Analysis of follow-up data

2020 ◽  
pp. 93-118
Author(s):  
Bendix Carstensen
Keyword(s):  
Data Collection ◽  
Time Scale ◽  
Poisson Regression ◽  
Time Dependent ◽  
Follow Up Study ◽  
Dependent Variables ◽  
The Status ◽  
Over Time

This chapter assesses the analysis and representation of follow-up data. follow-up refers to the process of monitoring persons over time for occurrence of a (set of) prespecified event(s). Practical data collection is often via look-up in registers or databases. The basic requirements for recordings in a follow-up study include date of entry to the study, date of exit from the study, and the status of the person at the exit date. The chapter then explains the likelihood from a follow-up study and why one can analyse rates using Poisson regression. The likelihood contribution from a single person's follow-up can be subdivided in contributions from subintervals of the follow-up. The chapter details the task of splitting the follow-up time along a time-scale. Finally, it considers time-dependent variables.

RACIAL ATTITUDES AMONG SOUTH AFRICAN UNIVERSITY STUDENTS: A FOLLOW-UP STUDY AFTER FOUR YEARS

2008 ◽  
Vol 36 (8) ◽  
pp. 1061-1062
Author(s):  
Neeshi Singh Pillay ◽  
Steven J. Collings
Keyword(s):  
Data Collection ◽  
South African ◽  
Representative Sample ◽  
Group Membership ◽  
Racial Group ◽  
Modern Racism ◽  
Follow Up Study ◽  
Item Scores ◽  
Over Time

In 2002, moderately high levels of modern and old-fashioned racism were documented in a representative sample of 433 students registered in undergraduate courses at a South African university (Pillay & Collings, 2004). In 2006, this survey was replicated using identical methods of data collection and a sample which was representative of university enrolments for 2006 in terms of gender and race: N = 543, gender = 50% female; race = black (40%), Indian (40%), white (17%), colored (3%). Over the four-year period, there was a significant increase in mean item-scores for old-fashioned racism [M = 1.95 vs. 2.15; F(1,971) = 15.16, p < .01], and this finding was supported by a significant study x race interaction, F(3,971) = 6.33, p < .05. Mean item scores increased significantly over time among Indians (2.11 vs. 2.29) but not among blacks (1.74 vs. 1.76), coloreds (2.01 vs. 2.04), or whites (2.33 vs. 2.35). A significant increase in levels of modern racism over the four-year period [M = 2.74 vs. 3.10; F(1,971) = 8.48, p < .01] was indicated by a significant study x race interaction, F(3,971) = 7.31, p < .05, with mean item scores increasing significantly over time among Indians (2.94 vs. 3.62) and whites (3.00 vs. 3.58) but not among blacks (2.04 vs. 2.06) or coloreds (2.47 vs. 2.49). Together these findings suggest that both overt and covert forms of racism persist, with levels of racism varying as a function of racial group membership.

scholarly journals Dynamic prediction of overall survival: a retrospective analysis on 979 patients with Ewing sarcoma from the German registry

BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e036376
Author(s):  
Chuchu Liu ◽  
Anja J Rueten-Budde ◽  
Andreas Ranft ◽  
Uta Dirksen ◽  
Hans Gelderblom ◽  
...  
Keyword(s):  
Prediction Model ◽  
Ewing Sarcoma ◽  
Prediction Models ◽  
Postoperative Radiotherapy ◽  
Time Dependent ◽  
Strong Impact ◽  
Dynamic Prediction ◽  
Dependent Variables ◽  
Over Time

ObjectivesThis study aimed at developing a dynamic prediction model for patients with Ewing sarcoma (ES) to provide predictions at different follow-up times. During follow-up, disease-related information becomes available, which has an impact on a patient’s prognosis. Many prediction models include predictors available at baseline and do not consider the evolution of disease over time.SettingIn the analysis, 979 patients with ES from the Gesellschaft für Pädiatrische Onkologie und Hämatologie registry, who underwent surgery and treatment between 1999 and 2009, were included.DesignA dynamic prediction model was developed to predict updated 5-year survival probabilities from different prediction time points during follow-up. Time-dependent variables, such as local recurrence (LR) and distant metastasis (DM), as well as covariates measured at baseline, were included in the model. The time effects of covariates were investigated by using interaction terms between each variable and time.ResultsDeveloping LR, DM in the lungs (DMp) or extrapulmonary DM (DMo) has a strong effect on the probability of surviving an additional 5 years with HRs and 95% CIs equal to 20.881 (14.365 to 30.353), 6.759 (4.465 to 10.230) and 17.532 (13.210 to 23.268), respectively. The effects of primary tumour location, postoperative radiotherapy (PORT), histological response and disease extent at diagnosis on survival were found to change over time. The HR of PORT versus no PORT at the time of surgery is equal to 0.774 (0.594 to 1.008). One year after surgery, the HR is equal to 1.091 (0.851 to 1.397).ConclusionsThe time-varying effects of several baseline variables, as well as the strong impact of time-dependent variables, show the importance of including updated information collected during follow-up in the prediction model to provide accurate predictions of survival.

Changes in DNA methylation persist over time in males with severe alcohol use disorder—A longitudinal follow‐up study

2021 ◽  
Author(s):  
Soundarya Soundararajan ◽  
Arpana Agrawal ◽  
Meera Purushottam ◽  
Shravanthi Daphne Anand ◽  
Bhagyalakshmi Shankarappa ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Alcohol Use ◽  
Alcohol Use Disorder ◽  
Follow Up Study ◽  
Over Time

scholarly journals Human Milk Antibodies Against SARS-CoV-2: A Longitudinal Follow-Up Study

2021 ◽  
pp. 089033442110301
Author(s):  
Hannah G. Juncker ◽  
M. Romijn ◽  
Veerle N. Loth ◽  
Tom G. Caniels ◽  
Christianne J.M. de Groot ◽  
...  
Keyword(s):  
Human Milk ◽  
Clinical Symptoms ◽  
Immunoglobulin A ◽  
Spike Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Follow Up Study ◽  
Lactating Mothers ◽  
Milk Antibodies ◽  
Over Time

Background: Human milk contains antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) following Coronavirus Disease 2019 (COVID-19). These antibodies may serve as protection against COVID-19 in infants. However, the evolution of these human milk antibodies over time is unclear. Research Aim: To elucidate the evolution of immunoglobulin A (IgA) against SARS-CoV-2 in human milk after a SARS-CoV-2 infection. Methods: This longitudinal follow-up study included lactating mothers ( N = 24) who had participated in the COVID MILK study. To assess the evolution of SARS-CoV-2 antibodies, serum and human milk samples were collected 14–143 days after the onset of clinical symptoms related to COVID-19. Enzyme-Linked ImmunoSorbent Assay was used to detect antibodies against the ectodomain of the SARS-CoV-2 spike protein. Results: SARS-CoV-2 antibodies remain present up to 5 months (143 days) in human milk after onset of COVID-19 symptoms. Overall, SARS-CoV-2 IgA in human milk seems to gradually decrease over time. Conclusion: Human milk from SARS-CoV-2 convalescent lactating mothers contains specific IgA antibodies against SARS-CoV-2 spike protein up to at least 5 months post-infection. Passive viral immunity can be transferred via human milk and may serve as protection for infants against COVID-19. Dutch Trial Register on May 1st, 2020, number: NL 8575, URL: https://www.trialregister.nl/trial/8575 .

scholarly journals Risk Factors for Prostate Cancer Detection After a Negative Biopsy: A Novel Multivariable Longitudinal Approach

2010 ◽  
Vol 28 (10) ◽  
pp. 1714-1720 ◽  
Author(s):  
Peter H. Gann ◽  
Angela Fought ◽  
Ryan Deaton ◽  
William J. Catalona ◽  
Edward Vonesh
Keyword(s):  
Prostate Cancer ◽  
Risk Factors ◽  
Specific Antigen ◽  
Time Dependent ◽  
Negative Biopsy ◽  
Gland Volume ◽  
Piecewise Exponential ◽  
Over Time ◽  
Negative Biopsies

Purpose To introduce a novel approach for the time-dependent quantification of risk factors for prostate cancer (PCa) detection after an initial negative biopsy. Patients and Methods Data for 1,871 men with initial negative biopsies and at least one follow-up biopsy were available. Piecewise exponential regression models were developed to quantify hazard ratios (HRs) and define cumulative incidence curves for PCa detection for subgroups with specific patterns of risk factors over time. Factors evaluated included age, race, serum prostate-specific antigen (PSA) concentration, PSA slope, digital rectal examination, dysplastic glands or prostatitis on biopsy, ultrasound gland volume, urinary symptoms, and number of negative biopsies. Results Four hundred sixty-five men had PCa detected, after a mean follow-up time of 2.8 years. All of the factors were independent predictors of PCa detection except for PSA slope, as a result of its correlation with time-dependent PSA level, and race. PSA (HR = 3.90 for > 10 v 2.5 to 3.9 ng/mL), high-grade prostatic intraepithelial neoplasia/atypical glands (HR = 2.97), gland volume (HR = 0.39 for > 50 v < 25 mL), and number of repeat biopsies (HR = 0.36 for two v zero repeat biopsies) were the strongest predictors. Men with high-risk versus low-risk event histories had a 20-fold difference in PCa detection over 5 years. Conclusion Piecewise exponential models provide an approach to longitudinal analysis of PCa risk that allows clinicians to see the interplay of risk factors as they unfold over time for individual patients. With these models, it is possible to identify distinct subpopulations with dramatically different needs for monitoring and repeat biopsy.

scholarly journals Media Representation of Children’s Privacy in the Context of the Use of “Smart” Toys and Commercial Data Collection

2019 ◽  
Vol 9 (18) ◽  
pp. 6-25 ◽  
Author(s):  
Tijana Milosevic ◽  
Patricia Dias ◽  
Charles Mifsud ◽  
Christine W. Trueltzsch-Wijnen
Keyword(s):  
Data Collection ◽  
Media Coverage ◽  
Media Representation ◽  
Children And Families ◽  
Follow Up Study ◽  
The Media ◽  
Children’S Voices ◽  
Privacy Risks

The growing use of “smart” toys has made it increasingly important to understand the various privacy implications of their use by children and families. The article is a case study of how the risks to young children’s privacy, posed by the commercial data collection of producers of “smart” toys, were represented in the media. Relying on a content analysis of media coverage in twelve European countries and Australia collected during the Christmas season of 2016/2017, and reporting on a follow-up study in selected countries during the Christmas season of 2017/2018, our article illustrates how the issue of children’s privacy risks was dealt with in a superficial manner, leaving relevant stakeholders without substantive information about the issue; and with minimum representation of children’s voices in the coverage itself.

Incidence of Mental Disorders in the Finnish UKKI Study

1996 ◽  
Vol 168 (6) ◽  
pp. 672-678 ◽  
Author(s):  
Ville Lehtinen ◽  
Juha Veijola ◽  
Tomi Lindholm ◽  
Juha Moring ◽  
Pauli Puukka ◽  
...  
Keyword(s):  
Mental Disorders ◽  
Data Collection ◽  
Psychotic Disorders ◽  
Diagnostic System ◽  
Annual Incidence ◽  
Baseline Survey ◽  
Psychiatric Interview ◽  
Neurotic Disorders ◽  
Follow Up Study

BackgroundThe aim was to give estimates of the incidence of different mental disorders from a Finnish prospective epidemiological follow-up study, the UKKI Study.MethodThe original probability sample consisted of 1000 persons, aged 15–64 years. The baseline survey took place in 1969–71, and follow-up surveys were conducted 5 and 16 years after the baseline survey. The research methods included a personal psychiatric interview and data collection from different registers. The diagnostic system was based on the ICD–8 classification.ResultsThe estimated annual incidence of all mental disorders was close to 15 per 1000 both between baseline and the 5-year follow-up as well as between the 5-year and the 16-year follow-up. During the entire 16-year follow-up period the annual incidence of all disorders was 14 per 1000 in men and 17 per 1000 in women. The annual incidence of neurotic disorders was 10 per 1000 in men and 14 per 1000 in women, and that of psychotic disorders 2 per 1000.ConclusionsIn the literature, there are huge differences in the results concerning incidence of mental disorders. The results of the present study were rather close to those of the Swedish Lundby Study, but nowhere near the results of the American ECA Study.

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