86
VOLUME 10 NUMBER 3 • SEPTEMBER 2013
RESEARCH ARTICLE
SA JOURNAL OF DIABETES & VASCULAR DISEASE
129 patients who experienced documented hypoglycaemic events
were also on sulphonylurea treatment. In the control group, of
the 24 patients who had documented hypoglycaemia in the past
year, 17 patients were on insulin, 6 patients were on sulphonylurea
treatment and one patient, who was on diet control only and
who was not on any glucose lowering medication, experienced
clinical symptoms of hypoglycaemia post-prandially which were
subsequently documented as hypoglycaemia.
In the control group, for those patients who did received glucose
lowering therapy (
n
= 229), documented hypoglycaemia in last year
was 10% (
n
= 23) compared with the DPP-4 inhibitors group (
p
<
0.02). There was no report of pancreatitis or pancreatic cancer in
either group.
Comparing the social support structures in the two groups, 9% of
the patients in the DPP-4 inhibitors group lived alone compared with
11% in the control group. Significantly fewer people in the DPP-4
group lived in sheltered accommodation, residential home or care
home than the control group, 2% vs. 9% respectively (
p
= 0.011).
The DPP-4 inhibitor group had a significantly lower (
p
= 0.013)
incidence of dementia (3%) than the control group (10%).
With respect to the patients in the DPP-4 inhibitor group,
74.3% received sitagliptin, 21.8% vildagliptin and 3.9% received
saxagliptin. The pre-treatment median (range) HbA
1C
was 8.3%
(5.5–12.7) and the post-treatment HbA
1C
was 7.4% (5.7–10.3). For
blood results to be included in the study, the patient had to have
received three months of continuous treatment with the medication
prior to the test being performed.
Discussion
Treating older patients with type 2 diabetes remains a challenge.
Older patients often have multiple co-morbidities, are more prone to
polypharmacy and more often require support in the administration
of their medication than younger adults. As age and frailty are
known risk factors for hypoglycaemia, the choice of treatment
for these patients becomes more limited due to safety concerns.
DPP-4 inhibitors provide a potential attractive treatment option for
older persons. However, despite its niche appeal, this drug class
has not been as extensively studied as in both younger and older
populations either. We are not aware of any specific data which
assess their utility in this population in a clinical practice setting.
Our results showed that patients who had been prescribed DDP-4
inhibitors had evidence of improved glycaemic control following
the initiation of treatment (median HbA
1C
improved from 8.3 to
7.4%). In addition, this group also had a lower rate of documented
hypoglycaemia than the non-DPP-4 inhibitors treated group
(3 vs 8%). We defined hypoglycaemia as an event which had
occurred in the past year and which was documented in the
patients’ medical records. This is likely an underestimate of the true
incidence of hypoglycaemia in our cohort when compared with
other reports,
9
due to the potential reporting bias in our population
and due to the limitations of the retrospective nature of our study.
It does however highlight the nature of hypoglycaemia reporting in
current clinical practice.
A recent study which specifically observed older adults assessed
the frequency and rates of hospitalisation after emergency
department visits for adverse drug events. It reported that insulin
and oral hypoglycaemic drugs were the second and fourth most
common culprits leading to 14 and 11% of all admissions.
10
Our study had a control group of individuals who were older
and more likely to be treated with injectable treatments such as
insulin. Moreover, more patients in this group lived alone or in a
care setting and had a higher incidence of dementia and chronic
kidney disease, all additional risk factors for hypoglycaemic events.
As clinicians have to weigh up the risks and benefits of treatments,
these factors may require re-evaluation.
In those patients in the control group who were controlled by
diet alone, 17 of the 72 (25%) had HbA
1C
concentrations > 6.5%
and 10% had HbA
1C
concentrations > 7%. Whilst recognising that
care needs to be individualised for patients, in particular for the
elderly, a potential treatment gap was identified between patients
who would otherwise be eligible for antidiabetic treatment and
those that actually receive this treatment.
The limitations of this study need to be considered and these
include the retrospective nature of data collection, the absence
of specific data on the reasons for prescribing of particular drugs
Table 2.
Comparison of glucose lowering treatments.
Glucose-lowering
medication
DPP-4 treated
Group (
n
=129)
Control group
(
n
= 302)
p-
value for
comparison
Metformin
113 (88%)
142 (47%)
< 0.001
Sulphonylurea
69 (53%)
75 (25%)
< 0.001
GLP-1 analogue
3 (2%)
9 (3%)
NS
Pioglitazone
22 (17%)
17 (6%)
< 0.001
Short-acting insulin
secretagogues
1 (1%)
1(<1%)
NA
Acarbose
2 (2%)
0 (0%)
NA
Insulin
9 (7%)
91 (30%)
< 0.001
DPP-4 inhibitor
129 (100%)
0 (0%)
NA
Monotherapy
3 (2%)
2 (1%)
NS
Dual therapy
44 (34%)
140 (46%)
0.019
Triple therapy
71 (55%)
68 (23%)
< 0.001
Four or more
medications
11 (9%)
19 (6%)
NS
DPP: dipeptidylpeptidase; GLP: glucagon like peptide; NA: not applicable;
NS: not significant,
p
> 0.05.
Table 3.
Incidence of hypoglycaemia and risk factors for events.
DPP-4 treated
group (
n
=129)
Control group
(
n
= 302)
p
-value for
comparison
Documented
hypoglycaemia (in
the last year)
4 (3%)
24 (8%)
0.062
Hypoglycaemia
requiring admission
to hospital (in the
last year)
0 (0%)
0 (0%)
NA
Lives alone
11 (9%)
32 (11%)
0.51
Lives in own home 126 (98%)
274 (91%)
NA
Lives in sheltered
accommodation,
residential home or
care home
3 (2%)
28 (9%)
0.011
Dementia
4 (3%)
31 (10%)
0.013
NA: not applicable.
