Use of Chest X-rays in 22 High Tuberculosis Burden Countries

Abstract

Purpose: Chest x-rays (CXR) are commonly used in high tuberculosis (TB) burden countries (HBC) however their role and scope for TB diagnosis is poorly understood. Furthermore, with the developments of digital radiography and computer-aided diagnostic (CAD) tools there is increasing interest to exploit CXR as a triage test for TB screening. Methods: We conducted a survey of the 22 HBC to assess how chest x-rays are being used in these settings. A questionnaire was created and refined via a pilot study. One National TB Program (NTP) representative, 1-2 clinical practitioners, and 1 private sector representative were contacted in each of the 22 HBC. The majority response was used for discrepant results, and "inconsistent" was coded if no majority was reached. Results: We received 77 completed surveys, at least 2 responses per country. A majority of HBC (86%) use conventional (film-based) radiography. Only 2 countries (Bangladesh and China) reported usage of semi-digital radiography; no country used only digital radiography. 64% (14) of HBC reported usage of chest radiography in TB prevalence surveys. 37% (8) of HBC did not routinely provide CXR to patients with suspected TB out of which, 6 (75%) used CXR only for smear/Xpert negative patients. 37% HBC used GeneXpert only on patients with abnormal CXR. As a sole diagnostic tool for diagnosing pulmonary TB (PTB), 45% of HBC reported that CXRs were rarely (<10%) used, and 32% (7) reported they were sometimes (10-50%) used. Only 2 countries, Bangladesh and Cambodia, reported that CXRs were often (>50%) used as the sole diagnostic tool for PTB in the public sector. The median cost to NTPs for CXRs was $5 USD (interquartile range 88.5). 41% countries used CXRs as an integral component of national guidelines to diagnose PTB. Conclusions: Chest x-rays are widely used in the 22 HBC, mostly for smear/Xpert negative patients and in TB prevalence surveys. Conventional (film-based) CXR is still the dominant technology, and some countries use it as the sole diagnostic technique for PTB. Clinical Implications: This survey suggests that CXRs continue to be a prominent tool for PTB screening in the 22 HBC.