Comparison of surveillance-based metrics for the assessment and monitoring of disease detection: simulation study about type 2 diabetes

BMC Med Res Methodol. 2017 Apr 11;17(1):54. doi: 10.1186/s12874-017-0328-2.


Background: Screening and detection of cases are a common public health priority for treatable chronic conditions with long subclinical periods. However, the validity of commonly-used metrics from surveillance systems for rates of detection (or case-finding) have not been evaluated.

Methods: Using data from a Danish diabetes register and a recently developed illness-death model of chronic diseases with subclinical conditions, we simulate two scenarios of different performance of case-finding. We report different epidemiological indices to assess case-finding in both scenarios and compare the validity of the results.

Results: The commonly used ratio of detected cases over total cases may lead to misleading conclusions. Instead, the ratio of undetected cases over persons without a diagnosis is a more valid index to distinguish the quality of case-finding. However, incidence-based measures are preferable to prevalence based indicators.

Conclusion: Prevalence-based indices for assessing case-finding should be interpreted with caution. If possible, incidence-based indices should be preferred.

Keywords: Case-finding; Chronic disease; Compartment model; Diabetes; Incidence; Prevalence; Screening; Undiagnosed disease.

MeSH terms

  • Chronic Disease / epidemiology*
  • Denmark / epidemiology
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Humans
  • Male
  • Mass Screening / methods*