Invisible in the system: Fragmented data and territorial inequalities in sickle cell disease in Brazil.

Sickle cell disease (SCD) is a genetic disorder strongly shaped by social, racial, and territorial inequalities. We identified, mapped, and characterized the population living with SCD in a state in Northeast Brazil and examined how fragmented institutional records affect the epidemiological visibility of the disease. We carried out a cross-sectional, multi-source study using institutional datasets on people with SCD. Records from these sources were consolidated and complemented by active tracing to update information. Adults were interviewed to describe their sociodemographic conditions, clinical profile, access to care, and experiences within the health system. Official counts substantially underestimated the affected population, reflecting unlinked information systems and limited record updating. The number of identified individuals increased from 266 to 471, corresponding to an estimated prevalence of 1.14 cases per 10,000 inhabitants. Interviewed adults (n = 119) showed high social vulnerability, with a predominance of Black participants, low educational attainment, low levels of income, and reliance on social benefits. A considerable proportion of participants were diagnosed only in adulthood. Specialized care was concentrated in the state capital and one additional urban center, creating major geographic barriers for residents of interior municipalities. Pain was frequent, severe, and functionally limiting, and many participants reported pain disbelief and stigmatizing labels during care. The gap between official records and identified cases indicates a significant weakness in health surveillance. Social vulnerability, geographically concentrated services, and routine delegitimization of pain suggest that historical inequalities, including racism, remain embedded even within a universal public health system such as Brazil's.