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

General discussion
and hence positive predictive value, will often already considerably improve the
knowledge of the number of patients and infectious disease incidence rates, as well as the
completeness of information on specific demographic, diagnostic or epidemiological
variables. An example of an infectious disease surveillance system that routinely links
notification data with laboratory data is the ETS in England and Wales. This type of
record-linkage should ideally be web-based for a timely reflection of trends. An example
of a web-based notification system is OSIRIS in the Netherlands but this system is not
linked to laboratory reports. 13 For improving quality, completeness and timeliness of
infectious disease surveillance, a web-based infectious disease surveillance system that
routinely links notification data with laboratory data could essentially fulfil the qualities
once attributed to capture-recapture analysis.
11.3 Conclusions and recommendations
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. Therefore previous successful infectious disease
capture-recapture studies cannot be repeated uncritically.
• Hospital episode statistics often contain many false-positive records, which, when not
identified, lead to biased capture-recapture estimates.
• When categorical covariates associated with the probability of capture in an infectious
disease register are present, covariate capture-recapture analysis can reduce bias as a
result of heterogeneity.
• In the absence of a gold standard, truncated models can be used as a heuristic tool to
identify possible failure in log-linear models, especially when saturated models are
selected.
Recommendations
• Infectious diseases capture-recapture studies should be performed with a multidisciplinary
team including public health physicians, clinicians, statisticians and data
managers.
• For more reliable record-linkage of notifiable infectious disease registers the Dutch
Infectious Disease Act 1999 should be amended and provide recording the date of
birth of the patients instead of the year of birth.
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