title: Glycemic control is related to the severity of impaired thermal sensations in type 2 diabetes.
abstract: BACKGROUND
  Small-fibre sensory neuropathy of diabetes presenting as impaired thermal sensations is associated with ominous consequences, such as foot ulcer and amputation, but there is a lack of systematic studies on its occurrence in large cohorts. We investigated (1) the impact of glycemic control on thermal thresholds, (2) the frequencies and patterns of sensory deficits, and (3) the contribution of sensory nerve abnormalities to neuropathic symptoms.
  
  
  METHODS
  Quantitative sensory testing and nerve conduction studies were performed to measure warm and cold thresholds of extremities, and amplitudes of nerve action potentials on 498 type 2 diabetic patients and 434 control subjects with similar age and gender distributions, enrolled during the same period.
  
  
  RESULTS
  The diabetic patients had higher thermal thresholds than control subjects (p < 0.0001). Thermal thresholds of the lower and upper extremities were linearly correlated with HbA1C on multiple linear regression analysis (p < 0.01). By the multivariate logistic regression analysis, HbA(1C) and age were the most important risk factors independently associated with elevated thermal thresholds (p < 0.01). Elevated warm threshold in the big toe was the most frequent abnormality (60.2%) compared to abnormal cold threshold in the big toe (39.6%) and abnormal sural nerves on nerve conduction studies (12.9%). Elevated thermal thresholds were risk factors for neuropathic symptoms independent of HbA(1C).
  
  
  CONCLUSIONS
  Small-fibre neuropathy with the impairment of thermal sensations is the most frequent sensory deficit in diabetes, and HbA1C is significantly associated with the elevated thermal thresholds.
authors.affiliation: Department of Neurology, National Taiwan University Hospital, Taipei 100, Taiwan.
authors.forename: Chi-Chao
authors.initials: CC
authors.lastname: Chao
authors.forename: Song-Chou
authors.initials: SC
authors.lastname: Hsieh
authors.forename: Wei-Shiung
authors.initials: WS
authors.lastname: Yang
authors.forename: Yea-Hui
authors.initials: YH
authors.lastname: Lin
authors.forename: Whei-Min
authors.initials: WM
authors.lastname: Lin
authors.forename: Tong-Yuan
authors.initials: TY
authors.lastname: Tai
authors.forename: Sung-Tsang
authors.initials: ST
authors.lastname: Hsieh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000503:physiopathology*; D003929:Diabetic Neuropathies / Q000097:blood / Q000503:physiopathology; D005385:Fingers; D005528:Foot; D006442:Glycated Hemoglobin / Q000032:analysis; D006358:Hot Temperature; D006801:Humans; D008475:Median Nerve / Q000502:physiology / Q000503:physiopathology; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D010543:Peroneal Nerve / Q000502:physiology / Q000503:physiopathology; D012016:Reference Values; D012684:Sensory Thresholds / Q000502:physiology*; D013497:Sural Nerve / Q000502:physiology / Q000503:physiopathology; D014034:Toes
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin