Drug Resistance Patterns, Temporal Trends, and Risk Factors Among Elderly Tuberculosis Patients in Anhui, China: A Retrospective Study (2020–2024)

Kexue Yu,1 Yuling Yang,1 Xuan Teng,1 Chengcheng Ma,1 Zhou Liu1,21Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, 230601, People’s Republic of China; 2Department of Clinical Laboratory Center, Anhui Chest Hospital, Hefei, 230031, People’s Republic of ChinaCorrespondence: Zhou Liu, Email [email protected]: To investigate the drug resistance profiles, epidemiological dynamics, and risk factors of Mycobacterium tuberculosis (M. tuberculosis) clinical isolates among geriatric patients (aged ≥ 60 years) in Anhui Province. The findings are intended to inform the formulation of targeted intervention strategies for drug-resistant tuberculosis (DR-TB) control in this demographic.Methods: A retrospective analysis was performed on the clinical records and drug susceptibility testing results of M. tuberculosis strains isolated from geriatric patients at Anhui Chest Hospital (January 2020 to December 2024). Resistance characteristics and temporal trends regarding the overall prevalence, four distinct phenotypes, and 12 anti-TB drugs were systematically analyzed. Independent risk factors for drug resistance were determined using univariable and multivariable logistic regression models.Results: Among 2752 M. tuberculosis isolates, the overall drug resistance rate was 21.91%. Rifampicin-resistant TB (RR-TB) and multidrug-resistant TB (MDR-TB) accounted for 10.17% and 6.14% of the isolates, respectively. The drug resistance burden was disproportionately concentrated among individuals with clinical comorbidities and those within the 60– 69 age cohort. Ninety-three resistance combinations were identified, with isoniazid, rifampicin, and streptomycin showing the highest resistance rates among the 12 tested drugs. Longitudinally (2020– 2024), rates of overall isoniazid resistance and the specific Hr-TB phenotype (isoniazid-resistant, rifampicin-susceptible) decreased. Conversely, resistance to rifabutin, moxifloxacin, levofloxacin, and para-aminosalicylic acid increased (all P < 0.05). Cross-resistance was observed among rifamycins, fluoroquinolones, and second-line injectable drugs. Retreatment and concurrent chronic pulmonary disease were confirmed as independent risk factors for resistance, while advancing age correlated paradoxically with a reduced risk.Conclusion: Drug resistance among geriatric TB patients in Anhui remains critical, driven independently by retreatment and chronic pulmonary disease. Despite declining INH resistance, the rising resistance to fluoroquinolones and secondary agents demands vigilance. Policymakers should prioritize targeted screening for high-risk cohorts and integrated comorbidity management to optimize therapeutic outcomes and curb regional transmission.Keywords: Mycobacterium tuberculosis, elderly, drug resistance, characteristic analysis, risk factors