  |
|
|
||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||
| Journal of the New Zealand Medical Association,
17-December-2004, Vol 117 No 1207
|
||||||||||||||||||||||||||||
|
Diabetes in children and young adults in
Waikato Province, New Zealand: outcomes of care
Adrian Scott, Susie Whitcombe, David Bouchier, Peter
Dunn
Children diagnosed with type 1 diabetes (T1DM) have a poor
prognosis compared to their non-diabetic
counterparts.1–4 It is 10 years since the
Diabetes Control and Complications Trial (DCCT) reported the beneficial effects
of tight glycaemic control in adults and
adolescents.5
Unfortunately, the care of young people with diabetes is
challenging and for many centres a mean HbA1c over 9% for this group is quite
common (despite intensive efforts) leading some clinicians to believe that poor
control is inevitable. Indeed, recent studies from Europe and Japan have
illustrated the difficulties of achieving and maintaining good glycaemic
control; the high prevalence of complications and the wide range of glycaemic
control between centres being unrelated to patient selection or choice of
insulin regimen.6–11
Nevertheless, some centres consistently have mean HbA1cs as
good if not better than the Intensive arm of DCCT, without the increased risk of
hypoglycaemia.12–14
Type 2 diabetes was once unknown in children but is increasingly recognised with
the rise of obesity. We have reviewed our own experience of managing these young
people.
SettingWaikato District Health Board (DHB)
serves approximately 9% (312,918 in the 1996 Census) of the total New Zealand
population, in a largely rural setting in the North Island. Approximately 20% of
the Waikato population identify themselves as Maori. An estimated 10,000 (New
Zealand Ministry of Health data) of these 312,918 people have diabetes
(predominantly type 2 diabetes mellitus [T2DM]), which is more common among
Maori and Pacific Islanders.
Children and young people with diabetes attend the Diabetes
Unit or Paediatric service in Hamilton City, or one of the outlying clinics, and
are looked after by an adult endocrinologist (PD) or paediatrician (DB) and
nurse educator (SW). Dietetic input is more limited and most advice comes from
the nurse educator.
Children up to age 16 were always admitted at diagnosis;
above that age, some patients living near the hospital may be treated as an
outpatient provided they were not in ketoacidosis. Since Waikato Hospital serves
a wide geographical area, most young people were admitted for at least 48 hours
for initiation of treatment and initial education.
Twice daily regimens were common but now most patients aged
over 7 years move swiftly to a basal bolus regimen with twice-daily Isophane and
mealtime short-acting insulin, predominantly Lispro or Aspart, although some
patients remain on soluble insulin. Insulin glargine was not available in New
Zealand at the time of the audit.
Under that age (7 years), twice daily regimens are more
common because of the difficulty of giving insulin during school hours. For
about 4 years we have taught carbohydrate-counting (to facilitate insulin
adjustment) and daily blood glucose testing before meals, and bedtime is
encouraged. Patients going on to pumps attend a 1-week education course with a
specially trained nurse specialist and dietitian.
Retinal screening is undertaken by retinal photography every
2 years from the age of 16 years. Photographs are taken with pupils dilated and
graded by a consultant ophthalmologist who undertakes slit lamp examination if
significant retinopathy is identified.
Foot examination is performed using either a biothesiometer
or a 10 gram monofilament. Data on severe hypoglycaemia is not consistently
recorded so has not been included. This audit of the outcomes of care of
children and young adults with diabetes was carried out in July 2003
MethodsA Microsoft Access database
holds data on all patients who are current attenders or have attended the
diabetes unit in Hamilton, Waikato. Records on 315 people with diabetes born
after 1st January 1978 were analysed. Type 1
diabetes was diagnosed in the presence of diagnostic blood sugars in combination
with ketonuria or ketoacidosis and/or positive anti IA2 and anti-GAD antibodies.
Type 2 diabetes was diagnosed in those individuals who had negative antibodies
or had no history of ketoacidosis. One patient had ketonaemia at diagnosis but
was not acidotic. When subsequently found to have negative antibodies his
insulin was successfully withdrawn and he was treated with Metformin for over 1
year with HbA1c of <7%. 251 (237 with T1DM, 13 with Type 2, 1 with secondary
diabetes) had attended at least once in the last 3 years. The remainder had
either moved away or been lost to follow-up and were excluded.
Where data was missing, the paper records were examined
(n=105). For missing blood and urine values, the local laboratories (Waikato
Hospital, Medlab, Pathlab) were contacted.
Admission and outpatient attendance data was obtained
by a query to the HOSPRO information system.
Where appropriate, data is expressed as mean (95%
Confidence Intervals).
Microalbuminuria defined as an Albumin / Creatinine
Ratio (ACR) >2.5 in males; >3.5 in females, on more than one occasion. Two
or more abnormal results are required to confirm persistent microalbuminuria.
Proteinuria was defined as ACR >30. Body mass index (BMI) was calculated from
weight (kg) / [height (m)]2
For patients under 20 years of age, BMI-for-age
percentiles were calculated using the National Center for Chronic Disease
Prevention Growth Charts.
For this audit, we used the American Diabetes
Association recommendations15 for treatment of
hyperlipidaemia over the age of 10, if the LDL cholesterol is ≥4.1 mmol/L
and to consider therapy if LDL is 3.4-4 mmol/L if there are other cardiovascular
risk factors present. Target LDL is < 2.6 mmol/L.
ResultsAll patientsThere were
251 young people with diabetes (237 Type 1; 13 Type 2; 1 chronic pancreatitis);
135 were female; and 212 described themselves as of European origin, 27 as
Maori, 5 as Pacific Islander, 4 as Asian (Chinese), and 3 as Indian.
Four patients (1.6%) were hypothyroid and 1 (0.4%) had
previously been thyrotoxic and was now euthyroid; 6 (2.4%) had coeliac disease.
Three patients had symptomatic peripheral neuropathy (1%) and 6 (2.4%) were
recorded as having depression.
Over 5 years there have been 504 in-patient episodes (2 per
patient) amounting to 1994 days in hospital (7.9 days per patient). There were a
total of 7063 outpatient attendances (5.6 per patient per year).
Type 1 diabetesDemographic details are indicated in
Table 1. Glycaemic control was generally poor but worst in the 15-19 year age
group (Table 2). There was no relationship between insulin regimen and glycaemic
control.
In the patients who were 15 years and younger with T1DM,
urine had been measured for protein in 48 of 99 (48%). In those patients aged 16
year and over, urine was measured for protein in 119 of 138 (86.2%). Proteinuria
was present in 4 patients, microalbuminuria in 25 patients (7 with intermittent
microalbuminuria but in 4 patients, only 1 specimen had been tested) giving a
prevalence of nephropathy of 18-29/119 (15-22%).
Of 220 children aged over 10 years, 166 (75%) had lipids
measured. One patient was taking a statin. There were 89 (54%) with an LDL
>2.6mmol/L, 14 (8.4%) with LDL≥4.1mmol/L, and 3 (1.8%) with LDL
3.4–4.0 mmol/L and one other risk factor (smoking, hypertension, or
microalbuminuria). All patients had smoking status recorded; 18 are current
smokers , 5 are ex-smokers.
Table 1. Type 1 diabetes by age—glycaemic control
and insulin regimens
In the patients aged 16 and over, blood pressure (BP) was
measured in 135 (97.8%) of them; 11 (8.1%) patients had a systolic BP ≥130
mmHg, and 10 (7.4%) patients had a diastolic BP ≥80 mmHg.
BP was measured in 89% of the patients aged 15 years and
younger; 2 (2.2%) patients had systolic BP >120 mmHg (1 with coarctation),
and 3 (3.4%) patients had a diastolic BP >70 mmHg.
Of those patients with T1DM, 26.9% of males and 29% of
females were overweight or obese. Of those patients aged under 20 years, 16
females and 9 males had a BMI-for-age between the
85-95th percentile; 5 females and 3 males under
20 year had a BMI-for-age ≥95th centile.
In the over 20 years age group, 16 males and 4 females were overweight, 4 males
and 12 females were obese.
Of those patients with T1DM, 67 had a duration of diabetes
over 10 years. Of these, 25% had evidence of nephropathy (12 had
microalbuminuria and 5 proteinuria), one of whom is on CAPD. Six (9%) patients
had no documented eye screening—but of the remainder, 25% had retinopathy
(10 background,
5 sight threatening); 41 (61%) had LDL cholesterol >2.6 mmol/L, and 9 (13.4%)
would qualify for statins using the ADA criteria. Nine (13.4%) patients are
current smokers, 2 (3%) peripheral neuropathy, and 3 (4.5%) are listed as
suffering from depression.
Type 2 diabetes:There were 13 patients (including 7
males) with T2DM. The 13 patients included 7 Maori, 1 Pacific Islander, 4
European, and 1 Asian Indian. One teenager had Prader Willi syndrome. The mean
age was 19.6 years (range 14–23 years) and duration of diabetes was 1.7
years.
All patients were obese with a BMI 39 (males 37.3; females
40.3). Mean HbA1c 8.8%. Six were treated with diet alone, 4 with Metformin
alone, 1 with insulin only, 2 with insulin plus Metformin, and 1 with insulin
plus Acarbose. Five (38%) patients had a systolic BP >130 mmHg or diastolic
BP >80 mmHg. Two (15%) had microalbuminuria, one of whom was on an ACE
inhibitor. Six (46%) patients had attended retinal screening—none had
retinopathy.
Nine patients had their fasting lipids measured; their mean
total cholesterol level was 5.6 mmol/L, HDL 1.1 mmol/L, triglycerides 6.4
mmol/L, and mean LDL 3.1 mmol/L. Three (33%) patients had LDL-C >3.4 mmol/L
and 1 (11%) patient had severe hypertriglyceridaemia (28 mmol/L).
Table 2. Glycaemic control by age in 251 children and
young adults with diabetes
DiscussionThis audit of the process and
outcomes of care of children and young adults with diabetes, in a semi-rural
district in North Island New Zealand, has demonstrated a disappointing picture
of poor glycaemic control and moderately high rates of microvascular
complications, as seen in other studies. Despite the use of multiple injection
therapy and carbohydrate-counting, few people achieved satisfactory control
(only 25% had a recent HbA1c ≤8%).
A limitation of our study is that the exact number of people
aged under 26 years with diabetes in Waikato is unknown. The published
literature on defaulters from follow-up, however, suggests they have worse
control and greater risk of
complications.16
Although glycaemic control is poor, it is similar to other
published studies in Europe of unselected young people with diabetes. Few data
on young people with diabetes in New Zealand are available. In Christchurch, the
mean HbA1c for people aged between 13 and 20 years was 10.2% and 9.5%,
respectively, for females and males.17
The type of insulin regimen (including use of pumps) does
not appear to have much impact on glycaemic control—although of 23
patients with a duration of diabetes >2 years and an HbA1c ≤7.5%, 6
were on 2 injections, 1 on 3 injections, 1 on 4 injections, and 13 on 5
injections (per day).
Twenty-two patients were using pumps. The pump data may be
misleading, however, as we have chosen to offer pump therapy to young people
having difficulty achieving satisfactory control with multiple injections, and
in this group there has been an overall reduction in HbA1c and admissions with
DKA (data not shown).
Age, sex, insulin regimen, BMI, season, social
circumstances, and family history were all associated with glycaemic control in
the Scottish study but not with deprivation score based on post code. Neither
the Hvidore nor the Scottish study6,10 were
able to identify definitive reasons for centre differences in mean HbA1c.
Dabaghdao18 suggested that
poor control in childhood led to poor control in adolescence and beyond. Other
studies have suggested that poor early control is associated with a four-fold
increase in the subsequent prevalence of
nephropathy19. An intriguing observation of the
DCCT collaborators was that the tight control (initiated 1 year after diagnosis)
was associated with preservation of islet cell function for a greater period
than the group randomised to conventional (poor)
control.20
There have been a few small studies, looking at the impact
on beta cell function and intensive normalisation of glycaemic control from
diagnosis with conflicting results, but no long-term randomised
studies.21,22
Interestingly, there are huge differences in the number of
children with a normal HbA1c during the first year after diagnosis. Some centres
achieve this result in as many as 74% of their
patients.23 Irrespective of the long-term
benefits, this implies significant differences in both expectation and training
of the person with diabetes.
Even when centres are benchmarked against others, it is
difficult to achieve a change in the overall mean
HbA1c.24 Nevertheless, Berger and colleagues
demonstrated that (in adults) a 5-day training course resulted in prolonged
overall improvements in HbA1c without a corresponding increase in severe
hypoglycaemia.25,26 Similar improvements were
seen in the DAFNE study in the UK, although adolescents were not
included.27
The prevalence of retinopathy among screened patients is
similar to published series,7,8,28,29 but there
were a worrying number of patients who appeared to have avoided retinal
screening for prolonged periods of time. Similarly, screening for
microalbuminuria appears to have been done in the majority of young people but
positive results were not always followed up.
Use of ACE inhibitors is reasonable in those with confirmed
nephropathy, although this partly depends on the criteria for diagnosis (of 13
young people with 3 or more abnormal results, 11 were on ACE inhibitors. None of
those patients with just 2 abnormal results were treated with ACE-inhibitors). A
significant proportion appear to have intermittent proteinuria and a recent
publication found that up to 60% of people with T1DM have spontaneous resolution
unrelated to ACE inhibitor use.30
Suboptimal lipid profiles were very common, and only one
patient was receiving any treatment. Cardiovascular risk charts will
underestimate risk and are inappropriate for this age
group.31 Only the American Diabetes Association
has published specific guidelines for young people with T1DM, and with the
knowledge that most will die prematurely from a vascular accident, earlier use
of statins may be appropriate. As with use of ACE inhibitors, however,
consideration has to be given to the risk to the developing foetus in the event
of conception occurring whilst taking them.
Nearly 30% of those with T1DM, and 100% with T2DM, are
overweight. This may reflect the rising incidence of obesity in children and
adolescents. In New Zealand, in 1997, approximately 25% of 15 to 18 year
olds and one in three 19 to 24 year olds were found to be overweight or
obese.32 Weight gain is common during
adolescence (especially in girls); and with intensive insulin therapy, the
weight gain can sometimes be spectacular33 and
likely to be a disincentive to better glycaemic control.
Perhaps the most worrying finding in our study was that of
those patients with T2DM. All 13 were diagnosed in the last 4 years (mean
duration 1.7 years) at an average age of 19.6 years. This rising incidence of
T2DM is predictable and parallels the increasing prevalence of obesity in
childhood.
Lastly, as we do not know how representative these data are
of New Zealand in general, we are undertaking a similar national audit in this
age group.
Author information:
Adrian R Scott, Consultant Endocrinologist, Regional Diabetes Service; Susie
Whitcombe, Diabetes Nurse Educator ; David Bouchier, Consultant Paediatrician,
Paediatric Department; Peter Dunn, Consultant Endocrinologist, Regional Diabetes
Service, Waikato Hospital, Hamilton
Correspondence: Dr
Adrian Scott, Diabetes Centre, Homerton University Hospital, Homerton Row,
London E9 6SR, UK. Fax: +44 208510501; email: xoe06@hotmail.com
References:
|
|
||||||||||||||||||||||||||
| | Current
issue | Search journal |
Archived issues | Classifieds
| Hotline (free ads) Subscribe | Contribute | Advertise | Contact Us | Copyright | Other Journals |
|