RESUMEN
Background: Over the last 20 years, the effectiveness of complex care programs aiming to prevent adverse outcomes in frail elderly people has been disappointing. Recently, we found no effectiveness of the CareWell primary care program. It is largely unknown to what extent incomplete implementation of these complex interventions influences their outcomes. Objective: To examine the association between the degree of implementation of the CareWell program and the prevention of functional decline in frail elderly people. Methods: Quantitative process evaluation conducted alongside a cluster-controlled trial. Two hundred and four frail elderly participants from six general practitioner practices in the Netherlands received care according to the CareWell program, consisting of four key components: multidisciplinary team meetings, proactive care planning, case management and medication reviews. We measured time registrations of team meetings, case management and medication reviews and care plan data as stored in a digital information portal. These data were aggregated into a total implementation score (TIS) representing the program's overall implementation. We measured functional decline with the Katz-15 change score (follow-up score at 12 months minus the baseline score). The association between TIS and functional decline was analyzed with linear mixed model analyses. Results: We found no statistically significant differences in functional decline between TIS groups (F = 1.350, P = 0.245). In the groups with the highest TISs, we found more functional decline. Conclusion: A higher degree of implementation of the CareWell program did not lead to the prevention of functional decline in frail elderly people.