Inverse Probability Weighted Least Squares Regression in the Analysis of Time-Censored Cost Data: An Evaluation of the Approach Using SEER-Medicare

Griffiths, Robert I.; Gleeson, Michelle; Danese, Mark D.; O'Hagan, Anthony

doi:10.1016/j.jval.2012.03.1388

Cited by 20 publications

(20 citation statements)

References 15 publications

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“…Costs were estimated by multiplying the quantity of each resource used by the corresponding unit cost of the resource. Inverse probability weighting was used to account for censoring and death when estimating total costs 32,33 . The intervals used for the weighting were two 6-month time intervals for the first year and annual intervals for years 2 and 3.…”

Section: End-points and Analysesmentioning

confidence: 99%

Methods for estimating costs in patients with hyperlipidemia experiencing their first cardiovascular event in the United Kingdom

Danese¹,

Gleeson²,

Griffiths

et al. 2017

Journal of Medical Economics

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Aims: Methods for integrating external costs into clinical databases are not well-characterized. The purpose of this research was to describe and implement methods for estimating the cost of hospitalizations, prescriptions, and general practitioner and specialist visits used to manage hyperlipidemia patients experiencing cardiovascular (CV) events in the United Kingdom (UK). Methods: This study was a retrospective cohort study using the Clinical Practice Research Datalink and Hospital Episode Statistics data. Costs were incorporated based on reference costs from the National Health Service, and labor costs from the Personal Social Services Research Unit. The study population included patients seen by general practitioners in the UK from 2006-2012. Patients 18 years were selected at the time of their first CV-related hospitalization defined as myocardial infarction, ischemic stroke, heart failure, transient ischemic attack, unstable angina, or revascularization. To be included, patients must have received 2 lipid-lowering therapies. Outcome measures included healthcare utilization and direct medical costs for hospitalizations, medications, general practitioner visits, and specialist visits during the 6-month acute period, starting with the CV hospitalization, and during the subsequent 30-month long-term period. Results: There were 24,093 patients with a CV hospitalization included in the cohort. This study identified and costed 69,240 hospitalizations, 673,069 GP visits, 32,942 specialist visits, and 2,572,792 prescriptions, representing 855 unique drug and dose combinations. The mean acute period and mean annualized long-term period costs (2014£) were £4,060 and £1,433 for hospitalizations, £377 and £518 for GP visits, £59 and £103 for specialist visits, and £98 and £209 for medications. Conclusions: Hospital costs represent the largest portion of acute and long-term costs in this population. Detailed costing using utilization data is feasible and representative of UK clinical practice, but is labor intensive. The availability of a standardized coding system in the UK drug costing data would greatly facilitate drug costing. ARTICLE HISTORY

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Section: End-points and Analysesmentioning

confidence: 99%

Methods for estimating costs in patients with hyperlipidemia experiencing their first cardiovascular event in the United Kingdom

Danese¹,

Gleeson²,

Griffiths

et al. 2017

Journal of Medical Economics

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“…IPW was used to calculate mean costs (6), and IPW estimating equations were used to estimate the median, 25th percentile, and 75th percentile costs (7). To protect against potential differences in the censoring pattern between treatment groups, the probability weights were estimated separately for the two groups (8).…”

Section: Discussionmentioning

confidence: 99%

An Economic Analysis of Sublobar Resection versus Thermal Ablation for Early-Stage Non–Small-Cell Lung Cancer

Kwan

Mortell

Hippe

et al. 2014

Journal of Vascular and Interventional Radiology

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“…The propensity scores were used to create inverse probability weights (IPWs) for each individual in each year of inclusion in the data equal to 1/propensity score for those who were ever diagnosed with HCV, and 1/(1‐propensity score) for those who were not. The purpose of IPW weighting is to balance the sample on potentially confounding covariates before the estimation of coefficients . Each weight was then multiplied by the individual's Medicare weight to avoid confounding from over‐representation of SEER file individuals.…”

Section: Methodsmentioning

confidence: 99%

The burden of hepatitis C to the United States Medicare system in 2009: Descriptive and economic characteristics

et al. 2016

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The aim of this work was to estimate and describe the Medicare beneficiaries diagnosed with hepatitis C virus (HCV) in 2009, incremental annual costs by disease stage, incremental total Medicare HCV payments in 2009 using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data covering the years 2002 to 2009. We weighted the 2009 SEER-Medicare data to create estimates of the number of patients with an HCV diagnosis, used an inverse probability-weighted two-part, probit, and generalized linear model to estimate incremental per patient per month costs, and used simulation to estimate annual 2009 Medicare burden, presented in 2014 dollars. We summarized patient characteristics, diagnoses, and costs from SEER-Medicare files into a person-year panel data set. We estimated there were 407,786 patients with diagnosed HCV in 2009, of whom 61.4% had one or more comorbidities defined by the study. In 2009, 68% of patients were diagnosed with chronic HCV only, 9% with cirrhosis, 12% with decompensated cirrhosis (DCC), 2% with liver cancer, 2% with a history of transplant, and 8% who died. Annual costs for patients with chronic infection only and DCC were higher than the values used in many previous cost-effectiveness studies, and treatment of DCC accounted for 63.9% of total Medicare's HCV expenditures. Medicare paid $2.7 billion (credible interval: $0.7-$4.6 billion) in incremental costs for HCV in 2009. Conclusions: The costs of HCV to Medicare in 2009 were substantial and expected to increase over the next decade. Annual costs for patients with chronic infection only and DCC were higher than values used in many cost-effectiveness analyses. (HEPATOLOGY 2016;63:1135-1144 H epatitis C virus (HCV) is the most common blood-borne infection in the United States, with at least 2.7 million chronically infected Americans.(1) Current patients with HCV were primarily infected by behavioral and medical exposures between the 1960s and the early 1990s, and as a result, an estimated 70.1% of those HCV antibody positive were born during the years of 1945-1965. (2,3) In 2010, the first members of the 1945-1965 birth cohort became eligible for the U.S. Medicare program through the aged (age 65) eligibility pathway, and many more are likely to enter the program over the coming decades.To date, no paper has attempted to estimate either the per person costs or the aggregate health impact of HCV on the Medicare system, and the number of HCV patients seeking care in Medicare is unknown. This is an important knowledge gap because at least 1 million new chronically infected persons are likely to age into Medicare over the next 10-20 years. (3) Costs for HCV patients in Medicare may be different than in private insurance owing to their age, the high prevalence of other comorbidities, and differences in Medicare reimbursements compared to other payers. Finally, the need to offer treatment to patients before Medicare entry is in dispute. (4)

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Inverse Probability Weighted Least Squares Regression in the Analysis of Time-Censored Cost Data: An Evaluation of the Approach Using SEER-Medicare

Abstract: IPW is a consistent estimator of population mean costs if the weight is correctly specified. If the censoring distribution depends on some covariates, a model that accommodates this dependency must be correctly specified in IPW to obtain accurate estimates.

Cited by 20 publications

References 15 publications

Methods for estimating costs in patients with hyperlipidemia experiencing their first cardiovascular event in the United Kingdom

Methods for estimating costs in patients with hyperlipidemia experiencing their first cardiovascular event in the United Kingdom

An Economic Analysis of Sublobar Resection versus Thermal Ablation for Early-Stage Non–Small-Cell Lung Cancer

The burden of hepatitis C to the United States Medicare system in 2009: Descriptive and economic characteristics

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