Estratégias de identificação, investigação e classificação de desfechos incidentes no ELSA-Brasil

Abstract

OBJECTIVE:The article describes the strategies adopted by the Brazilian Longitudinal Study for Adult Health (ELSA-Brasil) for participation and retention of subjects. This is key to ensure internal validity of longitudinal studies, and to identify, investigate, and ascertain outcomes of interest. METHODS:The follow-up strategies include annual telephone contacts with new assessments and interviews every three to four years this approach aims to identify transient outcomes (reversible or not), permanent outcomes as well as complications related to the progression of major diseases -cardiovascular diseases and diabetes -to be studied. RESULTS:Telephone interviews are designed to monitor subjects' health status and to identify potential health-related events such as hospital admissions, medical visits or pre-selected medical procedures. Subjects are also encouraged to report to the ELSA-Brasil team any new health-related events. When a potential event is identified, a thorough investigation is carried out to collect relevant information about that event from medical records. All data are blinded and reviewed and analyzed by a medical expert committee. Incident outcome ascertainment follows well-established international criteria to ensure data comparability and avoid misclassification. In addition to these strategies, the occurrence of health-related events is also investigated through linkage of secondary databases, such as national mortality and hospital admission databases.CONCLUSIONS: Accurate identification of outcomes will allow to estimating their incidence in the study cohort and to investigate the effect of the exposures studied in the ELSA-Brasil at baseline and at its subsequent waves.

Cohort Profile: Longitudinal Study of Adult Health (ELSA-Brasil)

“…Annual telephone interviews include questions on self-rated health, new diagnosis of conditions of interest, hospitalizations and specific medical procedures such as dialysis, revascularization and cancer biopsy. 7 Potential events are then investigated and classified according to study protocol by a panel of physicians trained according to international classification criteria. Surveillance of clinical events is also conducted through employer reports and linkage to national databases such as the National Mortality System.…”

“… 6 c Obtained with the International Physical Activity Questionnaire (IPAQ) – Short Form, and defined according to the IPAC Guidelines for Data Processing and Analysis. 7 d Defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg, or verified treatment with anti-hypertensive medication during the past 2 weeks. e Non-hypertensive participants with systolic blood pressure 120–139 mmHg or diastolic blood pressure 80–89 mmHg.…”

Frequency of cholecystectomy and associated sociodemographic and clinical risk factors in the ELSA-Brasil study

“…23 For this analysis, we used all information about gallbladder procedures from the first two years of follow-up data.…”

Construcao do Estudo Longitudinal de Saude do Adulto (ELSA-Brasil)

“…13,17 They also follow up subjects according to the guidelines set forth by the Clinical Outcome Committee (COC). 5 The reading centers are run at specifi c sites (Rio Grande do Sul, São Paulo, Minas Gerais and Espírito Santo) with local technical and staff capabilities. The central laboratory 13 and biobank 17 are hosted at the São Paulo site and the Data Center at the Rio Grande do Sul site.…”

“…14,15 The Clinical Outcome Committee set forth strategies and actions for subject follow-up and identifi cation, ascertainment and categorization of incident events of interest. 5 The Sampling and Laboratory Analysis Committee developed procedures for laboratory analyses and quality control of all tests and has supervised sample collection, analysis and transport locally at site laboratories. It also established storage procedures to ensure quality of frozen samples including training of technical staff in result monitoring.…”