PURPOSE: to identify the reason for absence of the patients from the Unified Health System who use hearing aids at the audiology follow up and analyze the the device adaptation in this population. METHOD: 27 absent patients were interviewed with opened questions about their absence and the implementation of the International Outcome Inventory for Hearing Aids, a self-assessment questionnaire for post adaptation evaluation. Comparison of absent patients' post adaptation was performed from a random selection of 30 questionnaires from patients who attended the audiologic follow-up at the Institution (control group) who were registered in a database. Descriptive and inferential statistics (Mann-Whitney test - significance level of 5%) were applied for data analysis. RESULTS: the majority of absent patients (25.92%) say they didn't remember the return date for follow up. The questionnaire's comparative results between the absent and non-absent groups showed statistically significant differences in almost every area of self-assessment questionnaire, except on benefit items, participation restriction and quality of life CONCLUSION: among the reasons for not attending the service, we can highlight: forgetting the appointment, health problems and work reasons. It was observed that patients who did not attend the audiologic follow-up showed statistically significant post-adaptation results inferior when compared to the patients who attended the follow-up.