Drivers of delay in tuberculosis diagnosis among underserved groups in Portugal: An exploratory convergent parallel mixed-methods study

BACKGROUND: Tuberculosis (TB) remains the leading infectious cause of death globally, disproportionately affecting people living with HIV and those with drug-resistant TB. In Portugal, TB incidence and notification rates exceed the European average, with diagnostic delays affecting underserved populations. RESEARCH QUESTION: This study investigated factors contributing to total diagnostic delay among people with TB in Portugal, particularly underserved groups, and identified strategies to reduce these delays. STUDY DESIGN AND METHODS: A convergent-parallel mixed-methods approach was used. Quantitative data came from 55 surveys, and qualitative data through 27 semi-structured interviews and two focus group discussions. Descriptive statistics and thematic analysis identified patterns of total diagnostic delay, contributing factors, and potential interventions. RESULTS: Median total diagnostic delay was 45 days (IQR 21-60 days). In exploratory comparisons, underserved groups reported longer total diagnostic delay than the general population. Key person-related barriers included symptom normalisation, financial and logistical constraints, stigma, and fragmented referral pathways. System-level obstacles such as complex paperwork, limited clinic hours, staff indifference, and language barriers compounded delays. Proposed solutions included clear and non-judgemental communication, mobile screening units, integrated electronic records, anti-stigma campaigns, and social support teams for healthcare navigation. CONCLUSION: Diagnostic delays remain a major challenge in TB control in Portugal, especially among underserved populations. Reducing these delays requires multi-level interventions, including enhanced primary care awareness, stigma reduction, compensation for indirect costs, and simpler administrative procedures. Addressing these barriers is essential to reduce preventable morbidity, limit ongoing transmission, and tackle health inequities, while supporting progress towards national and global TB targets.