Nested and multipart prospective observational studies, flaming fiasco or efficiently economical?: The Brain, Bone, Heart case study.

BACKGROUND: Collecting new data from cross-sectional/survey and cohort observational study designs can be expensive and time-consuming. Nested (hierarchically cocooned within an existing parent study) and/or Multipart (≥ 2 integrally interlinked projects) study designs can expand the scope of a prospective observational research program beyond what might otherwise be possible with available funding and personnel. The Brain, Bone, Heart (BBH) study provides an exemplary case to describe the real-world advantages, challenges, considerations, and insights from these complex designs. MAIN: BBH is a Nested, Multipart study conducted by the Specialized Center for Research Excellence (SCORE) on Sex Differences at Emory University. BBH is designed to examine whether estrogen insufficiency-induced inflammation compounds HIV-induced inflammation, leading to end-organ damage and aging-related co-morbidities affecting the neuro-hypothalamic-pituitary-adrenal axis (brain), musculoskeletal (bone), and cardiovascular (heart) organ systems. Using BBH as a real-world case study, we describe the advantages and challenges of Nested and Multipart prospective cohort study design in practice. While excessive dependence on its parent study can pose challenges in a Nested study, there are significant advantages to the study design as well. These include the ability to leverage a parent study's resources and personnel; more comprehensive data collection and data sharing options; a broadened community of researchers for collaboration; dedicated longitudinal research participants; and, access to historical data. Multipart, interlinked studies that share a common cohort of participants and pool of resources have the advantage of dedicated key personnel and the challenge of increased organizational complexity. Important considerations for each study design include the stability and administration of the parent study (Nested) and the cohesiveness of linkage elements and staff organizational capacity (Multipart). CONCLUSION: Using the experience of BBH as an example, Nested and/or Multipart study designs have both distinct advantages and potential vulnerabilities that warrant consideration and require strong biostatistics and data management leadership to optimize programmatic success and impact.

Bone, Brain, Heart study protocol: A resilient nested, tripartite prospective cohort study of the role of estrogen depletion on HIV pathology.

PURPOSE: We describe the rationale for and design of an innovative, nested, tripartite prospective observational cohort study examining whether relative estrogen insufficiency-induced inflammation amplifies HIV-induced inflammation to cause end organ damage and worsen age-related co-morbidities affecting the neuro-hypothalamic-pituitary-adrenal axis (Brain), skeletal (Bone), and cardiovascular (Heart/vessels) organ systems (BBH Study). METHODS: The BBH parent study is the Multicenter AIDS Cohort/Women's Interagency HIV Study Combined Cohort Study (MWCCS) with participants drawn from the Atlanta MWCCS site. BBH will enroll a single cohort of n = 120 women living with HIV and n = 60 HIV-negative women, equally distributed by menopausal status. The innovative multipart nested study design of BBH, which draws on data collected by the parent study, efficiently leverages resources for maximum research impact and requires extensive oversight and management in addition to careful implementation. The presence of strong infrastructure minimized BBH study disruptions due to changes in the parent study and the COVID-19 pandemic. CONCLUSION: BBH is poised to provide insight into sex and HIV associations with the neuro-hypothalamic-pituitary-adrenal axis, skeletal, and cardiovascular systems despite several major, unexpected challenges.