Delay in diagnosis and relative risk of treatment failure and deaths in pulmonary tuberculosis patients at the Antituberculosis center of Brazzaville, Republic of Congo

Introduction Tuberculosis (TB) remains a major public health concern worldwide. Early diagnosis is crucial to reduce TB transmission and improve treatment outcomes. This study assessed diagnostic delays and their impact on the treatment outcomes among pulmonary tuberculosis patients (PTB) at the Antituberculosis center in Brazzaville. Methods We conducted a prospective cohort study from July 2023 to August 2024. Sociodemographic, clinical characteristics, diagnostic delays, and treatment outcomes were recorded. Logistic regression models were used to identify risk factors, reporting crude and adjusted odds ratios (OR, AOR) with 95% confidence intervals (CI). A p-value < 0.05 was considered significant. Results A total of 313 patients were included (median age: 34 years, range 24–41); 295 (94.2%) were newly diagnosed, and 16 (5.1%) were HIV-positive. Men accounted for 69% of cases, and the age group 24–44 was the most represented (55.9%). The median patient delay was 30 days (IQR 21–62), and 135 (43.1%) experienced prolonged delays. Multivariate analysis showed that residence in Mfilou district was associated with longer delays (OR = 2.77, 95%CI: 1.22–6.30; p = 0.004), whereas diabetes mellitus was linked to shorter delays (OR = 0.15, 95%CI: 0.02–1.13; p = 0.008). Although diagnostic delay was not significantly associated with treatment outcomes, patients with delays > 30 days had higher odds of death (OR = 2.50, 95%CI: 0.78–7.76) and treatment failure (OR = 5.68, 95%CI: 0.92–69.81). Conclusion A high median diagnostic delay (30 days) was observed in Brazzaville. Residence and diabetes mellitus status were significant predictors of delay. Although not statistically significant, prolonged delays were associated with higher risks of death and treatment failure. Strengthening case-finding strategies and improving timely health-seeking behaviors are critical to reducing TB burden.