JMIR Publications

ABSTRACT

Background:

Cognitive complaints (CC) in individuals without dementia may predict future cognitive and functional decline. The GERO cohort aims to identify multidimensional risk factors associated with the prognosis of CC in older adults who are free of dementia. Longitudinal studies on cognitive complaints are essential for understanding their prognosis; however, such studies often face challenges in recruiting and retaining participants, which impacts the strength of the inferences drawn. Addressing these challenges is crucial for guiding future research efforts. The purpose of the study is to report the recruitment process at baseline and the attrition rates (i.e., participant dropout over time) at follow-up in the Chilean GERO cohort.

Objective:

To describe the baseline recruitment process and quantify attrition during follow-up in the Chilean GERO cohort, and to identify baseline factors associated with loss to follow-up among older adults with cognitive complaints who were free of dementia.

Methods:

The GERO cohort is a prospective study involving older adults without dementia, aged 70 years and above, living in three municipalities in Santiago, Chile. The study included assessments of cognitive performance, functionality, psychosocial factors, and other medical indicators. Baseline assessments were conducted from May 2017 to July 2021, with follow-up evaluations from December 2018 to December 2023.

Results:

Initially, 17,759 households were approached. Significant recruitment challenges included difficulties establishing contact, age limitations for participation, and high refusal rates, resulting in 291 participants being recruited at baseline. The participants were predominantly older women (80%), with an average age of 76.8 ± 5.1 years and 8.9 ± 4.8 years of education. The study attrition rate over three years was 42%. Factors associated with loss to follow-up included refusal to participate, illness, death of the participant, lack of contact after multiple attempts, and relocation. Univariate analysis revealed that age, cognitive status, and activities of daily living (ADL) were significant predictors of attrition. In contrast, in the multivariable analysis, only age and Instrumental Activities of Daily Living remained significant predictors of loss to follow-up.

Conclusions:

Our findings highlight the need to address barriers to recruitment and retention in aging studies. They emphasize the importance of age and functional ability as predictors of attrition, underscoring the need for strategies to mitigate these challenges in future research. Clinical Trial: NCT04265482 in ClinicalTrials.gov.