Online Peer Support Use Among Informal Caregivers of People Living With Alzheimer Disease or Related Dementias: National Cross-Sectional Web-Based Survey

Background: Informal caregivers of persons living with Alzheimer's disease or related dementias (ADRD) increasingly seek support in online environments. Prior work suggests that perceived value may shape online support use, yet practical and trust-related barriers may still impede uptake even when beliefs are favorable. Objective: To characterize patterns of online peer support use among informal ADRD caregivers and identify and analyze the predisposing, enabling, and need factors under the Andersen and Newman Framework of Health Services Utilization (ANFHSU) framework that are associated with use and nonuse behaviors. Methods: We conducted a cross-sectional, web-based survey that recruited a national, nonprobability sample of US adults through Qualtrics online panels from July 15 to September 16, 2023. Online peer support use was defined as searching for information or discussing caregiving topics in online communities during the past 3 months. Guided by ANFHSU, we measured predisposing characteristics, enabling resources, and need-related factors, along with additional technology-related preference measures, including willingness to use an experience-search tool and a caregiving-education tool. We summarized patterns in platform ecosystem and engagement modes and fitted 5 nested multivariable logistic regression models to identify factors associated with recent online peer support use. Among non-users, we evaluated multiple thresholds to identify a high-belief subgroup, summarized reported barriers, and modeled intention to use online peer support in the next 3 months. Results: Of 18,245 invited panel participants, 12,072 completed the survey (participation rate, 66.2%). After eligibility screening and data-quality exclusions, 1,113 unpaid informal ADRD caregivers comprised the analytic sample. Overall, 740/1,113 (66.5%) caregivers reported online peer support use in the past 3 months. Use was distributed across a fragmented platform ecosystem, with a long tail of infrequently named sources. More than half of users (402/740, 54.3%) primarily read rather than wrote posts, indicating substantial passive participation. In the fully adjusted model, higher belief in the value of online peer support was associated with greater odds of use (OR 1.04, 95% CI 1.01-1.08), along with higher eHealth literacy (OR 1.06, 95% CI 1.02-1.10), greater willingness to use an experience-search tool (OR 1.68, 95% CI 1.39-2.04), and higher caregiving stress (OR 1.03, 95% CI 1.01-1.05). Among non-users (373/1,113, 33.5%), 108/373 (28.9%) met the retained high-belief threshold despite reporting no recent use, indicating a belief-behavior gap. Among non-users, the most commonly reported barriers were sufficient offline support (118/373, 31.6%), lack of time (102/373, 27.3%), dislike of online communities (79/373, 21.2%), limited opportunity to join despite awareness (74/373, 19.8%), and security or trust concerns (67/373, 18.0%). Among non-users, 161/373 (43.2%) reported intending to use online peer support in the next 3 months. Conclusions: Our findings suggest that uptake of online peer support reflects perceived value, digital readiness, and caregiving-related need rather than need alone. A meaningful belief-behavior gap indicates that favorable beliefs do not ensure use when time, trust, and access barriers persist. These findings suggest that efforts to support ADRD caregivers should focus on reducing practical and trust-related barriers to online peer support and should recognize that engagement often occurs through reading rather than posting.