Screening scheme development for active TB prediction among HIV-infected patients

Abstract

The objective of this study was to develop and evaluate a simple scoring scheme to screen for active tuberculosis (TB) among HIV-infected patients. Two hundred fifty-seven HIV-infected patients were enrolled in the study between April 2009 and May 2010 from Mae Sai District Hospital and Lampang Regional Hospital. Participants underwent routine evaluations to diagnose TB. Data collection included demographics, medical history, signs and symptoms and laboratory results. Of the 257 HIV-infected patients enrolled, 66 (25.7%) were diagnosed with active TB. Six variables were statistically significant predictors of active TB (p<0.05): BMI ≤19 kg/m2, cough >2 weeks, shaking chills ≥1 week, not taking antiretroviral drugs, a CD4+ cell count level ≤200 cells/μl, and had a history of TB. A risk score (ranging from 0 to 16) gave a 92.1% sensitivity of being associated with active TB. A low risk score (≤ 2.0), a moderate risk score (3.0-7.0), and a high risk score (>7.0) gave positive likelihood ratios (LHR+) of 0.04 (95%CI 0.01-0.24), 2.56 (95%CI 1.71-3.85), and 11.72 (95%CI 4.91-27.96), respectively. This screening tool may be useful to identify patients who should have further diagnostic testing for TB, but requires further validation before adoption due to the variability of predicting factors and the prevalence of TB in the target population.