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RATIONALE: The causal relationship between undernutrition and response to anti-tuberculosis (TB) treatment and TB treatment outcomes among people with retreatment TB is understudied. OBJECTIVE: To evaluate the effect of undernutrition on treatment success and sputum smear conversion among people with retreatment drug-susceptible TB in Kampala, Uganda. METHODS: We conducted a quasi-experimental study utilizing propensity score weighting among people with retreatment drug-susceptible TB aged ≥ 15 years treated between 2012 and 2022 in Kampala. The primary exposure was undernutrition assessed using the mid-upper arm circumference at the time of TB diagnosis. The primary outcome was treatment success defined as cure or treatment completion at month 6. Sputum smear conversion was the secondary outcome and was measured as a change in sputum smear status from positive to negative at months 2, 5, and 6. We estimated the causal effect of undernutrition on the outcomes using a propensity-score weighted modified Poisson regression model with robust error variance. MEASUREMENTS AND MAIN RESULTS: Of the 605 participants, 432 (71.4 %) were male, 215 (35.5 %) were aged 25-34 years, 427 (70.6 %) had bacteriologically confirmed pulmonary TB, 133 (22.0 %) were undernourished and 398 (65.8 %) achieved treatment success. Of participants with bacteriologically confirmed pulmonary TB, 232 (59.0 %), 327 (59.3 %), and 360 (97.6 %) achieved sputum smear conversion at months 2, 5, and 6, respectively. Undernutrition reduced treatment success (RR 0.42, 95 % CI 0.32-0.55) as well as sputum smear conversion at months 2 (RR 0.45, 95 % CI 0.42-0.49) and 5 (RR 0.46, 95 % CI 0.43-0.51) but not month 6 (RR 0.99, 95 % CI 0.97-1.02). CONCLUSION: Undernutrition negatively impacts treatment outcomes. Therefore, nutritional assessment should be an integral component of TB care, with nutritional counseling and support offered to those undernourished to optimize their TB treatment response and outcomes.

Background: Treatment of drug-sensitive TB consists of an intensive phase of 2 months followed by a continuation phase of 4 months. After completion of intensive phase of therapy, sputum AFB smear microscopy is repeated and presence of smear conversion is suggested as a significant early predictor of treatment effectiveness. Delay in sputum conversion will lead to prolongation of the period of time that patients remain contagious. Objectives: To study the determinants of delayed sputum conversion among Tuberculosis patients in Malappuram district Methodology: A Case control study was conducted among tuberculosis patients residing in Malappuram district of Kerala and registered under NTEP in District Tuberculosis Centre (DTC), Manjeri, Malappuram. After satisfying inclusion and exclusion criteria, 90 tuberculosis patients who failed to achieve sputum smear negativity after completion of 2 months of intensive phase multi drug therapy were taken as cases. Another 90 tuberculosis patients those who achieved sputum smear negativity after completion of 2 months of intensive phase therapy were selected as control group. Data was collected by interview method. Results: Patients with lower socio-economic status (OR = 3.59, 95% CI 1.92- 6.73), low BMI or underweight (OR = 1.98, 95% CI 1.1 - 3.6), multiple symptoms (OR= 5.50, 95% CI 1.98 - 15.28), increased duration of symptoms (OR=4.54, 95% 2.24-9.19), co-morbid condition of diabetes mellitus (OR = 2.25, 95% CI 1.24 - 4.09) are at statistically significant risk of delay in sputum smear conversion after intensive phase of anti-tubercular therapy. Conclusion: Patients with lower socio-economic status, low BMI or underweight, multiple symptoms, increased duration of symptoms, co-morbid condition of diabetes mellitus are at statistically significant risk of delay in sputum smear conversion after intensive phase of anti-tubercular therapy. Treating physicians and public health experts should give special attention to TB patients with these risk factors.

ABSTRACT The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. This retrospective study was conducted in Taiwan between 2011 and 2020. A microbiological cure was defined as the requirement for a minimum of three consecutive negative cultures following culture conversion that continued until the completion of anti-MAC treatment. A total of 97 patients with MAC-PD were enrolled in this study. The sputum smear-negative conversion rate was 40% (19/47). Thirty (31%) patients achieved sputum culture-negative conversion rates within 3 years after treatment initiation. All patients with negative sputum culture conversion rates achieved microbiological cure. Patients treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than the other patients (39% vs 17%, P = 0.023). Patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate than those with negative sputum smears (6% vs 44%, P < 0.001). Among 30 patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 (0–483) days, and the 1-year relapse rate was 17%. Treatment with the M + R + EMB-based regimen was associated with a higher microbiological cure rate, and patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate. IMPORTANCE The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. In this study, patients with MAC-PD treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than those treated with other regimens. After 6 months of treatment, patients with persistently positive sputum smears had a lower microbiological cure rate than those with negative sputum smears. Among patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 days (range, 0–483), and the 1-year relapse rate was 17%.

Objectives: This study aimed to explore the effects of 25-hydroxy vitamin D (25[OH]D) on T lymphocyte subsets and sputum smear conversion during antituberculosis (TB) treatment. Methods: A total of 120 newly diagnosed patients with active pulmonary TB were collected and classified into vitamin D sufficiency group, vitamin D insufficiency group, and vitamin D deficiency group according to serum 25(OH)D levels. The clinical data and sputum smear conversion were collected and serum 25(OH)D and T lymphocyte subsets were also measured and compared. Results: Our data showed that 25(OH)D levels reached the lowest point at two months of anti-TB treatment. Significant differences existed in the increase of CD4+ and CD8+ T cells on the basis of vitamin D levels. The vitamin D sufficiency group had a significantly higher increase of CD4+ T cells during six months of anti-TB treatment and CD8+ T cells after four months of anti-TB treatment than the other groups. Vitamin D had no effect on the time-to-sputum smear conversion (vitamin D sufficiency group: adjusted hazard ratio: 1.27, 95% confidence interval [CI]: 0.78–2.06); vitamin D insufficiency group: adjusted hazard ratio: 1.05, 95% CI: 0.63–1.75)]. Conclusion: Through null effects on sputum smear conversion, vitamin D may have a beneficial effect on the increase of CD4+ and CD8+ T cells during anti-TB treatment.

• 25-hydroxy vitamin D levels reached the lowest point at two months of antituberculosis treatment. • Vitamin D may have a beneficial effect on the increase of CD4+ and CD8+ T cells. • Vitamin D had no effect on the time-to-sputum smear conversion. This study aimed to explore the effects of 25-hydroxy vitamin D (25[OH]D) on T lymphocyte subsets and sputum smear conversion during antituberculosis (TB) treatment. A total of 120 newly diagnosed patients with active pulmonary TB were collected and classified into vitamin D sufficiency group, vitamin D insufficiency group, and vitamin D deficiency group according to serum 25(OH)D levels. The clinical data and sputum smear conversion were collected and serum 25(OH)D and T lymphocyte subsets were also measured and compared. Our data showed that 25(OH)D levels reached the lowest point at two months of anti-TB treatment. Significant differences existed in the increase of CD4+ and CD8+ T cells on the basis of vitamin D levels. The vitamin D sufficiency group had a significantly higher increase of CD4+ T cells during six months of anti-TB treatment and CD8+ T cells after four months of anti-TB treatment than the other groups. Vitamin D had no effect on the time-to-sputum smear conversion (vitamin D sufficiency group: adjusted hazard ratio: 1.27, 95% confidence interval [CI]: 0.78–2.06); vitamin D insufficiency group: adjusted hazard ratio: 1.05, 95% CI: 0.63–1.75)]. Through null effects on sputum smear conversion, vitamin D may have a beneficial effect on the increase of CD4+ and CD8+ T cells during anti-TB treatment. [ABSTRACT FROM AUTHOR]

Rationale: The causal relationship between undernutrition and response to anti-tuberculosis (TB) treatment and TB treatment outcomes among people with retreatment TB is understudied., Objective: To evaluate the effect of undernutrition on treatment success and sputum smear conversion among people with retreatment drug-susceptible TB in Kampala, Uganda., Methods: We conducted a quasi-experimental study utilizing propensity score weighting among people with retreatment drug-susceptible TB aged ≥ 15 years treated between 2012 and 2022 in Kampala. The primary exposure was undernutrition assessed using the mid-upper arm circumference at the time of TB diagnosis. The primary outcome was treatment success defined as cure or treatment completion at month 6. Sputum smear conversion was the secondary outcome and was measured as a change in sputum smear status from positive to negative at months 2, 5, and 6. We estimated the causal effect of undernutrition on the outcomes using a propensity-score weighted modified Poisson regression model with robust error variance., Measurements and Main Results: Of the 605 participants, 432 (71.4 %) were male, 215 (35.5 %) were aged 25-34 years, 427 (70.6 %) had bacteriologically confirmed pulmonary TB, 133 (22.0 %) were undernourished and 398 (65.8 %) achieved treatment success. Of participants with bacteriologically confirmed pulmonary TB, 232 (59.0 %), 327 (59.3 %), and 360 (97.6 %) achieved sputum smear conversion at months 2, 5, and 6, respectively. Undernutrition reduced treatment success (RR 0.42, 95 % CI 0.32-0.55) as well as sputum smear conversion at months 2 (RR 0.45, 95 % CI 0.42-0.49) and 5 (RR 0.46, 95 % CI 0.43-0.51) but not month 6 (RR 0.99, 95 % CI 0.97-1.02)., Conclusion: Undernutrition negatively impacts treatment outcomes. Therefore, nutritional assessment should be an integral component of TB care, with nutritional counseling and support offered to those undernourished to optimize their TB treatment response and outcomes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

Rationale: Failure to convert sputum at two months of treatment among persons with bacteriologically confirmed pulmonary tuberculosis (BC-PTB) indicates poor response to treatment but data are limited on its assessment. Objective: We determined the frequency and factors associated with sputum smear non-conversion at two months among persons with BC-PTB in eastern Uganda. Methods: We abstracted data of adult persons with BC-PTB, from routinely available records from TB registers at 10 clinics in eastern Uganda. We determined factors that are independently associated with sputum smear non-conversion using logistic regression analysis. We expressed the results as odds ratio (OR) with 95% confidence interval (CI). Measurements and main results: Of 516 persons with BC-PTB, 81 (15.7%) did not achieve sputum smear conversion at two months of TB treatment. Higher Mycobacteria tuberculosis (MTB) load and treatment at a private-not-for-profit (PNFP) facility compared to government health facility were significantly associated with sputum smear non-conversion. A one unit (+1) increase in MTB load based on ZN stain counts was associated with a 48% increase in the odds of sputum smear non-conversion with adjusted odds ratio (AOR), 1.48 (95% CI, 1.02–2.18). TB treatment at private-not-for-profit health facility was associated with a two-fold increase in the odds of sputum smear non-conversion (AOR, 2.03; 95% CI, 1.01–3.92). Conclusions: Our study shows that sputum smear non-conversion is common at two months of treatment in this population. It is more likely among patients with higher baseline MTB load and those treated at PNFP facilities. Strategies targeting patients with these risk factors are needed to enhance sputum smear conversion.

Lingshuang Lv,1,* Tiecheng Li,2,* Kun Xu,1 Peiyi Shi,1 Biyu He,1 Weimin Kong,3 Jianming Wang,1 Jian Sun3 1Department of Epidemiology, Key Laboratory of Infectious Diseases, School of Public Health, Nanjing Medical University, Nanjing, China; 2Department of Tuberculosis, the Fourth People’s Hospital of Lianyungang City, Lianyungang, China; 3Department of Thoracic Surgery, the First People’s Hospital of Yancheng City, Yancheng, China *These authors contributed equally to this work Purpose: Multidrug-resistant tuberculosis (MDR-TB) requires long-term treatment, has a high fatality rate, and constitutes a global threat. Earlier detection of treatment failure is required to predict therapeutic efficacy.Patients and methods: We enrolled MDR-TB patients consecutively from January 2011 through December 2012 in Lianyungang, China. Sputum smear microscopy tests and sputum cultures were performed once a month for the first 6 months following initiation of antituberculosis treatment and once every 2 months thereafter until the end of therapy. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) were used with a 95% CI to estimate the role of sputum bacteriology conversion in predicting treatment outcomes.Results: Among the 92 MDR-TB patients enrolled in this study, 40.2% had poor treatment outcomes. The median initial sputum bacteriology conversion time was 1 month. Patients having 2-month sputum smear conversions (adjusted odds ratio [OR]: 7.19, 95% CI: 2.60–19.84) or culture conversions (adjusted OR: 2.88, 95% CI: 1.11–7.45) were more likely to experience good outcomes. The sensitivity and specificity obtained when using two-month sputum smear conversions to predict treatment outcomes were 67.6% (95% CI: 50.2–82.0) and 76.4% (95% CI: 63.0–86.8), respectively. The sensitivity and specificity obtained when using 2-month culture conversions to predict treatment outcomes were 48.6% (95% CI: 32.0–65.6) and 74.5% (95% CI: 61.0–85.3), respectively. The AUC for two-month smear conversions was 0.72 (95% CI: 0.62–0.81), significantly higher than that obtained for 2-month culture conversions (0.62, 95% CI: 0.52–0.72) (Χ2 = 4.18, P = 0.041).Conclusion: The prognoses of MDR-TB patients displaying persistent sputum positivity were inferior to those for whom sputum bacteriology conversion was observed. Thus, sputum smear conversion results obtained 2 months after treatment initiation may provide a potential means for predicting MDR-TB treatment outcomes. Keywords: multidrug-resistant tuberculosis, sputum smear conversion, sputum culture conversion, treatment outcome, prognosis

The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. This retrospective study was conducted in Taiwan between 2011 and 2020. A microbiological cure was defined as the requirement for a minimum of three consecutive negative cultures following culture conversion that continued until the completion of anti-MAC treatment. A total of 97 patients with MAC-PD were enrolled in this study. The sputum smear-negative conversion rate was 40% (19/47). Thirty (31%) patients achieved sputum culture-negative conversion rates within 3 years after treatment initiation. All patients with negative sputum culture conversion rates achieved microbiological cure. Patients treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than the other patients (39% vs 17%, P = 0.023). Patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate than those with negative sputum smears (6% vs 44%, P < 0.001). Among 30 patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 (0-483) days, and the 1-year relapse rate was 17%. Treatment with the M + R + EMB-based regimen was associated with a higher microbiological cure rate, and patients with persistently positive sputum smears after 6 months of treatment had a lower microbiological cure rate. IMPORTANCE The treatment responses and outcomes in patients with Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) remain uncertain. In this study, patients with MAC-PD treated with a macrolide + rifamycin + ethambutol (M + R + EMB)-based regimen had a higher microbiological cure rate than those treated with other regimens. After 6 months of treatment, patients with persistently positive sputum smears had a lower microbiological cure rate than those with negative sputum smears. Among patients with microbiological cure, the median time from sputum culture conversion to treatment completion was 221.5 days (range, 0-483), and the 1-year relapse rate was 17%.

Background and objective. Tuberculosis (TB) occurring in immigrants and resistance to drugs are major problems for TB control in Western countries. Directly observed therapy (DOT) reduces disease transmission, but this approach may have poor results among illegal immigrants. Our aim was to evaluate a prolonged hospitalisation programme to improve early outcome of TB treatment in high risk patients. Methods. All the consecutive adult patients with sputum smear-positive pulmonary TB admitted to 2 Italian referral TB Centres were evaluated. Hospital-based DOT was provided to high risk patients up-to smear conversion. Demographic, microbiological and clinical conditions, as potential factors associated with confirmed smear conversion at 60 and 90 days of anti-tuberculous therapy were evaluated. Results. 122 patients were studied, 45.9% of them were immigrants (20% illegal) from high-prevalence TB countries. HIV testing was negative in all cases. Twelve patients had M. tuberculosis resistant to ≥ 1 first-line anti-tuberculous agents. The rate of defaulting from TB treatment was 7.3%. Sputum smear became negative in 84.4% cases after 60 days and 93.3% cases after 90 days. At such time, smear conversion rates were similar among different high risk subgroups such as illegal immigrants (95.9%), legal foreign-born (92.5%) and Italian persons (94.8%). Persistent sputum smear positivity was independently correlated with the extent of pulmonary lesions at 60 (p

The purpose of this study was to examine factors associated with treatment outcome of multidrug-resistant tuberculosis (MDR-TB) cases in Nepal. A retrospective analysis of MDR-TB cases by demographic determinants and treatment was conducted. A total of 494 MDR-TB cases were registered from 2005 to 2008, with data obtained from the National Tuberculosis Center. Chi-squared tests were used to assess statistically the association between smear and culture conversion and treatment outcome. Determinants were analyzed with the use of Kaplan–Meier curves and Cox proportional hazards models to generate estimates of the associations with the time to treatment outcome. Sputum conversion status and culture conversion status were positively associated with treatment outcome for MDR-TB. In a multiple Cox proportional hazards regression model, no determinants were found to be associated with time to cure. [ABSTRACT FROM PUBLISHER]

Abstract: Aim: Diabetes and vitamin D deficiency are widely prevalent in India. Studies have proven correlation between low vitamin D levels and pulmonary tuberculosis (PTB) and low vitamin D levels and insulin resistance. We evaluated the effects of vitamin D supplementation on type 2 diabetes mellitus patients with pulmonary tuberculosis (PTB). Methods: Forty-five subjects (M:F=34:11) were screened. Inclusion criteria were age >15 years, newly diagnosed PTB cases with uncontrolled diabetes, serum vitamin D<20ng/ml. The patients with vitamin D level<20ng/ml were randomly assigned to 2 groups. Group 1 subjects received oral cholecalceferol (60,000units/week) and calcium carbonate (1g/day) along with anti tubercular treatment (ATT), while group 2 subjects did not. Sputum was checked at interval of 2 weeks for 12 weeks. Primary end point was time to achieve sputum smear conversion. Results: Fifteen patients having vitamin D>20ng/ml were excluded. Age of the patients was 42.9±13.2 years and serum vitamin D levels were 18.4±15.3ng/ml. Sputum smear conversion was 6 weeks in group 1 versus 8 weeks in group 2 (p =0.067). Glycated hemoglobin levels reduced from 11.1±1.3 to 7.7±0.9 in group1 versus 10.3±1.2 to 7.8±1.1 (p >0.1). Conclusion: Vitamin D can serve as adjuvant treatment of tuberculosis in diabetics with vitamin D deficiency. Further studies are required to validate this observation and define a cut off for vitamin D level to prevent immunological alterations. [Copyright &y& Elsevier]

Background and objective: Persistent smear-positivity in patients with pulmonary tuberculosis has been shown to predict an unfavourable outcome. This study was conducted to identify the factors influencing time to sputum smear conversion. Methods: From July 2003 to June 2007, all patients with smear-positive and culture-confirmed pulmonary tuberculosis, who had attended a medical centre and a local teaching hospital, were identified. Factors that might have influenced time to smear conversion were investigated using time-to-event analysis. Results: Altogether 305 patients (mean age: 58.6 years) were studied. Diabetes mellitus was the most common underlying comorbidity. Eight patients (2.6%) had AIDS. After 2 months of treatment, 34 (11.1%) patients remained smear- and culture-positive. Cox proportional hazard regression analysis indicated that the presence of a cavity on CXR, smear grading and the first 2-month treatment regimen were independent factors influencing the time to sputum smear conversion. Among patients who had received isoniazid in the first 2 months of treatment, the time to sputum smear conversion in the 24 patients whose isolate showed isoniazid resistance was not different from that in the 236 patients whose isolate was isoniazid-susceptible (hazard ratio 1.061; 95% CI: 0.697–1.616). Conclusions: This analysis revealed that 11.1% of tuberculosis patients remained smear-positive after 2 months of treatment. Patients with cavitation, higher smear grading and those who had not used isoniazid, rifampicin, ethambutol and pyrazinamide continuously in the initial treatment phase had a longer time to sputum smear conversion. [ABSTRACT FROM AUTHOR]

Background: The results of cross-sectional studies indicate that micronutrient deficiencies are common in patients with tuberculosis. No published data exist on the effect of vitamin A and zinc supplementation on antituberculosis treatment. Objective: Our goal was to investigate whether vitamin A and zinc supplementation increases the efficacy of antituberculosis treatment with respect to clinical response and nutritional status. Design: In this double-blind, placebo-controlled trial, patients with newly diagnosed tuberculosis were divided into 2 groups. One group (n = 40) received 1500 retinol equivalents (5000 IU) vitamin A (as retinyl acetate) and 15 mg Zn (as zinc sulfate) daily for 6 mo (micronutrient group). The second group (n = 40) received a placebo. Both groups received the same antituberculosis treatment recommended by the World Health Organization. Clinical examinations, assessments of micronutrient status, and anthropometric measurements were carried out before and after 2 and 6 mo of antituberculosis treatment. Results: At baseline, 64% of patients had a body mass index (in kg/m²) < 18.5, 32% had plasma retinol concentrations < 0.70 μmol/L, and 30% had plasma zinc concentrations < 10.7 μmol/L. After antituberculosis treatment, plasma zinc concentrations were not significantly different between groups. Plasma retinol concentrations were significantly higher in the micronutrient group than in the placebo group after 6 mo (P < 0.05). Sputum conversion (P < 0.05) and resolution of X-ray lesion area (P < 0.01) occurred earlier in the micronutrient group. Conclusion: Vitamin A and zinc supplementation improves the effect of tuberculosis medication after 2 mo of antituberculosis treatment and results in earlier sputum smear conversion. [ABSTRACT FROM AUTHOR]

Background: Diabetes mellitus (DM) and tuberculosis (TB) have been recognized as reemerging epidemics, especially in developing countries. Among all the risk factors, diabetes causes immunosuppression, increasing the risk of active TB three times. Vitamin D has been found as a link between DM-TB co-morbidity., Objective: Vitamin D affects the immune response, suppresses Mycobacterium tuberculosis (Mtb) growth, and affects insulin secretion. The present systematic review determines the effect of vitamin D supplementation on clinical and therapeutic outcomes of DM-TB patients., Method: A comprehensive literature search was carried out in PubMed, Cochrane, Web of Science, and Scopus database to determine eligible studies from inception to January 2021. Out of the 639 articles retrieved, three randomized controlled trials (RCTs) were included in the systematic review., Result: The effect of vitamin D3 or oral cholecalciferol supplementation was assessed on outcomes, such as duration to sputum smear conversion, TB scores improvement, change in glycemic parameters, including HbA1c, FBS, and PLBS, and laboratory parameters, such as Hb, ESR, and CRP. Duration of sputum smear conversion was decreased by two weeks in the vitamin D3 supplemented group in two studies. TB score improvement and changes in glycemic parameters were inclined towards supplemented group; however, they were not significant., Conclusion: The overall effect of vitamin D3 supplementation on TB patients with DM was not significant. Further studies are required in the future examining the effect of supplementation on outcomes in this population., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Rationale: Failure to convert sputum at two months of treatment among persons with bacteriologically confirmed pulmonary tuberculosis (BC-PTB) indicates poor response to treatment but data are limited on its assessment., Objective: We determined the frequency and factors associated with sputum smear non-conversion at two months among persons with BC-PTB in eastern Uganda., Methods: We abstracted data of adult persons with BC-PTB, from routinely available records from TB registers at 10 clinics in eastern Uganda. We determined factors that are independently associated with sputum smear non-conversion using logistic regression analysis. We expressed the results as odds ratio (OR) with 95% confidence interval (CI)., Measurements and Main Results: Of 516 persons with BC-PTB, 81 (15.7%) did not achieve sputum smear conversion at two months of TB treatment. Higher Mycobacteria tuberculosis (MTB) load and treatment at a private-not-for-profit (PNFP) facility compared to government health facility were significantly associated with sputum smear non-conversion. A one unit (+1) increase in MTB load based on ZN stain counts was associated with a 48% increase in the odds of sputum smear non-conversion with adjusted odds ratio (AOR), 1.48 (95% CI, 1.02-2.18). TB treatment at private-not-for-profit health facility was associated with a two-fold increase in the odds of sputum smear non-conversion (AOR, 2.03; 95% CI, 1.01-3.92)., Conclusions: Our study shows that sputum smear non-conversion is common at two months of treatment in this population. It is more likely among patients with higher baseline MTB load and those treated at PNFP facilities. Strategies targeting patients with these risk factors are needed to enhance sputum smear conversion., (© 2020 The Author(s).)

Sputum acid-fast bacilli smear conversion is a fundamental index of treatment response and reduced infectivity in patients with pulmonary tuberculosis (P-TB). To date, there are no models to predict the time to sputum conversion based on patient characteristics. This study aims to ascertain the time to sputum conversion in patients with smear-positive P-TB under treatment, and the variables associated with time to smear conversion. We retrospectively evaluated the time to sputum smear conversion of 89 patients with smear-positive P-TB undergoing treatment at the S. Orsola-Malpighi University Hospital, Bologna (Italy), a referral centre for the diagnosis of TB. Multivariate Cox regression analysis was performed to document variables independently associated with time to conversion. Median time to sputum smear conversion was 24 days (IQR 12-54); the sputum smear converted within the first 2 months of treatment in 78.7% patients. Multivariate Cox regression analysis showed that older age, high baseline mycobacterial load detected by Xpert MTB/RIF, and severity of lung involvement are predictors of persistent smear positivity. The identification of risk factors delaying smear conversion allowed us to develop predictive models that may greatly facilitate the management of smear-positive patients in terms of the duration of respiratory isolation and treatment.