Symptom‐based screening tool in ruling out active tuberculosis among HIV‐infected patients eligible for isoniazid preventive therapy in Tanzania

Abstract

We assessed the usefulness of the National TB and Leprosy Control Program (NTLP) symptom-based tuberculosis (TB) screening tool in identifying HIV-infected patients eligible for isoniazid preventive therapy in Muhimbili National Hospital, Dar es Salaam Tanzania. Descriptive cross-sectional study. Data collected included socio-demographic and clinical data. Chest X-ray, sputum for acid-fast bacilli (AFB) microscopy, mycobacterial culture, CD4 + count and complete blood count were performed. Patients were considered not having active TB if they presented with no symptom in the screening tool, which comprised these symptoms: cough, fever and excessive night sweats for ≥2weeks; weight loss of ≥3kg in 4weeks and haemoptysis of any duration. The reference standard was a negative culture for Mycobacterium tuberculosis. We enroled 373 patients, of whom 72.1% were females. Active pulmonary TB was found in 4.1% (14/338) of the participants as defined by a positive culture. The sensitivity and specificity of the NTLP screening tool were 71.4% (10/14) and 75.9% (246/324), respectively. False-negative rate was 28.6% (4/10). Cough, fever for ≥2weeks and weight loss were independent predictors of NTLP-defined TB. Cough ≥2weeks predicted TB when a positive culture was used to define TB. The screening tool had fairly good sensitivity and specificity for TB screening; however, there is a possibility that about 29% of the screened population will be given IPT while they are supposed to receive a full course of TB treatment.