Dementia screening: what’s the problem?

Whatever your political ideology, you can’t help be aware of the various vested interests at play in society.

Dementia is no different. Evidence-based policy is public policy informed by rigorously established objective evidence.  An important aspect of evidence-based policy is the use of scientifically rigorous studies to identify statistically-signfiicant conclusions, capable of improving policy-relevant outcomes. A business case, on the other hand, captures the reasoning for initiating a task. The logic of the business case is that, whenever resources such as money or effort are scarce, they should be in support of a specific business need, such as delivering a financial surplus or profit.

What is “screening for dementia”?

In the UK, physicians have been pretty clear that screening healthy people for disease or risk factors is justified only if there is strong evidence that the benefits outweigh the harms. Primary care, and the media at large,  can also help to open up a new market by referral to private health providers of screening services.

The “worried well” have traditionally tend to be natural targets, but it has been mooted recently that convincing someone that he or she “needs” to be screened for dementia is made much easier by the fact that she or she may be very frightened about such a diagnosis (Fox et al., 2013). Indeed, earlier this year, some leading medical practitioners warned that, “private health screening companies are using scare tactics to persuade people to part with their cash.”

Screening for dementia in England has been mooted before publicly, and largely has been driven by politicians rather than academics. Screening is defined as the process of identifying apparently healthy people who may be at increased risk of a disease or condition. They can then be offered information, further tests and appropriate treatment to reduce their risk and/or any complications arising from the disease or condition.

A specific problem to do with dementia is that dementia in fact covers a huge number of different causes with different clinical presentations, so it is not possible that there would be a single one ‘test’ for likely dementia in a person who is still living. Alzheimer’s disease, epitomised by early memory loss, is thought to be, by far, the most common type of dementia worldwide.

Are there any benefits of screening for dementia?

An evidence-based analysis of the likely benefits of treatment is important in any medical specialty. Dr Aseem Malhotra queried recently in the BMJ why an asymptomatic and active former US president, George W Bush, receive a stent after a yearly check up. Malhotra cites that, in economic terms, the average purchasing cost of the machine that works the pump is about £40 000 (a specialist cardiac hospital may buy one or two of these), and the individual pumps come at about £800 a patient. .

For the past few decades, scientists have been trying to identify reliable markers of substances found in the fluid surrounding the brain which might act as a marker of the most common type of dementia, Alzheimer’s disease, long before the onset of dementia. Other groups have desperately been trying to scan the brain to see if they can spot subtle changes in the brain much earlier on the onset of symptoms. Even parking aside the costs of these approaches, the results of these aggressive endeavours in biomarkers and neuroimaging have been poor.

There is no ‘cure’ for Alzheimer’s disease currently. “Cholinesterase inhibitors” constitute a class of drug used for Alzheimer’s disease, but the very modest effects of treatments to improve memory such as the cholinesterase inhibitors have in fact been well known for some considerable time (Holden and Kelly, 2002).  At the time of writing this article, these drugs were not shown reliably to slow down the rate of progression in the majority of clinical patients with this disease from any published study.

A mild cognitive impairment (“MCI”) is a clinical diagnosis in which deficits in cognitive function are evident but not of sufficient severity to warrant a diagnosis of dementia (Nelson and O’Connor, 2008). It might be attractive to think that MCI is a preclinical form of dementia of Alzheimer Type, but unfortunately the evidence is not there to back this claim up at present: only approximately 5-10% and most people with MCI will not progress to dementia even after ten years of follow-up (Mitchell and Shiri-Feshki, 2009).

However, it is argued by some that, In terms of service provision, one major issue is that in current systems less than a half of people with dementia have a formal diagnosis made, or contact with specialist services, at any time in their illness (National Audit Office, 2007). Such diagnosis and contact often only occurs late in the illness and in crisis when the opportunities for harm prevention are limited, according to Banerjee and Wittenberg (2009).

Leifer (2003) legitimately asks, “why diagnose a disease in its earliest stages if it cannot be cured?” A compelling reason is provided that patients and their friends or family have the moral right to know their diagnosis. On a practical level, it is reasonable to argue that any potential hazards can be minimised or eliminated (e.g., driving, use of a stove), and education of caregivers regarding the disease and its implications will allow them to adjust and adapt over a longer period of time.

Moral panic 

There has been much interest in working out why there has been a sense of ‘moral panic’ about certain public health messages. Dementia has often been presented as an ‘epidemic’ in the media, and Campos and colleagues (2006) believe that part of the answer may lie with overlapping (and often conflicting) set of economic interests among various public health constituencies. They cite that many of the leading obesity researchers who have created the official standards for what constitutes ‘overweight’ and ‘obese’ have also received sizable funding from the pharmaceutical and weight-loss industries.

People with financial interests seek out ways of affecting the social or political climate in which their business-oriented activities can thrive, to create new wealth. Tullock’s (1967) paper in the Western Economic Journal (now Economic Inquiry) is the foundational event in the theory of “rent seeking”. Whether  intended or not, the recent “Prime Minister Dementia Challenge” has created a perfect environment for such activities to take place.

Unfortunately, it is completely legal for the companies to offer these screening services, but their promotion of these services contrasts with the stance of the NHS which introduces screening programmes only after a robust review of the evidence against internationally recognised criteria by the UK National Screening Committee (McCartney, 2009). The UK National Screening Committee (“UKNHSC”) is responsible for making recommendations for screening across all clinical areas, including cancer. The last review completed in June 2010 decided that the UKNHSC did not recommend systematic national screening for Alzheimer’s disease in the UK.

This was yet further confirmed only a few months ago in the finding from a systematic review that screening the population for dementia offers no clinical benefits, while potential harms such as the risk of depression, anxiety, stigma or loss of independence remain unexamined in any study the researchers could find  (Hawkes, 2013). The study was presented this week at the Alzheimer’s Association International Conference in Boston.

All in it together?

There is now a ridiculous situation where even medics might be ‘divided’ over this issue. While the academic community is pretty consistent in their criticism, there is currently a policy in place for GPs to be paid for meeting targets in tests related to the dementia diagnosis known as “QOF” (currently under review.)

The ‘political drive’ in the UK most famously came under fierce criticism in the BMJ as follows:

Expanding the diagnosis of dementia mostly increases profit for corporations and industries involved with developing screening and early-diagnosis tests, and pharmaceutical and complementary medicines marketed to maintain cognition in old age.

.. The desire of politicians, dementia organisations, and academics and clinicians in the field to raise the profile of dementia is understandable, but we risk being conscripted into an unwanted “war against dementia.

(Le Couter et al., 2013)

The academic community, nonetheless, have possibly played a part in feeding this commercial “market”; they are themselves dependent on financial grants to survive.  The ‘Googlescope’, i.e. word searches through Google Scholar within the health-related literature, shows up a remarkably well-ordered increase in the proportion of papers mentioning ‘risk’ over 5-year periods from the 1950s to the present day (Heyman et al. 2009).

Conclusion

In any objective ‘Fact Check’, one cannot perhaps help avoid the conclusion that the case for dementia screening has been business case-led or evidence-based. It is a sad observation that the dementia policy is more to do with the economic, social and political power of vested interests rather than in the hands of experts who know about this field. Hopefully, with time, this mess will resolve itself.

 

Selected readings

Banerjee S, Wittenberg R. (2009) Clinical and cost effectiveness of services for early diagnosis and intervention in dementia. Int J Geriatr Psychiatry. 2009 Jul;24(7):748-54.

Campos P, Saguy A, Ernsberger P, Oliver E, Gaesser G. (2006) The epidemiology of overweight and obesity: public health crisis or moral panic?Int J Epidemiol, 35(1), pp. 55-60.

Fox C, Lafortune L, Boustani M, Dening T, Rait G, Brayne C. Screening for dementia – is it a no brainer? Int J Clin Pract. 2013 Aug 16. doi: 10.1111/ijcp.12239.

Hawkes N. Systematic review finds no benefits to population screening for dementia.BMJ. 2013 Jul 19;347:f4638. doi: 10.1136/bmj.f4638.

Heyman, B. Alaszewski, A, Shaw, M, Titterton, M. (2009) Risk, safety and clinical practice: health care through the lens of risk. Oxford: Oxford University Press.

Holden, M., and Kelly, C. (2002)) Use of the cholinesterase inhibitors in dementia, Advances in Psychiatric Treatment, 8, pp. 89-96.

Le Couteur DG, Doust J, Creasey H, Brayne C. Political drive to screen for pre-dementia: not evidence based and ignores the harms of diagnosis. BMJ. 2013 Sep 9;347:f5125. doi: 10.1136/bmj.f5125.

Leifer BP. Early diagnosis of Alzheimer’s disease: clinical and economic benefits. J Am Geriatr Soc. 2003 May;51(5 Suppl Dementia):S281-8.

McCartney M. (2012) What companies don’t tell you about screening. BMJ. 2012 Mar 28;344:e2311. doi: 10.1136/bmj.e2311.

Mitchell, A.J., and Shiri-Feshki, M. (2009) Rate of progression of mild cognitive impairment to dementia -meta-analysis of 41 robust inception cohort studies. Acta Psychiatr Scand, 119(4), pp. 252-65.

Nelson, A.P., and O’Connor, M.G. (2008) Mild cognitive impairment: a neuropsychological perspective, CNS Spectr, 13(1), pp. 56-64.