ArticlePharmacoepidemiology and drug safety2017
Controlling confounding by frailty when estimating influenza vaccine effectiveness using predictors of dependency in activities of daily living.
Article in Pharmacoepidemiology and drug safety, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 1 of them a synthesis that pooled it.
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
14 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Influenza vaccine effectiveness according to frailty status in adults aged ≥ 50 years: a systematic review and meta-analysis.BMC infectious diseases · 2026Pooled it
- Age-specific patterns of all-cause mortality across COVID-19 booster dose groups in two Japanese municipalities: an exploratory analysis.Frontiers in public health · 2026Observational
- Quantifying and Adjusting for Confounding From Health-Seeking Behavior and Health Care Access in Observational Research.Open forum infectious diseases · 2024Article
- Identifying markers of health-seeking behaviour and healthcare access in UK electronic health records.BMJ open · 2024Observational
- Longitudinal Changes in a Claims-Based Frailty Proxy Measure Compared to Concurrent Changes in the Fried Frailty Phenotype.The journals of gerontology. Series A, Biological sciences and medical sciences · 2024Article
- Assessing the Benefits and Harms of Pharmacotherapy in Older Adults with Frailty: Insights from Pharmacoepidemiologic Studies of Routine Health Care Data.Drugs & aging · 2024Review
- The State of Use and Utility of Negative Controls in Pharmacoepidemiologic Studies.American journal of epidemiology · 2024Review
- Translation of a Claims-Based Frailty Index From the International Classification of Diseases, Ninth Revision, Clinical Modification to the Tenth Revision.American journal of epidemiology · 2023Article
- Frailty, vaccination, and hospitalization following COVID-19 positivity in older veterans.Journal of the American Geriatrics Society · 2022Article
- Article
- Measuring Frailty in Health Care Databases for Clinical Care and Research.Annals of geriatric medicine and research · 2020Review
- The immune response to influenza in older humans: beyond immune senescence.Immunity & ageing : I & A · 2020Review
- Challenges in estimating influenza vaccine effectiveness.Expert review of vaccines · 2019Review
- The importance and implications of comparator selection in pharmacoepidemiologic research.Current epidemiology reports · 2018Article
Corrections and comments
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Authors and funding
5 authors.
Funding
Abstract
purposeTo improve control of confounding by frailty when estimating the effect of influenza vaccination on all-cause mortality by controlling for a published set of claims-based predictors of dependency in activities of daily living (ADL).
methodsUsing Medicare claims data, a cohort of beneficiaries >65 years of age was followed from September 1, 2007, to April 12, 2008, with covariates assessed in the 6 months before follow-up. We estimated Cox proportional hazards models of all-cause mortality, with influenza vaccination as a time-varying exposure. We controlled for common demographics, comorbidities, and health care utilization variables and then added 20 ADL dependency predictors. To gauge residual confounding, we estimated pre-influenza season hazard ratios (HRs) between September 1, 2007 and January 5, 2008, which should be 1.0 in the absence of bias.
resultsA cohort of 2 235 140 beneficiaries was created, with a median follow-up of 224 days. Overall, 52% were vaccinated and 4% died during follow-up. During the pre-influenza season period, controlling for demographics, comorbidities, and health care use resulted in a HR of 0.66 (0.64, 0.67). Adding the ADL dependency predictors moved the HR to 0.68 (0.67, 0.70). Controlling for demographics and ADL dependency predictors alone resulted in a HR of 0.68 (0.66, 0.70).
conclusionsResults were consistent with those in the literature, with significant uncontrolled confounding after adjustment for demographics, comorbidities, and health care use. Adding ADL dependency predictors moved HRs slightly closer to the null. Of the comorbidities, health care use variables, and ADL dependency predictors, the last set reduced confounding most. However, substantial uncontrolled confounding remained.
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