Importance of accounting for loss to follow-up when comparing mortality between immigrants and long-term residents: a population-based retrospective cohort
| Autor: | Moira K Kapral, Andreas Laupacis, Jiming Fang, Manav V. Vyas, Peter C. Austin, Matthew C. Cheung, Frank L. Silver |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | BMJ Open, Vol 11, Iss 11 (2021) |
| Druh dokumentu: | article |
| ISSN: | 2020-0463 2044-6055 |
| DOI: | 10.1136/bmjopen-2020-046377 |
| Popis: | Objectives To evaluate the association between immigration status and all-cause mortality in different disease cohorts, and the impact of loss to follow-up on the observed associations.Design Population-based retrospective cohort study using linked administrative health data in Ontario, Canada.Setting We followed adults with a first-ever diagnosis of ischaemic stroke, cancer or schizophrenia between 2002 and 2013 from index event to death, loss to follow-up, or end of follow-up in 2018.Primary and secondary outcome measures Our outcomes of interest were all-cause mortality and loss to follow-up. For each disease cohort, we calculated adjusted HRs of death in immigrants compared with long-term residents, adjusting for demographic characteristics and comorbidities, with and without censoring for those who were lost to follow-up. We calculated the ratio of two the HRs and the respective CL using bootstrapping methods.Results Immigrants were more likely to be lost to follow-up than long-term residents in all disease cohorts. Not accounting for this loss to follow-up overestimated the magnitude of the association between immigration status and mortality in those with ischaemic stroke (HR of death before vs after accounting for censoring: 0.78 vs 0.83, ratio=0.95; 95% CL 0.93 to 0.97), cancer (0.74 vs 0.78, ratio=0.96; 0.95 to 0.96), and schizophrenia (0.54 vs 0.56, ratio=0.97; 0.96 to 0.98).Conclusions Immigrants to Canada have a survival advantage that varies by the disease studied. The magnitude of this advantage is modestly overestimated by not accounting for the higher loss to follow-up in immigrants. |
| Databáze: | Directory of Open Access Journals |
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