Avoiding immortal time bias in observational studies

Suissa, Samy; Ernst, Pierre

doi:10.1183/13993003.00138-2020

Cited by 5 publications

(3 citation statements)

References 6 publications

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“…To avoid immortal time bias, 16 participants were transferred from the risk set who had not received a bivalent booster vaccination to the risk set who had received a bivalent booster vaccination at 7 days after receiving the vaccination, modifying their vaccination status from non-recipient to recipient. Consequently, the follow-up of participants who received a bivalent booster vaccination started at the end of the immortal period and lasted for a minimum of 14 days to allow sufficient time for hospitalisation events.…”

Section: Methodsmentioning

confidence: 99%

Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study

Arbel

Peretz

Sergienko

et al. 2023

The Lancet Infectious Diseases

105

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Section: Methodsmentioning

confidence: 99%

Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study

Arbel

Peretz

Sergienko

et al. 2023

The Lancet Infectious Diseases

105

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“…The initial visit for new patients and first prescription could help us to confirm if the patients are alive or not. These strict policies help us to eliminate the immortal time bias in this study ( Suissa and Ernst, 2020 ).…”

Section: Resultsmentioning

confidence: 99%

Asthma Therapies on Pulmonary Tuberculosis Pneumonia in Predominant Bronchiectasis–Asthma Combination

et al. 2022

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Background: It is sometimes difficult to distinguish between asthma and bronchiectasis as their symptoms overlap, and these two diseases are associated with pulmonary tuberculosis (PTB) or pneumonia.Objective: The purpose of this study is to determine the effects of bronchodilator drugs, steroids, antidepressants drugs, and antianxiety drugs on the risks of PTB or pneumonia in patients with bronchiectasis–asthma combination or bronchiectasis–asthma–chronic obstructive pulmonary disease combination—BCAS cohort.Methods: After propensity score matching, we retrospectively studied patients with BCAS (N = 620) and without BCAS (N = 2,314) through an analysis. The cumulative incidence of PTB or pneumonia was analyzed through Cox proportional regression. After adjustment for sex, age, comorbidities, and medications [including long-acting beta2 agonist/muscarinic antagonists (LABAs/LAMAs), short-acting beta2 agonist/muscarinic antagonists (SABAs/SAMAs), leukotriene receptor antagonist, montelukast, steroids (inhaled corticosteroids, ICSs; oral steroids, OSs), anti-depressants (fluoxetine), and anti-anxiety drugs (benzodiazepines, BZDs)], we calculated the adjusted hazard ratios (aHR) and their 95% confidence intervals (95% CI) for these risks. Similar to OSs, ICSs are associated with an increased risk of PTB or pneumonia, lumping these two as steroids (ICSs/OSs).Results: For the aHR (95% CI), with non-LABAs/non-OSs as the reference 1, the use of LABAs [0.70 (0.52–0.94)]/OSs [0.35 (0.29–0.44)] was associated with a lower risk of PTB or pneumonia. However, the current use of LABAs [2.39 (1.31–4.34)]/SABAs [1.61 (1.31–1.96)], steroids [ICSs 3.23 (1.96–5.29)]/OSs 1.76 (1.45–2.14)], and BZDs [alprazolam 1.73 (1.08–2.75)/fludiazepam 7.48 (1.93–28.9)] was associated with these risks. The current use of LAMAs [0.52 (0.14–1.84)]/SAMAs [1.45 (0.99–2.11)] was not associated with these risks.Conclusion: The current use of LAMAs/SAMAs is relatively safe with respect to PTB or pneumonia risks, but LABAs/SABAs, steroids, and BZDs could be used after evaluation of the benefit for the BCAS cohort. However, we must take the possible protopathic bias into account.

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“…This additional eligibility restriction was necessary in order to avoid immortal time-bias as well as to reduce confounding by disease severity by only comparing these characteristics among opioid users. 41,42 To maintain an appropriate temporal sequence that properly places the exposure relative to when the outcome occurs, only patients who lled their rst post-discharge opioid prescription before they had their rst post-discharge ED encounter were included in the model. 43 Cohort entry for this model was time of rst dispensation to further reduce the opportunity for immortal time bias.…”

Section: Statistical Analysesmentioning

confidence: 99%

Predictors of Frequent Emergency Department Visits among Hospitalized Cancer Patients: A Comparative Cohort Study Using Integrated Clinical and Administrative Data to Improve Care Delivery

Kurteva

Tamblyn

Meguerditchian

2023

Preprint

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Background Frequent emergency department (FED) visits by cancer patients represent a significant burden to the health system. This study identified determinants of FED in recently hospitalized cancer patients, with a particular focus on opioid use. Methods A prospective cohort discharged from surgical/medical units of the McGill University Health Centre was assembled. The outcome was FED use (≥ 4 ED visits) within one year of discharge. Data retrieved from the universal health insurance system was analyzed using Cox Proportional Hazards (PH) model, adopting the Lunn-McNeil approach for competing risk of death. Results Of 1253 patients, 14.5% became FED users. FED use was associated with chemotherapy one-year pre-admission (adjusted hazard ratio (aHR) 2.60, 95% CI: 1.80–3.70), ≥1 ED visit in the previous year (aHR: 1.80, 95% CI 1.20–2.80), ≥15 pre-admission ambulatory visits (aHR 1.54, 95% CI 1.06–2.34), previous opioid and benzodiazepine use (aHR: 1.40, 95% CI: 1.10–1.90 and aHR: 1.70, 95% CI: 1.10–2.40), Charlson Comorbidity Index ≥ 3 (aHR: 2.0, 95% CI: 1.2–3.4), diabetes (aHR: 1.60, 95% CI: 1.10–2.20), heart disease (aHR: 1.50, 95% CI: 1.10–2.20) and lung cancer (aHR: 1.70, 95% CI: 1.10–2.40). Surgery (cardiac (aHR: 0.33, 95% CI: 0.16–0.66), gastrointestinal (aHR: 0.34, 95% CI: 0.14–0.82) and thoracic (aHR: 0.45, 95% CI: 0.30–0.67) led to a decreased risk of FED use. Conclusions Cancer patients with higher co-morbidity, frequent use of the healthcare system, and opioid use were at increased risk of FED use. High-risk patients should be flagged for preventive intervention.

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Avoiding immortal time bias in observational studies

Cited by 5 publications

References 6 publications

Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study

Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study

Asthma Therapies on Pulmonary Tuberculosis Pneumonia in Predominant Bronchiectasis–Asthma Combination

Predictors of Frequent Emergency Department Visits among Hospitalized Cancer Patients: A Comparative Cohort Study Using Integrated Clinical and Administrative Data to Improve Care Delivery

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