Type 1 diabetes mellitus (T1DM) patients have a higher risk of premature death compared with that in general population [1, 2]. Excess of mortality in young T1DM patients was mainly caused by acute diabetes complications such as hypoglycemia and ketoacidosis. Whereas the leading cause of death among patients with duration of diabetes of more than 20 years was cardiovascular disease (CVD) [3]. Coronary events in T1DM patients have been reported to occur 10 to 15 years earlier than in people without diabetes [4]. Few trials have been conducted specifically in T1DM and recommendations were essentially extrapolated from those for type 2 diabetes mellitus (T2DM). The aim of this observational study was to assess the prevalence of cardiovascular risk factors in a Tunisian population of T1DM patients.
We conducted a cross-sectional study on Tunisian patients with T1DM followed in the National Institute of Nutrition (NIN) in Tunis. We included 60 patients who have been hospitalized at least once. Data were analyzed using SPSS 21.
The mean age of the patients was 34.9 ± 11 years with a sex ratio of 0.8. The mean duration of diabetes was 18.6 ± 10.6 years. Selected characteristics are presented in Table 1 and show no difference between male and female patients. Microvascular complications were present in 46 (76.6%) patients: 35 (58.3%) had diabetic retinopathy, 31 (51.6%) had diabetic neuropathy and 23 (38.3%) had diabetic nephropathy. Macrovascular complications were present in 12 (20%) patients: two (3.3%) patients had a stroke, 7 (11.7%) had a coronaropathy and 8 (13.3%) had a lower extremity occlusive arterial disease. Ninety-six percent of patients had at least one CVD risk factor at the moment of the study. Eighty-six percent of patient had one to four CVD risk factors and ten percent had more than four CVD risk factors as it is shown in the Table 2.
|
All participants |
Male |
Female |
P |
|
|
n |
60 |
32 |
28 |
|
|
Age [years] |
34.9 (11) |
36.2 (12.1) |
33.7 (10.1) |
0.31 |
|
Diabetes duration [years] |
18.6 (10.6) |
18.7 (10.8) |
18.6 (10.5) |
0.39 |
|
BMI [kg/m²] |
26.9 (26.2) |
22.1 (4.6) |
31.2 (35.3) |
0.12 |
|
Fasting plasma glucose |
13.5 (7.3) |
14.6 (8.5) |
12.5 (5.9) |
0.12 |
|
HbA1c [%] |
9.5 (2.5) |
9.7 (2.3) |
9.4 (2.7) |
0.95 |
|
Insulin analog use, n (%) |
20 (33.3) |
7 (11.6) |
13 (21.6) |
0.27 |
|
Risk factors |
All participants |
Male |
Female |
P |
|
Positive family history of CVD, n (%) |
17 (28.3) |
9 (15) |
8 (13.3) |
0.54 |
|
Poor glycemic control, n (%) |
50 (83.3) |
23 (38.3) |
27 (45) |
0.49 |
|
High LDL cholesterol* |
40 (66.6) |
19 (31.6) |
21 (35) |
0.53 |
|
Low HDL cholesterol** |
13 (21.6) |
6 (10) |
7 (11.6) |
1 |
|
Triglycerides ≥ 1.5 g/L |
15 (25) |
5 (8.3) |
10 (16.6) |
0.24 |
|
Hypertension |
14 (23.3) |
9 (15) |
5 (8.3) |
0.22 |
|
Obesity |
6 (10) |
2 (3.3) |
4 (6.6) |
0.67 |
|
Microalbuminuria/Proteinuria |
17 (28.3) |
11 (18.3) |
6 (10) |
0.15 |
|
Renal failure |
5 (8.3) |
3 (5) |
2 (3.3) |
0.66 |
|
Smoking |
26 (43.3) |
20 (33.3) |
6 (10) |
< 0.001 |
*LDL cholesterol ≥ 1g/L; **HDL cholesterol ≤ 0.4 g/L in men and ≤ 0.5 g/L in women
The most common risk factors in our patients were poor glycemic control, high LDL cholesterol level and smoking. This study shows high prevalence of CVD risk factors among Tunisian patients with T1DM as defined by the American Association of Diabetes (ADA). Ninety-six percent of the patients had at least one CVD risk factor and ten percent had more than four CVD risk factors. The rates in our study were higher than in other studies [5]. The most frequent risk factor observed in our study was poor glycemic control defined by HbA1c above target level. Increased levels of LDL cholesterol were the second most frequently diagnosed CVD risk factor in our study. There is little information about the prevalence or the effects of smoking among T1DM. Smoking increased CVD risk factors in T1DM patients by deteriorating glucose and lipid metabolism and endothelial function.
In conclusion, there is a high prevalence of CVD risk factors among T1DM patients. The most frequent risk factors were high levels of HbA1c as well as other common CVD risk factors (dyslipidemia, high blood pressure, microalbuminuria, and smoking). Even with intensive glucose-lowering therapy, statin use and blood pressure control, T1DM patients still have higher risk of cardiovascular events and mortality.
Conflict of interest
None declared.