On the 31 December 2014, 13-year-old Peter Baldwin from Cardiff, UK, was taken to
his GP with symptoms of a worsening chest infection, thirst and tiredness. His blood
glucose was not checked, new-onset type 1 diabetes was missed, and Peter subsequently
went on to develop severe diabetic ketoacidosis (DKA). Despite the best efforts of
paramedics and healthcare staff, Peter unfortunately did not get past the first few
days of his type 1 diabetes and passed away soon after. A tragic loss to all that
knew him, and of a promising young life [1].
Unacceptably high proportions of children are diagnosed in DKA (24% in England and
Wales, 30% in the US state of Colorado [2, 3]). In this issue of Diabetologia, Lundgren
and colleagues report the results of a study that extends our understanding of some
of the benefits of screening and allows us to explore more proactive approaches to
diagnosing type 1 diabetes [4].
Detectable evidence of beta cell immunity precedes the clinical presentation of type
1 diabetes by a number of years [5]. This immunity is most efficiently measured by
a blood test for autoantibodies to beta cell-associated proteins such as GAD, insulin
and islet antigen 2 (IA2) [6]. Combined with the use of genetic markers [7] and oral
glucose challenge, these tests allow detection of people at risk of developing type
1 diabetes long before the onset of hyperglycaemia and of symptoms [8]. Currently,
these investigations are used for research purposes, to understand the natural history
and development of type 1 diabetes, and to identify individuals in whom prevention
therapies can be tested.
However, cases like those of Peter Baldwin, and the significant proportion of children
who present with DKA at diagnosis, make us question whether these screening tests
should be rolled out to the general population. This is an emotive topic and one we
should explore carefully. The current thinking on this subject suggests we should
not be routinely screening for type 1 diabetes because there is no therapy currently
proven to prevent or significantly delay the onset of this condition. This is supported
by guidelines from respected authorities in this area [9]. However, this does not
consider the benefits associated with early detection of type 1 diabetes, not least
of which is prevention of death by DKA.
So, what are the benefits of screening for type 1 diabetes? A number of research studies
have now outlined what these may be (Table 1). These research studies have either
screened the general population or been more focused and screened people deemed at
risk because they have a family member with the disease. Screening has been undertaken
through genetic and autoantibody tests followed by glucose tolerance tests for those
deemed at risk. To date, screening studies have largely studied children and not explored
adults (the age group in which almost 40% of type 1 diabetes presents). The benefit
most consistently reported across these studies is avoidance of DKA. This is a significant
benefit, with a reduction from a quarter of new type 1 diabetes being diagnosed in
DKA down to 3%. Also, presumably because they are diagnosed at an earlier stage of
disease, there is more residual beta cell function (as measured by C-peptide), lower
insulin requirements and lower HbA1c at the time of diagnosis [10–15]. The paper by
Lundgren and colleagues [4] adds to the evidence. They report from follow-up of the
Diabetes Prediction in Skane (DiPiS) study, where almost 40,000 children in southern
Sweden were screened for type 1 diabetes. Of these, 6000 were deemed to be at some
degree of risk and offered follow-up. About two-thirds accepted this offer of follow-up.
Lundgren and colleagues report on the outcome of the 51 children who developed type
1 diabetes in the follow-up group, compared with the 78 who developed type 1 diabetes
but had not accepted the offer of follow-up. Children who chose follow-up had a lower
frequency of DKA (2% vs 18%), and lower HbA1c (9 mmol/mol [0.8%] lower) at diagnosis.
Importantly, HbA1c remained significantly better up to 5 years after diabetes diagnosis.
A potential caveat is that a greater proportion of the participants who opted for
follow-up had mothers of Swedish origin, and a greater engagement in research may
reflect a propensity for greater involvement in diabetes care following diagnosis.
That said, this is the first time that such a prolonged HbA1c benefit has been reported,
and this HbA1c benefit has a clear clinical and economic benefit. Furthermore, since
HbA1c generally tends to rise in the first years after diagnosis, and then stabilise
and ‘track’ after about 5 years [16], we could postulate that the lower HbA1c levels
in the follow-up group persist over the long term.
Table 1
Benefits associated with screen-detected type 1 diabetes
Study
Age group
Less DKA
Lower HbA1c
Lower insulin dose
Shorter period in hospital
Others
BabyDiab and Munich Family study [27]
Paediatric
Y
Y
N
Y
DiPiS [10, 11]
Paediatric
Y
Y
N
ND
TEDDY [13]
Paediatric
Y
Y
Y
ND
Higher residual C-peptide
DAISY [12]
Paediatric
Y
Y
Y
Y
DIPP [14, 15]
Paediatric
Y
Y
ND
ND
Less weight loss
DAISY, Diabetes Autoimmunity Study in the Young
DiPiS, Diabetes Prediction in Skane
DIPP, Finnish Type 1 diabetes Prediction and Prevention
ND, not determined
TEDDY, The Environmental Determinants of Diabetes in the Young
Do these benefits make a workable case for screening? There are those who would put
forward a scientific argument to support this case [17, 18]. To provide some clarity,
Table 2 presents the benefits of screening against the WHO guidelines for screening,
originally proposed almost 50 years ago [19]. Here, the benefits relate to early detection,
and not to prevention of the disease. There are a number of criteria that remain to
be satisfied.
Table 2
Screening for type 1 diabetes set against WHO criteria for screening [19]
Criterion
Satisfied
The condition sought should be an important health problem
YesType 1 diabetes is an important health problem. Whilst early screening does not
currently allow us to institute preventative therapy, it may prevent comorbidity associated
with late presentation
There should be an accepted treatment for patients with recognised disease
YesPeople at risk will be provided with education until they are formally diagnosed
with diabetes, at which time they will be initiated on insulin. Early education and
initiation of insulin are likely to be acceptable and effective
Facilities for diagnosis and treatment should be available
YesMost healthcare facilities have access to phlebotomy and oral glucose challenge
facilities. Samples can be sent to reference centres nationally for analysis
There should be a recognisable latent or early symptomatic stage
YesLatent and early symptomatic phase can be detected through autoantibody and glucose
challenge
There should be a suitable test or examination
YesPeripheral blood tests for antibodies and oral glucose challenge
The test should be acceptable to the population
Not knownThe psychological consequences of awareness of high risk of a chronic disease
for which there is no cure is not known
The natural history of the condition, including development from latent to declared
disease, should be adequately understood.
Not knownNatural history remains to be fully elucidated, different rates of progression
remain to be understood. Age, ethnicity and environment appear to influence natural
history and these effects remain to be elucidated
There should be an agreed policy on whom to treat as patients
YesPeople fulfilling standard WHO criteria for diabetes will be treated as diabetic
The cost of case-finding should be economically balanced in relation to possible expenditure
on medical care as a whole
Not known
Case-finding should be a continuing process and not a ‘once and for all’ project
YesA long-term programme can be implemented nationally
First, we do not know the psychological consequences of alerting a person to a condition
for which there is no current cure. Granted, this time may usefully be spent in educating
and preparing the person for managing type 1 diabetes. However, concurrent work on
the psychological impact of informing patients of high risk of type 2 diabetes suggests
that, even with a condition that can be significantly delayed, there can be a negative
psychological impact. These include negative markers of mental health, reduced motivation
and lack of engagement with behaviour change [20].
Second, the natural history of type 1 diabetes is still not clearly understood, and
the influence of age, ethnicity and environment remain to be elucidated. The environment
may influence the rate of development, as evidenced by migration studies, where populations
migrating from areas of low incidence to high appear to adopt the risk of the host
population [21]. Whilst we previously believed that rates of beta cell loss were faster
at a younger age, more recent work suggests that the rate may remain the same across
the age spectrum [22], despite islet histology changing with age of presentation [23].
Importantly, all major screening studies to date have focused on children.
Lastly, the cost benefit needs to be established for a formal screening programme.
Since 2015 the Bavarian Fr1da study has been screening children aged 3–4 years for
type 1 diabetes [24]. The aim is to screen 200,000 children, with each screening roughly
costing 20 Euros per child. If DKA and hospitalisation is prevented in 200 children,
this cost saving will in itself cover a third of the cost of the study. Furthermore,
patients presenting with DKA tend to have an HbA1c that is up to 1.4% higher than
those who do not over the long term [3]. If the lower HbA1c reported by Lundgren et
al persists to reduce the incidence and economic impact of diabetic complications,
combined with the saving on DKA cost, we may be a significant way to covering the
economic cost of screening. Further work is required in this area.
Until some of the issues above are resolved (and there is significant work ongoing)
the way forward is in public and healthcare education, and raising awareness. As a
direct result of the efforts of Peter Baldwin’s family, the Welsh government recently
(October 2018) discussed ten recommendations around raising awareness of type 1 diabetes.
These recommendations include adopting the Diabetes UK 4Ts campaign [25], and a recommendation
that all cases diagnosed in DKA are reviewed for shared learning [26]. These measures
are critical if we are going to make a meaningful change to the devastation caused
by death by DKA.