Completeness of TB notification: inventory studies and capture-recapture analyses, six European Union countries, 2014 to 2016


M. Straetemans, M. Bakker, S. Alba, C. Mergenthaler, E. Rood

In 2014, the World Health Organization (WHO) published the Action Framework towards TB elimination in low-incidence countries, and in 2016, the WHO Regional Office for Europe (WHO/Europe) published the Roadmap to implement the tuberculosis action plan for the WHO European Region 2016-2020: Towards ending TB and multidrug-resistant tuberculosis. They outline blueprints to carry out the WHO’s global End TB Strategy in Europe and to reach the sustainable development goal (SDG) target for tuberculosis (TB). Key strategic targets include reduction of global TB incidence by 80% in 2030 and 90% in 2035, compared with 2015. In the WHO European Region, the targets include a 25% reduction in TB incidence rate by the year 2020 compared with 2016. TB incidence can be derived from TB notification rates, assuming complete case detection and reporting. This is considered a strong assumption unlikely to hold in many settings, including European Union (EU) countries. Several studies across the EU/EEA, e.g. those from France, Spain, Italy and Romania, have revealed high rates of under-reporting.

Inventory studies (IS) are a widely accepted methodology to study the level of under-reporting of TB cases. To determine completeness of TB notification, TB IS compare the number of cases meeting standard case definitions and recorded in multiple TB-related registers, such as laboratory registers or hospital episode registers, with the cases notified to local and national authorities. For this comparison, record-linkage methodologies are used. Subsequently, through capture–recapture (CRC) analysis, the number of cases unknown to all registers can be estimated, thereby providing an estimate of the completeness of TB notification.

At the time of the study and writing this article, the United Kingdom (UK) was still part of the EU and only two EU countries, the Netherlands and the UK, had assessed the level of TB under-reporting using IS/CRC studies on a national basis. In 2016, the European Centre for Disease Prevention and Control (ECDC) commissioned an IS/CRC project to estimate TB under-notification in six to nine EU countries and expand the evidence base of the methodology.

The objective of this study was to assess observed and estimated TB notification completeness in EU countries, selected after an eligibility and feasibility appraisal, and determine whether data collected at national level reflect the real TB situation in these countries.

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