title: Predictors of vibration perception threshold in type 2 diabetic patients with proliferative retinopathy.
abstract: OBJECTIVE
  Distal peripheral neuropathy (DPN) is a troublesome complication of diabetes mellitus (DM). The factors associated with the disease are still incompletely understood. The purpose of this study was to investigate factors associated with vibration perception threshold (VPT) as a marker of DPN in a type 2 diabetic population with advanced microvascular disease.
  
  
  METHODS
  The study included 203 diabetic patients (117 male, 86 female) with proliferative diabetic retinopathy. Subjects were investigated by questionnaires, clinical examinations, blood and urine sampling, and review of medical records in the period from November 2008 through April 2009. Presence of DPN was defined as VPT ≥25 V.
  
  
  RESULTS
  The mean (±SD) age was 65.2 (±9.9) years and median (IQR) diabetes duration was 18 (10-25) years. Forty-six per cent of subjects were found to have DPN, defined as a VPT ≥25 V by neurothesiometer testing. Prevalence of DPN was found to be associated with age (p=0.038), male gender (p=0.046), low haemoglobin (p<0.001), high erythrocyte sedimentation rate (p=0.03), uric acid values (p=0.034), and peripheral vascular disease (PVD) (p=0.003) in univariate analysis. Multivariate logistic regression analysis revealed male gender (OR 5.52; p<0.001) and low haemoglobin values (B=-0.58; p<0.001) to be independent predictors of VPT ≥25 V in subjects with proliferative retinopathy, while linear regression analysis revealed male gender (p<0.001), haemoglobin (p=0.001), age (p=0.04), and PVD (p=0.001) to be significant predictors of VPT.
  
  
  CONCLUSIONS
  This study reports a novel independent association of DPN with low haemoglobin values. In the study population with type 2 DM and proliferative retinopathy, DPN was also independently associated with male gender, age, and PVD. Further studies are needed to confirm the association with low haemoglobin and identify the underlying mechanism.
authors.affiliation: Department of Internal Medicine, Mater Dei Hospital, Tal-Qroqq, Msida, Malta. cjmagri013@yahoo.com
authors.forename: Caroline Jane
authors.initials: CJ
authors.lastname: Magri
authors.forename: Neville
authors.initials: N
authors.lastname: Calleja
authors.forename: Gerald
authors.initials: G
authors.lastname: Buhagiar
authors.forename: Stephen
authors.initials: S
authors.lastname: Fava
authors.forename: Josanne
authors.initials: J
authors.lastname: Vassallo
mesh_terms: D000367:Age Factors; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009460:Neurologic Examination; D010465:Perception / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D012307:Risk Factors; D012684:Sensory Thresholds / Q000502:physiology; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014732:Vibration
chemical_list: D006454:Hemoglobins