Hypertension as a Risk Factor of Hearing Loss in Patients Attending the Hypertensive Clinic at the Kenyatta National Hospital

Abstract

Background: Hearing loss is the most frequent sensory deficit in the human population with World Health organization estimating 360 million people in the world to have disabling hearing loss of which 328 million (91%) are adults. Hypertension whose prevalence in developing countries is increasing, has been associated with sensorineural hearing loss in recent studies. Hypertension causes sensorineural hearing loss by microcirculatory insufficiency in the cochlear. Primary prevention, delaying onset of hypertension and consistent control of high blood pressure can significantly decrease the burden of hearing loss in patients. Study objective: To determine the association between hearing loss and hypertension in patients on treatment for hypertension at the Kenyatta National Hospital. Methods: Case control study with 51 hypertensive patients aged 45 to 64 years on treatment at KNH MOPC as cases and 51 non-hypertensive patients aged 45 to 64 years attending dental outpatient clinic as controls. A detailed history, physical examination, blood pressure measurement and otoscopy was done by the primary investigator. Pure tone audiometry (PTA) was conducted by a qualified audiologist in the ENT clinic. Results: Thirteen out of fifty one hypertensive patients (25.5%) and seven out of fifty one non-hypertensive patients (13.7%) had hearing loss. Four out of twenty two (18.2%) patients with grade 1 hypertension and three out of eleven (27.3%) with grade 2 hypertension had hearing loss. Among the hypertensive patients 29.0% who had been treated for 5 years or less had hearing loss while 33.3% who had hypertension for more than 10 years had hearing loss. Ten out of the 13 (76.9%) hypertensive patients had mild hearing loss. Twenty (39.2%) of the hypertensive patients had tinnitus. Conclusion: This study has shown that hypertension is a risk factor for hearing loss as demonstrated by the higher prevalence and raised hearing threshold levels by pure tone audiometry in all frequencies in the hypertensive patients. However, it is not statistically significant.