In January of this year the journal Age and Ageing published a commentary piece with the title Rationing by frailty during the COVID-19 pandemic. It discusses the guidance published by NICE in March 2020 on assessing older patients for their suitability for admission to critical care (i.e. artificial organ support).
The guidance, which includes a decision flow chart with a place for a frailty score, is regarded by the authors as controversial - hence their paper. An anodyne summary of the guidance might run like this: frailty scores can be helpful in making frailty assessments; and frailty assessments are important for decisions about the likely benefits of admission to critical care. Frailty assessments are important because individuals can be so frail that they are very unlikely to benefit from this kind of support (i.e. it fails to be a life-saving procedure).
So what do the authors regard as controversial? Three things. Firstly, the inclusion of a particular threshold score on a scale (Clinical Frailty Score or CFS) as a step in life-or-death clinical decision-making carries with it the risk that clinicians may rely too much on a score that becomes a substitute for clinical judgement rather than an aid. It’s hard to know what to say on this matter since the guidance is quite clear that a ‘high’ frailty score is not by itself decisive when it comes to making a judgement about the appropriateness of critical care. It’s intended to be more like a warning sign to the clinician.
Secondly, NICE recommends the use of the CFS only for patients aged 65 years and over. For patients younger than 65 years, the guidance is clear: do not use the CFS; rather carry out an individualised frailty assessment. There is a reason for this apparently arbitrary age cut-off, namely, that the CFS has been validated for use only in older (65+) patients. Even so it doesn’t have a good look.
Lastly, the authors raise concerns about the underlying rationale for the guidance, which is to help clinicians make best use of limited critical care resources (i.e. rationing). And as they rightly say this raises a question of ethics: should frailty be used as a criterion for resource allocation - even in the context of a pandemic when pressure on critical care resources may be very great?
It is now quite a few years since frailty took on a life of its own as a technical term in epidemiological research and clinical medicine, and in that time various instruments have been developed to assess individual frailty by means of a numeric score. The basic idea is a health state which is clearly distinct from either multi-morbidity or disability, namely a heightened vulnerability to adverse health outcomes, i.e. frail individuals lack physiological resilience (or reserve) to such an extent that even health small shocks may be potentially life-threatening. Frailty instruments are used to identify individuals as being in this condition of heightened vulnerability by means of a cluster of indicators (weakness etc..) that should be manifest in clinical assessment. The test of a good instrument is its predictive power - does it succeed in picking out those individuals who really are in a state of heightened vulnerability to shocks? More recent instruments allow for discrimination between different degrees of frailty.
Since frailty - by definition - is a present condition which is predictive of future outcomes in case of a health shock, it should come as no surprise that studies conducted over the last year have shown it to be strongly associated with COVID mortality. One example of this is the COPE study published in the Lancet Public Health last August. This is an observational study conducted in 10 hospitals in Italy and the UK last spring. Patients were eligible to participate only if they had been hospitalized with COVID and were 18+ years. All participants were assessed on admission for frailty with the Clinical Frailty Scale (CFS - the same scale recommended by NICE), and the main outcome measure was mortality 7 days after admission. The headline result is that the CFS score was a better predictor of mortality than either age or co-morbidity. Of course, this is just one study, and not all studies report the same finding. So the best evidence to use will come from a systematic review/meta-analysis - and the only one I found supported the conclusion of the COPE study. One caveat though, the threshold score used in the COPE analysis is higher than the score suggested by NICE. Indeed, as we might expect, there was a dose-response relationship between the level of frailty (as measured by the CFS) and mortality.
Retrospectively then we can say that there is an evidence base for the NICE recommendation to use CFS scores to help make a decision about the appropriateness of critical care. But this hardly settles the ethical question raised by the Age and Ageing paper. And besides there is the matter of the threshold score on the CFS. What should it be? The answer has to be that the score - whether the threshold is 5 or 7 - should not be decisive in making a judgement about the appropriateness of critical care. It should give the clinician pause for thought - “now give serious consideration to the question of the appropriateness of critical care”. There is, however, an implicit qualification to this - “now give serious consideration to this question if (and only if?) you are confident that there will be continuing - and exceptional - high demand for critical care beds over the next few days” (my quotation marks). What the qualification means is that the clinician is not making a decision based solely on an assessment of the balance of likely harms and benefits for this particular patient (i.e. this course of action is likely to cause needless suffering). They are being given permission - in a manner of speaking - to make a decision for this particular patient based on an assessment of the best use of the limited number of available beds.
Which brings us to the crux of the matter. Are there circumstances in which a clinician might be justified in making a decision about critical care on such a basis? Does a serious pandemic count as such circumstances? Is it ethical to use an assessment of frailty as an aid to decision-making in such circumstances?
The commentary refrains from giving a definite YES/NO answer to the last of these questions - though the authors are clearly troubled by the guidance. They do suggest, however, that the close correlation between age and loss of physiological reserve is perilously close to age-based rationing - even though they do hold back from saying that use the of frailty assessments in these circumstances actually amounts to age-based rationing. They are more guarded in their conclusion - “Rationing care based on estimated physiological reserve is undoubtedly intimately linked with chronological ageing, and the ethical implications of this have yet to be fully grappled with”.
About the Authors:
Kenneth Howse is a Senior Research Fellow at the Oxford Institute of Population Ageing. He is also a key member of The Oxford Programme on Fertility, Education and the Environment (OxFEE).
Opinions of the blogger is their own and not endorsed by the Institute
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