Factors leading to under-reporting of tuberculosis in the private sector in Korea

To identify factors associated with under-reporting of tuberculosis (TB) in the private sector in Korea.

A cross-sectional study of 37,820 cases in whom treatment was initiated between January and December 2008 using data from the Nationwide Medical Records Survey of Patients with TB. Adjusted odds ratios (aOR) for under-reporting with respect to socio-demographic and clinical factors were estimated.

Among the 37,820 identified cases, 21,611 (57.1%) were reported to the Korean TB Surveillance System. Factors associated with under-reporting on univariate analysis included young children, foreign-born persons, non-multidrug-resistant TB, persons prescribed fewer than four anti-tuberculosis drugs, non-performance of or negative result on sputum smear and extra-pulmonary TB (particularly abdominal or genitourinary TB). For pulmonary TB, cases with no sputum smear results vs. smear-positive patients (aOR 2.23, P < 0.001) and those prescribed <4 drugs vs. those who were prescribed ≥4 drugs (aOR 1.60, P < 0.001) were strongly related to under-reporting on multivariate analysis.

The extent of under-reporting was greater among young children, persons who had not received sputum smear testing and those who had been prescribed fewer than four drugs. Furthermore, TB diagnostic investigations were often inadequate. Education on reporting requirements, including the importance of following guidelines on TB management, and a stricter enforcement of the existing TB Prevention Law, are needed.