Phenotypic Atypia, Prolonged Diagnostic Delay and Altered Co-detection Patterns in Non-HIV Immunocompromised Pulmonary Tuberculosis.

Background

Health system delay (HSD), defined as the interval from first medical contact to microbiological confirmation of pulmonary tuberculosis (PTB), may contribute to delayed diagnosis in non-HIV immunocompromised hosts (ICH). Data on HSD in this population remain limited.

Methods

This retrospective study analyzed inpatients with liquid culture-positive PTB from 2020 to 2025. Baseline characteristics, HSD, microbiological co-detection, and specimen-specific diagnostic yields were compared. HSD >14 days was defined as long health system delay (LHSD).

Results

Among 578 patients, 71 were ICH and 507 were non-ICH. ICH patients had atypical radiological findings, with more bilateral lesions, pleural effusion, and lymphadenopathy but fewer cavities. Median HSD was longer in ICH patients (90 vs. 24 days, p <0.001). LHSD was more frequent in ICH patients (83.1% vs. 69.2%, p =0.012), and ICH was independently associated with LHSD (adjusted OR, 2.31; 95% CI, 1.03-5.18; p =0.042). Sputum acid-fast bacilli (AFB) smear positivity was lower in ICH patients (3.4% vs. 20.0%, p = 0.055), whereas bronchoalveolar lavage fluid (BALF) AFB smear positivity was higher (51.1% vs. 28.3%, p < 0.05). Sputum, BALF, and tissue Xpert MTB/RIF positivity exceeded 75% without significant between-group differences. Fungal, viral, and mixed co-detections were more frequent in ICH patients.

Conclusions

ICH patients with PTB had longer HSD and atypical radiological presentations, with more frequent fungal, viral, and mixed co-detections. Xpert testing of sputum and BALF may facilitate diagnosis, while sputum smear findings should be interpreted cautiously given its limited use in ICH patients.