Impacts of the hearing aid intervention on healthcare utilization and costs among middle-aged and older adults: results from a randomized controlled trial in rural China

BACKGROUND: Hearing impairment has become a major global health issue. To reduce the burden of hearing impairment, we explored impacts of the hearing aid intervention on healthcare utilization and costs. METHODS: In this randomized controlled trial, participants aged 45+ were allocated with a ratio of 1:1.5 (intervention: control). Neither the investigators nor the assessors were blinded to the allocation status. Those in the intervention group were fitted with hearing aids, and those in the control group received no care. We applied the difference-in-difference (DID) approach to examine the impacts on healthcare utilization and costs. Given that social network and age can be significant variables affecting effectiveness of the intervention, subgroup analyses by social network and age were used to explore the heterogeneity. FINDINGS: 395 subjects were successfully recruited and randomized. 10 subjects did not meet the inclusion criteria and therefore, 385 eligible subjects (150 in the treatment group and 235 in the control group) were analyzed. The intervention significantly reduced their total healthcare costs (average treatment effect (ATE) = −1.26, 95% CI = −2.39, −0.14, p = 0.028) and total out-of-pocket (OOP) healthcare costs (ATE = −1.29, 95% CI = −2.37, −0.20, p = 0.021) in the 20-month follow-up. To be exact, it reduced self-medication costs (ATE = −0.82, 95% CI = −1.49, −0.15, p = 0.016) and OOP self-medication costs (ATE = −0.84, 95% CI = −1.46, −0.21, p = 0.009). Subgroup analysis showed that the impacts on self-medication costs and OOP self-medication costs varied by social network (ATE for self-medication costs = −0.26, 95% CI = −0.50, −0.01, p = 0.041; ATE for OOP self-medication costs = −0.27, 95% CI = −0.52, −0.01, p = 0.038). The impacts also varied by age groups (ATE for self-medication costs = −0.22, 95% CI = −0.40, −0.04, p = 0.019; ATE for OOP self-medication costs = −0.17, 95% CI = −0.29, −0.04, p = 0.010). There were no adverse events or side effects during the trial. INTERPRETATION: Hearing aid use significantly lowered self-medication costs and total healthcare costs, but had no impacts on inpatient or outpatient services utilization or costs. The impacts were manifested among people with active social network or younger age. It can be speculated that the intervention may be adapted to other similar settings in developing countries to reduce healthcare costs. FUNDING: P.H. reports grants from National Natural Science Foundation of China (No. 71874005) and Major Project of the National Social Science Fund of China (No. 21&ZD187). TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR1900024739.