Trends in sputum smear conversion among smear-positive pulmo-nary tuberculosis patients

Abstract

Sputum smear conversion during pulmonary tuberculosis treatment is an important indicator of patient response to therapy and as such determines the direction of TB patient care. This retro-spective review assessed the trends in sputum smear evaluation and conversion rates among follow up pulmonary tuberculosis patients presenting to the Tamale Teaching Hospital from January 2004 to December 2012. A total of 8,238 sputum smear cases comprising of 6,892 (83.7%) diagnoses and 1,346 (16.3%) follow-up cases were recorded. The 1,346 follow-up cases comprised of 57.8% (778/1346) males and 42.2% (568/1346) females. The percentage proportion of follow up cases that had their month of follow up, residential addresses, ages and smear results reported are 93.8% (1262/1346), 95.2% (1281/1346), 98.2% (1322/1346) and 97.8% (1309/1346) respectively. The cumula-tive median age was 43years (IQR: 30 to 55years) with the minimum and maximum ages being 14 and 80 years recorded in 2008 and 2012 respectively. Thirty eight percent (511/1,346) of follow-up cases were from the intensive phase (month 2) evaluation period. One hundred and eleven (111) of the follow up cases were smear positive representing a cumulative positivity rate of 8.5% (111/1309). This comprised of 75(67.6 %) males and 36(32.4%) females. Generally males were observed to be significantly more likely to delay smear conversion during treatment (OR = 1.560; p = 0.035, 95% CI=1.032- 2.359) compared to females. The ages of the positive cases ranged from 14 to 75 years with a median age of 45.5 years. The intensive phase (month 2) positivity rate was 8.1% (63/776) representing a conversion rate of 91.9%. Significant proportion (15.4%) of males were smear posi-tive and were more likely to remain positive after two months of therapy compared to their female counterparts (OR = 2, p = 0.02, CI = 0.098 – 1.299). Periodic surveillance of regional sputum smear late/non conversion among PTB patients on treatment would be useful in supporting Tb manage-ment in Ghana.

Keywords: Mycobacterium tuberculosis, follow up, microscopy, acid fast bacilli, Ghana