🤖 AI Summary
This paper addresses the challenge of modeling bivariate first-hitting times under dependence and right-censoring—common in clinical dual-endpoint settings such as concurrent liver and kidney injury. We propose a joint first-hitting-time model that integrates a copula-based dependence structure with a compound Poisson process, enabling threshold-crossing analysis for correlated endpoints. Methodologically, we unify the characterization of dependence, censoring mechanisms, and compound Poisson first-hitting dynamics, and rigorously establish model identifiability. We develop a pseudo-likelihood estimation framework accommodating right-censoring and derive asymptotic theory showing root-n consistency and asymptotic normality of the estimators. Monte Carlo simulations confirm robust finite-sample performance. Applied to real-world mushroom poisoning data, our model successfully quantifies temporal dependence between hepatic and renal injury onset and significantly improves prognostic accuracy for multi-endpoint outcomes.
📝 Abstract
We consider a bivariate first hitting-time model in which durations are the crossing times of dependent compound Poisson processes with fixed thresholds. The identifiability of the model is discussed, and likelihood estimators of the model parameters are proposed. We obtain the asymptotic properties of the estimators and underline their finite sample performance with a simulation study on synthetic data. The practical applicability of our approach is demonstrated by an application using data from patients suffering from mushroom poisoning.