We consider prediction of graft survival when a kidney from a deceased donor is transplanted into a recipient, with a focus on the variation of survival with degree of human leukocyte antigen (HLA) mismatch. Previous studies have used data from the Scientific Registry of Transplant Recipients (SRTR) to predict survival conditional on partial characterization of HLA mismatch. Whereas earlier studies assumed proportional hazards models, we used nonparametric regression methods. These do not make the unrealistic assumption that relative risks are invariant as a function of time since transplant, and hence should be more accurate. To refine the predictions possible with partial knowledge of HLA mismatch, it has been suggested that HaploStats statistics on the frequencies of haplotypes within specified ethnic/national populations be used to impute complete HLA types. We counsel against this, showing that it cannot improve predictions on average and sometimes yields suboptimal transplant decisions. We show that the HaploStats frequency statistics are nevertheless useful when combined appropriately with the SRTR data. Analysis of the ecological inference problem shows that informative bounds on graft survival probabilities conditional on refined HLA typing are achievable by combining SRTR and HaploStats data with immunological knowledge of the relative effects of mismatch at different HLA loci.
The widespread electronic transmission of pornography allows for a variety of new data sources to objectively measure pornography use. Recent studies have begun to use these data to rank order US states by per capita online pornography use and to identify the determinants of pornography use at the state level. The aim of this paper is to compare two previous methodologies for evaluating pornography use by state, as well as to measure online pornography use using multiple data sources. We find that state-level rankings from Pornhub.com, Google Trends, and the New Family Structures Survey are significantly correlated with each other. In contrast, we find that rankings based on data from a single large paid subscription pornography website has no significant correlation with rankings based on the other three data sources. Since so much of online pornography is accessed for free, research based solely on paid subscription data may yield misleading conclusions.
Background In single-center studies, HLA-DQ mismatches stimulate the most pathogenic donor-specific antibodies. However, because of limitations of transplant registries, this cannot be directly confirmed with registry-based analyses.
Methods We evaluated patients in the Scientific Registry of Transplant Recipients who were relisted after renal graft failure with new, unacceptable antigens corresponding to the HLA typing of their previous donor (UA-PD) as a proxy for donor-specific antibodies. Linear regression was applied to estimate the effects of HLA mismatches on UA-PD and of UA-PD on calculated panel reactive antibody (cPRA) values for 4867 kidney recipients from 2010 to 2021.
Results Each additional HLA-DQ mismatch increased the probability of UA-PD by 25.2% among deceased donor transplant recipients and by 28.9% among living donor transplant recipients, significantly more than all other HLA loci (p<0.05). HLA-DQ UA-PD increased cPRA by 29.0% in living donor transplant recipients and by 23.5% in deceased donor transplant recipients—significantly more than all loci except for HLA-A in deceased donor transplant recipients (23.1%). African American deceased donor transplant recipients were significantly more likely than Hispanic and White recipients to develop HLA-DQ UA-PD; among living donor transplant recipients, African American or Hispanic recipients were significantly more likely to do so compared with White recipients. Models evaluating interactions between HLADR/DQ mismatches revealed largely independent effects of HLA-DQ mismatches on HLA-DQ UA-PD.
Conclusions HLA-DQ mismatches had the strongest associations with UA-PD, an effect that was greatest in African American and Hispanic recipients. Increases in cPRA with HLA-DQ UA-PD were equivalent to or larger than any other HLA locus, suggesting that considering the effects of HLA-DQ in kidney allocation may be needed.
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