Evaluation of a population-wide, systematic screening initiative for tuberculosis on Daru island, Western Province, Papua New Guinea.

BACKGROUND: A population-wide, systematic screening initiative for tuberculosis (TB) was implemented on Daru island in the Western Province of Papua New Guinea, where TB is known to be highly prevalent. The initiative used a mobile van equipped with a digital X-ray device, computer-aided detection (CAD) software to identify TB-related abnormalities on chest radiographs, and GeneXpert machines for follow-on diagnostic testing. We describe the results of the TB screening initiative, evaluate its population-level impact and examine risk factors associated with TB detection. METHODS: Through a retrospective review of screening data, we assessed the effectiveness of the screening by examining the enrolment coverage and the proportion of people with TB among screened subjects. A cascade analysis was performed to illustrate the flow of participants in the screening algorithm. We conducted univariate and multivariate analyses to identify factors associated with TB. Furthermore, we estimated the number of additional cases detected by the project by examining the trend of routine TB case notifications during the intervention period, compared to the historical baseline cases and trend-adjusted expected cases. RESULTS: Of the island's 18,854 residents, 8,085 (42.9%) were enrolled and 7,970 (98.6%) had chest X-ray interpreted by the CAD4TB software. A total of 1,116 (14.0%) participants were considered to have abnormal CXR. A total of 69 Xpert-positive cases were diagnosed, resulting in a detection rate of 853 per 100 000 population screened. 19.4% of people with TB had resistance to rifampicin. People who were in older age groups (aOR 6.6, 95%CI: 1.5-29.1 for the 45-59 age group), were severely underweight (aOR 2.5, 95%CI:1.0-6.1) or underweight (aOR 2.1, 95%CI: 1.1-3.8), lived in households < 5 people (aOR 3.4, 95%CI:1.8-6.6) and had a past history of TB (aOR 2.1, 95%CI: 1.2-3.6) were more likely to have TB. The number of bacteriologically confirmed TB notified during the intervention period was 79.3% and 90.8% higher than baseline notifications and forecasted notifications, respectively. CONCLUSION: The screening project demonstrated its effectiveness with the high Xpert-positive TB prevalence among the participants and by successfully yielding additional cases of bacteriologically confirmed TB including rifampicin-resistant TB. The results and lessons learnt from the project should inform future TB screening initiatives in Papua New Guinea.

Epidemiology of tuberculosis in the Pacific island countries and areas, 2000-2020.

Objective: Tuberculosis (TB) is one of the most important infectious diseases with an estimated 9.9 million people falling ill globally in 2020. We describe the epidemiology of TB in the Pacific island countries and areas (PICs) to inform potential priority actions to implement the Western Pacific Regional Framework to End TB 2021-2030. Methods: A descriptive analysis was conducted using annual TB surveillance data submitted by national TB programmes to the World Health Organization (WHO) and TB burden estimates (incidence rates and number of deaths) generated by WHO for the PICs, for the period 2000-2020. We also analysed TB case numbers, multidrug-resistant/rifampicin-resistant TB (MDR/RR-TB), recent risk factor indicators and treatment outcomes. Results: The estimated TB incidence rate in the PICs increased between 2000 and 2020 from 62 to 69 per 100 000 population, with an 8% reduction observed since 2015. TB cases increased by 29% during 2000-2020, with 1746 cases in 2020 and a high proportion in children (19%). Bacteriological diagnosis was used for 58% of total TB cases, although some countries reported clinical diagnoses in over 60% of cases. From 2015 to 2019, 52 MDR/RR-TB cases were reported and there were 94 TB/HIV coinfected cases in 2015-2020. Treatment success was 74% in 2019 due to 18% of cases being unevaluated. In 2020, the estimated proportion of TB cases attributable to smoking, malnutrition, alcohol abuse and diabetes was 17%, 16%, 11% and 9%, respectively. Discussion: There was an increasing trend in TB cases, estimated incidence and deaths between 2000 and 2020. Laboratory services were scaled up in some PICs and case-finding activities greatly contributed to the detection of cases. To end the incidence of TB, continued efforts on case finding, contact investigation and scaling up TB preventive treatment should be prioritized. At the same time, collaboration with other sectors for risk factor management and decentralized management need to be considered.