Survival Analysis

Author(s):  
Jorge Leite ◽  
Sandra Carvalho ◽  
Munir Boodhwani ◽  
Felipe Fregni

This chapter focuses on basic principles of survival analysis for the clinical investigator. Survival analysis is a specific type of standardized statistical analysis that focuses on assessing the time elapsed since the exposure/intervention to the occurrence of an event. Important concepts such as median survival time, cumulative probability of survival at specific time points by using Kaplan-Meier estimators, and the use of the use of log rank (Mantel–Cox) to compare survival functions are discussed. This chapter also discusses the concept of censoring, which happens when the event occurs outside the pre-specified time window, and how to develop hazard functions when there are several interrelated factors that can contribute to the increase or decrease of survival probability.

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1175.1-1175
Author(s):  
R. Hamdy Abdellatif Mohammed ◽  
H. Lotfy Fayed ◽  
N. Emara

Background:Systemic lupus erythematosus (SLE) is a complex autoimmune disorder with considerably high mortality.Objectives:To investigate the survival rates 5, 10, 15 and 20 years and the impact of disease related morbidity and mortality among Egyptians patients afflicted by SLE.Methods:This is a single center observational study performed in one of the leading medical school governmental hospital for teaching and training in the north African region and middle east sectors Kasr Alainy School of Medicine- Cairo University. Medical records of adult SLE patients ≥ 16 years (classified according to ACR 1997 SLE classification criteria set forth by Hochberg, 1997) who received longitudinal clinical care during the time period from 1999 to 2019 were included. Data analysis: causes of mortality, damage score and survival were determined from the time of SLE diagnosis to the last contact or date of death.Results:Records of two hundred and two SLE patients were included, 91.1% were females and 8.9% patients were males (ratio is 10:1). The mean age at diagnosis 26.71 ± 7.93 years with a mean follow up between mean: 6.6 ± 4.58 years, 34.15% had damage in at least one of the organ systems by SLICC/ACR-DI in the first 6 months. Considering an outcome label of dead or alive at the end of follow up period, results showed a total of 52 mortalities, 88.5% were females, the mean age at death onset was 30.9±8.8 years. Results identified the following death causalities in the studied SLE patients in order of frequency: Septic shock and disseminated intravascular coagulation in 11.5 %, acute respiratory distress syndrome ARDS in 11.5 %, congestive heart failure in 9.6%, thrombotic microangiopathy 5.7%, cerebritis, acute renal failure 5.7%, intracranial hemorrhage 5.7%, hypertensive encephalopathy in 5.7%. Alveolar hemorrhage, infection, intraoperative deaths each contributed to deaths in 3.8%. Hypovolemic shock, acute liver failure, brain edema, thrombotic thrombocytopenic purpura, end stage kidney disease, pulmonary renal syndrome, suicide and acute hydrocephalus contributed to fatalities in 1.9%. The cause of death was unclearly identified in 26.9%. Results of the Kaplan Meier survival curve in the studied SLE cohort showed an overall cumulative probability of survival at 5, 10, 15 and 20 years after SLE diagnosis was 82.9%, 68.8%,51.4% and 20.4%, respectively. Multivariate regression analysis revealed psychosis, chronic kidney disease and heart failure were independent predictors of survival (HR= 4.3 times, 3.58 times and 3 times respectively, p < 0.001), while the use of hydroxychloroquine and AZA showed a protective effect.Figure 1.Kaplan-Meier estimated survival function, starting at date of SLE diagnosis.Conclusion:The cumulative probability of survival at 5, 10, 15 and 20 years after SLE diagnosis was 82.9%, 68.8%,51.4% and 20.4%, respectively. The presence of renal manifestations, neuropsychiatric lupus and heart failure were independent predictors of poor survival in our cohort. The use of hydroxychloroquine and AZA were protective.Corresponding author: Reem Hamdy Abdellatif Mohammed (Reem H A Mohammed), e-mail: [email protected],. https://orcid.org/0000-0003-4994-7687, Scopus Author ID: 35280107100.References:[1]Hochberg MC. Updating the American College of Rheumatology revised criteria for the classification of systemic lupus erythematosus. Arthritis Rheum. 1997 Sep;40(9):1725. doi: 10.1002/art.1780400928. PMID: 9324032.[2]Kasitanon N, Magder LS, Petri M. Predictors of survival in systemic lupus erythematosus. Medicine (Baltimore) 2006;85:147–56.[3]Gladman D, Ginzler E, Goldsmith C, et al. The development and initial validation of the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index for systemic lupus erythematosus. Arthritis Rheum 1996;39:363–9.Disclosure of Interests:None declared


2020 ◽  
Vol 17 (4) ◽  
pp. 361-375
Author(s):  
Victor C. Schulz ◽  
Pedro S.C. de Magalhaes ◽  
Camila C. Carneiro ◽  
Julia I.T. da Silva ◽  
Vivian N. Silva ◽  
...  

Background: It is unknown if improvements in ischemic stroke (IS) outcomes reported after cerebral reperfusion therapies (CRT) in developed countries are also applicable to the “real world” scenario of low and middle-income countries. We aimed to measure the long-term outcomes of severe IS treated or not with CRT in Brazil. Methods: Patients from a stroke center of a state-run hospital were included. We compared the survival probability and functional status at 3 and 12 months in patients with severe IS treated or not with CRT. From 2010 to 2011, we performed intravenous reperfusion when patients arrived within 4.5 h time-window (IVT group) and after 2011, mechanical thrombectomy (MT) combined or not with intravenous alteplase (IAT group). Those who arrived >4.5 h in 2010-2011 and >6 h in 2012-2017 did not undergo CRT (NCRT group). Results: From 2010 to 2017, we registered 917 patients: 74% (677/917) in the NCRT group, 19% (178/917) in the IVT group and 7% (62/917) in the IAT group. Compared to the NCRT group, IVT patients had a 28% higher (HR: 0.72; 95% CI 0.53-0.96) 3-month adjusted probability of survival and risk of functional dependence was 19% lower (adjusted RR: 0.81; 95% CI 0.73-0.91). For those who underwent MT, the adjusted probability of survival was 59 % higher (HR: 0.41; 95% CI 0.21-0.77) and the risk of functional dependence was 21% lower (adjusted RR: 0.79; 95% CI 0.66-094). These outcomes remained significantly better throughout the first year. Conclusion: CRT led to better outcomes in patients with severe IS in Brazil.


2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 54-56
Author(s):  
D R Lim ◽  
M Tsai ◽  
S E Gruchy ◽  
J Jones ◽  
G Williams ◽  
...  

Abstract Background The COVID-2019 pandemic continues to restrict access to endoscopy, resulting in delays or cancellation of non-urgent endoscopic procedures. A delay in the removal or exchange of plastic biliary stents may lead to stent occlusion with consensus recommendation of stent removal or exchange at three-month intervals [1–4]. We postulated that delayed plastic biliary stent removal (DPBSR) would increase complication rates. Aims We aim to report our single-centre experience with complications arising from DPBSR. Methods This was a retrospective, single-center, observational cohort study. All subjects who had ERCP-guided plastic biliary stent placement in Halifax, Nova Scotia between Dec 2019 and June 2020 were included in the study. DPBSR was defined as stent removal &gt;=90 days from insertion. Four endpoints were assigned to patients: 1. Stent removed endoscopically, 2. Died with stent in-situ (measured from stent placement to documented date of death/last clinical encounter before death), 3. Pending removal (subjects clinically well, no liver enzyme elevation, not expired, endpoint 1 Nov 2020), and 4. Complication requiring urgent reintervention. Kaplan-Meier survival analysis was used to represent duration of stent patency (Fig.1). Results 102 (47.2%) had plastic biliary stents placed between 2/12/2019 and 29/6/2020. 49 (48%) were female, and the median age was 68 (R 16–91). Median follow-up was 167.5 days, 60 (58.8%) subjects had stent removal, 12 (11.8%) died before replacement, 21 (20.6%) were awaiting stent removal with no complications (median 230d, R 30–332), 9 (8.8%) had complications requiring urgent ERCP. Based on death reports, no deaths were related to stent-related complications. 72(70.6%) of patients had stents in-situ for &gt;= 90 days. In this population, median time to removal was 211.5d (R 91-441d). 3 (4.2%) subjects had stent-related complications requiring urgent ERCP, mean time to complication was 218.3d (R 94–441). Stent removal &gt;=90 days was not associated with complications such as occlusion, cholangitis, and migration (p=1.0). Days of stent in-situ was not associated with occlusion, cholangitis, and migration (p=0.57). Sex (p=0.275), cholecystectomy (p=1.0), cholangiocarcinoma (p=1.0), cholangitis (p=0.68) or pancreatitis (p=1.0) six weeks prior to ERCP, benign vs. malignant etiology (p=1.0) were not significantly associated with stent-related complications. Conclusions Plastic biliary stent longevity may have been previously underestimated. The findings of this study agree with CAG framework recommendations [5] that stent removal be prioritized as elective (P3). Limitations include small sample size that could affect Kaplan-Meier survival analysis. Despite prolonged indwelling stent time as a result of COVID-19, we did not observe an increased incidence of stent occlusion or other complications. Funding Agencies None


Gerontology ◽  
2021 ◽  
pp. 1-6
Author(s):  
Ana Fernandez-Suárez ◽  
Oriol Yuguero Torres

<b><i>Background:</i></b> The increase in life expectancy and low mortality have doubled the number of individuals older than 65 in the last 30 years. <b><i>Methods:</i></b> We conducted a retrospective study of 101 patients older than 80 years of age treated by low digestive hemorrhage (LDH) in an emergency department during 2018. Sociodemographic variables were evaluated, as well as comorbidity and survival at 18 months. Survival was assessed by a Kaplan-Meier test. <b><i>Results:</i></b> 52.5% of the subjects were women. The average comorbidity of the sample was 1.97. The survival rate per year was 60%. The finding on colonoscopy shows no association with mortality. However, those patients on anticoagulant/antiplatelet therapy have a higher survival rate. <b><i>Conclusion:</i></b> Survival per year is high, so urgent colonoscopy for an LDH should be performed after evaluating the patient’s stability and functional status in a scheduled and outpatient manner.


Risks ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 121
Author(s):  
Beata Bieszk-Stolorz ◽  
Krzysztof Dmytrów

The aim of our research was to compare the intensity of decline and then increase in the value of basic stock indices during the SARS-CoV-2 coronavirus pandemic in 2020. The survival analysis methods used to assess the risk of decline and chance of rise of the indices were: Kaplan–Meier estimator, logit model, and the Cox proportional hazards model. We observed the highest intensity of decline in the European stock exchanges, followed by the American and Asian plus Australian ones (after the fourth and eighth week since the peak). The highest risk of decline was in America, then in Europe, followed by Asia and Australia. The lowest risk was in Africa. The intensity of increase was the highest in the fourth and eleventh week since the minimal value had been reached. The highest odds of increase were in the American stock exchanges, followed by the European and Asian (including Australia and Oceania), and the lowest in the African ones. The odds and intensity of increase in the stock exchange indices varied from continent to continent. The increase was faster than the initial decline.


Author(s):  
Hiroshi Yokoyama ◽  
Masashi Takata ◽  
Fumi Gomi

Abstract Purpose To compare clinical success rates and reductions in intraocular pressure (IOP) and IOP-lowering medication use following suture trabeculotomy ab interno (S group) or microhook trabeculotomy (μ group). Methods This retrospective review collected data from S (n = 104, 122 eyes) and μ (n = 42, 47 eyes) groups who underwent treatment between June 1, 2016, and October 31, 2019, and had 12-month follow-up data including IOP, glaucoma medications, complications, and additional IOP-lowering procedures. The Kaplan–Meier survival analysis was used to evaluate treatment success rates defined as normal IOP (> 5 to ≤ 18 mm Hg), ≥ 20% reduction of IOP from baseline at two consecutive visits, and no further glaucoma surgery. Results Schlemm’s canal opening was longer in the S group than in the μ group (P < 0.0001). The Kaplan–Meier survival analysis of all eyes showed cumulative clinical success rates in S and µ groups were 71.1% and 61.7% (P = 0.230). The Kaplan–Meier survival analysis of eyes with preoperative IOP ≥ 21 mmHg showed cumulative clinical success rates in S and μ groups were 80.4% and 60.0% (P = 0.0192). There were no significant differences in postoperative IOP at 1, 3, and 6 months (S group, 14.9 ± 5.6, 14.6 ± 4.5, 14.6 ± 3.9 mmHg; μ group, 15.8 ± 5.9, 15.2 ± 4.4, 14.7 ± 3.7 mmHg; P = 0.364, 0.443, 0.823), but postoperative IOP was significantly lower in the S group at 12 months (S group, 14.1 ± 3.1 mmHg; μ group, 15.6 ± 4.1 mmHg; P = 0.0361). There were no significant differences in postoperative numbers of glaucoma medications at 1, 3, 6, and 12 months (S group, 1.8 ± 1.6, 1.8 ± 1.5, 2.0 ± 1.6, 1.8 ± 1.5; μ group, 2.0 ± 1.6, 2.0 ± 1.6, 2.1 ± 1.6, 2.2 ± 1.7; P = 0.699, 0.420, 0.737, 0.198). Conclusion S and µ group eyes achieved IOP reduction, but μ group eyes had lower clinical success rates among patients with high preoperative IOP at 12 months.


2021 ◽  
pp. 003288552110481
Author(s):  
Thomas Wojciechowski

Past research has indicated that Major Depressive Disorder and exposure to violence are risk factors for offending. However, researchers have yet to examine how this disorder may predict recidivism risk among juvenile offenders and how the disorder moderates the effect of exposure to violence. Kaplan-Meier survival analysis was used to determine the impact of Major Depressive Disorder on time to recidivism. Cox proportional hazard modeling was applied to examine Major Depressive Disorder as a moderator of exposure to violence. Results indicated that participants with Major Depressive Disorder demonstrate greater risk for recidivism post-adjudication. The proposed moderation effect was not supported.


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Jianqing She ◽  
Jiahao Feng ◽  
Yangyang Deng ◽  
Lizhe Sun ◽  
Yue Wu ◽  
...  

Objective. The pathophysiologic mechanism of how thyroid function is related to the development and prognosis of acute myocardial infarction (AMI) remains under explored, and there has been a lack of clinical investigations. In this study, we investigate the relationship between triiodothyronine (T3) level and cardiac ejection fraction (EF) as well as probrain natriuretic peptide (NT-proBNP) on admission and subsequent prognosis in AMI patients. Methods. We measured admission thyroid function, NT-proBNP, and EF by echocardiography in 345 patients diagnosed with AMI. Simple and multiregression analyses were performed to investigate the correlation between T3 level and EF as well as NT-proBNP. Major adverse cardiovascular events (MACE), including new-onset myocardial infarction, acute heart failure, and cardiac death, were documented during the follow-up. 248 participants were separated into three groups based on T3 and free triiodothyronine (FT3) levels for survival analysis during a 2-year follow-up. Results. 345 patients diagnosed with AMI were included in the initial observational analysis. 248 AMI patients were included in the follow-up survival analysis. The T3 levels were found to be significantly positively correlated with EF (R square=0.042, P<0.001) and negatively correlated with admission NT-proBNP levels (R square=0.059, P<0.001), which is the same with the correlation between FT3 and EF (R square=0.053, P<0.001) and admission NT-proBNP levels (R square=0.108, P<0.001). Kaplan-Meier survival analysis revealed no significant difference with regard to different T3 or FT3 levels at the end of follow-up. Conclusions. T3 and FT3 levels are moderately positively correlated with cardiac function on admission in AMI patients but did not predict a long-time survival rate. Further studies are needed to explain whether longer-term follow-up would further identify the prognosis effect of T3 on MACE and all-cause mortality.


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