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WHI Extension Study 2010-2020

Overview

The second WHI Extension Study from 2010 to 2015 enrolled 93,500 consenting participants from the first WHI Extension Study for an additional five years of follow-up Annual updates will continue to be collected and will focus on cardiovascular events and aging, much of which will complement the existing WHI resource. Only health events occurring in African-American or Hispanic women or former HT trial participants will be documented and adjudicated. Thus the overall WHI study population is divided into two new subsamples, the Medical Records Cohort (MRC) and the Self-Report Cohort (SRC), distinguishing the quality and extent of the outcome information collected.

Background

Between 1993 and 1998, more than 161,000 women between 50 and 79 years of age were enrolled in the Women’s Health Initiative (WHI), one of the largest studies on the health of postmenopausal women ever done. These participants were scheduled to complete study activities in March 2005. At that time, participants were invited to join the first WHI Extension Study, for an additional 5 years of follow-up. In 2010, the current participants were invited to continue for additional follow-up as part for the second Extension Study, and participant follow-up will continue through another extension of the study through 2020. Longer follow-up will provide important information on outcomes that might be affected by study treatments only many years after the initiation of intervention, and on outcomes that were too uncommon for clear results to emerge during the initial follow-up period. 

WHI Study Design

The original WHI study design was composed of two primary study components: a Clinical Trial (consisting of the Dietary Modification Trial, the Hormone Therapy Trials, and the Calcium/Vitamin D Trial) and an Observational Study. All participants enrolled in one or more components of WHI who were willing to provide written informed consent for extended follow-up were eligible for the Extension Study.

WHI participants were invited to join the first Extension Study (2005-2010) at either the final WHI clinic visit/contact (CT) or in the final annual follow-up mailing (OS). Efforts to recruit women were standardized to avoid differential accrual between randomization groups and components. For the Extension Study 2010-2015 participating women continue to be associated with the same components and randomization assignments in which they were originally participating in WHI. See Extension Study 2010-2015 by Study Component and Arm for the number of participants who joined the Extension Study by component, and Extension Study 2010-2015 by Age and Race/Ethnicity for data on age and race.

The primary health outcomes of interest remain as originally defined for the Clinical Trials, with additional emphasis on cardiovascular events and aging. Additional data collection will be done via linkage mechanisms with external data sources such as the National Death Index (NDI) and the Center for Medicare/Medicaid Services (CMS) and through other designated activities such as the Long Life Study. Only health events occurring in African-American or Hispanic women or former HT trial participants will be documented and adjudicated. Thus the overall WHI study population is divided into two new subsamples, the Medical Records Cohort (MRC) and the Self-Report Cohort (SRC), distinguishing the quality and extent of the outcome information collected. To support the broader scientific objectives of the Extension Study, information on additional health events is ascertained when information about these diagnoses can be reliably obtained through self-report within the available resources.

Follow-up

All Extension Study participants complete annual data collection forms primarily by mail, using procedures similar to those used to collect follow-up data from Observational Study participants during the initial WHI. Women in the Medical Record cohort reporting study outcomes are contacted by WHI regional center staff to obtain additional detail on health event dates and providers, and a signed release to obtain medical records, if needed. Outcomes documentation is then distributed to physician adjudicators who follow existing WHI procedures for adjudicating cases.

During the extension period, all participants receive an annual WHI newsletter. The purpose of the newsletter is to present WHI news and results, to encourage retention of study participants, and to help keep addresses up-to-date.

A subset of the participants in the Medical Record Cohort were invited to participate in a home visit (WHI Long Life Study) in which blood collection, physical measurement, and additional questionnaire data were collected. 7,875 WHI Extension Study participants between the ages of 63 and 99 years old participated in the WHI Long Life Study (LLS) in-person visits between March 2012 and May 2013. See Long Life Study for more detail.

Data Collection Forms

All Extension Study participants receive an annual Form 33 - Medical History Update​​ by mail; women reporting study outcomes that require documentation also complete the more detailed section of Form 33. All participants also receive an annual Form 151 - Activities of Daily Living, which is replaced by a longer Form 155 - Lifestyle Questionnaire in the second year of the Extension. The Medical Record Cohort receives a one-time Form 153 - Medication and Supplement Inventory and all participants receive a one-time Form 156 - Supplemental Questionnaire in the third year of the Extension.

Study Protocol and Consent Form