Temporal Patterns and Determinants of Tuberculosis in Karachi, Sindh: A Public Health Perspective

Abstract

Background: Tuberculosis (TB) is a major public health problem in Pakistan, with substantial disease burden concentrated in densely populated urban settings. Karachi, the largest city of Pakistan, presents several epidemiological conditions that  facilitate TB transmission including population density, overcrowded housing, socioeconomic inequalities, population mobility, delayed diagnosis and unequal access to healthcare. Recent population-based evidence from Karachi estimated the prevalence of bacteriologically confirmed pulmonary TB at 387 per 100,000 population, with lower prevalence in areas previously exposed to intensive active case-finding (ACF).

Objective: To evaluate the temporal pattern of tuberculosis occurrence in Karachi, Sindh  and to identify demographic, socioeconomic, behavioral, clinical, environmental and health-system determinants associated with TB burden.

Methods: A retrospective analytical public-health study was conducted using routinely notified TB cases data from Karachi over a defined period of 2020–2025, supplemented by demographic and socioeconomic information where available. Variables include year , month of diagnosis, age, sex, district, TB site, bacteriological confirmation, treatment history, drug resistance, diabetes, smoking, household crowding, socioeconomic characteristics, diagnostic delay and treatment outcome. Temporal trends was assessed using annual and monthly notification rates. Determinants was evaluated by using multivariable logistic regression according to the outcomes.

Results: The results showed the substantial heterogeneity in TB burden by geography and previous ACF exposure. A population-based survey conducted during 2020–2025 estimated bacteriologically confirmed pulmonary TB prevalence at 387/100,000, compared with 421/100,000 in areas without prior widespread ACF and 279/100,000 in the prior-ACF zone.  Spatial analysis has also demonstrated statistically significant clustering of bacteriologically positive TB and abnormal chest radiographs within Karachi.

Conclusion: TB in Karachi is  addressed as a geographically heterogeneous and socially determined public-health problem. Surveillance systems combine temporal monitoring with spatial targeting, early case detection, contact investigation, diagnostic strengthening, treatment adherence support  and interventions addressing overcrowding and socioeconomic vulnerability.