sease in Chinese Graded relationships between low electrochemical skin conductance measured by SUDOSCAN and severity of peripheral sensory neuropathy have been reported in people with diabetes. The use of SUDOSCAN to predict microvascular complications other than neuropathy has also been explored in several small studies. From our group, analysis of 50 patients with and 50 patients without DKD showed that electrochemical skin conductance was associated with GFR independent of age, gender, disease duration, PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19725016 smoking, alcohol, BP, triglyceride, hemoglobin, presence of other microvascular complications, and use of medications including RAS inhibitors and anti-hypertensive agents. Freedman and colleagues studied 390 African and European Americans with type 2 diabetes and 166 controls and found independent association between skin conductance and GFR in African but not European Americans. In the present cohort, we were able to confirm the independent association between SUDOSCAN-DKD score and estimated GFR. Sudomotor dysfunction may have similar pathogenic mechanisms to DKD. Processes downstream to sustained hyperglycaemia including activation of protein kinase C, activation of the polyol pathway, and formation of advanced glycosylation end products that are known to drive diabetic renal changes, have also been implicated in causing reduction PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19723429 of endoneurial blood flow and direct nerve injury. The natural progression of DKD involves the gradual transition from hyperfiltration to albuminuria, to decline in GFR. While microalbuminuria is traditionally viewed as an early indicator of diabetic renal involvement, its predictive value for advance renal disease is recently challenged by poor sensitivity and specificity. On the one hand, 169939-93-9 site normoalbuminuria does not preclude the presence of renal parenchymal changes and between 2070% of patients may progress to significant renal impairment while maintaining normoalbuminuria. On the other hand, albumin excretion may be increased in response to pathological or physiological processes unrelated to diabetes such as posture, exercise, puberty, smoking, obesity, and infection. In addition, spontaneous remission of microalbuminuria has been observed in 2060% of patients without specific anti-proteinuric therapy. The statistically significant but numerically small association between SUDOSCAN-DKD score and urine ACR in the present study might be due to its single measurement with marked inter- and intra-individual variations. The use of RAS inhibitors which have been shown to effectively lower urine ACR might also have confounded the relationship between SUDOSCAN-DKD score with urine 
ACR. In this analysis, the optimal SUDOSCAN-DKD score for detecting CKD was 53 with 77% sensitivity and 63% specificity. In our previous case-control cohort, the cutoff value of 55 had 94% sensitivity and 78% specificity. The better performance might be due to greater case dichotomization in our previous study. While these subtle differences in performance might be due to study design, selection criteria, sample size and ethnicity, the overall evidence supports the clinical utility of SUDOSCAN in discriminating subjects with CKD. We acknowledge the following limitations. One, despite the relatively large sample size of this cross-sectional cohort, prospective evaluation is needed to confirm the clinical utility of SUDOSCAN for risk stratification and prognostication in CKD. Two, only Chinese patients were studied and our results mig
