A new predictive model for an improved respiratory isolation strategy in HIV-infected patients with PTB.

Abstract

SettingLuigi Sacco Hospital, Milan, Italy, 1 January 2000-31 December 2010.ObjectivesTo develop a predictive score for identifying human immunodeficiency virus (HIV) infected patients with pulmonary tuberculosis (PTB).DesignRetrospective study based on the medical charts of HIV-infected patients admitted consecutively on presumption of PTB. Patients with culture-positive TB were included in the TB group. Culture-negative subjects formed the non-TB group. Risk factors for PTB were identified and a predictive model was developed. The diagnostic test accuracy of the derived score and that of previously developed scores were analysed.ResultsA total of 65 patients were included in the TB group and 505 subjects in the non-TB group. An eight-variable model (age, origin, alcohol use, respiratory rate, weight loss, haemoglobin, white blood cell count, typical chest X-ray) was derived. When compared with the different scores, this model showed the greatest area under the receiver operating characteristic curve (0.880). This score was the only one to present a negative likelihood ratio of <0.2, which is the threshold for giving strong diagnostic evidence against TB.ConclusionsThis model may be useful in predicting PTB in HIV patients in low-endemic countries. A validation study is necessary.