eprintid: 22836 rev_number: 12 eprint_status: archive userid: 1589 dir: disk0/00/02/28/36 datestamp: 2017-04-26 08:42:14 lastmod: 2024-03-09 20:19:12 status_changed: 2017-04-26 08:42:14 type: article metadata_visibility: show creators_name: Becher, Heiko creators_name: Winkler, Volker title: Estimating the standardized incidence ratio (SIR) with incomplete follow-up data subjects: ddc-610 divisions: i-912800 abstract: Background: A standard parameter to compare the disease incidence of a cohort relative to the population is the standardized incidence ratio (SIR). For statistical inference is commonly assumed that the denominator, the expected number of cases, is fixed. If a disease registry is available, incident cases can sometimes be identified by linkage with the registry, however, registries may not contain information on migration or death from other causes. A complete follow-up with a population registry may not be possible. In that case, end-of-follow-up date and therefore, exact person-years of observation are unknown. Methods: We have developed a method to estimate the observation times and to derive the expected number of cases using population data on mortality and migration rates. We investigate the impact of the underlying assumptions with a sensitivity analysis. Results: The method provides a useful estimate of the SIR. We illustrate the method with a numerical example, a simulation study and with a study on standardized cancer incidence ratios in a cohort of migrants relative to the German population. We show that the additional variance induced by the estimation method is small, so that standard methods for inference can be applied. Conclusions: Estimation of the observation time is possible for cohort studies with incomplete follow-up. date: 2017 publisher: BioMed Central; Springer id_scheme: DOI ppn_swb: 1657834042 own_urn: urn:nbn:de:bsz:16-heidok-228363 language: eng bibsort: BECHERHEIKESTIMATING2017 full_text_status: public publication: BMC Medical Research Methodology volume: 17 number: 55 place_of_pub: London; Berlin; Heidelberg pagerange: 1-10 issn: 1471-2288 citation: Becher, Heiko ; Winkler, Volker (2017) Estimating the standardized incidence ratio (SIR) with incomplete follow-up data. BMC Medical Research Methodology, 17 (55). pp. 1-10. ISSN 1471-2288 document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/22836/1/12874_2017_Article_335.pdf