Worldwide, an increase in life-expectancy and ageing of the baby boom generation is leading to a vastly expanding population of elders. In the Netherlands, the number of people aged 65 years or above will increase from 2.4 million in 2010 to 4.6 million in 2040. Furthermore, life expectancy in the Netherlands will increase from 78.8 years to 84.5 years for males and 82.7 years to 87.4 years for females in the time span .
Advancing age often implies an increase in the incidence of chronic diseases and multi morbidity with subsequent functional decline and social impairments, e.g. the loss of social support, financial limitations, and the lack of appropriate housing [2, 3]. The current system of health care delivery for community-dwelling frail elder people, with these numerous and complex health-related needs, is insufficient due to fragmentation and a lack of coordination and information exchange between health care professionals. Furthermore, sophisticated health information technologies that facilitate the essential processes of chronic care are not widely in use [4, 5]. Moreover, less urgent needs to optimally manage chronic illness and care for health related social and welfare problems are overshadowed by acute symptoms and concerns [6, 7]. Last, payment for and provision of medical and nursing care and social services are separated rather than integrated, and payment policies do not support supplemental services needed in providing chronic care [4, 5].
Frail elderly people are believed to benefit greatly from a coordinated chronic health care delivery system that integrates health and social care . A variety of models have been developed and tested over the last twenty-five years [9, 10]. This gave rise to an emerging vision of an optimal chronic care model in which health care organizations give priority to chronic care, health care providers are linked to community resources, chronic care management is separated from the acute care, elders receive self-management support, and evidence-based guidelines and clinical information systems are available to facilitate chronic care management [6, 7].
Few studies on such comprehensive chronic care models targeting frail elder persons have been conducted. Positive effects on functional performance , on self-reported quality of health care , and on informal caregiver satisfaction  are suggested, although overall (review) findings are inconsistent [14, 15]. Furthermore, previous studies have shown some cost-saving implications through a postponement or reduction in residential or nursing home admissions, hospital admissions and emergency department visits [11, 13, 16–18].
The CareWell-primary care program is a complex intervention integrating cure, care and welfare, that aims to prevent functional decline, improve quality of life and reduce or postpone hospital admissions and nursing home admissions in community-dwelling frail elderly. The program is based on existing chronic care models and is adapted to the Dutch health care system. It is designed as part of the National Care for the Elderly Program, which is launched in 2008 by the Netherlands Organization for Health Research and Development (ZonMW), in cooperation with the Nijmegen Network for the Care and Welfare of Elderly People . In developing the program, both health care professionals and a panel representing frail elderly and their informal caregivers were closely involved.
Complex interventions comprise multiple components that are interrelated or interdependent and therefore can be difficult to develop, document, evaluate and reproduce . To create a better understanding of how and why a complex intervention works, and to gain insight into costs and benefits, the framework for development and evaluation of complex interventions as published by the UK Medical Research Council is widely used . This framework emphasizes the value of including a process evaluation and an economic evaluation alongside the outcome evaluation. It provided the theoretical background for the design of our study. By gaining process information, we aim to detect gaps in implementation that might be responsible for the effectiveness of the program. Furthermore, we will explore why some general practices are more successful than others in improving the quality of care for their frail elderly patients .
This paper presents the elements of the CareWell-primary care program as well as the design of both the CareWell-primary care (cost-) effectiveness study and process evaluation.