Yield, NNS and prevalence of screening for DM and hypertension among pulmonary tuberculosis index cases and contacts through single time screening: A contact tracing-based study

INTRODUCTION: Diabetes mellitus (DM), hypertension and pulmonary tuberculosis (PTB) are catastrophic illnesses that collectively lead to increased mortality and premature death. However, the size of the problem and the appropriate approach to deal with the burden is still unclear. We aimed to evaluate the yield, number needed to screen (NNS) to prevent one death or adverse event for screening DM and hypertension and assess the prevalence and contributors to DM and/or hypertension. METHODS: Based on PTB contact tracing, a cross-sectional study was conducted among 801 PTB index cases and 972 household contacts from April 2019 to October 2020 in Guizhou, China. All the participants were screened for DM and hypertension. The yield was calculated as the proportion of newly detected cases among the study subjects, excluding known cases. The NNS was computed by dividing the number needed to treat for risk factors by the prevalence of the unrecognized diseases. The univariate and multivariate logistic regression analyses were applied to determine the independent predictors of DM and/or hypertension. RESULTS: Of the 1,773 participants, the prevalence of DM and hypertension was 8.7% (70/801) and 15.2% (122/801) in the PTB patients, 3.2% (31/972) and 14.0% (136/972) in the contacts, respectively. The prevalence of DM and/or hypertension was 21.2% (170/801) among the PTB patients and 15.4% (150/972) among their contacts. The screening yields to detect new cases of DM and hypertension among PTB patients were 1.9% and 5.2%, and that in the contacts were 0.8% and 4.8%, respectively. The NNS for DM was 359 for the PTB cases and 977 for the contacts, 299 for PTB cases and 325 for hypertension, respectively. Older age, under or overweight and obesity, family history hypertension and earlier diagnosis of other chronic conditions were the independent predictors for DM and/or hypertension among both PTB cases and their contacts. CONCLUSION: Screening for DM and hypertension should be mandated in PTB patients and their household contacts to disclose undetected cases of these two conditions during TB contact tracing, which might reduce the potential cardiovascular disease deaths.