|Year : 2020 | Volume
| Issue : 2 | Page : 122-126
Stage of chronic kidney disease and cochlear function: A cross-sectional survey
Mohammed Bello Fufore1, Abdullahi Musa Kirfi2, Abubakar Danjuma Salisu3, Thomas Musa Samdi4, Abdulhameed Bala Abubakar5, Paul Adekunle Onakoya6
1 Department of ENT, Federal Medical Centre, Yola, Adamawa State, Nigeria
2 Department of ENT, Abubakar Tafawa Balewa University Teaching Hospital, Bauchi, Bauchi State, Nigeria
3 Department of ENT, Aminu Kano Teaching Hospital, Kano, Kano State, Nigeria
4 Department of Clinical Services, National Ear Care Centre, Kaduna, Nigeria
5 Department of Internal Medicine, Barau Dikko Teaching Hospital, Kaduna, Nigeria
6 Department of ENT, University College Hospital, Ibadan, Nigeria
|Date of Submission||25-Sep-2019|
|Date of Decision||17-Jan-2020|
|Date of Acceptance||30-Jan-2020|
|Date of Web Publication||11-Apr-2020|
Dr. Mohammed Bello Fufore
Department of ENT, Federal Medical Centre, Yola, PMB 2017, Adamawa State
Source of Support: None, Conflict of Interest: None
Background: Studies have shown that hearing loss increases in patients with chronic kidney disease (CKD) with decreasing glomerular filtration rate. The hearing loss in CKD patients may worsen over time which in turn will negatively affect the patient's ability to effectively communicate with people, resulting in low self-esteem, social isolation, anger and depression. We aimed to assess the relationship between stage of CKD and hearing threshold in patients with CKD in Kaduna. Patients and Methods: A cross-sectional study of patients with CKD in Kaduna. Individuals were selected consecutively using convenience sampling. Ethical approval and informed consent were obtained. The patients were grouped based on the stage of the disease. The pure tone audiometry was carried out using a Diagnostic Audiometer (Graphic Digi-IS, USA). The hearing threshold of the patients was then compared based on stage of the disease. The data collected was analysed using Statistical Product and Service Solutions, version 20. Results: Sixty CKD patients (120 ears) were assessed. Their mean age was 43.2 ± 13.4 years and 70% were males. Of the 120 ears studied, 51 (42.5%) had normal hearing thresholds and 69 (57.5%) had hearing loss. Of the 69 ears with hearing loss, 11 (15.9%), 22 (31.9%) and 36 (52.2%) were in Stage III, IV and V, respectively, and the difference was statistically significant (P = 0.006). All those with Stage III CKD had mild hearing loss and the hearing loss worsen with advancing stage. Stage III CKD had significantly better hearing than those with stage IV and V (P < 0.001). Conclusion: Our study showed a statistically significant relationship between advancing stage of CKD and hearing loss. The hearing loss worsen with advancing stage of CKD.
Keywords: Chronic kidney disease, hearing loss, pure tone audiometry, stage
|How to cite this article:|
Fufore MB, Kirfi AM, Salisu AD, Samdi TM, Abubakar AB, Onakoya PA. Stage of chronic kidney disease and cochlear function: A cross-sectional survey. Niger Postgrad Med J 2020;27:122-6
|How to cite this URL:|
Fufore MB, Kirfi AM, Salisu AD, Samdi TM, Abubakar AB, Onakoya PA. Stage of chronic kidney disease and cochlear function: A cross-sectional survey. Niger Postgrad Med J [serial online] 2020 [cited 2020 May 29];27:122-6. Available from: http://www.npmj.org/text.asp?2020/27/2/122/282309
| Introduction|| |
Chronic kidney disease (CKD) is defined as 'Glomerular filtration rate (GFR) of <60 ml/min/1·73 m2, lasting for 3 months or more, with or without kidney damage'. The National Kidney Foundation estimated that about 20 million Americans have CKD with another 20 million individuals having an increased risk of developing the disease. Available studies in Nigeria have shown that the prevalence of CKD ranged between 3.6% and 19.9%.,, The causes of CKD in sub-Saharan Africa are many and this includes diabetes, hypertension, glomerulonephritis, leishmaniasis, schistosomiasis and human immunodeficiency virus (HIV). For instance, HIV alone affects more than 22 million people in sub-Saharan Africa, and this contributes to making the burden of CKD in the region overwhelmingly high.
Disease of the kidney simulates disease-associated loss of renal parenchyma making the kidney to develop a compensatory adaptation by increasing blood flow and glomerular hyperfiltration that maintain function at increased levels per nephron, leading to hypertrophy of glomeruli and tubules. As a consequence of these adaptations, kidneys structure and function deteriorate steadily, reaching an end-stage renal failure within months. Studies have shown that there is a link between the linings of the kidney and the inner ear.,, The cochlea of the inner ear and the kidney have some membranes held together by a substance called collagen, which are similar in both structure and function.,, Available literature revealed that hearing loss increases in patients with CKD with decreasing GFR.,, The literature have shown that based on auditory brainstem audiometry findings, the main site of lesion is cochlear and to some extent, retrocochlear. Studies have shown that CKD patients with hearing loss can have hearing loss ranging from mild to profound, with majority having mild to moderate hearing loss.,,, The hearing loss may worsen over time which in turn will negatively affect the patient's ability to effectively communicate with other people, resulting in low self-esteem, social isolation, anger and depression. This study aimed to assess the relationship between stage of CKD and hearing threshold in patients with CKD in Kaduna, Nigeria.
| Patients and Methods|| |
This was a hospital-based, cross-sectional study which was carried out from December 2017 to November 2018. This study recruited only individuals who were 18 years and above with GFR of 59 ml/min/1.73 m2 and below (i.e., Stage III, IV and V) at Barau Dikko Teaching Hospital, Kaduna. Individuals were selected consecutively using convenience sampling (those who were available during the study period). Ethical approval was obtained from the Ethics Committees of Barau Dikko Teaching Hospital and Kaduna State Ministry of Health (protocol numbers: 18-0004 and MOH/ADM/744/VOL. 1/510). Informed consent was obtained before enrolment.
The sample size was calculated using Fisher's formula for cross-sectional studies: n = Z2 pq/d2 whereP= prevalence (prevalence of CDK in Nigeria = 3.6%), q = p − 1, Z = standard normal deviate (which is 1.96 at 95% confidence interval) and d = degree of precision at 95% confidence interval. Thus: n = 3.842 × 0.036 × 0.964/0.05 × 0.05 = 53. The minimum sample size required for the study was 53; however, to make up for attrition (10% attrition, 53/100 × 10 = 5.3). Therefore, approximately 60 CKD patients were recruited for the study.
The stage of CKD was determined using the Cockcroft and Gault equation (GFR = 186 × [Cr] −1.154× [Age] −0.203 × 0.742 [if female] × 1.210 [if black]) standardized for body surface area. Those with persistent GFR of <60 mL/min/1.73 m2 were classified as having CKD, irrespective of whether there is the presence or absence of kidney damage.,, A GFR of more than 90 ml/min/1.73 m2 was referred to as stage I disease, GFR of between 60 and 89 ml/min/1.73 m2 was classified as Stage II, GFR of between 30 and 59 ml/min/1.73 m2 was referred to as Stage III kidney disease (Stage III CKD), whereas a GFR of between 15 and 29 ml/min/1.73 m2 and GFR of <15 ml/min/1.73 m2 were referred to as Stage IV and V kidney disease, respectively., This study recruited only individuals with CKD, Stages III, IV and V (GFR = 59 ml/min/1.73 m2 and below), regardless of whether they were newly diagnosed or were on follow-up visits. The patients were then grouped based on the stage of the disease (i.e., either Stage III, Stage IV or Stage V CKD).
Stages I and II kidney disease patients (GFR = 60 ml/min/1.73 m2 and above) and patients with history of ear disease, exposure to loud noise, sickle cell disease patients and those who were too ill to undergo an audiometric test and those with Type B or C tympagrams were excluded from the study. Headlight and otoscopy (Heine's battery operated hand otoscope, Italy) were used to examine the external auditory canal and tympanic membrane (TM) for wax, foreign body, discharge and TM for retraction or perforation. Those with impacted wax had it removed by evacuation, suctioning or ear syringing with warm normal saline before continuing with the procedure, and those not suitable were excluded.
The pure tone audiometry was carried out using a Diagnostic Audiometer (Model Graphic digi-IS, USA), calibrated to ISO standard (25th January 2017). There was no audiometric booth in the hospital; therefore, the test was carried out in the quietest room in the hospital where the mean ambient noise level of the test room was 33.2 dB (<40 dB) using a calibrated sound pressure level meter, Model TES1350A made in Taiwan. Tympanometry was carried out using a Micro-Audiometrics EarScan Tympanometer (Model ES3749B, USA) calibrated to ISO standard. The name of the organization in French is Organisation internationale de normalisation, and in Russian, ждунаронззт зтзззsизацит зз ттззнзттизации (Mezhdunarodnaya organizatsiya po standartizatsii). ISO is not an acronym. The organization adopted ISO as its abbreviated name in reference to the Greek word isos (ίσος, meaning “equal”), as its name in the three official languages would have had different acronyms. During the founding meetings of the new organization, the Greek word explanation was not invoked, so this meaning may have been made public later.
ISO gives this explanation of the name: “Because 'International Organization for Standardization' would have different acronyms in different languages (IOS in English, OIN in French), our founders decided to give it the short form ISO. ISO is derived from the Greek isos, meaning equal. Whatever the country, whatever the language, the short form of our name is always ISO.” Tympanometry was conducted after ensuring clear external auditory canal (EAC) and intact TM with appropriate size probe tip, sealed in each ear canal, from which a continuous pure tone was presented into the test ear. Antiseptic (hypochlorite) was used to appropriately clean the tip of the probe before and after use. The resulting tympanogram were classified into Type A, As, Ad, B and C (Jerger's classification system). Those with Types B and C were excluded from the study.
The patients that were tested were seated on a chair in the test room, and the procedure was clearly explained to each patient before commencement. The patients wore the headphones and signified on hearing the tone by pressing on a small handheld button as soon as the tone was heard. Pure tones were delivered to each ear consecutively through the ear phones to test for air conduction (AC). The duration of presentation was 2–3 s. Both ears were tested for hearing impairment.
The test was first conducted for the right ear at 1KHz, then 2KHz, 4KHz, 6KHz, 8KHz, then 500 Hz and 250 Hz in that order., The test started at 40 dB HL, if audible then was reduced in 10 dB steps till no response occurred, then it was increased in 5 dB steps till a response occurred and the results were plotted., The left ear was then tested and the same process for AC was repeated. For bone conduction (BC) test, the bone vibrator was placed on the mastoid bone of the test ear (the worse ear on AC) delivering different tones for each of the speech frequencies (500, 1000, 2000 and 4000 Hz)., Masking of the non-test ear was done through the plateau seeking method to obtain a reliable threshold when there was a 40 dB or more difference between the AC threshold of the test ear and AC threshold of the non-test ear or when there was a 15 dB or more difference between AC threshold of the test ear and the BC threshold of the same ear.,
The results of the audiometric tests for each ear were recorded separately on an audiogram. For AC test, frequencies recorded include 250 Hz–8 KHz while for BC test, the frequencies recorded include 500 Hz–4 KHz. The pure tone average was calculated for each ear at speech frequencies of 0.5, 1, 2 and 4 KHz.,, Sensorineural hearing loss (SNHL) was diagnosed when both AC and BC thresholds were more than 25 dB and the difference between the two was <10 dB while for conductive hearing loss, the diagnosis was made when only the AC threshold was more than 25 dB., Mixed hearing loss was diagnosed when both the AC and BC thresholds were more than 25 dB and the difference between the two was more than 10 dB.,
The classification of hearing threshold was as follows: normal threshold (≤25 dB), mild hearing loss (26–40 dB), moderate hearing loss (41–55 dB), moderately severe hearing loss (56–70 dB), severe hearing loss (71–91 dB) and profound hearing loss (>91 dB).,, All those with 25 dBHL or less were considered to have normal hearing thresholds while those with more than 25 dBHL were considered to have abnormal hearing thresholds. The hearing threshold of the patients were then compared based on stage of the disease (stages III, IV and V).
The data was analysed using the Statistical Product and Service Solutions (SPSS) software IBM SPSS Statistics for Windows, version 20 (IBM Corp., Armonk, NY, USA). Chi-square test and analysis of variance were used for statistical analysis. The level of statistical significance was set at P < 0.05.
| Results|| |
Sixty CKD patients were assessed. Their ages ranged between 20 and 68 years with mean age of 43.2 ± standard deviation of 13.4 years. Seventy per cent were males and 30% were females with a male:female ratio (M:F) of 2.3:1. [Table 1] shows that there was no statistically significant association between age and stage of CKD. Similarly, there was also no statistically significant association between gender and stage of CKD.
|Table 1: Age and sex distribution versus stage of chronic kidney disease|
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One hundred and eighteen out of the 120 ears examined were clear and the remaining two ears had soft wax which was removed and then had the audiometric assessment 1 week after syringing. The TMs were intact in all the patients. One hundred and twenty ears were assessed. Of these, 51 (42.5%) ears had normal hearing thresholds and the remaining 69 (57.5%) ears had hearing loss. Of the 69 ears with hearing loss, 11 (15.9%) were in Stage III, 22 (31.9%) were in Stage IV and 36 (52.2%) were in Stage V CKD. The difference between stage of CKD and hearing loss was statistically significant (χ2 = 10.123, P = 0.006). [Table 2] shows hearing threshold in different stages of CKD.
[Table 3] gives detail of stage of CKD and severity of hearing impairment. Sixteen subjects had Stage III CKD making a total of 32 ears, and of these, 21 (65.6%) ears had normal hearing thresholds and 11 (34.4%) ears had mild hearing loss. None of those with Stage III disease had either moderate, moderately severe, severe or profound hearing loss. Eighteen individuals had Stage IV CKD making a total of 36 ears. Of these, 14 (38.9%) ears had normal hearing threshold, 16 (44.4%) ears had mild degree hearing loss while 6 (16.7%) ears had moderate degree hearing loss. None of those with Stage IV disease had either moderately severe, severe or profound hearing loss.
Twenty-six subjects had Stage V CKD making a total of 52 ears. Of these, 16 (30.8%) had normal hearing threshold, 25 (48.1%) had mild degree hearing loss, 9 (17.3%) had moderate degree hearing loss and 2 (3.8%) had moderately severe hearing loss. The difference between degree of hearing loss and stage of CKD was statistically significant (χ2 = 14.770, P = 0.022).
Sixty-seven (97.1%) ears of the total 69 ears with hearing loss had SNHL, and the remaining 2 (2.9%) ears had mixed hearing loss. [Figure 1] shows a sample audiogram of one of the patients. Analysis of variance showed that there was significant difference between stage of CKD and degree of hearing loss (F = 7.227, P = 0.001). A post hoc test showed that Stage III CKD had significantly better hearing than those with Stage IV (P = 0.013) and Stage V (P < 0.001) CKD. However, there was no statistically significant difference between Stage IV and Stage V CKD (P = 0.284).
| Discussion|| |
Available literature revealed that hearing loss increases in patients with CKD with decreasing GFR.,, This present study showed hearing loss of 15.9%, 31.9% and 52.2% in patients with Stages III, IV and V, respectively. This finding was similar to a study carried out in South Africa by Govender et al. on CKD patients with all the five stages of kidney disease (I, II, III, IV and V) revealed that those with Stages I and II had normal hearing thresholds while those with Stages III, IV and V had shown varying degrees of hearing loss. This implies that, those in the later stages of CKD are more prone to developing auditory dysfunction resulting from possibly imbalances of creatinine, urea and electrolytes. Seo et al. conducted a large survey of 5226 participants on the Korean National Health and Nutritional Examination Survey to look at the association of hearing impairment with CKD and they reported that 46% of those with Stage III and above (i.e., GFR <60 ml/min/1.73 m2) had worse hearing thresholds compared to those with relatively higher GFR ≥60 ml/min/1.73 m2 (i.e., Stages I and II). Similarly, in a large population-based survey of 2564 participants, Vilayur et al. assessed the association between reduced GFR and hearing loss and found hearing impairment of 19%, 28.3%, 54.4% and 73% in patients with GFR ≥90 ml/min/1.73 m2 (Stage I), GFR ≥60 ml/min/1.73 m2 (Stage II), GFR <60 ml/min/1.73 m2 (Stage III) and GFR ≤45 ml/min/1.73 m2 (Stage IV and V), respectively. Most studies on the subject reported that hearing loss increases with decreasing GFR.,,,
Majority of CKD patients in this present study had mild degree hearing loss. This is similar to the findings in Brazil, Nigeria, India,, Italy and Iraq. The mild degree of hearing loss observed in this study was mostly associated with Stage III CKD. It is possible that this condition inflict the least injury on the inner ear resulting in mild hearing loss compared to long standing chronic disease (Stage IV and Stage V CKD). However, Rahman et al. in Bangladesh, Bendo et al. in Albania and Meena et al. in India all reported a more severe degree of hearing loss in their studies. Their studies revealed that individuals with advanced stage of disease had the more severe form of hearing loss. The implication of this finding is that if CKD can be detected early and managed successfully, the more deleterious long-term effects of the disease on the inner ear could be avoided and hearing loss may be limited at worse to a mild degree.
This study showed that Stage III CKD had significantly better hearing than those with Stage IV (P = 0.013) and Stage V (P < 0.001). However, there was no difference between Stage IV and V CKD (P = 0.284). Rahman et al. in their study of prevalence and patterns of hearing loss among CKD of various stages in Bangladeshi patients reported hearing loss of 6.6%, 33.3% and 60% in patients with Stages III, IV and V respectively. Vilayur et al. reported hearing loss in 73% of those with GFR <45 ml/min/1.73 m2 and the hearing loss worsen with decreasing GFR. Similarly, Balasubramanian et al. in India also reported worsening of hearing loss with advancing stage of kidney disease. This finding may suggest that the possibly worst injurious insults to the inner ear may be starting to take place in the stage IV disease.
| Conclusion|| |
Our study showed a statistically significant relationship between advancing stage of CKD and hearing loss. The hearing loss worsen with advancing stage of CKD. Stage III CKD had significantly better hearing than those with Stages IV and V, but there was no statistical difference between Stages IV and V.
Most of the patients were hypertensive and some were diabetic; these conditions may have affected the hearing thresholds. Hearing test was not carried out in a sound proof booth; background noise may have affected the hearing thresholds. Another limitation is the non-availability of auditory brainstem-evoked response machine in our centre which is a more sensitive hearing assessment tool and can distinguish between cochlear and retrocochlear affectation.
We wish to acknowledge Dr. US Grema of National Ear Care Centre, Kaduna for allowing us to use his own personal diagnostic audiometer for free.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]