Factors Related with Sputum Smear Conversion Time among Tuberculosis Patients

Humberto Guanche GARCELL, Mirtha M. CASTANEDA, Mylene de los A Rodriguez ARTILES, Francisco Gutierrez GARCIA, Miguel A. Paulino BASULTO, Anel Perez ALEJO, Ariadna Villanueva ARIAS


The article aims to determine the factors associated with smear sputum conversion in 64 patients with tuberculosis (TB) admitted at The Cuban Hospital (TCH) (Qatar). The patient characteristics at diagnosis (age, sex, smoking, alcohol, history of Diabetes mellitus or previous tuberculosis, and diagnostic's delay), nutritional indicators (Body mass index, Hemoglobin, lymphocytes count, iron, serum protein/albumin), platelet count, serial sputum, resistance to first line TB drugs, and radiological findings were collected. Kaplan Meier survival and log rank test or a Wilcoxon test were used. Significance level was set ≤ 0.05. The 75 % patients were below 39 years old (mean 32.61 years), male (78.1 %), non-smokers (90.6 %), no previous history of TB (96.9 %), 17.2 % had Diabetes mellitus. Diagnosis delay was over 30 days (65.6 %). Minimum smear conversion was 5 days and maximum 115 days (median: 30 days). The survival curves based on patient’s demographics, nutritional and radiological characteristics were not statistically significantly different. Regarding bacterial load, 50 days after starting treatment, the 2 patient´s group with ≤ 1000 bacilli had negative sputum. Patients who had > 1500 bacilli, yet after 100 days of treatment, had positive sputum (p = 0.02). Differences between groups with lower and higher bacilli count was significant (p = 0.04). Our data has shown that the main factor related to sputum conversion is the bacterial load, which will be useful to fix the case management of tuberculosis in Qatar.


Tuberculosis, sputum conversion, bacterial load, factors associated, Qatar

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Communicable diseases in the Eastern Mediterranean Region: Prevention and control 2005-2009, Available at: http://applications.emro.who.int/dsaf/dsa1226.pdf, accessed May 2014.

Annual Health Report, 2012. Hamad Medical Corporation. Chapter 6. Vital Health. Statistic and Preventive Medicine, Available at: http://site.hmc.org.qa/msrc/AHR2012/pdf/ch6.pdf, accessed May 2014.

Management of Tuberculosis in Qatar. 1st ed. Hamad Medical Corporation, 2011.

M Güler, E Unsal, B Dursun, O Aydln and N Capan. Factors influencing sputum smear and culture conversion time among patients with new case pulmonary tuberculosis. Int. J. Clin. Pract. 2007; 61, 231-5.

JAG Blanco, IS Toste, ML Fernández, RG Morales, RF Alvarez, GR Cuadrado, AM Gonzálvez and IJG Martín. Tobacco smoking and sputum smear conversion in pulmonary tuberculosis. Med. Clin. 2007; 128, 565-8.

EWP Yone, AP Kengne and C Kuaban. Non-conversion of sputum culture among patients with smear positive pulmonary tuberculosis in Cameroon: a prospective cohort study. BMC Infect. Dis. 2014; 14, 138.

RN de Boer, JBOS Filho, F Cobelens, PR Dde, PFC Miranda, KD Logo, H Oliveira, E Mesquita, MM Oliveira and A Kritski. Delayed culture conversion due to cigarette smoking in active pulmonary tuberculosis patients. Tuberculosis 2014; 94, 87-91.

EV Kurbatova, VM Gammino, J Bayona, MC Becerra, M Danilovitz, D Falzon, I Gelmanova, S Keshavjee, V Leimane, CD Mitnick, MI Quelapio, V Riekstina, A Taylor, P Viiklepp, M Zignol and JP Cegielski. Predictors of sputum culture conversion among patients treated for multidrug-resistant tuberculosis. Int. J. Tubercul. Lung Dis. 2012; 16, 1335-43.

F Mi, S Tan, L Liang, AD Harries, SG Hinderaker, Y Lin, W Yue, X Chen, B Liang, F Gong and J Du. Diabetes mellitus and tuberculosis: Pattern of tuberculosis, two-month smear conversion and treatment outcomes in Guangzhou, China. Trop. Med. Int. Health 2013; 18, 1379-85.

A Nakamura, E Hagiwara, J Hamai, M Taguri and Y Terauchi. Impact of underlying diabetes and presence of lung cavities on treatment outcomes in patients with pulmonary tuberculosis. Diabet. Med. 2014; 31, 707-13.

A Babalik, Z Kilicaslan, S Sevkan Caner, G Gungor, M Gonenc Ortakoylu, S Gencer and SA McCurdy. A registry-based Cohort study of pulmonary tuberculosis treatment outcomes in Istanbul, Turkey. Jpn. J. Infect. Dis. 2013; 66, 115-20.

R Parikh, G Nataraj, S Kanade, V Khatri and P Mehta. Time to sputum conversion in smear positive pulmonary TB patients on category I DOTS and factors delaying it. J. Assoc. Phys. India 2012; 60, 22-6.

SGN Piva, MCN Costa, FR Barreto and SM Pereira. Prevalence of nutritional deficiency in patients with pulmonary tuberculosis. J. Bras. Pneumol. 2013; 39, 476-83.

A Bhargava, M Chatterjee, Y Jain, B Chatterjee, A Kataria, M Bhargava, R Kataria, R D´Souza, R Jain, A Benedetti, M Pai and D Menzies. Nutritional status of adult patients with pulmonary tuberculosis in rural central India and its association with mortality. PLoS One 2013; 8, e77979.

F Putri, E Burhan, A Nawas, PZ Soepandi, DK Sutoyo, H Agustin, F Isbaniah and DW Dowdy. Body mass index predictive of sputum culture conversion among MDR-TB patients in Indonesia. Int. J. Tubercul. Lung Dis. 2014; 18, 564-70.

TJ Nagu, D Spiegelman, E Hertzmark, S Aboud, J Makani, MI Matee, W Fawzi and F Mugusi. Anemia at the initiation of tuberculosis therapy is associated with delayed sputum conversion among pulmonary tuberculosis patients in Dar-es-Salaam, Tanzania. PLoS One 2014; 9, e91229.

C Stoffel, R Lorenz, M Arce, M Rico, L Fernández and MS Imaz. Treatment of pulmonary tuberculosis in a low-prevalence urban area: Compliance and sputum conversion. Medicina 2014; 74, 9-18.

WJ Su, Y Feng, YC Chiu, SF Huang and YC Lee. Role of 2-month sputum smears in predicting culture conversion in pulmonary tuberculosis. Eur. Respir. J. 2011; 37, 376-83.

S Tiwari, A Kumar and SK Kapoor. Relationship between sputum smear grading and smear conversion rate and treatment outcome in the patients of pulmonary tuberculosis undergoing dots-a prospective cohort study. Indian J. Tubercul. 2012; 59, 135-40.

E Ünsal, M Güler, R Ofluoglu, N Capan and F Cimen. Factors associated with treatment outcome in 64 HIV negative patients with multidrug resistant tuberculosis. J. Thorac. Dis. 2013; 5, 435-9.

S Unsematham and P Kateruttanakul. Factors predicting sputum smear conversion and treatment outcomes in new smear-positive pulmonary tuberculosis. J. Med. Assoc. Thai 2013; 96, 644-9.

MJ Magee, RR Kempker, M Kipiani, N Tukvadze, PP Howards, KM Narayan and Blumberg. Diabetes mellitus, smoking status, and rate of sputum culture conversion in patients with multidrug-resistant tuberculosis: a cohort study from the country of Georgia. PLoS One 2014; 9, e94890.

JP Ceielski, L Arab and JC Huntley. Nutritional risk factors for tuberculosis among adults in the United States, 1971-1992. Am. J. Epidemiol. 2012; 176, 409-22.


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