Patient-related diagnostic delay and risk of unfavorable treatment outcomes among pulmonary tuberculosis patients at the antituberculosis center of Brazzaville, Republic of Congo

Tuberculosis (TB) remains a major public health concern worldwide. Early diagnosis is crucial to reduce TB transmission and improve treatment outcomes. This study assessed patient-related diagnostic delay and their impact on the treatment outcomes among pulmonary tuberculosis patients (PTB) at the Antituberculosis center in Brazzaville. We conducted a prospective cohort study from July 2023 to August 2024. Sociodemographic, clinical characteristics, patient-related diagnostic delays delay (short ≤ 30 days, prolonged > 30 days), 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. A total of 313 patients was 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 patient-related diagnostic delay was not significantly associated with treatment outcomes, patients with delays > 30 days had higher odds of death (OR = 2.30, 95%CI: 0.7-7.3) and treatment failure (OR = 5.4, 95%CI: 0.8-66.4). A high median patient-related diagnostic delay of 30 days was observed in Brazzaville. Residence in peripheral districts and diabetes mellitus status were significant predictors of delay. Although not statistically significant, prolonged patient delays tended to be associated with higher risks of death and treatment failure. Strengthening early case detection and promoting prompt healthcare-seeking and diagnosis among symptomatic individuals are critical for reducing TB diagnostic delays and improving treatment outcomes.