Utility of DN4 questionnaire in assessment of neuropathic pain and its clinical correlations in Turkish patients with diabetes mellitus.

AIM: We aimed to assess the utility of DN4 questionnaire (Douleur Neuropathique en 4 questions) to define the frequency and severity of neuropathic pain (NP) and also its clinical correlation to daily clinical practice. METHODS: We included 1357 patients with diabetes (56.5% women, 90.4% type 2 diabetes) who were followed up in our diabetes outpatient clinic. Presence of NP was evaluated by performing simultaneous DN4 questionnaires and physical examination. Those who had a DN4 score ≥4 were considered to have NP. RESULTS: The mean age was 58.2±12.1 years, mean duration was 12.5±7.5; (min-max: 1-45) years, mean HbA1c level was 7.8±1.6% (min-max: 5-16.2%), (61.7±6.0mmol/mol; min-max: 31.1-153.6mmol/mol). Three hundred thirteen patients (23%) were diagnosed with NP using the DN4 tool. Male gender (p=0.01), receiving antihypertensive treatment (p=0.01), presence of retinopathy (p<0.001), cardiovascular disease (CVD) (p=0.01) and previously diagnosed neuropathy (p<0.001) were significantly associated with higher NP scores. Those who had increased DN4 scores were more likely to be on oral hypoglycemic agents (OHA)+insulin combinations (p<0.001), had longer diabetes duration (p<0.001) and higher HbA1c levels (p=0.001). Logistic regression model revealed that diabetes duration (OR: 1.02, 95% CI: 1.00-1.04, p=0.007), elevated HbA1c levels (1.11, 1.02-1.21, 0.015), presence of retinopathy (1.41, 1.20-1.64, <0.001), management with at least one OHA (1.47; 1.12-1.92; 0.004) or any insulin regimen (1.62; 1.16-2.27; 0.005) (compared with diet only-regimens) were significantly associated with NP. CONCLUSION: Utilization of DN4 questionnaire in daily clinical practice is an effective tool in the identification of pain related with peripheral diabetic polyneuropathy.

The effect of nephropathy on plasma sphingosine 1-phosphate concentrations in patients with type 2 diabetes.

OBJECTIVES: Sphingosine 1-phosphate (S1P) is carried in plasma by the HDL particles and albumin. It mediates several protective functions of HDL. Because of its barrier-enhancing effect, it has attracted attention in diseases associated with endothelial dysfunction. We examined the impact of circulating levels of S1P in diabetic nephropathy together with apoprotein M, a S1P-binding protein in HDL. Plasma levels of dimethylarginines were evaluated in this context. DESIGN AND METHODS: Patients with type 2 diabetes mellitus were divided into three groups according to daily albumin excretion: normoalbuminuria, microalbuminuria and macroalbuminuria (n=30 in each). In addition to routine analysis, S1P and apo M in plasma were measured using the enzyme-linked immunosorbent assays. Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and l-arginine were determined by HPLC. Tukey's or Mann-Whitney U-test was used for the statistics. RESULTS: Plasma S1P levels showed a significant decline in parallel to kidney dysfunction. The highest significance was detected in the macroalbuminuric group. Although a significant increase in plasma SDMA in albuminuric groups was observed, apo M, l-arginine and ADMA levels were similar between the groups. CONCLUSION: Low plasma levels of S1P seemed to be associated with diabetic nephropathy. The main reason for the decreased S1P levels in our patients seems to be severe urinary albumin loss due to nephropathy. Low levels of S1P in patients with nephropathy may adversely affect the endothelial integrity and barrier function, thus causing a vicious circle.