The Bandim tuberculosis score: reliability and comparison with the Karnofsky performance score

This study was carried out in Guinea-Bissau's capital Bissau among inpatients and outpatients attending for tuberculosis (TB) treatment within the study area of the Bandim Health Project, a Health and Demographic Surveillance Site. Our aim was to assess the variability between 2 physicians in performing the Bandim tuberculosis score (TBscore), a clinical severity score for pulmonary TB (PTB), and to compare it to the Karnofsky performance score (KPS).

From December 2008 to July 2009 we assessed the TBscore and the KPS of 100 PTB patients at inclusion in the TB cohort and/or at 1 or more follow-up visits; 61 baseline and 130 follow-up double assessments were obtained.

The inter-observer variability of the TBscore (5 symptoms and 6 clinical findings) varied from slight to almost perfect agreement. For the TBscore, all 3 severity classes (SC I-III) were observed, while the KPS only yielded 2 of its 3 possible classes. The grading of PTB patients into severity classes showed moderate agreement for both the TBscore (κ(w) = 0.52, 95% confidence interval 0.46-0.56) and the KPS (κ(w) = 0.49, 95% confidence interval 0.33-0.65). The intra-class correlation coefficient (ICC) was larger for the TBscore than for the KPS (0.822 vs 0.632).

The Bandim TBscore had an acceptable inter-observer variability, seemed to be more disease-related, and performed better than the KPS.