Abstract:

Objective To explore the role of tuberculosis (TB) symptom screening in the diagnosis and exclusion of active tuberculosis in HIV/AIDS patients, so as to provide reference for grassroots doctors. Methods A total of 688 HIV/AIDS patients were screened for tuberculosis in “two townships and one town” of Butuo County, Liangshan Yi Autonomous Prefecture, Sichuan Province. A multi-phase screening method was used. Six hundred and eighty-eight TB suspicious symptom screening questionnaire were sent out, 628 were recovered and 623 were effective.TB suspicious symptoms in the questionnaire were: (1) coughing and expectoration lasting for at least 2 weeks; (2) repeatedly coughing with bloody sputum; (3) recurrent fever lasting for more than 2 weeks; (4) frequent sweating at night; (5) unexplained weight loss; (6) frequent fatigue or shortness of breath; (7) lymphadenopathy. Having one or more symptoms of the above (1)~(7) lymphadenopathy. Having one or more symptoms of the above (1)~(7) were defined as positive for TB symptom screening. Basing on suspicious symptom questionnaire screening, sputum smear microscopy, chest X-ray film, sputum culture, tuberculin test and T-lymphocyte spot test (T-SPOT.TB), an expert group made TB diagnosis decisions for those 623 patients. The sensitivity, specificity, positive predictive value, negative predictive value, Youden index and Kappa value of TB symptom screening in the diagnosis of active TB were calculated with the diagnosis result of the expert group as reference standard, and the application value of TB symptom screening in HIV/AIDS patients was evaluated. Results In the field TB symptom screening, the positive rate of TB symptom was 66.29% (413/623). A total of 113 active TB patients were diagnosed by the expert group. Sensitivity, specificity, positive predictive value, negative predictive value, Youden index and Kappa value were 69.03% (78/113), 34.31%(175/510),18.89%(78/413),83.33%(175/210),0.03 and -0.76,respectively. Conclusion The Youden index and Kappa value of TB symptom screening positive in HIV/AIDS patients were relatively low comparing with expert group diagnosis result. However, because of the low cost, simple and effective operation, symptom screening can be used as an early warning indicator for TB screening in remote areas and ethnic minority areas where medical resources are particularly scarce.

Key words: HIV infection/AIDS patients, Tuberculosis, Multiphasic screening, Small area analysis, Data description, statistics