ≥70 years with osteopenia and no previous fractures was studied.

Measures

Fractures, deaths, years of life lived, quality-adjusted life years (QALYs) lived and costs. Data inputs were obtained from published sources. A 3% annual discount rate was applied to future health benefits and costs.

Results

Women in the standard care group incurred 327 fractures during 7341.0 years and 4914.2 QALYs lived. Women in the intervention group incurred 300 fractures (number needed to treat 37) during 7359.2 years and 4928.8 QALYs lived. Net costs were USD $4,862,669 and $4,952,004, respectively, equating to 18.1 years of life saved and 14.6 QALYs saved, and incremental cost-effectiveness ratios of $4992 per year of life saved and $6135 per QALY saved. These ratios are well within the threshold considered to be cost-effective. Sensitivity analyses indicated the results were robust.

Relative to standard of care, ‘global’ and ‘targeted’ treatment respectively resulted in 0.0364 vs. 0.0181 years of life (YoLS) saved per person, and 0.0292 and 0.0146 QALYs saved per person. The net costs per person for the respective approaches were $US 359 and $US 89. The incremental cost-effectiveness ratios were $9864 per YoLS and $12,290 per QALY saved for the ‘global’ approach and $4992 per YoLS and $6135 per QALY saved for the ‘targeted’ approach.

Conclusion

Identifying and treating women ≥70 years of age with osteopenia and microstructural deterioration with zoledronate cost-effectively reduces the morbidity and mortality imposed by fragility fractures. This ‘targeted’ approach is more cost-effective than a ‘global’ approach and incurs only 25% of total costs.

Implication

Women with osteopenia with bone fragility due to microstructural deterioration should be identified and targeted for treatment.

Summary

Women with osteopenia have 70% of fractures. Treating those with microstructural deterioration conferred an incremental cost-effectiveness ratio of $4992/year of life saved and $6135 per QALY saved.

Introduction

Advancing age is associated with bone fragility and an increased fracture risk [1]. The fracture burden is rising because longevity is increasing the number of older people in the community [2]. The term ‘osteoporosis’ is assigned to persons with bone mineral density (BMD) T-score of ≤−2.5 standardized deviations (SDs) below the premenopausal mean (1), but bone fragility is not confined to women with osteoporosis. Postmenopausal women with more modest deficits in BMD categorized as osteopenia, a BMD T-score between −1 and −2.5 SD, have a lower risk of fracture than women with osteoporosis, but they are not free of fracture risk [3].

Over 70% of all fragility fractures arise among the majority of postmenopausal women in the population with osteopenia [[3], [4], [5]]. This is similar to the burden of cardiovascular disease; most events arise from individuals with moderately hypertension or hyperlipidemia [6]. Thus, confining treatment to only women with osteoporosis fails to address the population burden of fractures.

Most fractures, particularly non-vertebral and hip fractures, which comprise over 70% of all fractures, occur in women over 70 years of age. Measurement of bone density forms part of the standard assessment of fracture risk in women presenting following a first fragility fracture or concerned about the possibility of a first fracture. However, uptake of therapy remains suboptimal, especially in women found to have osteopenia, even in the presence of a fragility fracture [7].

To curb this burden requires a strategy to identify and target postmenopausal women with osteopenia with bone fragility. Women with osteopenia at imminent risk (within 1–2 years) and intermediate risk (within 2–4 years) for fracture have bone fragility partly due to microstructural deterioration [[7], [8], [9], [10], [11]]. BMD does not capture this fragility because microstructural deterioration increases fragility disproportionately to the bone loss producing it and the modest BMD deficits of osteopenia [12].

These women can be identified by measuring microstructural deterioration using high resolution peripheral quantitative tomography (HRpQCT) and targeting them for therapy. We have quantified cortical and trabecular microstructural deterioration and expressed this deterioration as a structural fragility score. We reported using a threshold denoting severe structural deterioration captures a large proportion of women with osteopenia sustaining fractures before the event [3]. Treating women with osteopenia using zoledronate reduces fracture risk [13]. However, it is uncertain whether complementing a BMD measurement with additional measurement of the structural fragility score using HRpQCT to identify those at high risk with microstructural deterioration is cost-effective compared to current standard of care. We addressed this issue in the present study, adopting the perspective of the US healthcare system. We also evaluated and compared the economic outcomes of a ‘global approach of treating all women ≥70 years of age with osteopenia compared to current standard of care.

Section snippets

Model

A state-transition Markov model was developed in Microsoft Excel to simulate the progress of women aged ≥70 years with osteopenia, no previous fractures and a SFS of ≥70 at baseline [14]. The model comprised three health states: ‘Alive, no prior fracture’, ‘Alive, post fracture’ and ‘Dead’ (Fig. 1). ‘Fracture’ comprised major fragility fracture involving the hip, vertebra or wrist. All subjects began the simulation in the health state ‘Alive, no fracture’, and over yearly cycles, could develop

Results

The model predicted that in the Standard Care Group, 327 fractures (284 first and 43 recurrent) would have occurred over the 10-year time horizon among the 1000 subjects compared to 300 fractures (261 first and 39 recurrent) in the Intervention Group assessed using HRpQCT and treated based on finding SFS to be ≥70 units. Hence, targeting treatment based on the presence of severe microstructural deterioration prevented 27 fractures over the 10-year period, equating to a number needed to treat

Discussion

Measurement of severe microstructural deterioration identifies women aged ≥70 years with osteopenia at imminent risk for fracture [3]. Over 70% of the fracture burden in the community arises among women with osteopenia or normal BMD [[3], [4], [5],10]. The preliminary health economic analyses in that report [3], provided an indicative measure of cost-effectiveness using a simplified model structure and key data inputs with a modelled time horizon to five years. The parameters of the present

CRediT authorship contribution statement

D Liew: conceptualization, methology, software formal analysis, writing.

RD Chapurlat: investigation, resources, supervision, project administration, funding.

E Sornay-Rendu: investigation, resources, supervision, project administration.

Eric Lespessailles: investigation, resources, supervision, project administration.

Yu Peng: methodology, software, resources.

E Seeman: conceptualization, writing.

Declaration of competing interest

ES is a board member and shareholder in Straxcorp. YP is employee of Straxcorp.

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