Landmark analysis: A primer

Morgan, Charity

doi:10.1007/s12350-019-01624-z

Cited by 124 publications

(82 citation statements)

References 7 publications

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“…There is inherent uncertainty in extrapolating long-term OS based on OS data available from trials. Different distributional assumptions were therefore tested in scenario analyses that applied the shorter-tailed exponential curve to conservatively model OS under pembrolizumab/axitinib, or used landmark response survival models 26 of OS. Across these scenarios, ICERs of pembrolizumab/axitinib versus comparators remained below $180,000/QALY.…”

Section: Discussionmentioning

confidence: 99%

“…Log-logistic OS was used for pembrolizumab/axitinib to reflect a long-term survival benefit with a plateau based on clinical experts' expectation and OS evidence for immune checkpoint inhibitors 25 . Scenario analyses were conducted using alternative distributions, or a landmark response survival analysis 26 that modeled OS separately for patients with and without disease progression by week 13. Details are provided in the Supplemental Methods and Supplemental Figures S1-S4.…”

Section: Effectivenessmentioning

confidence: 99%

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Cost-effectiveness of pembrolizumab with axitinib as first-line treatment for advanced renal cell carcinoma

Bensimon

Zhong

Swami

et al. 2020

Current Medical Research and Opinion

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Objective: Pembrolizumab/axitinib significantly prolonged overall survival (OS) and progression-free survival (PFS), and increased objective response rate versus sunitinib in the phase III trial KEYNOTE-426 among previously untreated patients with advanced renal cell carcinoma (RCC). This study assessed the cost-effectiveness of pembrolizumab/axitinib versus other first-line treatments of advanced RCC from a US public healthcare payer perspective. Methods: A partitioned survival model with three states (progression-free, progressed, death) evaluated lifetime costs and quality-adjusted life-years (QALYs) for pembrolizumab/axitinib and other firstline regimens: sunitinib, pazopanib and avelumab/axitinib in the overall population; and sunitinib, cabozantinib and nivolumab/ipilimumab in the subgroup with intermediate/poor prognostic risk. Costs of treatments, adverse events and medical resources were estimated. OS, PFS and treatment duration were extrapolated using parametric models fitted to KEYNOTE-426 data and hazard ratios from network meta-analyses. Utilities were derived through mixed-effects regressions of KEYNOTE-426 EuroQol-5 Dimensions-3 Levels data.

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Section: Discussionmentioning

confidence: 99%

Section: Effectivenessmentioning

confidence: 99%

Cost-effectiveness of pembrolizumab with axitinib as first-line treatment for advanced renal cell carcinoma

Bensimon

Zhong

Swami

et al. 2020

Current Medical Research and Opinion

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“…We then select for patients with at least one note before the specified time. We also perform landmark analysis to avoid immortal-time bias [43] and select only patients who survived at least 6 months past their date of diagnosis. Landmark analysis refers to the practice of designating a time point during the follow-up period and analyzing only patients who have survived until the landmark time [43].…”

Section: Methodsmentioning

confidence: 99%

“…We also perform landmark analysis to avoid immortal-time bias [43] and select only patients who survived at least 6 months past their date of diagnosis. Landmark analysis refers to the practice of designating a time point during the follow-up period and analyzing only patients who have survived until the landmark time [43]. To ensure the proportional hazard condition, patients who are still living are censored at time of last follow-up [44].…”

Section: Methodsmentioning

confidence: 99%

Uncovering interpretable potential confounders in electronic medical records

Zeng

et al. 2021

Preprint

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In medicine, randomized clinical trials (RCT) are the gold standard for informing treatment decisions. Observational comparative effectiveness research (CER) is often plagued by selection bias, and expert-selected covariates may not be sufficient to adjust for confounding. We explore how the unstructured clinical text in electronic medical records (EMR) can be used to reduce selection bias and improve medical practice. We develop a method based on natural language processing to uncover interpretable potential confounders from the clinical text. We validate our method by comparing the hazard ratio (HR) from survival analysis with and without the confounders against the results from established RCTs. We apply our method to four study cohorts built from localized prostate and lung cancer datasets from the Stanford Cancer Institute Research Database and show that our method adjusts the HR estimate towards the RCT results. We further confirm that the uncovered terms can be interpreted by an oncologist as potential confounders. This research helps enable more credible causal inference using data from EMRs, offers a transparent way to improve the design of observational CER, and could inform high-stake medical decisions. Our method can also be applied to studies within and beyond medicine to extract important information from observational data to support decisions.

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“…Patients can receive RRT at any time during their ICU stay, and RRT patients are guaranteed to survive at least until the time of RRT; this is known as the guarantee-time bias or the immortal time bias. 13 Landmark analysis is used extensively in medical research to correct for this type of bias inherent in an analysis of time-to-event outcome between groups (in this study, RRT and no RRT) that were determined during study follow-up. 14…”

Section: Landmark Survival Analysismentioning

confidence: 99%

Renal Replacement Therapy in Patients With Stage IV Cancer Admitted to the Intensive Care Unit With Acute Kidney Injury at a Comprehensive Cancer Center Was Not Associated With Survival

Abudayyeh

Song

Abdelrahim

et al. 2020

Am J Hosp Palliat Care

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Introduction: In patients with advanced cancer, prolongation of life with treatment often incurs substantial emotional and financial expense. Among hospitalized patients with cancer since acute kidney injury (AKI) is known to be associated with much higher odds for hospital mortality, we investigated whether renal replacement therapy (RRT) use in the intensive care unit (ICU) was a significant independent predictor of worse outcomes. Methods: We retrospectively reviewed patients admitted in 2005 to 2014 who were diagnosed with stage IV solid tumors, had AKI, and a nephrology consult. The main outcomes were survival times from the landmark time points, inpatient mortality, and longer term survival after hospital discharge. Logistic regression and Cox proportional regression were used to compare inpatient mortality and longer term survival between RRT and non-RRT groups. Propensity score-matched landmark survival analyses were performed with 2 landmark time points chosen at day 2 and at day 7 from ICU admission. Results: Of the 465 patients with stage IV cancer admitted to the ICU with AKI, 176 needed RRT. In the multivariate logistic regression model after adjusting for baseline serum albumin and baseline maximum Sequential Organ Failure Assessment (SOFA), the patients who received RRT were not significantly different from non-RRT patients in inpatient mortality (odds ratio: 1.004 [95% confidence interval: 0.598-1.684], P = .9892). In total, 189 patients were evaluated for the impact of RRT on long-term survival and concluded that RRT was not significantly associated with long-term survival after discharge for patients who discharged alive. Landmark analyses at day 2 and day 7 confirmed the same findings. Conclusions: Our study found that receiving RRT in the ICU was not significantly associated with inpatient mortality, survival times from the landmark time points, and long-term survival after discharge for patients with stage IV cancer with AKI.

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Landmark analysis: A primer

Cited by 124 publications

References 7 publications

Cost-effectiveness of pembrolizumab with axitinib as first-line treatment for advanced renal cell carcinoma

Cost-effectiveness of pembrolizumab with axitinib as first-line treatment for advanced renal cell carcinoma

Uncovering interpretable potential confounders in electronic medical records

Renal Replacement Therapy in Patients With Stage IV Cancer Admitted to the Intensive Care Unit With Acute Kidney Injury at a Comprehensive Cancer Center Was Not Associated With Survival

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