The Diagnostic Performance of Chest-X-Ray and Erythrocyte Sedimentation Rate in Comparison with GeneXpert® for Tuberculosis Case Notification Among Patients Living with Human Immunodeficiency Virus in a Resource-Limited Setting: A Cross-Sectional Study

Abstract

Introduction: For many years, chest-X-ray (CXR) has been used as a diagnostic tool to complement clinical diagnosis of bacteriologically negative tuberculosis (TB) cases. Increased erythrocyte sedimentation rate (ESR) was also used as laboratory surrogates to augment the diagnosis of bacteriological test negative TB cases. The objective of this study was to evaluate the diagnostic performance of CXR and ESR in comparison with geneXpert^® for TB case notification among PLHIV in a resource-limited setting.

Methods: An institution-based cross-sectional study was carried out from February 1, 2018-January 31, 2019. During regular HIV-clinic visits, PLHIVs were assessed for TB using the National and WHO screening tool, and those with positive results were further evaluated using ESR, CXR and sputum for AFB and GeneXpert^®. Patients were interviewed for demographic and clinical data using a standardized tool. Collected data were analyzed using SPSS 21. Frequency, percentage, cross tabulation and proportion were used to describe variables of importance. Logistic regression was used to assess factors affecting CXR and ESR findings. Kappa was used to assess reliability, and a p-value <0.05 was considered significant.

Results: A total of 384 patients with presumptive TB-HIV co-infection were included of which 165 (43.0%) were diagnosed to have TB, and 79 (53.3%) of these were confirmed by GeneXpert^®, and the remaining 77 (46.7%) TB cases were diagnosed using clinical judgment, CXR and ESR. The sensitivity, specificity, positive predictive value and negative predictive value of CXR were 67.9%, 77.3%, 43.8%, and 90.3%, and that of ESR were 49.4%, 55.1%, 22.1%, and 83.0%, respectively. The overall agreement between CXR and GeneXpert^® was good with a kappa value of 0.38 while that of ESR and GeneXpert^® was poor with a kappa value of 0.028.

Conclusion: CXR in diagnostic work of TB among PLHIV plays an unprecedented role while ESR has little clinical significance in the evaluation of TB.

Keywords: CXR; ESR; GeneXpert; HIV; PLHIV; TB.