Propensity Score Methods for Confounding Control in Nonexperimental Research

Brookhart, M. Alan; Wyss, Richard; Layton, J. Bradley; Stürmer, Til

doi:10.1161/circoutcomes.113.000359

Cited by 453 publications

(400 citation statements)

References 45 publications

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“…First, propensity scores from a logistic regression model with no hierarchical structure were used to estimate treatment effects using inverse probability weighting, which estimates treatment effects in a population with risk factor distribution similar to the full study population (20,21). Second, we developed a hierarchical generalized linear model adjusting for patient characteristics and including a random hospital effect to assess the effect of NIV on the study outcomes.…”

Section: Discussionmentioning

confidence: 99%

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

et al. 2016

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Rationale: Little is known about the effectiveness of noninvasive ventilation for patients hospitalized with asthma exacerbation.Objectives: To assess clinical outcomes of noninvasive (NIV) and invasive mechanical ventilation (IMV) and examine predictors for NIV use in patients hospitalized with asthma.Methods: This was a retrospective cohort study at 97 U.S. hospitals using an electronic medical record database. We developed a hierarchical regression model to identify factors associated with the choice of initial ventilation and used the Laboratory Acute Physiological Score to adjust for differences in the severity of illness. We assessed the outcomes of patients treated with initial NIV or IMV in a propensity-matched cohort.Measurements and Main Results: Among 13,930 subjects, 73% were women and 54% were white. The median age was 53 years. Overall, 1,254 patients (9%) required ventilatory support (NIV or IMV). NIV was the initial ventilation method for 556 patients (4.0%) and IMV for 668 (5.0%). Twenty-six patients (4.7% of patients treated with NIV) had to be intubated (NIV failure). The in-hospital mortality was 0.2, 2.3, 14.5, and 15.4%, and the median length of stay was 2.9, 4.1, 6.7, and 10.9 days among those not ventilated, ventilated with NIV, ventilated with IMV, and with NIV failure, respectively. Older patients were more likely to receive NIV (odds ratio, 1.06 per 5 yr; 95% confidence interval [CI], 1.01-1.11), whereas those with higher acuity (Laboratory Acute Physiological Score per 5 units: odds ratio, 0.85; 95% CI, 0.82-0.88) and those with concomitant pneumonia were less likely to receive NIV. In a propensity-matched sample, NIV was associated with a lower inpatient risk of dying (risk ratio, 0.12; 95% CI, 0.03-0.51) and shorter lengths of stay (4.3 d less; 95% CI, 2.9-5.8) than IMV.Conclusions: Among patients hospitalized with asthma exacerbation and requiring ventilatory support (NIV or IMV), more than 40% received NIV. Although patients successfully treated with NIV appear to have better outcomes than those treated with IMV, the low rate of NIV failure suggests that NIV was being used selectively in a lower risk group. The increased risk of mortality for patients who fail NIV highlights the need for careful monitoring to avoid possible delay in intubation.

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Section: Discussionmentioning

confidence: 99%

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

et al. 2016

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“…A multivariable logistic regression model, including all univariate significant predictors of mannitol treatment and the primary outcome, and other clinically important factors (sex and randomized BP-lowering treatment), was constructed to produce estimates of the treatment effect of mannitol (Tables I and II in the online-only Data Supplement). 14,15 On the basis of coefficients from this model, we generated a PS 14,16 for each patient. Only patients with complete data were included in the analyses to maximize balancing of the PS analysis with the largest number of variables and to avoid the need to impute data.…”

Section: Discussionmentioning

confidence: 99%

Mannitol and Outcome in Intracerebral Hemorrhage

Wang

Arima

Yang

et al. 2015

Stroke

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Mannitol is frequently used in the management of patients with spontaneous intracerebral hemorrhage (ICH), 1 particularly in China 2 and India. 3 It is an intravascular osmostic agent that establishes an osmotic gradient between plasma and neurons, thereby drawing water from the cerebral extracellular space into the vasculature to reduce cerebral edema. 4 Mannitol also increases cardiac preload and cerebral perfusion pressure, which contributes to a decrease in intracranial pressure through cerebral vasoreactivity. Although guidelines recommend using mannitol where there is increased intracranial pressure in ICH, 5 uncertainty exists over the magnitude of potential benefit, with various observational studies, 6,7 clinical Background and Purpose-Mannitol is often used to reduce cerebral edema in acute intracerebral hemorrhage but without strong supporting evidence of benefit. We aimed to determine the impact of mannitol on outcome among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial (INTERACT2). Methods-INTERACT2 was an international, open, blinded end point, randomized controlled trial of 2839 patients with spontaneous intracerebral hemorrhage (<6 hours) and elevated systolic blood pressure allocated to intensive (target systolic blood pressure, <140 mm Hg within 1 hour) or guideline-recommended (target systolic blood pressure, <180 mm Hg) blood pressure-lowering treatment. Propensity score and multivariable analyses were performed to investigate the relationship between mannitol treatment (within 7 days) and poor outcome, defined by death or major disability on the modified Rankin Scale score (3-6) at 90 days. Results-There was no significant difference in poor outcome between mannitol (n=1533) and nonmannitol (n=993) groups: propensity score-matched odds ratio of 0.90 (95% confidence interval, 0.

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“…On the basis of coefficients from the multivariable logistic regression model, we generated a PS [7, 8] for each patient. Only patients with complete data were included in the analyses to maximize balancing of the PS analysis with the largest number of variables and to avoid the need to impute data.…”

Section: Methodsmentioning

confidence: 99%

Lipid-Lowering Pretreatment and Outcome Following Intravenous Thrombolysis for Acute Ischaemic Stroke: A Post Hoc Analysis of the Enhanced Control of Hypertension and Thrombolysis Stroke Study Trial

et al. 2018

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Background: Debate exists as to whether statin pretreatment confers an increased risk of 90-day mortality and symptomatic intracranial haemorrhage (sICH) in acute ischaemic stroke (AIS) patients treated with intravenous thrombolysis. We assessed the effects of undifferentiated lipid-lowering pretreatment on outcomes and interaction with low-dose versus standard-dose alteplase in a post hoc subgroup analysis of the Enhanced Control of Hypertension and Thrombolysis Stroke Study. Methods: In all, 3,284 thrombolysis-eligible AIS patients (mean age 66.6 years; 38% women), with information on lipid-lowering pretreatment, were randomly assigned to low-dose (0.6 mg/kg) or standard-dose (0.9 mg/kg) intravenous alteplase within 4.5 h of symptom onset. Of the total number of patients, 615 (19%) received statin or other lipid-lowering pretreatment. The primary clinical outcome was combined endpoint of death or disability (modified Rankin Scale scores 2–6) at 90 days. Results: Compared with patients with no lipid-lowering pretreatment, those with lipid-lowering pretreatment were significantly older, more likely to be non-Asian and more likely to have a medical history including vascular co-morbidity. After propensity analysis assessment and adjustment for important baseline variables at the time of randomisation, as well as imbalances in management during the first 7 days of hospital admission, there were no significant differences in mortality (OR 0.85; 95% CI 0.58–1.25, p = 0.42), or in overall 90-day death and disability (OR 0.85, 95% CI 0.67–1.09, p = 0.19), despite a significant decrease in sICH among those with lipid-lowering pretreatment according to the European Co-operative Acute Stroke Study 2 definition (OR 0.49, 95% CI 0.28–0.83, p = 0.009). No differences in key efficacy or safety outcomes were seen in patients with and without lipid-lowering pretreatment between low- and standard-dose alteplase arms. Conclusions: Lipid-lowering pretreatment is not associated with adverse outcome in AIS patients treated with intravenous alteplase, whether assessed by 90-day death and disability or death alone.

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Propensity Score Methods for Confounding Control in Nonexperimental Research

Cited by 453 publications

References 45 publications

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

Outcomes of Noninvasive and Invasive Ventilation in Patients Hospitalized with Asthma Exacerbation

Mannitol and Outcome in Intracerebral Hemorrhage

Lipid-Lowering Pretreatment and Outcome Following Intravenous Thrombolysis for Acute Ischaemic Stroke: A Post Hoc Analysis of the Enhanced Control of Hypertension and Thrombolysis Stroke Study Trial

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