Supplemental Material for: Progressive Hearing Loss in Childhood - A Prognostic Factor Systematic Review

A PROSPERO-registered systematic review (ID: CRD42023492129) was conducted to identify and evaluate prognostic factors associated with childhood PHL. MEDLINE, EMBASE, and Cochrane Library databases were searched for studies published between 2000 and 2025 in English, including patients aged 0–18 years, with confirmed permanent hearing loss. Study design quality was assessed using CHARMS-PF, and risk of bias was evaluated with QUIPS.

Due to heterogeneity in definitions and outcomes, a narrative synthesis was performed.</p><p dir="ltr">Results: Eighteen (participants n= 1,497) studies were included in the narrative synthesis and eligible for risk of bias assessment; only two were deemed low risk. Exploratory prognostic factors included congenital cytomegalovirus infection, enlarged vestibular aqueduct, platinum-based chemotherapy, and radiotherapy. The influence of these factors on the rate and severity of hearing loss was variable, and current evidence was insufficient for meta-analysis or definitive prognostic conclusions.</p><p dir="ltr">Conclusion: Evidence on prognostic factors for PHL is limited and heterogeneous.

High-quality, methodologically robust studies are needed to confirm these factors and develop predictive, multivariable models. Such models could guide personalised surveillance and intervention strategies, enabling clinicians to deliver the right intervention at the optimal time and improving long-term auditory and developmental outcomes for children at risk of PHL. </p>