Change needs to be sustained if the benefits are to be fully realised and maintained, and the investment of time and resources worthwhile. The benefits are quality of care, and in the case of chronic conditions may need to be sustained over an extended period. Yet in a 2016 study, Tricco  found that sustainability was not considered in KT strategies applied to chronic disease, and the tendency to divert resources away from the strategy continues to be a problem. [1,2]
Full spectrum models including guidance for sustainability of KT strategies include Action research, Collaborative model for achieving breakthrough improvement, PDSA, and Re-AIM. 
Wensing  notes that it is essential for improvements to be embedded in routine practice in order to prevent relapse. To help you with this, the Registered Nurses’ Association of Ontario (RNAO) has developed a leading change toolkit based on the Knowledge-to-Action framework. This includes templates for developing implementation and sustainability action plans.
For interventions that demonstrate efficacy (produces the desired result under controlled conditions) and effectiveness (produces the desired result under real world conditions) the question of wider application may come up as part of sustainability. There are frameworks available to help. First step is to define what you want to achieve. Is it scale-up or scalability?
The World Health Organization defines scale up as ‘deliberate efforts to increase the impact of successfully tested health innovations so as to benefit more people and to foster policy and programme development on a lasting basis’. 
Milat , in work underpinning the NSW Health ISAT tool defines scalability as, ‘the ability of a health intervention shown to be efficacious on a small scale and/or under controlled conditions to be expanded under real world conditions to reach a greater proportion of the eligible population while retaining effectiveness.’
Download The Intervention Scalability Assessment Tool (1.4MB pdf)
Visit RNAO Leading Change toolkit
Visit WHO Nine steps for scaling-up (512kb pdf)
Watch: IRL - Sustainability: Part I
Page created 16 May 2022