A Study on the Prevalence and Risk Factors Associated with Peripheral Vascular Disease in Type 2 Diabetes Mellitus

INTRODUCTION: Peripheral vascular disease (PVD) is one of the significant Macro vascular complication of type 2 diabetes mellitus. Peripheral vascular disease assumes importance, for prevention of morbidity and mortality related to diabetic foot. PVD is the single most important factor which raises the incidence of leg amputation risk in type 2 DM patients. While peripheral neuropathy alone leads to, tropic ulcer which has an chronic indolent course provided super added infection is prevented and controlled, the presence of PVD leads to ischaemic foot which leads to rapid spread of infection, by means of two mechanisms. I) Due to decreased supply of oxygen, nutrients and decreased accessibility of neutrophils and immune effectors to the area of injury and infection. II) Decreased antibiotic accessibility to the affected area due to ischaemia. Further the importance of PVD assessment assumes importance in the light of a long duration of asymptomatic period in the natural course of the disease. Further the avenues for development of claudication symptoms of PVD in today’s fast changing sedentary life style of the people are restricted, and hence the importance of active screening for the same with special emphasis on ankle – Brachial index gains importance for saving the limbs of Diabetic patients. BACKGROUND AND PURPOSE: Although Diabetic Peripheral Neuropathy and Peripheral Vascular Disease (PVD) both contribute to the development of diabetic foot, the risk of amputation raises steeply only if there is associated PVD. Once there is presence of PVD in an individual, the time duration taken up for development of gross limb and life threatening sepsis after an injury is very rapid and interventions to augment peripheral blood flow during such an acute active sepsis is not possible always. Hence the importance lies in identifying the risk factors responsible for the development of PVD in type 2 diabetes, and in active screening for PVD in all diabetic subjects. Effective implementation of preventive measures in the targeted high risk group will pave the way for Limb protection. Moreover PVD is a sign of severe generalized atherosclerosis (especially CAD), which should be treated aggressively. Diabetes predominately leads to PVD in the infrageniculate arteries and the risk factors associated with development of PVD in diabetes are found to be advancing age, uncontrolled hyperglycemia, hypertension, dyslipidaemia and smoking. AIM OF THE STUDY: 1. To investigate the prevalence of PVD among type 2 diabetes patients. 2. To assess the risk factors associated with development of PVD. 3. To correlate the prevalence of cardiovascular risk factors and vascular complications of type 2 diabetes with abnormal ABI (ABI<1). MATERIALS AND METHODS: 112 randomly chosen type 2 diabetic subjects attending our Government Rajaji Hospital, Diabetology department OP between June 2008 to November 2008 have formed the study sample. Patients who have other potential causes for PVD other than diabetes related factors were excluded from the study. The exclusion criteria used were 1. Clinical evidence of thromboangitisobliterans. 2. Suspected arteritis subjects. 3. Patients suffering from hypercoagulable states including heamotologic diseases. 4. Hypothyroidism 5. Collagen vascular disorders 6. Valvular heart disease STUDY DESIGN: Cross sectional observational analytical study. Patients were interviewed with special note on elicitation of history regarding symptoms of PVD, in the form of intermittent claudication, Ischeamic rest pain, history of foot ulcers in the past and present. Smoking was recorded in pack-years of cigarettes smoked. SUMMARY: 1. Prevalence of peripheral vascular Disease in the study was 17.9% among Type2 Diabetes patients. 2. Prevalence of PVD was 20% among males and 14.9% among females. 3. There was a linear progressive raise in PVD prevalence as age advanced, in the study group subjects. 4. 50% of the patients with PVD are totally asymptomatic. 5. Waist – Hip ratio and BMI were significantly higher for the PVD subset. 6. As the duration of diabetes increased, the risk of PVD increased. There was relatively poor glycaemic control in the PVD sub-set. 7. Hypertension, when associated with Type2 Diabetes raised the risk of PVD nearly three fold. The duration of Hypertension also significantly correlated with the risk of PVD. 8. Smokers had more than four fold increased risk of PVD. Smoking was found to be the single most important independent risk factor for development of PVD. 9. There was relatively higher LDL – Cholesterol, low HDLCholesterol, and high Serum Triglycerides in the PVD sub-set. 10. Co-Morbid Coronary artery Disease was widely prevalent (about 60%) among the PVD sub-group (ABI < 1). 11. Diabetic Nephropathy patients had a significantly higher prevalence of PVD. CONCLUSION: 1. Prevalence of peripheral vascular disease is about 18% in the present study. This has to be viewed seriously considering the huge type 2 diabetic population. Thus a significant proportion of type 2 diabetic subjects are affected by PVD, and hence due importance to be given for screening and prevention of PVD among type 2 diabetes patients. 2. About 50% of the PVD patients are totally asymptomatic and hence the need for active screening with estimation of ABI is to be done annually for all type 2 diabetes patients. This is important for prevention of lower extremity amputation. 3. Central obesity, Uncontrolled hyperglycemia, hypertension, high LDL cholesterol, high tri glycerides, low-HDL cholesterol and smoking are the modifiable risk factors associated with development of PVD. Advancing age and male gender were found to be the non modifiable risk factors for development of PVD. 4. Concordance rate for co-morbid CAD was very high (>50%) in PVD patients and hence active screening for CAD in all the PVD patients has to be done, even if there is no CAD symptoms. 5. PVD has to be given due importance, and ABI has to be estimated in all type 2 diabetic patients. Low ABI is associated with cardiovascular complications. Thus, ABI is a good indicator of underlying complications of diabetes mellitus, particularly CAD. ABI estimation is a non invasive cheap, bed-side, and rapid test with a high degree of validity and predictive power and which does not need specially trained persons or costly equipments. Hence, ABI estimation should be done for all diabetic patients annually