Background and aims: The aim of this study was to examine the prevalence of neuropathy and nephropathy in patients with type 2 (T2DM) complicated by proliferate retinopathy (PDR) and coronary artery occlusive disease (CAOD) treated with stent or bypass surgery.
Materials and methods: Comparisons were made between 22 patients with T2DM and bypass or stenting of coronary arteries with normal fundoscopic finding (G1) and 21 age matched controls without diabetic retinopathy and CAOD, and also between 23 patients with T2DM and PDR (G2) and 21 age and diabetes duration matched controls. Clinical examination of the eyes was performed through dilated pupils using a slit lamp and a magnifying lens. Vibration perception threshold (VPT) was measured by semi quantitative tuning fork C128 (grade 08) and ankle reflexes were recorded. Body weight (kg), serum creatinine, fibrinogen and urine protein concentration were measured, and the presence of macro vascular (coronary, cerebrovascular and peripheral arterial) complications was also documented.
Results: In T2DM patients with CAOD were ones with lower HDL than it was the case with the control group of patients (1.14±0.22 vs 1.38±0.44 mmol/l, P 0.03) that had higher triglycerides (Tg)/ HDL (2.9±2.36 vs 1.64±1.43), shorter duration of diabetes (15±6.8 vs 22.5±6.4 years), higher creatinine (121.2±28.7 vs 95.9±28.7 mmol/l; P 0.002). However, VPT was not significantly different between the two groups (6.8±1.8 vs 6.9±1.3). A positive history of hyperlipidemia was more common in T2DM with CAOD than among Controls (90.9 vs 61.9%; P=0.004). In addition to that, the tendency was present for hypertension (50 vs 33.3%; P 0.08) and HDL cholesterol was negatively correlated with HbA1c (r −0.42, P 0.05). VPT was significantly worse in patients T2DM and PDR compared with controls (2.98±2.9 vs 6.88±1.33, P<0.001), as it was the case with ankle reflexes (3.5±0.9 vs 2.8±1.74, P<0.05), fibrinogen (4.1±0.89 vs 0.89 g/l), proteinuria (1488.9±2676 vs 225±209 mg/dU), creatinin (135.8±75 vs 95.9±28.7 mmol/l; P 0.02). A positive history of hyperlipidemia was more common in G2 than among Controls (82.6 vs 61.9%, P 0.03), secondary insulin dependence (73.9 vs 38.1%; P 0.0001), low smoking habit (34.8 vs 76.2%, P<00001). Total cholesterol showed positive correlation with HbA1c (r=+0.51, P 0.01) and pulse rate (r=+0.38, P 0.07). Vibration perception for all three groups (G1, G2, Controls) was negatively correlated with pulse rate (r=−0.23, P 0.07), HDL cholesterol (r=−0.22, P 0.07), fibrinogen (r=−0.30, P 0.018), duration of diabetes (r=−0.28, P 0.02), proteinuria (r=−0.31, P 0.01), creatinin r=−0.23, P 0.09), ankle reflexes (r=−0.34, P 0.006). After multiple regression analysis the correlations with duration of diabetes (P=0.0001) remained significant.
Conclusion: Worsening VPT in T2DM is strongly associated with duration of diabetes where the worst outcome is in patients who developed diabetic proliferate retinopathy and nephropathy. In T2DM with coronary artery occlusive disease endogenous insulin exerts protective effect on microvascular complications. On the other hand, the same endogenous insulin, in the presence of classical macro vascular risk factors and compromised reverse cholesterol transport caused by hyperglycemia, exerts atherogenesis on coronary arteries.