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Isolation and Transplantation of Hematopoietic Stem Cells HSCs
Published on: February 25, 2007
SEMIPARAMETRIC REGRESSION MODEL FOR RECURRENT BACTERIAL INFECTIONS AFTER HEMATOPOIETIC STEM CELL TRANSPLANTATION
Chi Hyun Lee1, Chiung-Yu Huang2, Todd E DeFor3
1Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Abstract:
Patients who undergo hematopoietic stem cell transplantation (HSCT) often experience multiple bacterial infections during the early post-transplant period. In this article, we consider a semiparametric regression model that correlates patient- and transplant-related risk factors with inter-infection gap times. Existing regression methods for recurrent gap times are not directly applicable to study post-transplant infection because the initiating event (transplant) is different than the recurrent events of interest (post-transplant infections); as a result, the time from transplant to the first infection and the time elapsed between consecutive infections have distinct biological meanings and hence follow different distributions. Moreover, risk factors may have different effects on these two types of gap times. We propose a semiparametric estimation procedure to evaluate the covariate effects on time from transplant to thefirst infection and on gap times between consecutive infections simultaneously. The proposed estimator accounts for dependent censoring induced by within-subject correlation among recurrent gap times and length bias in the last censored gap time due to intercept sampling. We study the finite sample properties through simulations and present an application of the proposed method to the post-HSCT bacterial infection data collected at the University of Minnesota.
Insights
Hematopoietic stem cell transplantation (HSCT) patients face bacterial infections. A new statistical model analyzes risk factors for infection timing, improving understanding of post-transplant health outcomes.
Area of Science:
- Statistics
- Infectious Disease Epidemiology
- Hematology
Background:
- Hematopoietic stem cell transplantation (HSCT) patients are highly susceptible to recurrent bacterial infections post-procedure.
- Standard statistical models for recurrent events are inadequate for analyzing infection patterns after HSCT due to distinct event timings.
Purpose of the Study:
- To develop a novel semiparametric regression model to simultaneously analyze risk factors influencing the time to the first infection and subsequent infection intervals post-HSCT.
- To address statistical challenges including dependent censoring and length bias inherent in recurrent event data.
Main Methods:
- Proposed a semiparametric estimation procedure to model covariate effects on both time-to-first-event and recurrent event gap times.
- The method accounts for within-subject correlation and length-biased sampling in censored gap times.
- Validated the model's performance using simulation studies and applied it to real-world post-HSCT infection data.
Main Results:
- The developed statistical model effectively estimates the impact of patient- and transplant-related factors on infection occurrence.
- Demonstrated the model's ability to handle complex dependencies and biases in recurrent event data.
- Successfully applied the methodology to identify key risk factors for bacterial infections in HSCT recipients.
Conclusions:
- The proposed semiparametric model provides a robust framework for analyzing recurrent infection patterns in HSCT patients.
- This approach enhances the understanding of infection dynamics and aids in identifying high-risk individuals.
- The findings have implications for optimizing infection prevention and management strategies in HSCT care.
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