scholarly journals 1062Effectiveness of recruitment and retention strategies in a population based prospective LoCARPoN AIIMS cohort study

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Renu Bhasin ◽  
Kameshwar Prasad ◽  
Sadanand Dwivedi ◽  
Shashi Kant ◽  
Deepti Vibha ◽  
...  
Keyword(s):  
Cohort Study ◽  
Cognitive Disorders ◽  
Population Based ◽  
National Capital Region ◽  
Aging Research ◽  
Efficient System ◽  
Recruitment And Retention ◽  
Multiple Strategies ◽  
National Capital ◽  
Cognition And Aging

Abstract Background In Indian population, recruitment and retention of elderly population for any study is challenging due to different demographic variations and ageing effects. In LoCARPoN (Longitudinal Cognition and Aging Research in the Population of National Capital Region) Cohort study which is first study in India to identify the risk factors for stroke or major cognitive disorders among elderly different multiple strategies were adopted for recruitment and retention of healthy participants aged 50 years and above . Methods The study was conducted in urban population in Delhi, India. The strategies adopted for recruitment and retention of participants for 3 years including follow up is done by following multiple principles viz, participants centric, resource management, system functionality, approachable facilities and other reinforcement tactics. Results Among 18294 households, 9817 households were found to be eligible to participate in the study. Out of that 7383 houses were approachable others refused (2434) at first stage. By following the strategies which incorporates participants’ satisfaction, efficient system functionality and reliable information a total of 12250 eligible participants in 7383 houses were contacted, out of them 8858 (72.3%) were consented to visit medical sites . Out of he Consented individuals 7505 (61.3 %) visited medical site. Conclusions The multiple strategies used were very effective for recruitment and retention of cohort participants Key messages Multiple strategies concerning study participants needs flexible and approachable techniques helps in recruitment and retention in any longitudinal cohort studies.

scholarly journals Reconciling epidemiological models with misclassified case-counts for SARS-CoV-2 with seroprevalence surveys: A case study in Delhi, India

2020 ◽  
Author(s):  
Rupam Bhattacharyya ◽  
Ritwik Bhaduri ◽  
Ritoban Kundu ◽  
Maxwell Salvatore ◽  
Bhramar Mukherjee
Keyword(s):  
Diagnostic Tests ◽  
False Negative ◽  
False Negative Rate ◽  
Antibody Test ◽  
Population Based ◽  
National Capital Region ◽  
Rt Pcr ◽  
High False Negative Rate ◽  
True Number ◽  
National Capital

Underreporting of COVID-19 cases and deaths is a hindrance to correctly modeling and monitoring the pandemic. This is primarily due to limited testing, lack of reporting infrastructure and a large number of asymptomatic infections. In addition, diagnostic tests (RT-PCR tests for detecting current infection) and serological antibody tests for IgG (to assess past infections) are imperfect. In particular, the diagnostic tests have a high false negative rate. Epidemiologic models with a latent compartment for unascertained infections like the Susceptible-Exposed-Infected-Removed (SEIR) models can provide predictions for unreported cases and deaths under certain assumptions. Typically, the number of unascertained cases is unobserved and thus we cannot validate these estimates for a real study except for simulation studies. Population-based seroprevalence studies can provide a rough estimate of the total number of infections and help us check epidemiologic model projections. In this paper, we develop a method to account for high false negative rates in RT-PCR in an extension to the classic SEIR model. We apply this method to Delhi, the national capital region of India, with a population of 19.8 million and a COVID-19 hotspot of the country, obtaining estimates of underreporting factor for cases at 34-53 times and that for deaths at 8-13 times. Based on a recently released serological survey for Delhi with an estimated 22.86% seroprevalence, we compute adjusted estimates of the true number of infections reported by the survey (after accounting for misclassification of the antibody test results) which is largely consistent with the model outputs, yielding an underreporting factor for cases from 30-42. Together with the model and the serosurvey, this implies approximately 96-98% cases in Delhi remained unreported and whereas only 109,140 cases were reported on July 10, the true number of infections varied somewhere between 4.4-4.6 million across different estimates. While repeated serological monitoring is resource intensive, model-based adjustments, run with the most up to date data, can provide a viable option to keep track of the unreported cases and deaths and gauge the true extent of transmission of this insidious virus.

Estimated GFR and Incidence of Major Surgery: A Population-Based Cohort Study

2020 ◽  
Author(s):  
Tyrone G. Harrison ◽  
Shannon M. Ruzycki ◽  
Matthew T. James ◽  
Paul E. Ronksley ◽  
Kelly B. Zarnke ◽  
...  
Keyword(s):  
Cohort Study ◽  
Population Based ◽  
Major Surgery ◽  
Estimated Gfr

Epidemiology of pheochromocytoma and paraganglioma: population-based cohort study

2021 ◽  
Vol 184 (1) ◽  
pp. 19-28
Author(s):  
Alexander A Leung ◽  
Janice L Pasieka ◽  
Martin D Hyrcza ◽  
Danièle Pacaud ◽  
Yuan Dong ◽  
...  
Keyword(s):  
Cohort Study ◽  
Administrative Data ◽  
Laboratory Data ◽  
Population Based ◽  
Incidence Rates ◽  
Primary Objective ◽  
Administrative Databases ◽  
Secondary Objective ◽  
True Frequency ◽  
Clinical Records

Objective Despite the significant morbidity and mortality associated with pheochromocytoma and paraganglioma, little is known about their epidemiology. The primary objective was to determine the incidence of pheochromocytoma and paraganglioma in an ethnically diverse population. A secondary objective was to develop and validate algorithms for case detection using laboratory and administrative data. Design Population-based cohort study in Alberta, Canada from 2012 to 2019. Methods Patients with pheochromocytoma or paraganglioma were identified using linked administrative databases and clinical records. Annual incidence rates per 100 000 people were calculated and stratified according to age and sex. Algorithms to identify pheochromocytoma and paraganglioma, based on laboratory and administrative data, were evaluated. Results A total of 239 patients with pheochromocytoma or paraganglioma (collectively with 251 tumors) were identified from a population of 5 196 368 people over a period of 7 years. The overall incidence of pheochromocytoma or paraganglioma was 0.66 cases per 100 000 people per year. The frequency of pheochromocytoma and paraganglioma increased with age and was highest in individuals aged 60–79 years (8.85 and 14.68 cases per 100 000 people per year for males and females, respectively). An algorithm based on laboratory data (metanephrine >two-fold or normetanephrine >three-fold higher than the upper limit of normal) closely approximated the true frequency of pheochromocytoma and paraganglioma with an estimated incidence of 0.54 cases per 100 000 people per year. Conslusion The incidence of pheochromocytoma and paraganglioma in an unselected population of western Canada was unexpectedly higher than rates reported from other areas of the world.

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