Smear grading at initial treatment association with treatment outcomes among new smear positive pulmonary tuberculosis patients: A retrospective study.

Introduction: Tuberculosis (TB) is one of the most challenging diseases in diagnosis, treatment and control. We aimed to assess the association of the initial grading of Mycobacterium Sputum Smear (MSS) on the outcomes of TB treatment.

Materials and methods: In a retrospective study, data of 418 positive pulmonary smear patients were retrieved from the TB registration system in Iran during 2014 to 2021. Patients' data included demographic, laboratory and clinical information and were recorded in our checklist. The grading of Mycobacterium Sputum Smear (MSS) at the initial treatment was assessed based on World Health Organization (WHO) guidelines. Chi-square test was used to assess the relationship between tuberculosis treatment outcomes and Mycobacterium grade at initial treatment in SPSS.

Results: The mean age of cases was 51.19 ± 22.29 years old and varied between 14 and 95 years. Laboratory results showed that the rate of 1-9, 1+,2+ and 3+ Mycobacterium tuberculosis was 17.7%, 44.3%, 19.4% and 18.7%, respectively. The rate of cure, death and treatment failure in patients was 87.1%, 6.9%, and 1.2%, respectively. The highest mortality rate (11.5%) occurred in patients with 3+ and the lower rate of cure was 79.5% in this group. Moreover, by increasing the Mycobacterium grade the rate of transferred out and lost to follow up from treatment increased (p = 0.024).

Conclusion: High smear grading of sputum is inversely associated with lower curing and on-time treatment. Moreover, by increasing the Mycobacterium grade at initial treatment, treatment failure and lost to follow up increased Therefore, improvement the health system and patient-diagnosis and screening programs is necessary to on-time diagnosis and facilitate the treatment process.