The multifaceted links between hearing loss and chronic kidney disease.

Hearing loss affects nearly 1.6 billion people and is the third-leading cause of disability worldwide. Chronic kidney disease (CKD) is also a common condition that is associated with adverse clinical outcomes and high health-care costs. From a developmental perspective, the structures responsible for hearing have a common morphogenetic origin with the kidney, and genetic abnormalities that cause familial forms of hearing loss can also lead to kidney disease. On a cellular level, normal kidney and cochlea function both depend on cilial activities at the apical surface, and kidney tubular cells and sensory epithelial cells of the inner ear use similar transport mechanisms to modify luminal fluid. The two organs also share the same collagen IV basement membrane network. Thus, strong developmental and physiological links exist between hearing and kidney function. These theoretical considerations are supported by epidemiological data demonstrating that CKD is associated with a graded and independent excess risk of sensorineural hearing loss. In addition to developmental and physiological links between kidney and cochlear function, hearing loss in patients with CKD may be driven by specific medications or treatments, including haemodialysis. The associations between these two common conditions are not commonly appreciated, yet have important implications for research and clinical practice. Chronic kidney disease is associated with a graded and independent excess risk of sensorineural hearing loss. This Review describes how disruption of shared signalling pathways that are important for the development of both the ear and the kidney and/or the presence of clinical drivers, such as specific medications or treatments, may underlie these associations. Key points: Chronic kidney disease (CKD) and hearing loss are common conditions that individually cause tremendous morbidity but which often coexist. The kidneys and the hearing organs share a common morphogenetic origin and rely on similar biological structures (for example, cilia) and processes (for example, specialized cellular transport mechanisms) to function. Genetic abnormalities that cause CKD can also cause hearing loss, and vice versa. A strong, graded and independent relationship exists between kidney function and the risk of hearing loss; the highest risk is observed in patients on haemodialysis, but kidney transplant recipients and people with mild CKD are also at increased risk. Infants, children and possibly adults with malformation or dysfunction of their hearing organs should be evaluated for the presence of malformation or dysfunction of their kidneys, and vice versa. Additional funding is needed to support basic, clinical and health services research that explores the intersection between these two relatively neglected conditions. [ABSTRACT FROM AUTHOR]