Some new approaches for modeling the incubation period of HIV/AIDS epidemic

The time duration between HIV seroconversion to AIDS known as Incubation period is very long and highly variable across groups. Several models for incubation period distribution were studied by many author. In this paper we propose new approaches to model the distribution of the incubation period of HIV/AIDS epidemic using the stages of the disease, the threshold level and cumulative invasion of the immune system. But each model has its own limitations

Predicting hospital costs for patients receiving renal replacement therapy to inform an economic evaluation.

OBJECTIVE: To develop a model to predict annual hospital costs for patients with established renal failure, taking into account the effect of patient and treatment characteristics of potential relevance for conducting an economic evaluation, such as age, comorbidities and time on treatment. The analysis focuses on factors leading to variations in inpatient and outpatient costs and excludes fixed costs associated with dialysis, transplant surgery and high cost drugs. METHODS: Annual costs of inpatient and outpatient hospital episodes for patients starting renal replacement therapy in England were obtained from a large retrospective dataset. Multiple imputation was performed to estimate missing costs due to administrative censoring. Two-part models were developed using logistic regression to first predict the probability of incurring any hospital costs before fitting generalised linear models to estimate the level of cost in patients with positive costs. Separate models were developed to predict inpatient and outpatient costs for each treatment modality. RESULTS: Data on hospital costs were available for 15,869 incident dialysis patients and 4511 incident transplant patients. The two-part models showed a decreasing trend in costs with increasing number of years on treatment, with the exception of dialysis outpatient costs. Age did not have a consistent effect on hospital costs; however, comorbidities such as diabetes and peripheral vascular disease were strong predictors of higher hospital costs in all four models. CONCLUSION: Analysis of patient-level data can result in a deeper understanding of factors associated with variations in hospital costs and can improve the accuracy with which costs are estimated in the context of economic evaluations.<br/

The global impact of COVID-19 on solid organ transplantation: two years into a pandemic

The coronavirus disease 2019 (COVID-19) pandemic has had a major global impact on solid organ transplantation (SOT). An estimated 16% global reduction in transplant activity occurred over the course of 2020, most markedly impacting kidney transplant and living donor programs, resulting in substantial knock-on effects for waitlisted patients. The increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection risk and excess deaths in transplant candidates has resulted in substantial effort to prioritize the safe restart and continuation of transplant programs over the second year of the pandemic, with transplant rates returning towards prepandemic levels. Over the past 2 y, COVID-19 mortality in SOT recipients has fallen from 20%–25% to 8%–10%, attributed to the increased and early availability of SARS-CoV-2 testing, adherence to nonpharmaceutical interventions, development of novel treatments, and vaccination. Despite these positive steps, transplant programs and SOT recipients continue to face challenges. Vaccine efficacy in SOT recipients is substantially lower than the general population and SOT recipients remain at an increased risk of adverse outcomes if they develop COVID-19. SOT recipients and transplant teams need to remain vigilant and ongoing adherence to nonpharmaceutical interventions appears essential. In this review, we summarize the global impact of COVID-19 on transplant activity, donor evaluation, and patient outcomes over the past 2 y, discuss the current strategies aimed at preventing and treating SARS-CoV-2 infection in SOT recipients, and based on lessons learnt from this pandemic, propose steps the transplant community could consider as preparation for future pandemics

Variation between centres in access to renal transplantation in UK: longitudinal cohort study

Objective To assess whether equity exists in access to renal transplantation in the UK after adjustment for case mix in incident patients with end stage renal disease

Inequity in access to transplantation in the UK

Background and objectives Despite the presence of a universal health care system, it is unclear if there is intercenter variation in access to kidney transplantation in the United Kingdom. This study aims to assess whether equity exists in access to kidney transplantation in the United Kingdom after adjustment for patient-specific factors and center practice patterns. Design, setting, participants, & measurements In this prospective, observational cohort study including all 71 United Kingdom kidney centers, incident RRT patients recruited between November 2011 and March 2013 as part of the Access to Transplantation and Transplant Outcome Measures study were analyzed to assess preemptive listing (n=2676) and listing within 2 years of starting dialysis (n=1970) by center. Results Seven hundred and six participants (26%) were listed preemptively, whereas 585 (30%) were listed within 2 years of commencing dialysis. The interquartile range across centers was 6%–33% for preemptive listing and 25%–40% for listing after starting dialysis. Patient factors, including increasing age, most comorbidities, body mass index >35 kg/m2, and lower socioeconomic status, were associated with a lower likelihood of being listed and accounted for 89% and 97% of measured intercenter variation for preemptive listing and listing within 2 years of starting dialysis, respectively. Asian (odds ratio, 0.49; 95% confidence interval, 0.33 to 0.72) and Black (odds ratio, 0.43; 95% confidence interval, 0.26 to 0.71) participants were both associated with reduced access to preemptive listing; however Asian participants were associated with a higher likelihood of being listed after starting dialysis (odds ratio, 1.42; 95% confidence interval, 1.12 to 1.79). As for center factors, being registered at a transplanting center (odds ratio, 3.1; 95% confidence interval, 2.36 to 4.07) and a universal approach to discussing transplantation (odds ratio, 1.4; 95% confidence interval, 1.08 to 1.78) were associated with higher preemptive listing, whereas using a written protocol was associated negatively with listing within 2 years of starting dialysis (odds ratio, 0.7; 95% confidence interval, 0.58 to 0.9). Conclusions Patient case mix accounts for most of the intercenter variation seen in access to transplantation in the United Kingdom, with practice patterns also contributing some variation. Socioeconomic inequity exists despite having a universal health care system

Understanding cost of care for patients on renal replacement therapy: looking beyond fixed tariffs.

BACKGROUND: In a number of countries, reimbursement to hospitals providing renal dialysis services is set according to a fixed tariff. While the cost of maintenance dialysis and transplant surgery are amenable to a system of fixed tariffs, patients with established renal failure commonly present with comorbid conditions that can lead to variations in the need for hospitalization beyond the provision of renal replacement therapy. METHODS: Patient-level cost data for incident renal replacement therapy patients in England were obtained as a result of linkage of the Hospital Episodes Statistics dataset to UK Renal Registry data. Regression models were developed to explore variations in hospital costs in relation to treatment modality, number of years on treatment and factors such as age and comorbidities. The final models were then used to predict annual costs for patients with different sets of characteristics. RESULTS: Excluding the cost of renal replacement therapy itself, inpatient costs generally decreased with number of years on treatment for haemodialysis and transplant patients, whereas costs for patients receiving peritoneal dialysis remained constant. Diabetes was associated with higher mean annual costs for all patients irrespective of treatment modality and hospital setting. Age did not have a consistent effect on costs. CONCLUSIONS: Combining predicted hospital costs with the fixed costs of renal replacement therapy showed that the total cost differential for a patient continuing on dialysis rather than receiving a transplant is considerable following the first year of renal replacement therapy, thus reinforcing the longer-term economic advantage of transplantation over dialysis for the health service.<br/

Estimating Health-State Utility Values in Kidney Transplant Recipients and Waiting-List Patients Using the EQ-5D-5L.

OBJECTIVES: To report health-state utility values measured using the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) in a large sample of patients with end-stage renal disease and to explore how these values vary in relation to patient characteristics and treatment factors. METHODS: As part of the prospective observational study entitled "Access to Transplantation and Transplant Outcome Measures," we captured information on patient characteristics and treatment factors in a cohort of incident kidney transplant recipients and a cohort of prevalent patients on the transplant waiting list in the United Kingdom. We assessed patients' health status using the EQ-5D-5L and conducted multivariable regression analyses of index scores. RESULTS: EQ-5D-5L responses were available for 512 transplant recipients and 1704 waiting-list patients. Mean index scores were higher in transplant recipients at 6 months after transplant surgery (0.83) compared with patients on the waiting list (0.77). In combined regression analyses, a primary renal diagnosis of diabetes was associated with the largest decrement in utility scores. When separate regression models were fitted to each cohort, female gender and Asian ethnicity were associated with lower utility scores among waiting-list patients but not among transplant recipients. Among waiting-list patients, longer time spent on dialysis was also associated with poorer utility scores. When comorbidities were included, the presence of mental illness resulted in a utility decrement of 0.12 in both cohorts. CONCLUSIONS: This study provides new insights into variations in health-state utility values from a single source that can be used to inform cost-effectiveness evaluations in patients with end-stage renal disease

Assessing Consensus Between UK Renal Clinicians on Listing for Kidney Transplantation: A Modified Delphi Study.

BACKGROUND: It is well recognized that there is significant variation between centers in access to kidney transplantation. In the absence of high-grade evidence, it is unclear whether variation is due to patient case mix, other center factors, or individual clinician decisions. This study sought consensus between UK clinicians on factors that should influence access to kidney transplantation. METHODS: As part of the Access to Transplantation and Transplant Outcome Measures project, consultant nephrologists and transplant surgeons in 71 centers were invited to participate in a Delphi study involving 2 rounds. During rounds 1 and 2, participants rated their agreement to 29 statements covering 8 topics regarding kidney transplantation. A stakeholder meeting was used to discuss statements of interest after the 2 rounds. RESULTS: In total, 122 nephrologists and 16 transplant surgeons from 45 units participated in rounds 1 and 2. After 2 rounds, 12 of 29 statements reached consensus. Fifty people participated in the stakeholder meeting. After the stakeholder meeting, a further 4 statements reached agreement. Of the 8 topics covered, consensus was reached in 6: use of a transplant protocol, patient age, body mass index, patient compliance with treatment, cardiac workup, and use of multidisciplinary meetings. Consensus was not reached on screening for malignancy and use of peripheral Doppler studies. CONCLUSIONS: The Delphi process identified factors upon which clinicians agreed and areas where consensus could not be achieved. The findings should inform national guidelines to support decision making in the absence of high quality evidence and to guide areas that warrant future research

Kidney Transplantation From Deceased Donors With Vaccine-induced Immune Thrombocytopenia and Thrombosis: An Updated Analysis of the UK Experience

Background: The emergence and attendant mortality of vaccine-induced immune thrombocytopenia and thrombosis (VITT) as a consequence of vaccination against severe acute respiratory syndrome coronavirus 2 have resulted in some patients with VITT being considered as deceased organ donors. Outcomes after kidney transplantation in this context are poorly described. Because the disease seems to be mediated by antiplatelet factor 4 antibodies, there is a theoretical risk of transmission via passenger leukocytes within the allograft. Methods: We analyzed the experience of kidney transplantation from donors with VITT in the United Kingdom between January and June 2021. We followed-up all recipients of kidney-only transplants from donors with VITT to detect major postoperative complications or features of disease transmission and assess graft survival and function. Results: There were 16 kidney donors and 30 single kidney transplant recipients in our study period. Of 11 preimplantation biopsies, 4 showed widespread glomerular microthrombi. After a median of 5 mo, patient and graft survival were 97% and 90%, respectively. The median 3-mo estimated glomerular filtration rate was 51 mL/min/1.73 m2. Two recipients had detectable antiplatelet factor 4 antibodies but no evidence of clinical disease after transplantation. Major hemorrhagic complications occurred in 3 recipients, all of whom had independent risk factors for bleeding, resulting in the loss of 2 grafts. The involvement of VITT could not be completely excluded in one of these cases. Conclusions: The UK experience to date shows that favorable outcomes are possible after kidney transplantation from donors with VITT but highlights the need for ongoing vigilance for donor-related complications in these patients