Long-Term DHI Outcomes in Patients with Chronic Dizziness and Initially Uncertain Diagnosis: A Retrospective Follow-Up Study.

Background: Dizziness is a common symptom arising from disorders across multiple organ systems. Diagnostic pathways are often prolonged, and uncertainty may increase patients' subjective burden. Aims/Objectives: This study describes the long-term course of functional impairment in patients with chronic, complex dizziness with delayed or inconclusive diagnostic classification using longitudinal DHI data. Material and Methods: This retrospective longitudinal study included patients presenting between 2009 and 2012 with persistent dizziness of at least one year and no definitive diagnosis at baseline. Initial DHI scores were compared with follow-up data collected 14-17 years later via structured telephone interviews. Changes in total and subdomain scores (functional, emotional, and physical) were analyzed, with subgroup analyses (sex, age, and diagnostic status). Results: Fifty-one patients were included. Median total DHI score decreased from 48.0 to 14.0 (Z = -6.13, p < 0.001). Median within-patient change was -28 (95% CI: -44 to -15). A total of 49/51 patients (96%) showed improvement. All DHI subdomains improved significantly, with the largest change observed in the functional domain (median -10, 95% CI: -15 to -4). Improvements were consistent across subgroups and largely independent of epidemiological and diagnostic factors. Conclusions and Significance: Patients with complex chronic dizziness show substantial long-term improvement in DHI scores. Further studies in larger cohorts are needed to determine whether a generalizable prognosis can be established.