Process evaluation of a multicomponent dyadic intervention study with exercise and support for people with dementia and their family caregivers
BACKGROUND
A randomized controlled trial of a multicomponent dyadic intervention (a translated and adapted version of an intervention that has been shown to be effective for people with dementia in the USA) was performed. The exercise and support intervention was intended to reduce depressive symptoms of people with dementia and their caregivers. The purpose of this process evaluation is to create in-depth insight into the delivery of the intervention and the effect analysis, to prevent drawing inappropriate conclusions on the efficacy or effectiveness of the intervention, and to formulate recommendations for future studies on complex geriatric interventions.


METHODS
Qualitative and quantitative data were collected. The process evaluation was performed according to the model presented by Reelick and colleagues, which encompasses the following three process components: (1) success rate of recruitment and quality of the study population; (2) the quality of execution of the complex intervention; and (3) the process of acquisition of the data.


RESULTS
The study design met high research standards and the intervention was carefully delivered. Evaluation of the study population quality revealed a profound recruitment process resulting in a reasonable sample size. Attrition rate during follow-up was acceptable. With regard to the evaluation of the intervention quality, most interviewed participants experienced benefits of the intervention. Attendance at the home visits was high and attrition to homework was moderate. Evaluation of the data acquisition showed the positive value of the use of a mixed design; qualitative analysis of the intervention revealed outcomes not measured in the quantitative analysis.


CONCLUSIONS
The process evaluation revealed a carefully and soundly performed study. The mixed design contributed to valuable insights. However, there were some restrictions worth considering. The intervention components may have a different feasibility by moderate attrition to homework and some negative experiences of participants, which may be an indication of too intensive an intervention for this frail population in this specific country. As a result, the results of the statistical effect analysis should be interpreted with caution.


TRIAL REGISTRATION
The study has been registered at the Netherlands National Trial Register: NTR1802, registration date 6 May 2009.