Variation of tuberculosis prevalence across diagnostic approaches and geographical areas of Indonesia (2021)

The study utilized data obtained from the Health Research and Development Agency of the Tuberculosis Unit, Indonesian Ministry of Health (HRDA-MoH). The dataset included diagnostic information gathered through sputum acid-fast bacilli (AFB) examination, sputum culture, sputum genetic testing, and chest X-ray assessments. 

The original dataset covered all 34 provinces of Indonesia, which were grouped into three major regions: Sumatra, Java-Bali, and other islands (primarily in the eastern part of the country with smaller populations). A stratified multi-stage cluster sampling method was applied during the primary data collection to ensure representative coverage. The inclusion criteria comprised individuals aged 15 years and older who had resided in the selected clusters for at least one month. Individuals living in institutional or temporary settings such as military barracks, dormitories, hospitals, diplomatic residences, and hotels were excluded.

In the field, all chest X-ray images collected were sent to a central reading team for evaluation by three independent radiologists who were blinded to the field screening results. The images were classified as normal, abnormal with TB or non-TB features, or other findings. TB-related abnormalities included infiltrates, nodules, consolidation, cavitary lesions, fibrosis, calcification, pleural effusion, and pleural thickening. The central readings were used to establish the case definition for TB, while field readings guided sputum sample collection. Out of 15,446 participants, 11,202 had abnormal X-ray results, and notably, 43.6% of participants with positive X-ray findings reported no symptoms such as persistent cough or hemoptysis.

Findings from the chest X-ray readings showed a TB prevalence of 725.2 per 100,000 population aged 15 years and older. The highest prevalence occurred among individuals aged 15–24 years, with 783.8 per 100,000 population. Males had a higher prevalence (200.8 per 100,000) compared to females (133.5 per 100,000). Regional analysis revealed that the “other regions” category had the highest prevalence (864 per 100,000), followed by Sumatra and Java-Bali. The rates were generally higher in rural areas. These results underscored the substantial burden of undiagnosed or asymptomatic TB cases detected through radiographic screening.

For the sputum AFB examination, TB diagnosis was determined by identifying acid-fast bacilli in unprocessed sputum samples using the Ziehl–Neelsen staining technique. The TB prevalence based on AFB results was 256.5 per 100,000 population. The rate increased with age, peaking among those aged 65 years and older (527.6 per 100,000), and was lowest among the 15–24-year age group (137.5 per 100,000). The prevalence was markedly higher in males (392.5 per 100,000) than in females (131.0 per 100,000). Urban areas and the Sumatra region showed the highest AFB-based TB prevalence, suggesting potential demographic and regional disparities in TB infection or detection.

The culture-based diagnostic results were derived from both spot and morning sputum samples using the Lowenstein–Jensen medium. Some contamination was noted, particularly in spot sputum samples. The prevalence of culture-positive TB was 545.0 per 100,000 population, while culture-negative TB prevalence reached 945.5 per 100,000. Consistent with other diagnostic results, prevalence was higher among males (607.9 per 100,000) than females (463.0 per 100,000) and higher in urban areas than rural ones. The “other islands” region showed the highest culture-positive TB rate at 2,129.8 per 100,000 population. TB prevalence increased with age, with the highest rate found among participants aged 65 years and older (678.9 per 100,000).

Sputum genetic testing was performed using the Xpert MTB/RIF assay, an automated nucleic acid amplification technique that detects Mycobacterium tuberculosis and rifampicin resistance. The analysis identified 213 MTB-positive samples, consisting of 184 rifampicin-susceptible, 19 rifampicin-resistant, and 10 indeterminate cases. The estimated TB prevalence based on this method was 894.9 per 100,000 population. Regional distribution showed the highest prevalence in the “other regions” (941.2 per 100,000), followed by Sumatra (875.0 per 100,000) and Java-Bali (838.7 per 100,000). The highest prevalence by age group was found among individuals aged 35–44 years (933.3 per 100,000). Slight differences were noted between males and females, with slightly higher rates in males and in urban populations.

Overall, this secondary data analysis concluded that the national TB prevalence among individuals aged 15 years and older was 759.1 per 100,000 population (95% CI: 589.7–960.8). TB prevalence increased steadily with age, reaching its highest level among individuals aged 65 years and older (1,581.7 per 100,000). Urban areas consistently demonstrated higher TB prevalence across all diagnostic methods compared to rural areas, and the Sumatra region recorded the highest regional rates. These findings highlight the persistent burden of tuberculosis in Indonesia and the need for comprehensive diagnostic strategies that combine clinical, radiological, and molecular methods to improve detection and control efforts nationwide.

Source: Noviyani, A., Nopsopon, T. and Pongpirul, K., 2021. Variation of tuberculosis prevalence across diagnostic approaches and geographical areas of Indonesia. PLoS One, 16(10), p.e0258809.