Predictive factors of delayed sputum conversion in pulmonary tuberculosis

<b>Introduction:</b> Sputum smear and culture conversion are indicative factors of the effectiveness of treatment and the infectivity of the patient. <b>Aim of study:</b> Identify parameters influencing sputum smear and culture conversion delay among patients with pulmonary tuberculosis(PT) <b>Methods:</b> Retrospective study(2011-2018)including patients with PT and treated according to WHO recommendations in pulmonary department C(Mami hospital in Tunisia). Population was divided to 2 groups: G1(n=168): patients with delayed sputum smear and culture conversion (sputum smear and culture positive at 2months of TB treatment); G2(n=292):patients without delayed sputum smear and culture conversion <b>Results:</b> A total of 460 patients were included(mean age 40.07+/-16.37,61.3% were men),G1 patients were older than G2(40.17vs 39.86years;p=0.071). Delayed sputum smear and culture conversion occurred in 35% of the patients. Smoking was significantly more frequent in G1(66% vs 50%;p=0.048). Diabetes(17.4%vs8.72%;p=0.006)and family history of PT(27% vs 16.3%;p=0.004) were significantly presents in G1. For clinical symptoms cough, acute respiratory failure and hemoptysis were significantly more observed in G1 than G2. Infiltrate in the chest-X-Ray was significantly more frequent in G1(3.35%) than in G2(0.7%)(p=0.007). White blood cell and CPR were higher in G1 than G2. Smear grade &gt;20 acid fast bacilli/field in the first sputum smear was significantly associated with delayed sputum smear and culture conversion <b>Conclusion:</b> Delayed sputum smear and culture conversion occurred in about 1/3 of patients. Diabetes, smoking, hemoptysis and smear grade are predictive factors of delayed sputum smear and culture conversion. These patients need special healthcare.