External adjustment of unmeasured confounders in a case-control study of benzodiazepine use and cancer risk

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External adjustment of unmeasured confounders in a case-control study of benzodiazepine use and cancer risk. / Thygesen, Lau Caspar; Pottegård, Anton; Ersbøll, Annette Kjaer; Friis, Søren; Stürmer, Til; Hallas, Jesper.

In: British Journal of Clinical Pharmacology, Vol. 83, No. 11, 2017, p. 2517–2527.

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@article{644306115c8346e2b0b195b609c02fad,
title = "External adjustment of unmeasured confounders in a case-control study of benzodiazepine use and cancer risk",
abstract = "AIMS: Previous studies have reported diverging results on the association between benzodiazepine use and cancer risk.METHODS: We investigated this association in a matched case-control study including incident cancer cases during 2002-2009 in the Danish Cancer Registry (n = 94 923) and age- and sex-matched (1:8) population controls (n = 759 334). Long-term benzodiazepine use was defined as ≥500 defined daily doses 1-5 years prior to the index date. We implemented propensity score (PS) calibration using external information on confounders available from a survey of the Danish population. Two PSs were used: The error-prone PS using register-based confounders and the calibrated PS based on both register- and survey-based confounders, retrieved from the Health Interview Survey.RESULTS: Register-based data showed that cancer cases had more diagnoses, higher comorbidity score and more co-medication then population controls. Survey-based data showed lower self-rated health, more self-reported diseases, and more smokers as well as subjects with sedentary lifestyle among benzodiazepine users. By PS calibration, the odds ratio for cancer overall associated with benzodiazepine use decreased from 1.16 to 1.09 (95{\%} confidence interval 1.00-1.19) and for smoking-related cancers from 1.20 to 1.10 (95{\%} confidence interval 1.00-1.21).CONCLUSION: We conclude that the increased risk observed in the solely register-based study could partly be attributed to unmeasured confounding.",
keywords = "Journal Article",
author = "Thygesen, {Lau Caspar} and Anton Potteg{\aa}rd and Ersb{\o}ll, {Annette Kjaer} and S{\o}ren Friis and Til St{\"u}rmer and Jesper Hallas",
note = "{\circledC} 2017 The British Pharmacological Society.",
year = "2017",
doi = "10.1111/bcp.13342",
language = "English",
volume = "83",
pages = "2517–2527",
journal = "British Journal of Clinical Pharmacology",
issn = "0306-5251",
publisher = "Wiley-Blackwell",
number = "11",

}

RIS

TY - JOUR

T1 - External adjustment of unmeasured confounders in a case-control study of benzodiazepine use and cancer risk

AU - Thygesen,Lau Caspar

AU - Pottegård,Anton

AU - Ersbøll,Annette Kjaer

AU - Friis,Søren

AU - Stürmer,Til

AU - Hallas,Jesper

N1 - © 2017 The British Pharmacological Society.

PY - 2017

Y1 - 2017

N2 - AIMS: Previous studies have reported diverging results on the association between benzodiazepine use and cancer risk.METHODS: We investigated this association in a matched case-control study including incident cancer cases during 2002-2009 in the Danish Cancer Registry (n = 94 923) and age- and sex-matched (1:8) population controls (n = 759 334). Long-term benzodiazepine use was defined as ≥500 defined daily doses 1-5 years prior to the index date. We implemented propensity score (PS) calibration using external information on confounders available from a survey of the Danish population. Two PSs were used: The error-prone PS using register-based confounders and the calibrated PS based on both register- and survey-based confounders, retrieved from the Health Interview Survey.RESULTS: Register-based data showed that cancer cases had more diagnoses, higher comorbidity score and more co-medication then population controls. Survey-based data showed lower self-rated health, more self-reported diseases, and more smokers as well as subjects with sedentary lifestyle among benzodiazepine users. By PS calibration, the odds ratio for cancer overall associated with benzodiazepine use decreased from 1.16 to 1.09 (95% confidence interval 1.00-1.19) and for smoking-related cancers from 1.20 to 1.10 (95% confidence interval 1.00-1.21).CONCLUSION: We conclude that the increased risk observed in the solely register-based study could partly be attributed to unmeasured confounding.

AB - AIMS: Previous studies have reported diverging results on the association between benzodiazepine use and cancer risk.METHODS: We investigated this association in a matched case-control study including incident cancer cases during 2002-2009 in the Danish Cancer Registry (n = 94 923) and age- and sex-matched (1:8) population controls (n = 759 334). Long-term benzodiazepine use was defined as ≥500 defined daily doses 1-5 years prior to the index date. We implemented propensity score (PS) calibration using external information on confounders available from a survey of the Danish population. Two PSs were used: The error-prone PS using register-based confounders and the calibrated PS based on both register- and survey-based confounders, retrieved from the Health Interview Survey.RESULTS: Register-based data showed that cancer cases had more diagnoses, higher comorbidity score and more co-medication then population controls. Survey-based data showed lower self-rated health, more self-reported diseases, and more smokers as well as subjects with sedentary lifestyle among benzodiazepine users. By PS calibration, the odds ratio for cancer overall associated with benzodiazepine use decreased from 1.16 to 1.09 (95% confidence interval 1.00-1.19) and for smoking-related cancers from 1.20 to 1.10 (95% confidence interval 1.00-1.21).CONCLUSION: We conclude that the increased risk observed in the solely register-based study could partly be attributed to unmeasured confounding.

KW - Journal Article

U2 - 10.1111/bcp.13342

DO - 10.1111/bcp.13342

M3 - Journal article

VL - 83

SP - 2517

EP - 2527

JO - British Journal of Clinical Pharmacology

T2 - British Journal of Clinical Pharmacology

JF - British Journal of Clinical Pharmacology

SN - 0306-5251

IS - 11

ER -