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FAQ



Q1.In the resource paper that justifies intervention thresholds, a willingness to pay of £20,000 per QALY gained has been used. The NOS and others have repeatedly pushed NICE to adopt a threshold of £30,000/QALY gained, as in other long term conditions. Why has the higher threshold not been adopted in these analyses?
A1.Health economic data were not used to set intervention thresholds. Rather, the intervention thresholds were based on RCP guidelines. It so happens that the NOGG recommendations are cost-effective even using a willingness to pay threshold as low as £20,000/QALY.
Q2.How has FRAX® been used alongside the economic modelling, since the latter uses a lifetime horizon and FRAX® uses a 10 year horizon to calculate absolute risk.
A2.The approach used is the same as used by NICE for the appraisal on the statins. i.e. the clinical management is based on 10 year risk but the cost-effectiveness is based on lifetime horizons. The output of FRAX® as a 10 year probability is a balance between incidence (approximately a 1 year probability) and lifetime probability. The former yields such low numbers as to be unmanageable by physicians and patients. Lifetime probabilities decrease in old age and are only of relevance to patients if they commit to lifetime treatment.
Q3.Why are there different thresholds for BMD testing and treatment based on age, given that FRAX already includes age as a risk factor? An 80 year old woman has to have four times the risk of having a fracture compared to a 50 year old in order to access treatment. Does this not discriminate against the elderly?
A3.The intervention thresholds are based on RCP and European guidelines. The threshold fracture probability thresholds are set at the fracture probability equivalent to an individual with a prior fracture. This is age dependent so that the use of FRAX® ensures that treatment decisions are based entirely on age-specific absolute risk .The proportion of women eligible for treatment increases with age.
Q4.Why not use a single intervention threshold for all ages?
A4.If a single intervention threshold were to be used, this would result in under-treatment of younger people and over-treatment of older people. It is important to ensure that younger patients at risk of fracture are not neglected, but their inclusion has not been at the expense of older individuals.

Treatment with and without DXA

Q5.Has the availability of DXA has been considered in setting the upper and lower assessment thresholds? Is this not a form of rationing?
A5.The availability of scanners was not considered in developing the strategy for the UK. It is true that FRAX® can be used without BMD, and indeed the performance characteristics of FRAX without BMD are about as good as BMD alone in fracture prediction. The decision to recommend BMD in a segment of the population, rather than the whole population is that, with the exception of North America, no agency including government agencies in the UK, currently supports the use of population screening. This is because of the low sensitivity of BMD for fracture prediction. The assessment thresholds chosen by NOGG are based on minimising the likelihood of incorrectly misclassifying a high risk patient as low risk and minimising the likelihood of incorrectly misclassifying a low risk patient as high risk. For details see the resource documents.
Q6.As this guideline will offer "best practice" advice, should not clinicians use BMD testing when they feel that this is appropriate, rather than be driven by assessment thresholds?
A6.There is nothing in the wording of our guideline that prevents a clinician from performing DXA where he or she feels that this is clinically appropriate. As with all guidelines, there has to be some flexibility and room for clinical judgement.
Q7.Should not FRAX® be used in conjunction with BMD rather than as a replacement for it?
A7.The FRAX tool incorporates BMD. The decision to do a BMD measurement depends on whether the test could influence patient management. The assessment thresholds used make incorrect classification unlikely. Having decided to treat, a physician may well order a BMD test to monitor treatment
Q8.I am concerned about the use of treatment without a BMD test because most of the clinical trials have used treatments on the basis of BMD.
A8.It is true that the majority of the evidence base for fracture reduction with pharmacological interventions is based on women with osteoporosis or established osteoporosis. There are several reasons that indicate that responses to treatment would not be impaired in women without osteoporosis. First, there are now several trials where good treatment effects are seen with women recruited on the basis of a prior fracture, age or glucocorticoid exposure. Second, several studies have shown the expected benefits on fracture risk in women from the general population and not selected on the basis of any risk factors for fracture. Third, in the vast majority of phase III studies comparable effectiveness has been shown in subgroups with and without the clinical risk factors used in FRAX. Fourth, the vast majority of women with high fracture probability as assessed by FRAX® have low BMD. Finally, recent phase III studies have shown that the use of FRAX, even without BMD, identifies women in whom treatment is effective.

The CHMP of the European Medicines Evaluation Agency have endorsed the use of fracture probability based on clinical risk factors and BMD in their revised guidelines issued in May 2007 and now demand that all new studies of pharmacological treatment enrol on the basis of fracture probability, not BMD ± fracture. As noted, recent phase III studies have shown efficacy of interventions for vertebral and non-vertebral fracture outcomes in patients selected on the basis of clinical risk factors.
Q9.Will treating individuals with a fracture without BMD mean that those who have severe osteoporosis with very low BMD will not be differentiated from those with normal BMD and will not undergo appropriate testing for underlying causes?
A9.A decision to intervene without knowledge of BMD is not the same as mandating that a BMD should not be undertaken. A clinician can still decide to request a BMD measurement where investigation is required or as a baseline to monitor treatment.