Tuberculosis in the elderly population: Findings from a State-level TB prevalence survey (2022) from India

Background & objectives Population-based data on tuberculosis (TB) epidemiology are sparsely available from India. A large-scale cross-sectional TB survey was conducted among individuals aged 15 yr and above across Tamil Nadu in India by the State government. Advanced age is one of the major risk factor for TB, so this study undertook a sub-analysis of the data on elderly population from the original TB survey sample. Methods The screening used digital X-ray and sputum testing to diagnose microbiologically confirmed PTB (MCPTB). Results In this study, 1,30,932 participants were screened for TB. Of them, 16,555 (12.64%) were elderly (≥60 yr). Among the elderly, the number of participants diagnosed with MCPTB was 74 (0.45%); MCPTB cases in adults< 60 yr of age were 170 (0.15%). Among the elderly, the crude prevalence of MCPTB per lakh was 447 [95% confidence interval (CI): 351-561], and the adjusted prevalence per lakh was 482 (95% CI: 385-578). Among adults, the crude prevalence of MCPTB per lakh was 130 (95% CI: 111-151), and the adjusted prevalence per lakh was 166 (95% CI: 137-195). Among the elderly population-adjusted prevalence ratio (aPR) of MCPTB was 2.99 (95% CI 2.25-3.98, P<0.0001). Male sex (aPR:2.54; 95% CI: 1.41-4.57), undernutrition (aPR: 3.53; 95% CI: 1.65-7.54), smoking (aPR: 1.94; 95% CI: 1.02-3.71) and past history of TB (aPR: 2.26; 95% CI: 0.92-5.51) were having significantly higher aPR of MCPTB in the elderly population. The number needed to screen (NNS) to diagnose one individual with MCPTB among the elderly group was 224 (95% CI: 178-285), and the total screened population from 15 yr and above was 537 (95% CI: 473-611). Among the elderly participants, NNS was very low among those with a history of TB (56; 95% CI: 26-152), smokers (75; 95% CI: 52-112), and alcohol history (78; 95% CI: 55-114). Interpretation & conclusions Among the elderly individuals, the prevalence of MCPTB was threefold higher, and males, undernutrition, and smoking in the elderly were more likely to have TB.