Exchangeability in the case-crossover design

Mittleman, Murray A.; Mostofsky, Elizabeth

doi:10.1093/ije/dyu081

Cited by 114 publications

(130 citation statements)

References 40 publications

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“…Case-crossover design is analogous to a matched retrospective case-control design in which only matched pairs that are discordant for exposure contribute to the information [18][19][20]. As case-crossover design is a self-matched design [18][19][20][21], therefore we did not require adjusting for the independent risk factors which are unchanged within a person such as Body Mass Index (BMI), age, sex.…”

Section: Discussionmentioning

confidence: 99%

“…In a case-crossover design, selfmatching of each participant eliminates bias in control selection and self-confounding removes confounding effects of factors that are constant over time within individuals but differ among study participants (e.g. age, genetics, race, education) [18][19][20][21].…”

Section: Discussionmentioning

confidence: 99%

“…The casecrossover design uses each participant (case) as his/her own control and is best suited [18][19][20][21] to assess effects of transient and intermittent exposures (triggers) on acute events (e.g. pain flares).…”

Section: Methodsmentioning

confidence: 99%

“…pain flares). It specifically compares the frequency of risk factors occurring during the period right before participant experiences pain exacerbation (case period) with the period when the same participant did not experience pain exacerbation (control period) [18][19][20][21].…”

Section: Methodsmentioning

confidence: 99%

“…The Internet is an efficient tool to collect data and allowed us to capture both exposure and outcome in real time [21]. Participants were followed for 3 months and asked to complete online questionnaires at 10-day intervals (control periods).…”

Section: Methodsmentioning

confidence: 99%

See 4 more Smart Citations

Psychological Factors and Pain Exacerbation in Knee Osteoarthritis: A Web Based Case-Crossover Study

F¹

2015

Rheumatology (Sunnyvale)

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Objectives: The pain experienced by osteoarthritis (OA) patients is neither constant nor unchanging and patients experience episodes of pain exacerbations. Using an innovative web based case-crossover design, we evaluated whether psychological factors are risk factors for pain exacerbations in patients with knee OA. Methods:In a 3-months internet-based case-crossover study, participants with symptomatic knee OA were recruited and followed at 10-day intervals (control periods). Participants were also instructed to log on to the study website if they experienced a knee pain exacerbation (case periods). Pain exacerbation was defined as an increase of ≥ 2 on a participant's numerical rating scale (0-10) from his/her usual background pain score reported at baseline visit. The periods were 10 days for affect measures and 30 days for pain coping/perceived stress measures. The relation of psychological factors to the risk of pain exacerbation was examined using conditional logistic regression. Results:Of 298 participants recruited, 149 and 54 provided both case and control periods with no overlap for examining affect and pain coping/perceived stress factors respectively. Higher negative affect (negative affect score ≥ 18: odds ratio (OR) 6.49; 95% CI 3.45-12.2) and passive coping strategies (OR 1.26; 95% CI 1.05-1.50) were associated with increased risk of pain exacerbations; while higher active coping strategies (OR 0.81; 95% CI 0.66-0.98) had a protective effect. Conclusion:The findings emphasize the need for avoidance of negative affect and passive pain coping strategies and conversely reinforce the benefit of active pain coping strategies in prevention and management of OA pain exacerbations.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Psychological Factors and Pain Exacerbation in Knee Osteoarthritis: A Web Based Case-Crossover Study

F¹

2015

Rheumatology (Sunnyvale)

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Temporal Association Between Episodes of Atrial Fibrillation and Risk of Ischemic Stroke

et al. 2021

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IMPORTANCEUnderstanding the temporal association between atrial fibrillation (AF) and ischemic stroke informs our understanding of the AF-stroke mechanism and treatment of paroxysmal AF.OBJECTIVE To define the temporal association between episodes of AF and stroke in patients with cardiac implantable electronic devices (CIEDs). DESIGN, SETTING, AND PARTICIPANTSIn this case-crossover study, data from a large national electronic health record database were linked with a single-vendor database of heart rhythm records of patients with CIEDs capable of continuous heart rhythm monitoring. Patients with CIEDs who sustained an ischemic stroke who also had 120 days of continuous remote rhythm monitoring prestroke were included. Data were collected from January 2007 to March 2017, and data were analyzed from November 2019 to June 2020.EXPOSURE AF for 5.5 hours or more on any given day during days 1 to 30 vs days 91 to 120 prestroke. MAIN OUTCOMES AND MEASURESOdds ratio for stroke comparing AF during days 1 to 30 vs 91 to 120 prestroke. This analysis was planned prior to the study. RESULTSFrom 466 635 patients included in both the Optum electronic health record and CareLink databases, 891 patients with CIEDs and ischemic stroke with continuous monitoring in the 120 days prestroke were identified. Of 891 included patients, 575 (64.5%) were male, and the median (interquartile range) age was 76 (67-82) years. The vast majority of patients with stroke had either no AF meeting the threshold duration of 5.5 hours or more in both the case and control periods (682 of 891 [76.5%]) or AF of 5.5 hours or more in both periods (143 of 891 [16.0%]). For those not meeting the 5.5-hour AF threshold in either period, there was no or very little AF throughout the 120 days prestroke. A total of 66 patients had informative, discordant arrhythmic states, with 52 having AF of 5.5 hours or more in the case period vs 14 in the control period (odds ratio [OR], 3.71; 95% CI, 2.06-6.70). Stroke risk was increased most in days 1 to 5 following an AF episode (OR, 5.00; 95% CI, 2.62-9.55). AF greater than 23 hours on a given day was associated with the clearest increase in stroke risk (OR, 5.00; 95% CI, 2.08-12.01). CONCLUSIONS AND RELEVANCEIn this large cohort of patients with CIEDs and continuous rhythm monitoring prior to ischemic stroke, excess stroke risk above baseline was highest within 5 days of an episode of AF of 5.5 hours or more in duration and diminished rapidly thereafter. Our findings are consistent with the traditional view that AF is directly and transiently associated with ischemic stroke. These results provide support for trials of time-delimited anticoagulation for patients with infrequent multihour episodes of AF and rigorous, continuous rhythm monitoring.

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Association of Testosterone Therapy With Risk of Venous Thromboembolism Among Men With and Without Hypogonadism

et al. 2020

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IMPORTANCE Testosterone therapy is increasingly prescribed in patients without a diagnosis of hypogonadism. This therapy may be associated with increased risk of venous thromboembolism (VTE) through several mechanisms, including elevated hematocrit levels, which increase blood viscosity.OBJECTIVE To assess whether short-term testosterone therapy exposure is associated with increased short-term risk of VTE in men with and without evidence of hypogonadism. DESIGN, SETTING, AND PARTICIPANTSThis case-crossover study analyzed data on 39 622 men from the IBM MarketScan Commercial Claims and Encounter Database and the Medicare Supplemental Database from January 1, 2011, to December 31, 2017, with 12 months of follow-up. Men with VTE cases who were free of cancer at baseline and had 12 months of continuous enrollment before the VTE event were identified by International Classification of Diseases codes. Men in the case period were matched with themselves in the control period. Case periods of 6 months, 3 months, and 1 month before the VTE events were defined, with equivalent control periods (6 months, 3 months, and 1 month) in the 6 months before the case period.EXPOSURES National drug codes were used to identify billed testosterone therapy prescriptions in the case period (0-6 months before the VTE) and the control period (6-12 months before the VTE). MAIN OUTCOMES AND MEASURESThe main outcome in this case-only experiment was first VTE event stratified by the presence or absence of hypogonadism.RESULTS A total of 39 622 men (mean [SD] age, 57.4 [14.2] years) were enrolled in the study, and 3110 men (7.8%) had evidence of hypogonadism. In age-adjusted models, testosterone therapy use in all case periods was associated with a higher risk of VTE in men with (odds ratio [OR], 2.32; 95% CI, 1.97-2.74) and without (OR, 2.02; 95% CI, 1.47-2.77) hypogonadism. Among men without hypogonadism, the point estimate for testosterone therapy and VTE risk in the 3-month case period was higher for men younger than 65 years (OR, 2.99; 95% CI, 1.91-4.68) than for older men (OR, 1.68; 95% CI, 0.90-3.14), although this interaction was not statistically significant (P = .14). CONCLUSIONS AND RELEVANCETestosterone therapy was associated with an increase in short-term risk for VTE among men with and without hypogonadism, with some evidence that the association was more pronounced among younger men. These findings suggest that caution should be used when prescribing testosterone therapy.

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Exchangeability in the case-crossover design

Cited by 114 publications

References 40 publications

Psychological Factors and Pain Exacerbation in Knee Osteoarthritis: A Web Based Case-Crossover Study

Psychological Factors and Pain Exacerbation in Knee Osteoarthritis: A Web Based Case-Crossover Study

Temporal Association Between Episodes of Atrial Fibrillation and Risk of Ischemic Stroke

Association of Testosterone Therapy With Risk of Venous Thromboembolism Among Men With and Without Hypogonadism

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