Abstract
Background: Adult hearing loss is common, yet hearing-aid uptake remains inadequate due to systemic and financial barriers in traditional audiologist-based fitting models. Over-the-counter (OTC) and self-fitting strategies have emerged to improve accessibility, allowing users to select and adjust their devices independently. However, concerns remain that reducing professional involvement may compromise electroacoustic accuracy, speech-in-noise outcomes, and overall patient satisfaction. Methods: A comprehensive literature search across PubMed, Web of Science, CENTRAL, Scopus, and Embase was conducted up to 1 June 2026. Parallel-group and crossover randomized controlled trials (RCTs) comparing self-fitting with professional-fitting were included. The primary outcome was patient-reported hearing benefit. Standardized mean differences (SMDs) and risk ratios (RRs) were pooled using a random-effects model. Results: Seven RCTs involving 1092 participants were included. The analysis revealed no statistically significant difference between self-fitting and professional-fitting strategies regarding patient-reported hearing benefit (SMD: 0.01, 95% CI [−0.44, 0.46], p = 0.97, I2 = 89.2%, very low certainty of evidence). Similarly, no significant differences were observed across secondary outcomes, including speech-in-noise performance (SMD: 0.11, 95% CI [−0.25, 0.47]; p = 0.55), hearing loss (p = 0.12), hearing-aid satisfaction (p = 0.31), device adherence (p = 0.65), or the need for follow-up adjustment (RR: 0.46, 95% CI [0.12, 1.71]; p = 0.25). Safety outcomes were sparse and did not demonstrate a statistically significant difference between the fitting approaches; however, the evidence was imprecise and inconclusive. Conclusions: Self-fitting hearing aids showed no clear differences from professional best-practice fitting across several patient-reported and functional outcomes in adults with uncomplicated mild-to-moderate hearing loss. However, the certainty of evidence was very low because of risk of bias, substantial heterogeneity, imprecision, and the small number of trials. These findings are therefore hypothesis-generating and suggest that well-designed self-fitting pathways may have potential as an accessible alternative for selected users, but larger, rigorous, and longer-term trials are needed before broader clinical implementation can be recommended.