TBscore II: Refining and validating a simple clinical score for treatment monitoring of patients with pulmonary tuberculosis

• Background: The TBscore, based on simple signs and symptoms, was introduced to predict unsuccessful outcome in tuberculosis patients on treatment. A recent inter-observer variation study showed profound variation in some variables. Further, some variables depend on a physician assessing them, making the score less applicable. The aim of the present study was to simplify the TBscore. Methods: Inter-observer variation assessment and exploratory factor analysis were combined to develop a simplified score, the TBscore II. To validate TBscore II we assessed the association between start score and failure (i.e. death or treatment failure), responsiveness using Cohens effect size, and the relationship between severity class at treatment start and a decrease andlt; 25% in score from the start until the end of the second treatment month and subsequent mortality. Results: We analyzed data from 1070 Guinean (2003-2012) and 432 Ethiopian (2007-2012) pulmonary tuberculosis patients. For the refined score, items with less than substantial agreement (kappa andlt;= 0.6) and/or not associated with the underlying constructs were excluded. Items kept were: cough, dyspnea, chest pain, anemia, body mass index (BMI) andlt; 18 kg/m(2), BMI andlt; 16 kg/m(2), mid upper arm circumference (MUAC) andlt; 220 mm, and MUAC andlt; 200 mm. The effect sizes for the change between the start of treatment and the 2-month follow-up were 0.51 in Guinea-Bissau and 0.68 in Ethiopia, and for the change between the start of treatment and the end of treatment were 0.68 in Guinea-Bissau and 0.74 in Ethiopia. Severity class placement at treatment start predicted failure (p andlt; 0.001 Guinea-Bissau, p = 0.208 Ethiopia). Inability to decrease at least 25% in score was associated with a higher failure rate during the remaining 4 months of treatment (p = 0.063 Guinea-Bissau, p = 0.008 Ethiopia). Conclusion: The TBscore II could be a useful monitoring tool, aiding triage at the beginning of treatment and during treatment.

Nyckelord

Triage

low income setting

mortality prediction

MEDICINE

MEDICIN

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