Associations between hearing loss, peripheral neuropathy, balance, and survival in older primary care patients

Background: Both age-associated hearing loss (AAHL) and peripheral neuropathy (PN) are common in older patients, and both are associated with impaired balance, falls, and premature mortality. The objectives of this study were to document the prevalence and severity of AAHL in older primary care patients, and to explore associations between AAHL, PN, balance, falls, and mortality. Methods: We analyzed information obtained in 1999 from 793 primary care patients recruited from practices participating in the Oklahoma Longitudinal Assessment of the Health Outcomes of Mature Adults (OKLAHOMA) Studies. Available data included demographic and health information, history of falls and hospitalizations, audiometry, balance testing, examination of the peripheral nerves, 50 foot timed gait, and dates of death up to 22 calendar years and 8106 person-years of follow-up. Proportionate hazards (PH) and structural equation modeling (SEM) were used to examine associations between AAHL, PN, balance, gait time, and mortality. Results: 501 of the 793 participants (63%) had AAHL. Another 156 (20%) had low frequency and 32 (4%) had unilateral deficits. Those with moderate or severe AAHL and the 255 (32%) with PN had impaired balance (p < 0.0001), increased gait time (p = 0.0001), and reduced survival time (p < 0.0001). In the PH model, both AAHL and PN were associated with earlier mortality (H.Rs. [95% C.I.]: 1.36 [1.13-1.64] and 1.32 [1.10-1.59] respectively). The combination of moderate or severe AAHL and PN, present in 24% of participants, predicted earlier mortality than predicted by either deficit alone (O.R. [95% C.I.I] 1.55 [1.25-1.92]). In the SEM models, the impacts of both moderate or severe AAHL and PN on survival were mediated, in part, through loss of balance. Conclusions: Hearing loss and PN, both common in older patients, appear to be independently and additively associated with premature mortality. Those associations may be mediated in part by impaired balance. The Mechanisms are likely multiple and complex.