Abstract Rationale There is a growing number of tuberculosis (TB) survivors, the majority of whom recover with persistent respiratory symptoms called post-tuberculosis lung disease (PTLD). However, diagnosing PTLD can be resource-intensive and not readily affordable in low-income settings where TB is endemic. The consensus guidelines recommend combining lung imaging, spirometry, and symptom assessment, yet the former two are often unavailable in resource-limited settings. We aimed to develop a simple screening tool for PTLD that could be implemented for screening in areas where specialized testing is scarce to select patients for referral to specialty care. Methods We enrolled Ugandan adults from an outpatient TB clinic with an index diagnosis of microbiologically confirmed drug sensitive pulmonary TB (sputum smear microscopy, or Xpert-Ultra). At TB cure (∼6 months after treatment initiation), participants underwent spirometry assessment using ATS/ERS criteria, and completed the six-minute walk test distance (6MWD) and the Saint George’s Respiratory Questionnaire for COPD (SGRQ-C), a shorter version of the SGRQ. The reference standard was PTLD defined by spirometry-based air flow impairment. We defined 6MWD impairment as % predicted less than the lower limit of normal. We evaluated symptom score thresholds from the SGRQ-C symptoms domain, with score thresholds ( ≥25, ≥ 30, ≥35), both individually and in combination with 6MWD against the spirometry-defined PTLD outcome at TB cure. Results Out of 302 participants enrolled, 186 were eligible for lung function testing. Of the 186, mean age was 39 ± 14 years, 72 (38 %) were HIV-positive, 134 (72%) were men, 134 (72%) met criteria for pre-treatment severe- TB disease, 86 (42.6%) had a BMI 18.5 kg/m2, and the mean % predicted 6MWD at TB cure was 82.03 ± 22%. SGRQ ≥ 25 alone identified approximately two-thirds of PTLD cases with a sensitivity of 69% and a specificity of 48.1%. Increasing the threshold to ≥30 and ≥35 showed a lower sensitivity and slightly higher specificity (see Table). 6MWD impairment alone had a low sensitivity (62%) and specificity (71%). Specifying a combined screening threshold of SGRQ ≥25 or impaired 6MWD yielded an increased sensitivity (80%) but a lower specificity (36%), whereas a combined threshold of SGRQ ≥25 and impaired 6MWD yielded a lower sensitivity (47%) but improved specificity (82%). Conclusion In settings where spirometry is not available, either SGRQ ≥25 or 6MWD impairment is a reasonable first-line screening test for PTLD. This abstract is funded by: National Institutes of Health
Nuwagira et al. (Fri,) studied this question.