Rob van Hest Capture-recapture Methods in Surveillance - RePub ...

Summary
linkage of notification and laboratory registers, as performed in ETS, improves the
accuracy of surveillance data as well as the completeness of case-ascertainment of
tuberculosis. The validity of capture-recapture analysis, especially when the saturated
model is selected, and truncated population estimation models, in the context of
infectious disease surveillance, should be further examined.
In the context of the third research question of this thesis in Chapter 9 we
estimate the coverage of a periodic radiological mobile tuberculosis screening programme
among illicit drug users and homeless persons in Rotterdam, using truncated population
estimation models. We extracted the total and annual number and frequency counts of
chest X-rays taken in this screening programme from a single data source. According to
the two truncated models used, the tuberculosis screening programme reached
approximately two-third of the estimated target population at least once per year and the
coverage of the intended aim, at least two chest X-rays per person per year, was estimated
at approximately 23%. We conclude that truncated models can be used relatively easily on
available single source routine data to estimate the coverage of tuberculosis screening
among illicit drug users and homeless persons. In Chapter 10 we re-examine nineteen
datasets of published and current three-source log-linear model capture-recapture studies
on infectious disease incidence with three truncated models for incomplete count data: a
binomial model, a Poisson mixture model and a Poisson heterogeneity model. Specific
attention was given to the ratio between the number of clients registered once (f1) and
twice (f2) and the kind of log-linear model selected. We discuss the (dis)agreement
between the various estimates and possible violation of the underlying assumptions,
especially the equiprobability assumption. We conclude that for estimating infectious
disease incidence independent and parsimonious three-source log-linear capture-recapture
models are preferable but truncated models can be used as a heuristic tool to identify
possible failure in the log-linear model, especially when saturated models produce
unexpectedly high and implausible estimates.
The General Discussion in Chapter 11 reviews the research questions and the
results of the studies in this thesis. It discusses aspects of the feasibility and validity of
three-source log-linear capture-recapture analysis and related truncated models for
estimating the incidence of tuberculosis and other infectious diseases. The conclusions
and recommendations that follow from the research in this thesis are formulated and are
described below.
Conclusions
• Infectious disease incidence capture-recapture analysis requires adequate knowledge
of disease, patients and registrations.
• In capture-recapture analysis small variations in the quality of data and record-linkage
can lead to highly variable outcomes.
• Hospital episode statistics often contain many false-positive records, leading to
biased capture-recapture estimates.
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