scholarly journals Analysis of Recurrent Events with Associated Informative Censoring: Application to HIV Data

Author(s):  
Jonathan Ejoku ◽  
Collins Odhiambo ◽  
Linda Chaba ◽  

In this study, we adapt a Cox-based model for recurrent events; the Prentice, Williams and Peterson Total -Time (PWP-TT) that has largely, been used under the assumption of non-informative censoring and evaluate it under an informative censoring setting. Empirical evaluation was undertaken with the aid of the semi-parametric framework for recurrent events suggested by Huang [1] and implemented in R Studio software. For validation we used data from a typical HIV care setting in Kenya. Of the three models under consideration; the standard Cox Model had gender hazard ratio (HR) of 0.66 (p-value=0.165), Andersen-Gill had HR 0.46 (with borderline p-value=0.054) and extended PWP TT had HR 0.22 (p-value=0.006). The PWP-TT model performed better as compared to other models under informative setting. In terms of risk factors under informative setting, LTFU due to stigma; gender [base=Male] had HR 0.544 (p-value =0.002), age [base is < 37] had HR 0.772 (p-value=0.008), ART regimen [base= First line] had HR 0.518 (p-value= 0.233) and differentiated care model (Base=not on DCM) had HR 0.77(p-value=0.036). In conclusion, in spite of the multiple interventions designed to address incidences of LTFU among HIV patients, within-person cases of LTFU are usually common and recurrent in nature, with the present likelihood of a person getting LTFU influenced by previous occurrences and therefore informative censoring should be checked.

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 159-159 ◽  
Author(s):  
J. C. Yao ◽  
J. D. Hainsworth ◽  
E. Baudin ◽  
M. Peeters ◽  
D. Hoersch ◽  
...  

159 Background: Octreotide LAR has been the foundation of NET therapy; however, additional treatment options are needed. Everolimus, an oral inhibitor of mTOR, demonstrated promising antitumor activity in patients with NET as a single agent and in combination with octreotide LAR in two phase II studies. Methods: Patients (n = 429) with well or moderately differentiated advanced NET and history of carcinoid symptoms received oral everolimus 10 mg/d + octreotide LAR 30 mg IM q 28 days (n = 216) or placebo + octreotide LAR (n = 213). Common primary sites included the small intestine, lung, and colon. The primary endpoint was progression-free survival (PFS) per central review by RECIST. Crossover from P+O to open-label E+O was allowed at disease progression. Results: Median PFS (95% CI) with E+O was 16.4 months (13.67-21.19) vs. 11.3 months (8.44-14.59) for P+O. E+O was associated with a 23% reduction in risk of progression: HR = 0.77; 95% CI: 0.59-1.00; one-sided p-value = .026 (pre-specified significance boundary is p ≤ .0246). A high rate of informative censoring resulted in loss of power in central review results. Correcting for the informative censoring bias, the pre-specified marginal Cox model using inverse probability of censoring weights (IPCW) analysis showed a significant 5.5-month improvement in median PFS with E+O; HR = 0.60; 95% CI: 0.44-0.84, with one-sided p-value = .0014. The benefit of E+O was seen across all patient subgroups. Updated analyses of the impact of pre-study and post-progression octreotide LAR therapy will be reported. Most frequent drug-related adverse events (AEs) with E+O were stomatitis, rash, fatigue, and diarrhea; mostly grade 1-2. Grade 3-4 AEs reported in >5% were stomatitis, fatigue, diarrhea, infections, and hyperglycemia. Conclusions: In this large phase III trial, E+O provided a 5.1-month clinically meaningful increase in median PFS compared with P+O in the central adjudicated review. Correcting for the informative censoring bias, a significant PFS improvement of 5.5 months was seen, with a p value = .0014. The safety profile of E+O was acceptable. [Table: see text]


2019 ◽  
Author(s):  
Vincent Guilamo-Ramos ◽  
Marco Thimm-Kaiser ◽  
Adam Benzekri ◽  
Donna Futterman

Despite significant progress in the fight against HIV/AIDS in the United States, HIV prevention and treatment disparities among key populations remain a national public health concern. While new HIV diagnoses are increasing among people under age 30—in particular among racial, ethnic, and sexual minority adolescents and young adults (AYA)—dominant prevention and treatment paradigms too often inadequately consider the unique HIV service needs of AYA. To address this gap, we characterize persistent and largely overlooked AYA disparities across the HIV prevention and treatment continuum, identify AYA-specific limitations in extant resources for improving HIV service delivery in the United States, and propose a novel AYA-centered differentiated care framework adapted to the unique ecological and developmental factors shaping engagement, adherence, and retention in HIV services among AYA. Shifting the paradigm for AYA to differentiated HIV care is a promising approach that warrants implementation and evaluation as part of reinforced national efforts to end the HIV epidemic in the United States by 2030.


2019 ◽  
pp. 1-2

A study of of endometrial thickness on TVS in relation with histopathology report on dilation and curettage. AIM AND OBJECTIVE-To set a cut off limit of endometrial thickness on TVS for differtiating between normal and abnormal endometrium. MATERIAL AND METHOD-hospital based comparative study. RESULTS-TVS is non invasive ,simple first line procedure in AUB women. Mean endometrial thickness in normal endometrial group was 8.00±2.44 mm and in abnormal endometrial group was 15.16±33 mm.The difference was found highly significant (p value<.001)


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
W. Chris Buck ◽  
Hanh Nguyen ◽  
Mariana Siapka ◽  
Lopa Basu ◽  
Jessica Greenberg Cowan ◽  
...  

Abstract Background Pediatric tuberculosis (TB), human immunodeficiency virus (HIV), and TB-HIV co-infection are health problems with evidence-based diagnostic and treatment algorithms that can reduce morbidity and mortality. Implementation and operational barriers affect adherence to guidelines in many resource-constrained settings, negatively affecting patient outcomes. This study aimed to assess performance in the pediatric HIV and TB care cascades in Mozambique. Methods A retrospective analysis of routine PEPFAR site-level HIV and TB data from 2012 to 2016 was performed. Patients 0–14 years of age were included. Descriptive statistics were used to report trends in TB and HIV indicators. Linear regression was done to assess associations of site-level variables with performance in the pediatric TB and HIV care cascades using 2016 data. Results Routine HIV testing and cotrimoxazole initiation for co-infected children in the TB program were nearly optimal at 99% and 96% in 2016, respectively. Antiretroviral therapy (ART) initiation was lower at 87%, but steadily improved from 2012 to 2016. From the HIV program, TB screening at the last consultation rose steadily over the study period, reaching 82% in 2016. The percentage of newly enrolled children who received either TB treatment or isoniazid preventive treatment (IPT) also steadily improved in all provinces, but in 2016 was only at 42% nationally. Larger volume sites were significantly more likely to complete the pediatric HIV and TB care cascades in 2016 (p value range 0.05 to < 0.001). Conclusions Mozambique has made significant strides in improving the pediatric care cascades for children with TB and HIV, but there were missed opportunities for TB diagnosis and prevention, with IPT utilization being particularly problematic. Strengthened TB/HIV programming that continues to focus on pediatric ART scale-up while improving delivery of TB preventive therapy, either with IPT or newer rifapentine-based regimens for age-eligible children, is needed.


2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
E Rodenas Alesina ◽  
P Jordan ◽  
L Herrador ◽  
C Espinet-Coll ◽  
N Pizzi ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): CIBER-CV AIMS The scintigraphic translation of Q waves in patients with ischemic cardiomyopathy and LVEF &lt; 40% has not yet been assessed. The aim of this study was to explore the relationship between Q waves and necrotic tissue and to analyze their impact in prognosis. METHODS AND RESULTS A retrospective study enrolling 487 consecutive patients (67,0 [57,4 – 75,4] years), with ischemic cardiomyopathy, LVEF &lt;40% and narrow QRS who underwent stress-rest SPECT was conducted. Patients with Q waves (320 patients [65,7%]) had less comorbidity and ischemia, but more necrosis. Q waves correlated poorly with lack of viability (AUC = 0,63) and were independently associated with the subendocardial extent of the necrosis. After a follow-up of 5,07 years, the primary outcome (cardiovascular death, heart failure hospitalization or myocardial infarction) occurred in 192 (39,4%) patients, without differences between groups in multivariate analysis. After accounting for non-cardiovascular death as a competitive risk, the interaction between &gt;10% of ischemia and revascularization remained in Cox model both in the total cohort (aHR= 0,46 [0,24 – 0,86]), and in patients with Q waves (aHR = 0,27 [0,11–0,69]). CONCLUSION Patients with ischemic cardiomyopathy with Q waves have larger subendocardial scarring and more transmural necrosis, although correlation between Q waves and transmural scarring is poor. Revascularization if &gt;10% ischemia is present is associated with a better prognosis. Ischemia burden should be assessed and accordingly treated in these patients, and no differences in management should be made in the presence of Q waves. Table 1. Cox proportional hazards model Total cohort (N = 471) Patients with Q waves (N = 315) aHR p-value 95% CI aHR p-value 95% CI Age (per year) 1,02 0,007 1,01 - 1,04 n.s. Diabetes mellitus 1,35 0,047 1,00 - 1,81 1,54 0,016 1,09 - 2,20 eGFR &lt; 60 ml/min 1,59 0,005 1,15 - 2,21 1,96 &lt;0,001 1,36 - 2,82 Previous HF hospitalization 1,71 0,002 1,23 - 2,38 1,76 0,007 1,17 - 2,64 Previous PCI 1,32 0,069 0,98 - 1,78 n.s. Previous CABG n.s. 1,77 0,009 1,15 - 2,72 Angina or dyspnea 1,68 0,001 1,24 - 2,28 1,71 0,004 1,19 - 2,46 Indexed TDV (per quartile) 1,16 0,047 1,02 - 1,33 n.s. Revascularization*ischemia &gt; 10% 0,46 0,015 0,24 - 0,86 0,27 0,006 0,11 - 0,69 Cox regression for the primary endpoint (cardiovascular death, heart failure hospitalization or myocardial infarction), accounting for non-cardiovascular death as a competitive risk. Abstract Figure. Survival for the primary endpoint


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 547.1-547
Author(s):  
C. Deakin ◽  
G. Littlejohn ◽  
H. Griffiths ◽  
T. Smith ◽  
C. Osullivan ◽  
...  

Background:The availability of biosimilars as non-proprietary versions of established biologic disease-modifying anti-rheumatic drugs (bDMARDs) is enabling greater access for patients with rheumatic diseases to effective medications at a lower cost. Since April 2017 both the originator and a biosimilar for etanercept (trade names Enbrel and Brenzys, respectively) have been available for use in Australia.Objectives:[1]To model effectiveness of etanercept originator or biosimilar in reducing Disease Activity Score 28-joint count C reactive protein (DAS28CRP) in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or ankylosing spondylitis (AS) treated with either drug as first-line bDMARD[2]To describe persistence on etanercept originator or biosimilar as first-line bDMARD in patients with RA, PsA or ASMethods:Clinical data were obtained from the Optimising Patient outcomes in Australian rheumatoLogy (OPAL) dataset, derived from electronic medical records. Eligible patients with RA, PsA or AS who initiated etanercept originator (n=856) or biosimilar (n=477) as first-line bDMARD between 1 April 2017 and 31 December 2020 were identified. Propensity score matching was performed to select patients on originator (n=230) or biosimilar (n=136) with similar characteristics in terms of diagnosis, disease duration, joint count, age, sex and concomitant medications. Data on clinical outcomes were recorded at 3 months after baseline, and then at 6-monthly intervals. Outcomes data that were missing at a recorded visit were imputed.Effectiveness of the originator, relative to the biosimilar, for reducing DAS28CRP over time was modelled in the matched population using linear mixed models with both random intercepts and slopes to allow for individual heterogeneity, and weighting of individuals by inverse probability of treatment weights to ensure comparability between treatment groups. Time was modelled as a combination of linear, quadratic and cubic continuous variables.Persistence on the originator or biosimilar was analysed using survival analysis (log-rank test).Results:Reduction in DAS28CRP was associated with both time and etanercept originator treatment (Table 1). The conditional R-squared for the model was 0.31. The average predicted DAS28CRP at baseline, 3 months, 6 months, 9 months and 12 months were 4.0 and 4.4, 3.1 and 3.4, 2.6 and 2.8, 2.3 and 2.6, and 2.2 and 2.4 for the originator and biosimilar, respectively, indicating a clinically meaningful effect of time for patients on either drug and an additional modest improvement for patients on the originator.Median time to 50% of patients stopping treatment was 25.5 months for the originator and 24.1 months for the biosimilar (p=0.53). An adverse event was the reason for discontinuing treatment in 33 patients (14.5%) on the originator and 18 patients (12.9%) on the biosimilar.Conclusion:Analysis using a large national real-world dataset showed treatment with either the etanercept originator or the biosimilar was associated with a reduction in DAS28CRP over time, with the originator being associated with a further modest reduction in DAS28CRP that was not clinically significant. Persistence on treatment was not different between the two drugs.Table 1.Respondent characteristics.Fixed EffectEstimate95% Confidence Intervalp-valueTime (linear)0.900.89, 0.911.5e-63Time (quadratic)1.011.00, 1.011.3e-33Time (cubic)1.001.00, 1.007.1e-23Originator0.910.86, 0.960.0013Acknowledgements:The authors acknowledge the members of OPAL Rheumatology Ltd and their patients for providing clinical data for this study, and Software4Specialists Pty Ltd for providing the Audit4 platform.Supported in part by a research grant from Investigator-Initiated Studies Program of Merck & Co Inc, Kenilworth, NJ, USA. The opinions expressed in this paper are those of the authors and do not necessarily represent those of Merck & Co Inc, Kenilworth, NJ, USA.Disclosure of Interests:Claire Deakin: None declared, Geoff Littlejohn Consultant of: Over the last 5 years Geoffrey Littlejohn has received educational grants and consulting fees from AbbVie, Bristol Myers Squibb, Eli Lilly, Gilead, Novartis, Pfizer, Janssen, Sandoz, Sanofi and Seqirus., Hedley Griffiths Consultant of: AbbVie, Gilead, Novartis and Lilly., Tegan Smith: None declared, Catherine OSullivan: None declared, Paul Bird Speakers bureau: Eli Lilly, abbvie, pfizer, BMS, UCB, Gilead, Novartis


2019 ◽  
Vol 48 (Supplement_3) ◽  
pp. iii17-iii65
Author(s):  
Recie Davern ◽  
Helena Hobbs ◽  
Hannah Murugan ◽  
Paul Cotter

Abstract Background Patients prescribed oral anticoagulants (OAC) for atrial fibrillation (AF) can still present with stroke. The mechanism for stroke in these patients can be due to multiple factors including subtherapeutic dosing and non-compliance. With the increasing use of direct-acting OACs (DOACs) in favour of warfarin, it is unclear if the incidence of stroke in those already taking OAC has reduced. Methods Data was extracted from our unit’s stroke registry, a prospectively maintained database, for patients who presented with stroke while receiving OAC for AF from 2013 to 2017. Type of OAC, type of stroke, OAC dosing at time of event including non-compliance, stroke management and outcome were recorded. Results 67 patients were included for analysis, with 55 ischaemic and 12 haemorrhagic strokes. 52 patients were receiving warfarin at the time of their stroke vs. 15 receiving DOACs. 33/55 (60%) of ischaemic strokes occurred in patients taking warfarin with a sub-therapeutic INR. In 3/55 (5%) of ischaemic strokes, the OAC was held for a procedure while in 6/55 cases (11%) the OAC had been stopped for another reasons e.g. bleeding. 5/55 (7%) were due to non-compliance. 1 ischaemic stroke was due to under-dosing of a DOAC (dabigatran). 16 strokes were recorded in 2013 for patients prescribed OAC vs. 3 in 2017. Overall the number of ischaemic strokes due to subtherapeutic OAC decreased from 14 in 2013 to 1 in 2017 (p value 0.06). Conclusion The majority of strokes occurring in anticoagulated patients are related to warfarin use. We observed an almost significant reduction in the proportion of ischaemic strokes due to under-dosing of OAC over the study period. Warfarin continues to be recommended as the first line anticoagulant for stroke prevention in atrial fibrillation by the HSE Medicines Management Programme, a decision which we would argue warrants review.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e15586-e15586
Author(s):  
Mohamed Alghamdi ◽  
Shouki Bazarbashi ◽  
Elsamany Shereef ◽  
Mervat Mahrous ◽  
Omar Al shaer ◽  
...  

e15586 Background: In Saudi Arabia, the incidence of colorectal cancer has been increased over the past few years. The optimal treatment beyond the second line is not fully understood. To the best of our knowledge, the efficacy and disease outcomes of triflurodine/tipiracil in Saudi patients with refractory metastatic colorectal cancer(mCRC) has not been studied yet. Our study is a real-life practice evaluation of the efficacy of triflurodine/tipiracil in patients with refractory mCRC. Moreover, the prognosis and the prognostic significance of the different clinical variables have been analyzed. Methods: A retrospective, multi-centers ( 5 centers representative of Saudi Arabia )observational study in patients with mCRC who have received triflurodine/tipiracil beyond oxaliplatin & Irinotecan-based chemotherapy between December 2018-December 2020.We aimed to assess the response to triflurodine/tipiracil, to evaluate the progression-free survival (PFS ), the overall survival (OS), and the associated factors of prognostic significance. Results:The data of 100 patients with refractory mCRC who has received triflurodine/tipiracil have been analyzed. The mean age was 55.2 +11.8 years. Forty-two patients were (42%) females and 58 (58%) were male patients. Sigmoid was the most common primary site of cancer in 35 (35%) patients, followed by rectum 29 (29%). Peritoneal metastasis was present in 17 (23.3%) patients ,liver in 51(56.6%) and lung in 39 (50.7%). Metastatic sites were ≥ 2 in 45 (45%) patients. Metastatic lesions were ≥ 5 in 65 (65%) patients. Xelox chemotherapy regimen was the most commonly used first-line chemotherapy which represents 43%, while Folfiri or Xeliri combination was the most used second line in 57 (60%). For the third line, Folfox or Xelox was used in 81 (83.5%) patients. The fourth line was given to 49 (67.1%). For first-line biological agents, Cetuximab was used most frequently 31 (46.3%).Evaluation of the response to treatment with triflurodine/tipiracil revealed one patient (1%) with a complete response,3 patients (3%) with partial response, 28 (28%) patients with stable disease, and 66 (66%) showed progressive disease. The estimated median progression-free survival was 5 months ( 3.839 - 6.161) and the median overall survival was 12 months (9.732-14.268). The log-rank analysis showed that the baseline neutrophils ≤ 75 % ( P-value= 0.0092) and low hemoglobin level (P-value= 0.0245) were strongly associated with a higher survival. By multivariate Cox regression analysis, the neutrophil count ≤ 75 % was the only independent predictor for survival. Conclusions: Trifluridine/tipiracil is effective in patients with refractory mCRC. The low neutrophil count might predict a better overall survival.


2015 ◽  
Vol 26 (4) ◽  
pp. 1969-1981 ◽  
Author(s):  
Jing Ning ◽  
Mohammad H Rahbar ◽  
Sangbum Choi ◽  
Jin Piao ◽  
Chuan Hong ◽  
...  

In comparative effectiveness studies of multicomponent, sequential interventions like blood product transfusion (plasma, platelets, red blood cells) for trauma and critical care patients, the timing and dynamics of treatment relative to the fragility of a patient’s condition is often overlooked and underappreciated. While many hospitals have established massive transfusion protocols to ensure that physiologically optimal combinations of blood products are rapidly available, the period of time required to achieve a specified massive transfusion standard (e.g. a 1:1 or 1:2 ratio of plasma or platelets:red blood cells) has been ignored. To account for the time-varying characteristics of transfusions, we use semiparametric rate models for multivariate recurrent events to estimate blood product ratios. We use latent variables to account for multiple sources of informative censoring (early surgical or endovascular hemorrhage control procedures or death). The major advantage is that the distributions of latent variables and the dependence structure between the multivariate recurrent events and informative censoring need not be specified. Thus, our approach is robust to complex model assumptions. We establish asymptotic properties and evaluate finite sample performance through simulations, and apply the method to data from the PRospective Observational Multicenter Major Trauma Transfusion study.


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