World Journal of Cardiovascular Diseases, 2013, 3, 401-405 WJCD
http://dx.doi.org/10.4236/wjcd.2013.36062 Published Online September 2013 (http://www.scirp.org/journal/wjcd/)
Effects of duration of type 2 diabetes mellitus on
lengthening and enlargement of small abdominal aortic
aneursym
Shijun Li, Jianguo Wang, Tingshu Yang
Geriatric Cardiology of Chinese PLA General Hospital, Beijing, China
Received 26 June 2013; revised 27 July 2013; accepted 6 August 2013
Copyright © 2013 Shijun Li et al. This is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Objective: The purpose of our study aimed at evalu-
ating the relationship of type 2 diabetes with longitu-
dinal extension of AAA. Methods: All of 460 AAA pa-
tients aged from 41 to 92 years were retrospected in
our study, and they were at least twice admitted into
our hospital from January 2000 to April 2010. All
patients received ultrasound measurement of aorta
during each admission. Results: Our results indicated
that changes of length of AAA were significantly grea-
ter in patients with diabetes than those in patients
without diabetes. Type 2 diabetes was associated with
length extension of AAA. In subgroup analysis, type 2
diabetes was only related to length change of small
AAA rather than large AAA. Diabetes was not an
independent risk factor for length extension of small
AAA. There was no significant difference of glycosy-
lated hemoglobin between diabetes patients and non-
diabetes patients. Conclusions: Type 2 diabetes mel-
litus is closely related to length growth of small AAA,
whereas diabetes is not an independent risk factor for
length extension of small AAA, and serum glucose
under better control could not bring about better re-
sult in limiting length extension of small AAA.
Keywords: Diabetes; Lengthening; Small Abdominal
Aortic Aneurysm
1. INTRODUCTION
Abdominal aortic aneurysm (AAA) is defined as a per-
manent dilatation of the abdominal aorta and is a com-
mon and frequently lethal disease process in the elderly.
The development of an AAA involved in changes in the
mechanical properties of the arterial wall, which ulti-
mately brought about widening of the vessel lumen and
loss of structural integrity. Some studies argued that
AAA development was associated with advanced athero-
sclerosis [1], and atherosclerotic risk factors such as ad-
vanced age, hypertension, smoking and hypercholes-
terolemia contributed to AAA progression [2-4].
Previous studies showed that the prevalence of both
diabetes and AAA has risen [5-8]. Recently, a Chinese
study documented that diabetes affects around 10% of
the Chinese population [9]. However, after reviewing the
past studies, it was showed that most of the literature
regarding diabetes and AAA was aimed at the relation-
ship between diabetes and AAA incidence. It was unclear
whether diabetes was related to AAA changes in the
lengthening. It was well known that length growth of
AAA could possibly involve in renal artery ostia and/or
downward extent to abdominal aortic bifurcation, thus
increasing operative difficulty in open repair or endovas-
cular aneurysm repair and operative expenses owing to
increasing number of implanted stents and length of
transplanted blood vessel. Therefore, the emphasis of our
study was focused on evaluating the relationship of type
2 diabetes with longitudinal extension of AAA.
2. MATERIALS AND METHODS
2.1. Study Population
In our study, a total of 460 patients with AAA of our
hospital were reviewed from the year 2000 till 2010.
Their age was from 41 to 92 years, and males were 327
cases and females were 133 cases. Diameter of AAA of
all patients ranged from 3.2 cm to 9.6 cm. The number of
patients with small AAA of less than 5 cm in diameter
was 170 cases, and the number of patients with large
AAA greater than 5 cm in diameter was 290 cases. 74
cases of all patients were diagnosed with diabetes. All
patients received ultrasound measurement of arota during
each admission and treatment with the following drugs

S. J. Li et al. / World Journal of Cardiovascular Diseases 3 (2013) 401-405 402
or combination of some of them such as statins, angio-
tensin II receptor blockers, calcium channel blocker,
beta-blockers or angiotensin-converting enzyme inhibit-
tors.
2.2. Diagnostic Criteria of Diabetes
Diabetes mellitus was diagnosed, according to the WHO,
by the classic symptoms of polyuria, polydipsia and un-
explained weight loss, and/or a hyperglycaemia 11.1
mmol/l (200 mg/dl) in a random sample or fasting (no
caloric intake for 8 hrs), plasma glucose 7.0 mmol/l (126
mg/dl) and/or postprandial value 11.1 mmol/l (200 mg/dl)
(2 hours plasma glucose level during an oral glucose
tolerance test).
2.3. Ultrasound Measurement of Abdominal
Aortic Aneurysms
Ultrasound examination of AAA was conducted by
trained personnel in fast state by using color doppler ul-
trasound (GE Healthcare Technologies, Ultrasound,
Milwaukee, WI, USA) with transducer 5 MHz. An ab-
dominal aortic aneurysm is defined as an enlargement of
the aorta of at least 1.5 times its normal diameter or
greater than 3 cm diameter in total. Ultrasound meas-
urement was operated by trained technicians in our hos-
pital. Firstly, to scan transverse section of abdominal
aorta, then to scan longitudinal section of abdominal
aorta to observe aortic wall and lumen and shape of AAA
neck, lastly to measure distances from entrance of AAA
to osrium of renal artery and from exit of AAA to bifur-
cation of bilateral common iliac artery. Largest antero-
posterior (AP) diameter was measured in longitudinal
section, and largest transverse (TRV) diameter was de-
termined in transverse section, and largest AAA length
was measured from entrance of AAA to exit of AAA in
longitudinal section (Figure 1). Changes of length and
diameter of AP and TRV were obtained from difference
Figure 1. Ultrasound measurement of abdominal aortic an-
eurysms. Notes: Abdominal aortic aneurysm, AAA; Antero-
posterior, AP; transverse, TRV.
of measurement results determined by the last and first
hospital admission.
2.4. Other Parameters
Height and weight were measured when the patient was
admitted lastly into our hospital, and body mass index
(BMI) was computed as weight divided by height
squared (kg/m2). Age was recoded when patient was
lastly admitted into hospital. Blood pressure was a mean
value of three times measures in the last admission. The
study was approved by the local ethical committee.
2.5. Statistical Analysis
All statistical processing was performed using SPSS-PC
17.0 (Chicago, IL, USA). All variables are presented as
the mean value ± SD. Independent samples t-test was
performed for comparative analysis of normally distri-
buted variables, and the Mann-Whitney test was used for
nonparametric analysis. Chi-square test was used to test
the difference of the frequencies of associated history.
Analyses of Pearson’s bivariate correlation and partial
correlation analysis were performed to evaluate the cor-
relation between two parameters. Stepwise regression
analysis was employed to further assess whether diabetes
was an independent risk factor for length extension in
AAA or not. A P value of <0.05 was considered as statis-
tically significant.
3. RESULTS
3.1. Clinical Characteristics of Diabetes Patients
Compared with Non-Diabetes Patients
There were significantly difference in age and ratio of
gender in patients with diabetes compared those without
diabetes. The prevalence of coronary artery disease, hy-
perlipoidemia and hypertension was obviously higher in
diabetes patients than non-diabetes patients. Glycosy-
lated hemoglobin wasn’t significantly different between
diabetes patients and non-diabetes patients. Changes of
length of AAA were significantly increased in diabetes
patients compared with those non-diabetes patients (Ta-
ble 1). There wasn’t of difference between patient with
diabetes and those without diabetes in treatment with
statins, ARB, CCB, beta-blockers or ACE inhibitors.
3.2. Correlation Analysis between Structural
Changes of AAA and Type 2 Diabetes in
AAA Patients
Bivariate correlation analysis showed that length change
of AAA was closely related to history of diabetes melli-
tus, and wasn’t associated with glycosylated hemoglobin
(Table 2). Because there was significant difference be-
ween diabetes patients and non-diabetes patients in age, t

S. J. Li et al. / World Journal of Cardiovascular Diseases 3 (2013) 401-405 403
Table 1. Clinical characteristics of diabetes patients compared with non-diabetes patients (
x
± SD).
Non-diabetes patients (n = 386 ) Diabetes patients (n = 74)
Age, yr 70.89 ± 11.63 74.66 ± 10.44*
Gender (Male/Female) 338/48 55/19*
BMI, kg/m2 24.30 ± 6.06 24.39 ± 2.46
Observed time span, month 17.46 ± 25.55 21.16 ± 28.03
Smoking history, % 20.35 24.07
History of CAD, % 31.05 56.86*
History of hyperlipoidemia, % 3.67 17.65*
History of hypertension, % 52.57 66.67*
Systolic pressure, mmHg 151.94 ± 19.82 153.40 ± 20.54
Diastolic pressure, mmHg 90.14 ± 13.02 86.60 ± 14.52
Fasting serum glucose, mmol/L
Glycosylated hemoglobin, % 6.29 ± 0.82 6.17 ± 0.99
Length changes, cm 1.14 ± 1.17 1.99 ± 1.13*
Transverse changes, cm 1.00 ± 0.77 0.8 6 ± 0.41
Notes: BMI: body mass index; CAD: coronary artery disease. *P < 0.05: Patients with diabetes vs Patients without diabetes.
Table 2. Bivariate correlation analysis between structural
changes of AAA and type 2 diabetes in all patients with AAA.
Table 3. Correlation analysis of between changes of AAA and
type 2 diabetes mellitus in small and large AAA patients.
Bivariate correlation analysis Partial correlation analysis
Length
changes
Transverse
changes
Length
changes
Transverse
changes
Diabetes
history, % 0.295* −0.087 0.343* 0.047
Small abdominal aortic
aneurysm
Large abdominal aortic
aneurysm
Length
change
Transverse
change
Length
change
Transverse
change
Diabetes
history, % 0.606** 0.156 0.202 −0.161
HbA1c −0.028 −0.696 −0.317 −0.272
Notes: Control Variables: age, gender, history of coronary artery disease,
hypertension and hyperlipoidemia. *P < 0.05: Correlation is significant at
the 0.05 level (2-trailed).
Notes: HbA1c: glycosylated hemoglobin. **Correlation is significant at the
0.01 level (2-tailed).
gender, history of coronary artery disease, hyperlipoide-
mia and hypertension in our study. To exclude impacts of
these confounding factors on length of AAA, partial cor-
relation analysis was employed. The result confirmed
that diabetes was still related to length extension of AAA
(Ta bl e 2 ). Since biological behavior of small AAA was
different from large AAA. To further elucidate relation-
ship of diabetes with length changes of small and large
abdominal aortic aneurysms, we performed correlation
analysis of subgroup. The results showed that type 2
diabetes was only related to length change of small AAA
rather than large AAA (Table 3).
rior changes of small AAA increased in diabetes patients
compared with non-diabetes patients. There wasn’t sig-
nificant difference in transverse changes between diabe-
tes patients and non-diabetes patients. Glycosylated he-
moglobin wasn’t different in diabetes patients compared
with non-diabetes patients (Table 4).
3.4. Multiple Stepwise Re gression Analysis of
Length of Small AAA as Dependend
Variable
To identify whether diabetes was independent risk factor
for length extension of small AAA, we perform multiple
stepwise regression analysis. The results showed that
only observational time span entered into multiple step-
wise regression model, and diabetes wasn’t independent
risk factor for length extension of small AAA (Table 5 ).
3.3. Clinical Characteristics of Diabetes Patients
Compared with Non-Diabetes Patients in All
Patients with Small Abdominal Aortic
Aneurysm
In all patients with small AAA, length and anteroposte-

S. J. Li et al. / World Journal of Cardiovascular Diseases 3 (2013) 401-405 404
Table 4. Clinical characteristics of diabetes patients compared
with non-diabetes patients in all patients with small abdominal
aortic aneurysm. (
x
± SD).
Non-diabetes patients
(n = 57)
Diabetes patients
(n = 17)
Length change 0.58 ± 0.71 1.94 ± 1.00*
Transverse change 0.63 ± 0.35 0.75 ± 0.30
HbA1c 5.80 ± 0.46 6.40 ± 0.85
Notes: HbA1c: glycosylated hemoglobin. *P < 0.05: Patients with diabetes
vs Patients without diabetes.
Table 5. Stepwise regression analysis of length changes in
small abdominal aortic aneurysm as dependend variable.
Unstandardized
Coefficients
Standardized
Coefficients
Model
B Std. ErrorBeta
t Sig.
(Constant) 0.597 0.229 2.605 0.012
1
Time span 0.022 0.005 0.559 4.5270.000
Notes: Dependent variable: Length changes; B: Unstandardized coefficients;
Beta: Standardized coefficients.
4. DISCUSSION
The predominant risk factors, such as male sex, increas-
ing age, smoking, hyperlipidaemia, hypertension and a
family history, were attributed to the development of
AAA [10,11]. Most of the literature regarding relation-
ship of diabetes and AAA was aiming at whether diabe-
tes was involved in the incidence of AAA. Little studies
focused on association between diabetes and aortic di-
ameter enlargement, and suggested inverse relationship
between diabetes and aortic diameter in men over 65
years [12,13], and treatment of hyperglycemia could li-
mit experimental aortic aneurysm enlargement in ApoE(-/-)
mice [14].
To date it was unclear whether AAA length extension
was related to diabetes. Because length growth of AAA
could possibly involve in renal artery ostia and/or down-
ward extent to abdominal aortic bifurcation, thus in-
creasing operative difficulty in open repair or endovas-
cular aneurysm repair and operative expenses owing to
increasing number of implanted stents and length of
transplanted blood vessel. Therefore, it is important to
investigate the relationship of type 2 diabetes with lon-
gitudinal extension of AAA.
In our study, all patients were classified as diabetes
group and non-diabetes group to evaluate the role of
diabetes mellitus played in longitudinal extension of
AAA. The results disclosed that the length of AAA was
significantly increased in diabetes patients compared
with non-diabetes patients. Bivariate correlation analysis
indicated that the length extension of AAA was closely
related to diabetes, which indicated that diabetes was
closely related to length of AAA. In our study, there was
significant difference between diabetes patients and
non-diabetes patients in age, gender, history of coronary
artery disease, hyperlipoidemia and hypertension. To
exclude impacts of these confounding factors on length
of AAA, partial correlation analysis was employed. The
result confirmed that diabetes was still related to length
growth of AAA. Since small AAA was different from
large AAA in biological behavior, small aneurysms are
prone to growth and rupture. Aneurysm rupture is more
likely to occur in aneurysms with larger absolute diame-
ter growth [15]. Therefore, we performed correlation
analysis of subgroup and further evaluated the relation-
ship of diabetes with the lengthening of small AAA and
large AAA respectively. The results showed that type 2
diabetes was only related to length change of small AAA
rather than large AAA. In all patients with small AAA,
length changes of small AAA obviously were increased
in diabetes patients compared with non-diabetes patients.
These results suggest that diabetes is closely related to
length increase in the early development of AAA, and
possibly actively controlling blood glucose could limit
the lengthening of small AAA. To further identify whe-
ther diabetes was an independent risk factor for longitu-
dinal extension of small AAA, we perform multiple
stepwise regression. The result showed that type 2 dia-
betes was not an independent risk factor for length ex-
tension of small AAA, and multiple factors possibly pre-
disposed to longitudinal extension of small AAA.
The hemoglobin test can reveal average blood glucose
over a period of two to three months and is often used in
setting and achieving treatment goals [16]. In our study,
we observed that there was no significant difference of
glycosylated hemoglobin between diabetes patients and
non-diabetes patients, which possibly suggested that se-
rum glucose under better control could not bring about
better result in limiting AAA extension.
Color doppler ultrasound with transducer 5 MHz was
employed to examine changes of length and anteroposte-
rior and transverse diameter of AAA by trained personnel
in our study. The objectivity of ultrasound examination
for AAA aroused controversy. At present, the majority of
scholars agree that ultrasound is the standard imaging
tool; if performed by trained personnel, it has sensitiv-
ity and specificity approaching 100 and 96 percent, re-
spectively, for the detection of infrarenal AAA [17]. All
ultrasound technicians of our hospital received systemic
and formal training, therefore, ultrasound examination
for AAA can provide reliable results in our study.
In conclusion, type 2 diabetes mellitus is closely re-
lated to length growth of small AAA, whereas diabetes is
not an independent risk factor for length extension of

S. J. Li et al. / World Journal of Cardiovascular Diseases 3 (2013) 401-405 405
small AAA, and serum glucose under better control
could not possibly bring about better result in limiting
AAA extension.
5. ACKNOWLEDGEMENTS
The authors gratefully acknowledge the staff of the Geriatric Cardio-
vascular Division of Chinese PLA General Hospital for their helpful
suggestions and for collecting the clinical data. This research did not
receive any specific grant from any funding agency in the public, com-
mercial, or not-for-profit sector.
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