Comparison of Acid Fast Bacilli Smear Microscopy Examination and Xpert MTB/RIF for the Diagnosis of Pulmonary Tuberculosis in Diabetes Mellitus Patients

Abstract

People with diabetes mellitus (DM) have 2‐3 times the risk of developing tuberculosis (TB). It has been previously reported (Pablos‐Mendez et al) that only poorly controlled or uncontrolled DM is associated with an increased risk of TB. The main objective of this study was to determine the sensitivity and specificity of Acid Fast Bacilli (AFB) smear and Xpert MTB/RIF for the diagnosis of TB in DM patients. This study was a cross‐sectional descriptive analytic study in patients with DM who underwent treatment at Persahabatan Hospital in 2014. The study was conducted in the Pulmonary and Internal Medicine clinics. Samples were collected from 57 patients with 2 samples excluded due to proven AFB smear but not checked by Xpert MTB/RIF. Among 55 patients, there were 32 males (58.2%) and 23 females (41.8%).The blood sugar ranged between 110‐481 g/dl with a mean of 244.8 ± 98.5 g/dl. HbA1c values were between 5.3‐17.7 with a mean of 9.83 ± 3,00. 41 patients (74.5%) had no previous history of TB; 9 patients (16.4%) were cured of TB; and 5 patients (9.1%) had failure or withdrawal of TB treatment. 28 samples (50.9%) were positive for both AFB smear and Xpert , 1 sample was AFB smear positive and Xpert negative, 8 samples (14.5%) were AFB smear negative but Xpert positive, and 18 samples (32.7%) were negative by both AFB smear and Xpert. Sensitivity and specificity by using both methods were 77.8% and 94.7%, respectively. We conclude that there is no difference in the sensitivity and specificity of AFB smear and Xpert MTB/RIF for TB diagnosis in DM patients.