Calculating incidence rates and prevalence proportions: not as simple as it seems.

Autor: Spronk I; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands. i.spronk@nivel.nl.; Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. i.spronk@nivel.nl., Korevaar JC; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands., Poos R; Centre for Health and Society, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands., Davids R; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands., Hilderink H; Centre for Health and Society, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands., Schellevis FG; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands.; Department of General Practice & Elderly Care Medicine/EMGO Institute for health and care research, VU University Medical Center, Amsterdam, The Netherlands., Verheij RA; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands., Nielen MMJ; Nivel, Netherlands Institute for Health Services Research, P.O. Box 1568, 3500BN, Utrecht, The Netherlands.; Centre for Health and Society, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
Jazyk: angličtina
Zdroj: BMC public health [BMC Public Health] 2019 May 06; Vol. 19 (1), pp. 512. Date of Electronic Publication: 2019 May 06.
DOI: 10.1186/s12889-019-6820-3
Abstrakt: Background: Incidence rates and prevalence proportions are commonly used to express the populations health status. Since there are several methods used to calculate these epidemiological measures, good comparison between studies and countries is difficult. This study investigates the impact of different operational definitions of numerators and denominators on incidence rates and prevalence proportions.
Methods: Data from routine electronic health records of general practices contributing to NIVEL Primary Care Database was used. Incidence rates were calculated using different denominators (person-years at-risk, person-years and midterm population). Three different prevalence proportions were determined: 1 year period prevalence proportions, point-prevalence proportions and contact prevalence proportions.
Results: One year period prevalence proportions were substantially higher than point-prevalence (58.3 - 206.6%) for long-lasting diseases, and one year period prevalence proportions were higher than contact prevalence proportions (26.2 - 79.7%). For incidence rates, the use of different denominators resulted in small differences between the different calculation methods (-1.3 - 14.8%). Using person-years at-risk or a midterm population resulted in higher rates compared to using person-years.
Conclusions: All different operational definitions affect incidence rates and prevalence proportions to some extent. Therefore, it is important that the terminology and methodology is well described by sources reporting these epidemiological measures. When comparing incidence rates and prevalence proportions from different sources, it is important to be aware of the operational definitions applied and their impact.
Databáze: MEDLINE
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