English abstract
Background: In the era of Direct Observation Treatment (DOT)
for tuberculosis, clinicians need to focus on high-risk groups. We
present sputum conversion rate at one and two months following
DOT and its predictors in Oman.
Study design: Hospital-based clinical intervention type of case
series.
Methods: Chest physicians in a referral hospital examined
sputum-positive cases of tuberculosis between 2001 and
2006. Patients with HIV infection and treated in the past
were excluded. History of smoking, diabetes and duration of
symptoms were noted. Sputum was tested for bacillus density.
Blood was tested for platelet count and blood sugar levels. One
and two months following treatment, the sputum was retested to
determine sputum conversion. Regression analysis was done to
identify the predictor of late conversion.
Results: Of the 112 sputum-positive TB cases, 39 (34.8%) and
49 (43.7%) cases were sputum negative one and two months
respectively after DOT. Lower platelet count was significantly
associated with early sputum conversion. (Diff of mean = 38.3
cells x 9/L (95% CI 36.9 – 39.7). On univariate analysis, duration
of symptoms, history of diabetes, smoking and ESR were not
associated with the early sputum conversion. Knowledge of
platelet count seems to assist the clinician to predict the early
sputum conversion following DOT for pulmonary TB.
Conclusions: Sputum conversion rate among tuberculosis
patients treated with DOT for one and two months in Oman
was 34.8% and 78.6% respectively. Platelet count could assist in
predicting early sputum conversion.
