Double Inverse-Weighted Estimation of Cumulative Treatment Effects Under Nonproportional Hazards and Dependent Censoring

Schaubel, Douglas E.; Wei, Guanghui

doi:10.1111/j.1541-0420.2010.01449.x

Cited by 45 publications

(44 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the IPTW method of Wei , the assumption on the censoring distribution is the same as ours, although the IPTW method does not involve inverse probability of censoring weighting. It should be noted that the IPTW method of Wei has been extended to handle dependent censoring easily, under the ‘no‐unmeasured‐confounders‐for‐censoring’ assumption, by inverse probability of censoring weighting, wherein one models the probability of censoring conditional on baseline and/or time‐dependent covariates and modifies the weight function

w_{ij} 1.19em (\overset{θ}{false} 1.19em)

by further weighting it by the inverse probability of remaining uncensored . However, it is not straightforward to extend the proposed method to accommodate dependent censoring because, in addition to modifying the weight, one needs to modify the second term in both the numerator and the denominator of as well.…”

Section: Discussionmentioning

confidence: 99%

Contrasting treatment‐specific survival using double‐robust estimators

Zhang

Schaubel

2012

Statistics in Medicine

Self Cite

View full text Add to dashboard Cite

In settings where a randomized trial is infeasible, observational data are frequently used to compare treatment-specific survival. The average causal effect (ACE) can be used to make inference regarding treatment policies on patient populations, and a valid ACE estimator must account for imbalances with respect to treatment-specific covariate distributions. One method through which the ACE on survival can be estimated involves appropriately averaging over Cox-regression-based fitted survival functions. A second available method balances the treatment-specific covariate distributions through Inverse Probability of Treatment Weighting (IPTW), then contrasts weighted nonparametric survival function estimators. Since both methods have their advantages and disadvantages, we propose methods which essentially combine both estimators. The proposed methods are double-robust, in the sense that they are consistent if at least one of the two working regression models (i.e., logistic model for treatment, and Cox model for death hazard) is correct. The proposed methods involve estimating the ACE with respect to restricted mean survival time, defined as the area under the survival curve up to some pre-specified time point. Asymptotic results are derived and evaluated through simulation. We apply the proposed methods to estimate the ACE of donation-after-cardiac-death kidney transplantation using data obtained from multiple centers in the Netherlands.

show abstract

w_{ij} 1.19em (\overset{θ}{false} 1.19em)

Section: Discussionmentioning

confidence: 99%

Contrasting treatment‐specific survival using double‐robust estimators

Zhang

Schaubel

2012

Statistics in Medicine

Self Cite

View full text Add to dashboard Cite

show abstract

“…As a sensitivity analysis to address potential imbalance in patient characteristics between treated patients and controls and potential informative censoring in the analysis of CVD-free survival, we performed an inverse probability weighted approach as proposed and conducted by several other investigators. [30][31][32][33] A logistic regression model was used to predict treatment status with baseline characteristics that included race, age, alcohol, drug, sex, smoking, obesity, dyslipidemia, diabetes, hypertension, body mass index, and advanced chronic kidney disease. Then, a time-dependent Cox model was used to predict the probability of remaining uncensored over time given these baseline characteristics and time-dependent covariates: logarithm of HCV RNA and FIB-4 score.…”

Section: Additional and Sensitivity Analysesmentioning

confidence: 99%

Direct-Acting Antiviral Therapy for HCV Infection Is Associated With a Reduced Risk of Cardiovascular Disease Events

et al. 2019

View full text Add to dashboard Cite

is associated with an increased risk of cardiovascular disease (CVD) events. It is not clear whether treatment with directacting antiviral (DAA) agents affects risk of CVD. METHODS:We searched the Electronically Retrieved Cohort of HCV-Infected Veterans database for patients with chronic HCV infection (n ¼ 242,680) and identified patients who had been treated with a pegylated interferon and ribavirin regimen (n ¼ 4436) or a DAA-containing regimen (n ¼ 12,667). Treated patients were matched for age, race, sex, and baseline values with patients who had never received treatment for HCV infection (controls). All subjects were free of any CVD event diagnosis of HCV infection at baseline. The primary outcome was incident CVD events, identified by International Classification of Diseases, Ninth Edition, Clinical Modification or International Classification of Diseases, Tenth Edition code, in the different groups and in patients with vs without a sustained virologic response to therapy. RESULTS: There were 1239 (7.2%) incident CVD events in the treated groups and 2361 (13.8%) events in the control group. Incidence rates were 30.9 per 1000 patient-years (95% CI 29.6-32.1) in the control group and 20.3 per 1000 patientyears (95% CI 19.2-21.5) in the treated groups (P < .0001). Treatment with pegylated interferon and ribavirin (hazard ratio 0.78; 95% CI 0.71-0.85) or a DAA regimen (hazard ratio 0.57; 95% CI 0.51-0.65) was associated with a significantly lower risk of a CVD event compared with no treatment (controls). Incidence rates for CVD events were 23.5 per 1000 patient-years (95% CI 21.8-25.3) in the group treated with the pegylated interferon and ribavirin regimen, 16.3 per 1000 patient-years (95% CI 14.7-18.0) in the group treated with a DAA regimen, and 30.4 (95% CI 29.2-31.7) in the control group. A sustained virologic response was associated with a lower risk of incident CVD events (hazard ratio 0.87; 95% CI 0.77-0.98). CONCLUSIONS: In an analysis of a cohort of HCV-infected veterans, treatment of HCV infection was associated with a significant decrease in risk of CVD events. Patients treated with a DAA regimen and patients who achieved sustained virologic responses had the lowest risk for CVD events.

show abstract

“…Although the methods allow for treatment to be time varying, proportional hazards are assumed under the marginal structural model employed. Chen and Tsiatis [5], Schaubel and Wei [18], and Zhang and Schaubel [23] used restricted mean survival time as an effect measure, such that subgroup contrasts are cumulative in nature. However, contrasts between restricted mean lifetime do not describe how the essential effect changes over time.…”

Section: Discussionmentioning

confidence: 99%

“…In Sect. 6, we contrast the proposed methods with many existing methods which accommodate dependent censoring through IPCW, such as Robins et al [17]; Hernan et al [10,11]; Chen and Tsiatis [5]; Schaubel and Wei [18]; and Zhang and Schaubel [23]. …”

Section: Introductionmentioning

confidence: 99%

Semiparametric Contrasts of Cumulative Pre-Treatment Mortality in the Presence of Dependent Censoring

Gong

Schaubel

2014

Stat Biosci

Self Cite

View full text Add to dashboard Cite

In clinical settings, the necessity of treatment is often measured in terms of the patient’s prognosis in the absence of treatment. Along these lines, it is often of interest to compare subgroups of patients (e.g., based on underlying diagnosis) with respect to pre-treatment survival. Such comparisons may be complicated by at least two important issues. First, mortality contrasts by subgroup may differ over follow-up time, as opposed to being constant, and may follow a form that is difficult to model parametrically. Moreover, in settings where the proportional hazards assumption fails, investigators tend to be more interested in cumulative (as opposed to instantaneous) effects on mortality. Second, pre-treatment death is censored by the receipt of treatment and in settings where treatment assignment depends on time-dependent factors that also affect mortality, such censoring is likely to be informative. We propose semiparametric methods for contrasting subgroup-specific cumulative mortality in the presence of dependent censoring. The proposed estimators are based on the cumulative hazard function, with pre-treatment mortality assumed to follow a stratified Cox model. No functional form is assumed for the nature of the non-proportionality. Asymptotic properties of the proposed estimators are derived, and simulation studies show that the proposed methods are applicable to practical sample sizes. The methods are then applied to contrast pre-transplant mortality for acute versus chronic End-Stage Liver Disease patients.

show abstract

Double Inverse-Weighted Estimation of Cumulative Treatment Effects Under Nonproportional Hazards and Dependent Censoring

Cited by 45 publications

References 37 publications

Contrasting treatment‐specific survival using double‐robust estimators

Contrasting treatment‐specific survival using double‐robust estimators

Direct-Acting Antiviral Therapy for HCV Infection Is Associated With a Reduced Risk of Cardiovascular Disease Events

Semiparametric Contrasts of Cumulative Pre-Treatment Mortality in the Presence of Dependent Censoring

Contact Info

Product

Resources

About