A cross sectional survey on the prevalence of active pulmonary tuberculosis in three ‘key’ elderly population

Abstract

To conduct a survey on the prevalence of active pulmonary tuberculosis among 65 year olds or above. Study subjects would include those with characteristics of TB suspicious symptoms, diabetes and close contacts. Purpose-sampling method was applied to choose 3 counties in Shandong province as the study sites, relying on the local basic public health service, for those elderly under 65 years old or above. The study team would introduce the process and contents of this study to the subjects followed by chest X-ray and sputum smears on those registered tuberculosis suspects, patients with diabetes, TB close contacts in the past 2 years, from January to September, 2013. 82 active pulmonary TB cases were identified among 9 041 cases who received the examination, with a crude prevalence rate as 9.1‰. From patients having both suspicious TB and diabetic symptoms, patients with diabetes or having suspicious symptoms of TB, the prevalence rates of active TB were 115‰, 3.4‰, 0.9‰ respectively. No active pulmonary TB case was found in the TB close contacts, patients with diabetes, or those people with suspicious TB symptoms. TB prevalence rates among all the above mentioned groups were significantly different (χ(2) = 697.478, P = 0.000). Prevalence rate of active pulmonary TB with diabetes was 18 times (RR = 17.951) higher than those non-diabetic patients, and 2 times higher than those with suspicious symptoms (RR = 3.860). Results from single factor analysis showed that diabetes were closely related to the prevalence of pulmonary tuberculosis(χ(2) = 46.637, P = 0.000), the longer duration of diabetes and the higher risk of tuberculosis(RR > 1). Our data showed that active pulmonary TB prevalence was high in elderly diabetes patients which suggesting that 'Key crowd screening program' should be introduced into case-finding strategy on TB, with special focus on TB patients with diabetes or those people having suspicious symptoms of TB.