Study to identify incidence and risk factors associated Residual pleural opacity in tubercular pleural effusion

Residual pleural opacity (RPO) is a common radiographic sequela in patients with tubercular pleural effusion at the end of the treatment. This study was designed to find out the risk factors associated with residual pleural opacity (RPO).

This was a prospective longitudinal study performed to analyse data of 56 patients (46 males & 10 females) who were diagnosed as tubercular pleural effusion and treated for the same between 1st Jan 2019 to 30th March 2020. Chest X-ray posteroanterior & Lateral view was done (performed) at 0 and 6 months of treatment to quantify the amount of pleural effusion and measured the residual pleural opacity at the end of the treatment. RPO included both non resolving pleural effusion as well as residual pleural thickening (RPT). All statistical analysis was done using SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). Multivariate logistic regression was performed to explore the association of risk factors and Residual pleural opacity. The statistical significance level was set at 0.05 (two-tailed).

The incidence of Residual pleural opacity (RPO) at the end of 6 months of antituberculosis treatment was 53.57% (30/56)). The study patients were divided into RPO and non- RPO group. Male gender had significantly higher incidence of RPO (93.3% vs 69.2% P = 0.01)). Patients with RPO group had significantly more cough and weight loss as compared to non RPO group (96.6% vs 65.3% P = 0.002 and 60% vs 23% P = 0.005). The proportion of patients who underwent therapeutic aspiration and gained weight of more than 5kg during treatment (19.5% vs 7.6% P = 0.02 & 46.6% vs 7.6% P = 0.001) was significantly higher in RPO group. A significantly lower protein, glucose and higher LDH level in pleural fluid was observed in the RPO group compared to non-RPO group (P = 0.006, P = 0.01, P = 0.001)). No significant difference was found in the pleural fluid ADA, lymphocyte, neutrophil levels between the two groups (p > 0.05). Logistic regression analysis showed that the male gender, low pleural fluid glucose, presence of cough and weight loss were associated with significantly increased risk of residual pleural opacity and thickening (p < 0.05).

Tubercular pleural effusion is associated with residual pleural opacity in more than half of the patients. Male gender and low glucose levels in pleural fluid was associated with increased risk of residual pleural opacity.