The Correlative Research Between Early Diabetic Nephropathy And Vestibular And Auditory Function In Type 2 Diabetes

Background and AimsDiabetes mellitus(DM)is the most common chronic endocrine metabolic disease.It can cause lots of compliments,such as vascular lesions,but microvescular lesions,such as retinopathy,nephropathy,neuropathy,are most common and most important.And these compliments can affect the quality of patients seriously.Recently the relationship between inner ear and DM is debated,and many studies have indicated that hearing impairment is associated with DM.The typical hearing loss described is a progressive,bilateral sensori-neural deafness of gradual onset which affects predominantly the higher frequencies.But the causes and pathogenesis are still unknown.Some evident indicated that DM may inducing hearing impairment through loss of outer hair cells(OHCs),spiral ganglion neuron atrophy and electrolyte imbalance.Some evident have indicated that the inner ear and kidney have anatomical and physiological similarities.From electron microscopic studies,both the stria vascularis and the glomerulus of the kidney are epithelial structures intimately associated with vascular system.the diabetic nephropathy is the important complication of the DM.So the purpose of the investigation was to study the vestibulo-cochlear functions in diabetic nephropathy or non-nephropathy and analyze the related clinical index of diabetes.MethodThe study includes 90subjects.30 diabetes without nephropathy were categorized in the group 1(15 males and 15 females),30 patients with nephropathy in the group2(16males and 14 females),and 30 healthy subjects were categorized in the group 3(6males and 10 females).And the duration of DM,BMI,SBP(systolic blood pressure),waist,C peptide,insulin,fasting plasma sugar(FBG),blood urea nitrogen(BUN),creatinine,eGFR,total cholesterol,triglyceride,low-density lipoprotein cholesterol,high-density lipoprotein cholesterol,uric acid and Glycosylanted hemoglobin(GHbA,C)were measured for all subjects.An electromyogram,ophthalmological evaluation and the carotid ultrasound were also examined.We evaluated the auditory function and vestibular function by pure tone audiometry,Otoacoustic Emissions,Calotic test,electronystagmography and vestibular evoked myogenic potentials.Clinical indexes are measured and their relations of vestibule-cochlear functions also analyzed.Result1.Clinical characteristics of 3 groupsAs shown in Table 1,GHbAlc,FBG,SBP,C-peptide,WHR,TC,TG,LDL-c,HDL-c and UA of two diabetic groups were both significantly higher than those of healthy subjects(p<0.05).Otherwise,BMI,waist and HCY of DM group were higher than those of healthy group(p<0.05).And there is a significant difference between DM group and DR group in duration of DM,HCY and cys-C(p>0.05),and there is no difference between the two groups in Cr,BUN and eGFR(p<0.05).Ophthalmologic evaluation showed diabetic retinopathy in 7(23.33%)patients in group DM,and 27(90%)patients in group DN.Peripheral neuropathy was identified in 8(26.67%)patients in group DM,and 23(76.67%)patients in group DR by electromyogram.We also see that 12(40%)patients in group DM and 27(90%)patients in group DNwere diagnosed sclerosis in carotid artery by carotid ultrasound.2.Pure tone audiometryTwo diabetic groups both demonstrated a deficit at high frequencies with elevated threshold at 500,1000,2000,4000,8000Hz(p<0.05)when compared to healthy subjects.And group DN had sever hearing impairment in every frequency(p<0.05).There is no significant difference between left and right ear(p>0.05).According to the result of pure tone audiometry,relationship between GHbAlc,waist,ACR,eGFR and elevated threshold of type 2 diabetes had statistically significant(p<0.05).3.Otoacoustic EmissionsAs shown in Figure 2,group DN had significant difference in left ear(4kHz)and right ear(0.75.2.4kHz)when compared to healthy subjects(p<0.05).The group DM had significant difference when compared to the healthy subjects in right ear(0.75kHz.4kHz)(p<0.05)and there is no difference between left and right ear(p>0.05).4.Electronystagmography and Calotic testAs shown in Table 2,the electronystagmography results of all 3 groups are normal.As for Caloric test,5(16.67%)patients in group DM showed vestibular dysfunction,and 9(30%)patients in group DN showed vestibular dysfunction.But there no significant difference between 3 groups(p>0.05).According to the result of caloric test,relationship between GHbAlc,ACR and vestibular dysfunction of type 2 diabetes had statistically significant(p<0.05).vestibular evoked myogenic potentials5.VEMPsIn right ear,2(6.67%)in group NC,3(10%)in group DM and 5(16.67%)in group DN were not appear VEMPs amplitudes.In left ear,1(3.33%)in group NC,1(3.33%)in group DM and 2(6.67%)in group DN were not appear VEMPs amplitudes.Otherwise,2(6.67%)in group DM and 3(10%)in group DR were not show VEMPs amplitude in both ears.As shown in Figure 3,the two diabetic group had lower amplitude when compared to the group NC(p<0.05),but there is no difference between group DN and group DM(p>0.05).From table 5 and table 6,we can know that the decrease of amplitude of VEMPs was related to duration of DM,GHbAlc,LDL-c and diabetic retinopathy.Conlusion1.Hearing impairment is associated with DM.The typical hearing loss described is a progressive,bilateral sensori-neural deafness of gradual onset which affects predominantly the higher frequencies.And if diabetes had diabetic nephropathy,they had a more sever hearing impairment.2.Inner ear dysfunction is progressive,and hearing impairment appears early than vestibular dysfunction.If diabetes already had hearing impairment,they seem to have a vestibular dysfunction.3.The level of clinical indexes such as GHbAlc,waist,ACR and eGFR can affect the auditory function of type 2 diabetes.And the level of ACR,duration of DM,GHbAlc,LDL-c and diabetic retinopathy may affect the vestibular function of type 2 diabetes.4.The society has already realized the importance of diabetic nephropathy and has little patience to the auditory and vestibular dysfunction in diabetic patients.When a patient has had diabetic nephropathy,there is already a auditory and vestibular dysfunction.We can diagnose early and enhance the quality of life of the diabetes.