π€ AI Summary
This paper addresses the challenge of nonparametric estimation of transition intensities in acyclic Markov multistate models under hybrid interval and right censoring. We propose a novel nonparametric estimation method based on the EM algorithm. Our approach achieves, for the first time, consistent nonparametric estimation of transition intensities without imposing structural assumptions (e.g., parametric forms or proportional hazards) in acyclic models. We rigorously establish convergence criteria for the EM algorithm and significantly reduce computational complexity through an efficient latent-variable construction. Simulation studies demonstrate that our estimator attains accuracy comparable to existing compatible estimators while achieving substantially faster computation. We apply the method to longitudinal data on childrenβs dental eruption, confirming its practical utility. An open-source software package implementing the method is publicly available, supporting flexible modeling and real-world deployment.
π Abstract
Interval-censored multi state data is collected when the state of a subject is observed periodically. The analysis of such data using non-parametric multi-state models was not possible until recently, but is very desirable as it allows for more flexibility than its parametric counterparts. The single available result to date has some unique drawbacks. We propose a non-parametric estimator of the transition intensities for interval-censored multi state data using an Expectation Maximisation algorithm. The method allows for a mix of interval-censored and right-censored (exactly observed) transitions. A condition to check for the convergence of the algorithm is given. A simulation study comparing the proposed estimator to a consistent estimator is performed, and shown to yield near identical estimates at smaller computational cost. A data set on the emergence of teeth in children is analysed. Software to perform the analyses is publicly available.