Nelson Aalen Research Articles

Risk factors for suicide in patients with pancreatic ductal adenocarcinoma: A population‐based study

AbstractBackgroundPatients diagnosed with pancreatic ductal adenocarcinoma (PDAC) face a notable risk of suicide. However, comprehensive population‐based studies on suicide risk in PDAC patients have been lacking. This study seeks to explore the suicide risk in PDAC patients and identify the specific risk factors associated with suicide‐related mortality.MethodsA cohort of 101,382 PDAC patients was extracted from the Surveillance, Epidemiology, and End Results database, spanning from January 1, 2000, to December 31, 2017. The study employed the standardized mortality ratio (SMR) to assess the relative risk of suicide in PDAC patients compared to the general US population. The Nelson–Aalen estimator and the Fine and Grey method were utilized to pinpoint the risk factors linked to suicide‐specific mortality.ResultsPDAC patients exhibited a 3.51‐fold higher risk of suicide compared to the general US population. This risk demonstrated an upward trend over the years. Notably, individuals aged 70–74 years faced a significantly elevated risk of suicide (SMR = 5.14, 95% CI: 3.10–8.03). Furthermore, there were distinct peaks in suicide risk at 1–4‐ and 25–28‐month post‐diagnoses (SMR = 15.04 and 2.72, respectively). Factors, such as gender, chemotherapy status, and marital status, emerged as significant independent predictors of suicide‐specific mortality in PDAC patients.ConclusionsThis study highlights a heightened suicide risk among PDAC patients in comparison to the general US population. It underscores the crucial need for continuous monitoring of the psychological well‐being of all PDAC patients. Additionally, considering the elevated risk, the application of antidepressant therapy could be beneficial for those identified as having a higher risk of suicide.

KAPLAN-MEIER AND NELSON-AALEN ESTIMATORS FOR CREDIT SCORING

Financial institutions use credit scoring analysis to predict the probability that a customer will default. In this paper, we determine the probability of default using nonparametric survival analysis that are Kaplan-Meier and Nelson-Aalen. The analysis is based on survival function curves, cumulative hazard function curves, mean survival time, and standard error of estimators. Based on the curves of survival function for both Kaplan Meier and Nelson Aalen estimators relatively the same. Based on the curves of cumulative hazard function, mean survival time, and standard error the Nelson-Aalen estimators are slightly higher than Kaplan-Meier.

Comparison of 5- and 10-year breast cancer risk predictions.

10529 Background: Breast cancer risk assessment is valuable in personalizing risk-reduction and screening approaches for the general population. Maximizing the benefits while reducing the harms associated with current breast cancer screening and risk-reduction recommendations should increase the efficacy of these paradigms. Because healthcare providers have limited time with their patients, we developed a risk prediction model, BRISK, which uses the most important clinical risk factors for breast cancer (in an easily collected format), polygenic risk and mammographic density. We previously validated BRISK 5-year risk predictions and found that it performed better than IBISv7 and BCRAT. Methods: The dataset comprised 241,633 women (mean age at baseline assessment = 56.6 years). We included all races/ethnicities available in the UK Biobank. There were 3726 women affected during the first five years of follow-up and 7482 women affected during the full 10 years of follow-up. We compared the performance of the 5-year and 10-year risk predictions by assessing the association with breast cancer using Cox regression to estimate the hazard ratio (HR) per SD of risk, discrimination using calculating Harrell’s C-index and calibration using logistic regression to estimate the slope and the intercept of the logit of the risk predictions. Nelson–Aalen estimates of the hazard function by quintiles of risk and standardized incidence ratios (SIRs) of the number of breast cancer cases expected were used to illustrate performance. Results: The predictive performance of BRISK was consistent for 5-year and 10-year risk predictions. Discrimination was similar, with a Harrell’s C-index of 0.645 (95% CI = 0.636, 0.654) for the 5-year risk and of 0.638 (95% CI = 0.632, 0.645) for the 10-year risk. We used Nelson_Aalen cumulative hazard estimates to compare breast cancer incidence by risk quintile for both 5 and 10-year risk. Both risk scores overestimated risk in the top two deciles with the 5-year expected risks of 2.8% and 5.0% corresponding to observed risks of 2.3% and 3.3%. The 10-year expected risks for the top two deciles were 5.6% and 9.8% while the corresponding observed risks were 4.6% and 6.4%. Finally, we used clinically actionable thresholds to show the standard incidence ratios (SIR) of 1.77 (95% CI = 1.69, 1.85) for women ≥3% 5-year risk and 2.05 (95% CI = 1.93, 2.18) ≥8% 10-year risk. Conclusions: The BRISK 5-year and 10-year risk prediction perform equally well. There is an overestimation of risk for the top decile in both models. This is important to consider in risk-management conversations between clinician and patient. While the observed risk of the top decile remained above the 3% 5-year risk threshold used in the United States, the top decile observed risk dropped below the 8% 10-year risk threshold used in the United Kingdom. Risk scores are not used in isolation, but it may be preferable to err on the side of overestimation rather than underestimation.

Estimation of median survival time and its 95% confidence interval using SAS PROC LIFETEST

ABSTRACT Estimation of median survival and its 95% confidence interval depends on the choice of the survival function, standard error, and a method for constructing the confidence interval. This paper outlines several available possibilities in SAS® (version 9.4) PROC LIFETEST and compares them on theoretical grounds and using simulated data, with criteria: ability to estimate the 95% CI, coverage probability, interval width, and appropriateness for practical use. Data are generated with varying hazard patterns, N, % censoring, and censoring patterns (early, uniform, late, last visit). LIFETEST was run using the Kaplan–Meier and Nelson–Aalen estimators and the transformations available (linear, log, logit, complementary log–log, and arcsine square root). Using the Kaplan–Meier estimator with the logarithmic transformation as well as with the logit leads to a high frequency of LIFETEST not being able to estimate the 95% CI. The combination of Kaplan–Meier with the linear transformation is associated with poor coverage achieved. For small samples, late/last visit censoring has a negative effect on being able to estimate the 95% CI. Heavy early censoring can lead to low coverage of the 95% CI of median survival for sample sizes up to and including N = 40. The two combinations that are optimal for being able to estimate the 95% CI and having adequate coverage are the Kaplan–Meier estimator with complementary log–log transformation, and the Nelson–Aalen estimator with linear transformation. The former fares best on the third criterion (smaller width) and is also the SAS® default and validates the choice of default.

82. Incidence rates of invasive aspergillosis among lung transplant recipients in timeperiods with universal and targeted antifungal prophylaxis - a nationwide cohort study

Abstract Background The best stategy for prevention of invasive aspergillosis (IA) after lung transplantation (LTX) has not been determined. In 2016, Danish guidelines for IA prophylaxis was changed from 12 weeks of universal prophylaxis with voriconazole to targeted prophylaxis with posaconazole and inhaled amphotericin B for high risk patients. In a previous study we found significantly higher rates of adverse events in the period with universal prophylaxis. The objectives of this study were to compare rates of IA 1) in time periods before and after change of guidelines; 2) during persontime on vs. persontime without antifungal prophylaxis in the total study period. Methods In a Danish nationwide study we included all adult lung transplant recipients (LTXr), 2010–2019. Proven and probable IA were defined using ISHLT criteria. Patients were censored at the first of following events: death, retransplantation, end of 2019, or one year after LTX. The cumulative hazard of IA was calculated using the Nelson Aalen estimator. Rates of IA were analyzed in bi- and multivariate Poisson regression models adjusted for the time period after LTX (0–6 and 6–12 months). Persontime on protocol prophylaxis (start to end + 14 days) was treated as time-updated variable. Results A total of 295 LTXr were followed for 245 person-years, of whom 183/193 vs. 6/102 initiated antifungal prophylaxis during the universal vs. the targeted prophylaxis period (Table 1). IA was diagnosed in 34/193 (17.6%) vs. 15/102 (14.7%) LTXr the first year after transplantation in the universal vs. targeted prophylaxis period. Overall, similar cumulative hazards of IA were observed between the universal and targeted prophylaxis period (p=0.59, Figure 1). The adjusted incidence rate ratio (aIRR) of IA during the universal vs. targeted prophylaxis period was 1.30 (95% CI 0.69–2.44), (Table 2). In the total study period, the aIRR of IA during persontime on vs. persontime without antifungal prophylaxis was 0.87 (95% CI 0.40–1.88), (Table 2). Characteristics of lung transplant recipients in time periods with universal voriconazole and targeted posaconazole and inhaled amphotericin B prophylaxis. Proven and probable invasive aspergillosis including anastomosis infection, trakeobronkitis and pneumonia according to ISHLT criteria. *) Underlying diseases categorized as high risk of invasive aspergillosis. Incidence rates (IR) and incidence rate ratios (IRR) of invasive aspergillosis in lung transplant recipients in two multivariate models. Poisson regression models comparing rates of IA in model 1) during universal prophylaxis time period versus targeted prophylaxis time period and in model 2) during persontime on prophylaxis (start to end + 14 days) versus persontime without prophylaxis in the total study period 2010–2019. Adjusted for time after LTX IRR: Bivariable model including the listed variables in bold and adjustment for time after transplantation (time-updated). Fully adjusted IRR: Multivariable model with adjustment for sex, age, high risk underlying disease, single/double lung transplant, Aspergillus prior to transplantation and time after transplantation (time-updated). Abbreviations: LTX = lung transplant recipients; CI = confidence interval; IR = incidence rates per 100 person-years; IRR = incidence rate ratio; Ref. = reference. Cumulative hazards of invasive aspergillosis the first year after lung transplantation in time periods with universal voriconazole versus targeted posaconazole and inhaled amphotericin B prophylaxis. Conclusion A strategy of targeted prophylaxis, for high risk patients only, may be preferred over universal voriconazole prophylaxis after LTX due to similar rates of IA and lower rates of adverse events. Disclosures Maiken C. Arendrup, DMSci, PhD, MD, Chiesi, Gilead: Honoraria|F2G, Cidara, Scynexis: Grant/Research Support Michael Perch, MD, Boeringer-Ingelheim: Travel grant|PulmonX: Expert Testimony|Roche: Grant/Research Support|Takeda: Expert Testimony|Therakos: Honoraria|Zambon: Advisor/Consultant|Zambon: Expert Testimony Marie Helleberg, PhD, DMSc, AstraZeneca: Advisor/Consultant|Gilead: Advisor/Consultant|Gilead: Honoraria|GSK: Advisor/Consultant|GSK: Honoraria|Janssen: Advisor/Consultant|Roche: Advisor/Consultant|Sobi: Advisor/Consultant.

Incidence and Clinical Description of Lymphomas in Children and Adolescents with Vertical Transmission of HIV in Rio de Janeiro, Brazil, in Pre- and Post-Combined Antiretroviral Therapy Eras: A Multicentric Hospital-Based Survival Analysis Study.

The incidence of cancer in children living with HIV (CLWH) is high and lymphomas are the most common type of cancer in this population. The combined antiretroviral therapy (cART) changed the natural history of HIV infection. To determine the incidence and profile of these CLWH malignancies in Rio de Janeiro (RJ), Brazil, we conducted a retrospective and observational study of vertically infected CLWH, ranging from 0-20 incomplete years, from 1995 to 2018, at five reference centers. The study period was divided into three eras in accordance with the widespread use of cART in Brazil. 1306 patients were included. Of the 25 lymphomas found, 19 were AIDS-defining malignancies (ADM); 6 were non-AIDS-defining malignancies (NADM). The incidence rate (IR) of lymphoma developing was 1.70 per 1000 children-year (95% CI 1.09-2.50). ADM development IR decreased from 2.09-1.75-0.19 per 1000 children-year (p < 0.001) through cART eras. Cumulative Nelson-Aalen hazards of developing ADM over a 20-year period were 3.73% in the Early-cART era, 3.07% in the Mid-cART era, and 0.32% in the Late-cART era (p = 0.013). This study demonstrates the IR of lymphoma in CLWH in RJ, Brazil, as well as the benefit of cART in reducing ADM and death occurrence in the Post-cART era.

Under age five children survival times in Nigeria: a Bayesian spatial modeling approach

BackgroundNigeria is among the top five countries in the world with the highest under-five mortality rates. In addition to the general leading causes of under-five mortality, studies have shown that disparity in sociocultural values and practices across ethnic groups in Nigeria influence child survival, thus there is a need for scientific validation. This study quantified the survival probabilities and the impact of socioeconomic and demographic factors, proximate and biological determinants, and environmental factors on the risk of under-five mortality in Nigeria.MethodsThe Kaplan-Meier survival curve, Nelson Aalen hazard curve, and components survival probabilities were estimated. The Exponential, Gamma, Log-normal, Weibull, and Cox hazard models in a Bayesian mixed effect hierarchical hazard modeling framework with spatial components were considered, and the Deviance and Watanabe Akaike information criteria were used to select the best model for inference. A 5% level of significance was assumed throughout this work. The 2018 Nigeria Demographic and Health Survey dataset was used, and the outcome variable was the time between birth and death or birth and the date of interview for children who were alive on the day of the interview.ResultsFindings show that the probability of a child dying within the first two months is 0.04, and the probability of a boy child dying before attaining age five is 0.106, while a girl child is 0.094 probability. Gender, maternal education, household wealth status, source of water and toilet facility, residence, mass media, frequency of antenatal and postnatal visits, marital status, place of delivery, multiple births, who decide healthcare use, use of bednet are significant risk factors of child mortality in Nigeria. The mortality risk is high among the maternal age group below 24 and above 44years, and birth weight below 2.5Kg and above 4.5Kg. The under-five mortality risk is severe in Kebbi, Kaduna, Jigawa, Adamawa, Gombe, Kano, Kogi, Nasarawa, Plateau, and Sokoto states in Nigeria.ConclusionThis study accentuates the need for special attention for the first two months after childbirth as it is the age group with the highest expected mortality. A practicable way to minimize death in the early life of children is to improve maternal healthcare service, promote maternal education, encourage delivery in healthcare facilities, positive parental attitude to support multiple births, poverty alleviation programs for the less privileged, and a prioritized intervention to Northern Nigeria.

Impact of Asymptomatic Superior Mesenteric Vein Thrombosis on the Outcomes of Patients with Liver Cirrhosis.

The impact of asymptomatic superior mesenteric vein (SMV) thrombosis on the outcomes of cirrhotic patients remains uncertain. Nonmalignant cirrhotic patients who were consecutively admitted between December 2014 and September 2021 and underwent contrast-enhanced computed tomography/magnetic resonance imaging scans were screened. Portal venous system thrombosis (PVST) was identified. Death and hepatic decompensation were the outcomes of interest. Nelson-Aalen cumulative risk curve analysis and competing risk regression analysis were performed to evaluate the impact of asymptomatic SMV thrombosis and portal vein thrombosis (PVT) on the outcomes. Overall, 475 patients were included, of whom 67 (14.1%) had asymptomatic SMV thrombosis, 95 (20%) had PVT, and 344 (72.4%) did not have any PVST. Nelson-Aalen cumulative risk curve analyses showed that the cumulative incidences of death (p = 0.653) and hepatic decompensation (p = 0.630) were not significantly different between patients with asymptomatic SMV thrombosis and those without PVST, but the cumulative incidences of death (p = 0.021) and hepatic decompensation (p = 0.004) were significantly higher in patients with PVT than those without PVST. Competing risk regression analyses demonstrated that asymptomatic SMV thrombosis was not a significant risk factor for death (subdistribution hazard ratio [sHR] = 0.89, p = 0.65) or hepatic decompensation (sHR = 1.09, p = 0.63), but PVT was a significant risk factor for death (sHR = 1.56, p = 0.02) and hepatic decompensation (sHR = 1.50, p = 0.006). These statistical results remained in competing risk regression analyses after adjusting for age, sex, and Child-Pugh score. Asymptomatic SMV thrombosis may not influence the outcomes of cirrhotic patients. The timing of intervention for asymptomatic SMV thrombosis in liver cirrhosis should be further explored.

Cardiovascular Mortality Risk in Patients with Bladder Cancer: A Population-Based Study.

Background: The purpose of this study was to evaluate the risk of cardiovascular mortality (CVM) among patients with bladder cancer (BC). Methods and Materials: Data were collected from the Surveillance, Epidemiology, and End Results (SEER) database for patients who were diagnosed with BC by pathology between 2000 and 2016. The standardized mortality rate (SMR) was calculated based on reference data from the general population. Nelson–Aalen cumulative hazard curves were used to assess the risk of experiencing CVM in BC patients. Multivariate competing risk models were performed. Results: In total, data from 237,563 BC patients were obtained from the SEER database for further analysis, of which 21,822 patients experienced CVM; the overall SMR for CVM in BC patients was 1.16 (95% CI: 1.14–1.17). Age, race, sex, year of diagnosis, histologic type, summary stage, surgery, marital status, and college education level were independent predictors of CVM in patients with BC. Conclusions: Patients with BC have a significantly increased risk of experiencing CVM compared to the general population. Pre-identification of high-risk groups and cardiovascular protection interventions are important measures to effectively improve survival in this group of patients.

A Simultaneous Estimation of the Baseline Intensity and Parameters for Modulated Renewal Processes

This paper proposes a semiparametric solution to estimate the intensity (hazard) function of modulated renewal processes: a nonparametric estimate for the baseline intensity function together with a parametric estimate of the model parameters of the covariate processes. Based on the martingale property associated with the conditional intensity, we construct a statistic from a residual analysis to estimate the baseline renewal intensity function, when the model parameters of the covariate processes are known. In addition, when the baseline intensity is obtained, the model parameters can be estimated using the usual maximum likelihood estimation. In practice, both the baseline intensity and model parameters are suggested to be estimated simultaneously via an expectation–maximization (E–M)-type iterative algorithm. A more important feature of the newly proposed algorithm is that, given n events in the observation dataset, its computation time is of order O(n2), while the Nelson–Aalen–Breslow estimator takes a computation time of order O(n3). For illustration, we apply the proposed estimation procedure to a set of data simulated from a modulated gamma renewal process and the aftershock sequence following the Ms8 Wenchuan earthquake, which occurred in Sichuan Province, China on 12 May 2008.

POS0200 POST-mRNA VACCINE FLARES IN AUTOIMMUNE INFLAMMATORY RHEUMATIC DISEASES: INTERIM RESULTS FROM THE CORONAVIRUS NATIONAL VACCINE REGISTRY FOR IMMUNE DISEASES SINGAPORE (CONVIN-SING)

POS0200 POST-mRNA VACCINE FLARES IN AUTOIMMUNE INFLAMMATORY RHEUMATIC DISEASES: INTERIM RESULTS FROM THE CORONAVIRUS NATIONAL VACCINE REGISTRY FOR IMMUNE DISEASES SINGAPORE (CONVIN-SING)

One-shot device test data analysis using non-parametric and semi-parametric inferential methods and applications

A one-shot device, such as an automobile airbag, electro-explosive unit or munition, is a product that can be used only once. Its actual lifetime is unobservable, rendering the corresponding reliability analysis quite challenging. In this paper, two non-parametric methodologies—maximum likelihood estimation via EM-algorithm and Nelson–Aalen based estimation are developed for identical testing environment on one-shot devices. The EM-algorithm is usually used for unobserved failure times under some specific parametric models. But, here the EM-algorithm is adopted for the number of failures in each time interval in a non-parametric manner. Next, a semi-parametric approach, based on proportional hazards assumption, is developed for nonidentical testing environments, such as under an accelerated life-test. A Monte Carlo simulation study is then carried out for evaluating the performance of the inferential methods developed here. Finally, two data sets are analyzed for illustrative purpose.

Determinants of mortality\xa0among under-five children admitted with severe acute malnutrition in Addis Ababa, Ethiopia

BackgroundManagement of severe acute malnutrition (SAM) has been a program priority in Ethiopia, but it remains the leading cause of mortality in under-five children. Hence, this study aimed to identify the incidence density rate of mortality and determinants among under-five children with severe acute malnutrition in St. Paul’s Hospital Millennium Medical College, 2012 to 2019.MethodsA retrospective cohort study was conducted and data were collected using a structured checklist from 673 charts, of which 610 charts were included in the final analysis. The Kaplan-Meier survival curve with Log-rank test was used to estimate the survival time. Bi-variable and multi-variable Cox proportional hazard regression models were fitted to identify determinants of death. Schoenfeld residuals test was used to check a proportional hazard assumption. Goodness of fit of the final model was checked using Nelson Aalen cumulative hazard function against Cox-Snell residual.ResultsIn this study, 61 (10%) children died making the incidence density rate of death 5.6 (95% CI: 4.4, 7.2) per 1000 child-days. Shock (Adjusted Hazard Ratio) [AHR] =3.2; 95% CI: 1.6, 6.3)), IV fluid infusion (AHR = 5.2; 95% CI: 2.4, 10.4), supplementing F100 (AHR = 0.12; 95%CI: 0.06, 0.23) and zinc (AHR = 0.45; 95% CI: 0.22, 0.93) were determinants of death.ConclusionThe overall proportion of deaths was within the range put forth by the Sphere standard and the national SAM management protocol. Shock and IV fluid infusion increased the hazard of death, whereas F100 & zinc were found to decrease the likelihood death. Children with SAM presented with shock should be handled carefully and IV fluids should be given with precautions.

The Estimation of (Covid-19) Cases in Kurdistan Region Using Nelson Aalen Estimator

It is described how the Nelson–Aalen estimator may be used to control the rate of a nonparametric estimate of the cumulative hazard rate function based on right censored as well as left condensed survival data, furthermore how the Nelson–Aalen estimator can be utilized to estimate various amounts. This technique is mostly applied to survival data and product quality data similar to the incorporated relative mortality in a multiplicative model with outer rates and the cumulative infection rate in a straightforward epidemic model. It is shown that tallying measures produce a structure that permits to a brought together treatment of all these different conditions, and the main little and massive sample properties of the assessor are summarized. This estimator is a weighted average of the Nelson-Aalen reliability estimates over two time periods. The suggested estimator's suitability and utility in model selection are reviewed. And a real-world dataset is evaluated to demonstrate the proposed estimator's suitability and utility. This work proposes a simple and nearly unbiased estimator to fill this gap. The information was gathered from the Ministry of Health's website between October 1, 2020, and February 28, 2021. The results of the Nelson Allen Estimator demonstrated that the odds of surviving were higher during a short period of time after being exposed to the virus. As time passes, the possibilities become slimmer. The closer the estimate comes to value 1 from 0.5 upward, the greater the chances of surviving the infection.

Outcomes and issues of 12 chordomas treated in a single center

BackgroundChordomas stem from notochordal vestiges and rank as low-grade bone malignancies although fraught with high risk of recurrence. This study assesses the clinical outcomes of twelve chordoma cases treated in our clinic, in an effort to shed light on the often under-represented pool of results deriving from non-referral centers.MethodsWe reviewed the clinicopathological traits of all chordoma patients registered in our center since 1991. Major endpoints were overall survival (OS) and progression-free survival (PFS) estimated using the Kaplan–Meier and Nelson–Aalen methods.ResultsTwelve patients, aged on average 47.9 years, were treated for primary or recurrent disease. Seven had chordomas originating in the cranium, 5 in the spine, including a bifocal tumor, and the mean time lapse between the beginning of symptoms and diagnosis was 15.4 months, marked by dull ache. Subtotal resection was achieved in 5 cases, incomplete in 5, while in 2, only biopsy was accomplished. Conformal radiotherapy was administered to 5 and stereotactic radiosurgery to 2 in the setting of recurrence. Protons were used once and targeted agents induced no clinical response in 3 patients. Median OS and PFS were 36 and 12 months, respectively, with the best outlook linked to maximal resection, spinal location, and good preoperative functional status. In all, 6 patients died of chordoma, 4 are alive, and 1 was lost. Relapse was the rule for most cases, except 2, and pulmonary metastases were ascertained in 1.ConclusionsOur cases were typical of chordomas, implying that inadequate surgical margins and successive recurrence are negative determinants of prognosis and that interinstitutional cooperation counterbalances shortages in non-referral institutes.

Event history and topological data analysis

Summary Persistent homology is used to track the appearance and disappearance of features as we move through a nested sequence of topological spaces. Equating the nested sequence to a filtration and the appearance and disappearance of features to events, we show that simple event history methods can be used for the analysis of topological data. We propose a version of the well-known Nelson–Aalen cumulative hazard estimator for the comparison of topological features of random fields and for testing parametric assumptions. We suggest a Cox proportional hazards approach for the analysis of embedded metric trees. The Nelson–Aalen method is illustrated on globally distributed climate data and on neutral hydrogen distribution in the Milky Way. The Cox method is used to compare vascular patterns in fundus images of the eyes of healthy and diabetic retinopathy patients.

Cryopreserved valved femoral vein homografts for right ventricular outflow tract reconstruction in infants

BackgroundWe have previously reported use of cryopreserved valve femoral vein homograft (FVH) conduits for biventricular repairs in infants needing right ventricular outflow tract (RVOT) reconstruction. This study aims to compare FVH conduits with aortic (A) and pulmonary (P) homografts with regards to intermediate- and long-term outcomes. MethodsRetrospective review was conducted of all infants between 2004 and 2016 who underwent biventricular repair with RVOT reconstruction using homograft conduits. Patients were divided into A, P, and FVH groups based upon type of conduit received (N = 57 [A = 13; P = 21, FVH = 23]). Groups were compared using univariate and multivariable Cox regression analyses. The Nelson–Aalen estimator of cumulative hazard and Kaplan–Meier curves were used to identify differences in freedom from catheter reintervention and reoperation. ResultsThe 2 groups were comparable except for greater incidence of delayed sternal closure and longer hospital length of stay in the FVH group. The follow-up was longer for A and P groups compared with the FVH group (P < .001). Multivariable Cox regression, adjusting for difference in the length of follow-up, revealed comparable freedom from overall reintervention between the groups. Younger age at implantation was the only independent predictor of overall reintervention (hazard ratio per day younger age, 1.06; 95% confidence interval, 1.02-1.11; P = .002). Nelson–Aalen cumulative hazard analysis revealed greater freedom from percutaneous reintervention with use of FVH. Kaplan–Meier analysis showed comparable freedom from reoperation for all three conduits. ConclusionsValved femoral vein homograft conduits are comparable with aortic and pulmonary homografts for RVOT reconstruction in infants undergoing biventricular repairs.

Survival of Children Living With HIV on Art in Zambia: A 13-Years Retrospective Cohort Analysis.

Background: Research conducted before the introduction of anti-retroviral therapy (ART), showed that the majority of children living with HIV (CLHIV) would die before their second birthday. In Zambia, ART was rolled out to the public health system in 2004 with subsequent improved survival in CLHIV. However, the survival rates of CLHIV on ART in Zambia since 2004 have not been extensively documented. We assessed survival experiences and the factors associated with survival in CLHIV on ART in Zambia.Methods: We conducted a retrospective cohort analysis of CLHIV (aged up to 15 years) using routinely collected data from health facilities across Zambia, over 13 years to ascertain mortality rates. We explored survival factors using Cox regression giving adjusted hazard ratios (AHR) and 95% confidence intervals (95% CI). Nelson Aalen estimates were used to show the cumulative hazards of mortality for different levels of explanatory factors.Results: A total of 65,448 eligible children, were initiated on ART between 2005 and 2018, of which 33,483 (51%) where female. They contributed a total survival time of 275,715-person years at risk during which 3,265 children died which translated into an incidence rate of 1.1 deaths per 100 person-years during the review period. Mortality rates were highest in children in the first year of life (Mortality rate 2.24; 95% CI = 2.08–2.42) and during the first year on ART (Mortality rate 3.82 95% CI = 3.67–3.98). Over 50% of the children had been on ART for 5–10 years by 2018, and they had the lowest risk of mortality compared to children who had been on ART for <5 years.Conclusions: Children with HIV in Zambia are surviving much longer than was predicted before ART was introduced 14 years ago. This key finding adds to the literature on analysis of survival in CLHIV in low income settings like Zambia. However, this survival is dependent on the age at which ART is initiated and the time on ART highlighting the need to increase investments in early infant diagnosis (EID) to ensure timely HIV testing and ART initiation for CLHIV.

Effectiveness of Lifelong ART (Option B+) in the Prevention of Mother-to-Child Transmission of HIV Programme in Zambia: Observations Based on Routinely Collected Health Data.

Background: Mother to child transmission of HIV (MTCT) is a global challenge affecting many countries especially in sub-Saharan Africa. In 2009 about 370,000 infants were infected with HIV mainly through MTCT and most of them in sub-Saharan Africa. We aimed to determine the effectiveness of Option B+ compared to other options in reducing rates of early MTCT of HIV infections in Zambia.Methods: This was a retrospective cohort study based on routinely collected data using SmartCare in Zambia. Survival analysis with Cox Proportional Hazard regression was used to determine association between MTCT and regimen type of mothers. Kaplan-Meier (K-M) curves were used to compare MTCT for infants born to mothers option B+ to those on other options, and Wilcoxon (Breslow) test was used to establish statistical significance.Results: Overall (n = 1,444), mother-baby pairs with complete data were included in the analysis, with the median age of mothers being 33 (28–38) years; and 57% of these women were on Option B+. MTCT rate was estimated at 5% (73/1,444) [P = 0.025]. A Kaplan-Meier estimate showed that HIV Exposed Infants (HEI) of mothers on Option B+ had lower MTCT rate than those who were on other MTCT prevention interventions [Wilcoxon test; chi2 = 4.97; P = 0.025]. Furthermore, The Nelson Aalen cumulative hazard estimates indicated similar evidence of option B+ being more effective than other options with some statistical significance [HR = 0.63, P = 0.068]. HEI of option B+ mothers had 50% reduced risk of having HIV infection compared to option A/B [adjusted HR = 0.4; 95% CI = 0.28–0.84; P = 0.010]. HEI to women who were married had an increased risk 50% of getting infected compared to those not married [adjusted HR = 1.5; 95% CI = 3.43–6.30; P < 0.001]. Exposed infants whose mothers had assisted delivery had 3 times increased risk of getting infected compared to those born through normal vaginal delivery [Adjusted HR = 3.2; 95% CI = 0.98–10.21; P = 0.050].Conclusions: The use of Option B+ as PMTCT intervention was found to be more effective in reducing MTCT of HIV compared to other options. Scaling up access to life-long ART and improving retention for women on treatment can potentially reduce further vertical transmission.

Risk of Subsequent Primary Cancers After External Beam Radiotherapy Treatment of Pediatric Low Grade Gliomas: A Surveillance, Epidemiology, and End Results Analysis 1973 to 2015

Abstract INTRODUCTION Past studies have associated external beam radiotherapy (EBRT) with higher incidences of subsequent primary malignancies (SPMs). This link has been documented for leukemias, and prostate, thyroid, and bone cancers. However, the effects of EBRT on SPM development from low grade gliomas (LGGs) are not well understood. The aim of the present study was to characterize the risk of SPM development after EBRT treatment of LGGs. METHODS A total of 1439 pediatric (age 0-17) records between 1973 and 2015 were assembled from the Surveillance, Epidemiology, and End Results (SEER) database. Univariable and multivariable Cox regressions were used to evaluate the prognostic impact of demographic, tumor, and treatment-related covariates. Propensity score matching was used to balance baseline characteristics. Survival and cumulative hazard analyses measured the time to, and risk of, SPM development, stratified by receipt of EBRT. RESULTS Of the 1439 pediatric patients we analyzed, 450 received EBRT and 989 did not. A total of 65 pediatric patients were identified who developed SPMs after LGG diagnosis, and 35 of these patients received EBRT (OR: 2.70). Unadjusted Cox regressions revealed a significantly elevated SPM risk in EBRT-treated pediatric patients with LGGs (HR: 2.22, CI: 1.34-3.67). After adjusting for covariates such as race, gender, income, chemotherapy, and grade (World Health Organization I vs II), there was still a clear association between EBRT and the development of SPMs (HR: 2.52, CI: 1.50-4.23). Propensity score matching across covariates did not significantly impact the hazard ratio. Time-to-event Kaplan Meier curves demonstrated earlier SPM development in the EBRT-treated LGG pediatric population, and Nelson–Aalen cumulative hazard estimates showed higher incidences of SPM development at all time points. CONCLUSION EBRT treatment for LGGs is associated with an elevated incidence of SPMs, even after controlling for available covariates. This suggests less aggressive EBRT use in the pediatric LGG population may be warranted.