Abstract
BACKGROUND: China's rapidly aging urban population has intensified demand for sustainable community-based eldercare. Volunteer-supported eldercare services are increasingly promoted as complements to formal care, yet their contribution to functional, relational, informational, and managerial continuity remains insufficiently understood. This study examined systemic barriers to continuity and explored strategies for embedding volunteers within integrated eldercare systems. METHODS: An explanatory sequential mixed-methods design Quantitative → Qualitative (QUAN→QUAL) was conducted in Shanghai's most aged districts, Hongkou and Huangpu. A cross-sectional survey of 880 older adults assessed service willingness, utilization, and predictors of dissatisfaction using binary logistic regression. Subsequently, 21 in-depth interviews with older adults, volunteers, and Red Cross staff explored mechanisms underlying observed discontinuities. Quantitative and qualitative findings were integrated using the Pillar Integration Process and mapped onto Haggerty's four-dimensional continuity framework. RESULTS: Although 96.3% of respondents expressed willingness to use volunteer-supported eldercare services, only 46.5% had done so. Service dissatisfaction was strongly associated with frequent volunteer turnover (aOR = 2.31; 95% CI: 1.83-3.14) and digital illiteracy, particularly among adults aged ≥ 80 years (89.3%). Integrated analyses identified four interrelated barriers undermining continuity: restrictive Long-Term Care Insurance (LTCI) eligibility excluding moderately disabled older adults; unstable volunteer-client relationships; digital and informational gaps compromising coordination and safety; and fragmented governance limiting cross-sector collaboration. CONCLUSIONS: Bridging the willingness-utilization gap requires systemic reform across policy, organizational, service, and individual levels. Priorities include expanding LTCI eligibility, formalizing volunteer roles within interdisciplinary teams, establishing navigation mechanisms for unmet "grey-zone" needs, and enhancing digital literacy through hybrid information systems. By extending Haggerty's continuity framework beyond clinical care, this study illustrates how volunteers can be positioned as integrated extensions of professional teams-supported by stable governance and interoperable information platforms-to enable person-centered, sustainable eldercare in super-aged urban settings.