National portrait of amyotrophic lateral sclerosis care in Brazil's Unified Health System (2023–2025): patient-level treatment, persistence, and geographic access from linked administrative microdata

Background Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease for which riluzole remains the main disease-modifying therapy available in many health systems. Nationwide, patient-level descriptions of ALS care pathways in low- and middle-income countries with universal health coverage are scarce. We aimed to characterize ALS treatment, treatment persistence, and geographic access within the Brazilian Unified Health System (SUS) using nationwide administrative microdata. Methods We conducted a retrospective nationwide study using deidentified administrative microdata from SUS between January 2023 and December 2025. We identified patients at the individual level using an encrypted national health identifier based on the ICD-10 code G12.2 and/or riluzole dispensing, an ALS-specific treatment marker in Brazil. Ambulatory services and care centers were analyzed at the aggregate level. Treatment persistence was estimated using Kaplan-Meier methods. Geographic access was assessed by comparing the distribution of treated patients with expected ALS prevalence estimates across Brazilian states. Results We identified 10,598 patients receiving ALS-related treatment and 890 probably diagnosed but untreated patients, corresponding to an estimated treatment gap of approximately 7.7%. Median age at first record was 62 years, and the male-to-female ratio was 1.22:1. Among patients with available race and ethnicity information, 54.4% were classified as White, 38.3% as mixed, and 3.9% as Black. Riluzole dispensing was monthly in 94.6% of observed intervals; median treatment persistence was 19 months (95% CI 18–20), with 61.4% of patients remaining on treatment at 12 months and only 35.3% achieving a medication coverage proportion of at least 0.80. Rehabilitation services represented most ambulatory care contacts, whereas ALS-specific diagnostic coding was rarely captured in SUS administrative data. Medication dispensing and multidisciplinary clinical care were structurally separated across care sites. Treatment coverage demonstrated substantial regional variation, with markedly lower capture in northern states, including Acre (38%), Roraima (39%), and Amazonas (47%). Conclusions Within the SUS, ALS treatment availability approached the expected population burden overall, but important inequities remained in treatment continuity, geographic access, and diagnostic recognition. These findings highlight the need for improved diagnostic pathways, active identification of patients with ALS, and integrated regional networks for multidisciplinary care.