Studying trajectories of multimorbidity: a systematic scoping review of longitudinal approaches and evidence.

OBJECTIVES: Multimorbidity-the co-occurrence of at least two chronic diseases in an individual-is an important public health challenge in ageing societies. The vast majority of multimorbidity research takes a cross-sectional approach, but longitudinal approaches to understanding multimorbidity are an emerging research area, being encouraged by multiple funders. To support development in this research area, the aim of this study is to scope the methodological approaches and substantive findings of studies that have investigated longitudinal multimorbidity trajectories. DESIGN: We conducted a systematic search for relevant studies in four online databases (Medline, Scopus, Web of Science and Embase) in May 2020 using predefined search terms and inclusion and exclusion criteria. The search was complemented by searching reference lists of relevant papers. From the selected studies, we systematically extracted data on study methodology and findings and summarised them in a narrative synthesis. RESULTS: We identified 35 studies investigating multimorbidity longitudinally, all published in the last decade, and predominantly in high-income countries from the Global North. Longitudinal approaches employed included constructing change variables, multilevel regression analysis (eg, growth curve modelling), longitudinal group-based methodologies (eg, latent class modelling), analysing disease transitions and visualisation techniques. Commonly identified risk factors for multimorbidity onset and progression were older age, higher socioeconomic and area-level deprivation, overweight and poorer health behaviours. CONCLUSION: The nascent research area employs a diverse range of longitudinal approaches that characterise accumulation and disease combinations and to a lesser extent disease sequencing and progression. Gaps include understanding the long-term, life course determinants of different multimorbidity trajectories, and doing so across diverse populations, including those from low-income and middle-income countries. This can provide a detailed picture of morbidity development, with important implications from a clinical and intervention perspective.

Development and Testing of a Novel Measure to Assess Fidelity of Implementation: Example of the Mini-AFTERc Intervention.

BACKGROUND: Fidelity of implementation (FOI) reflects whether an intervention was implemented in clinical practice according to the originally developed manual and is a key aspect in understanding intervention effectiveness. To illustrate this process of developing a fidelity measure, this study uses the Mini-AFTERc, a brief psychological intervention aimed at managing breast cancer patients' fear of cancer recurrence, as an example. OBJECTIVES: To illustrate the development of an FOI measure through (1) applying this process to the Mini-AFTERc intervention, by including the design of a scoring system and rating criteria; (2) content validating the FOI measure using thematic framework analysis as a qualitative approach; (3) testing consistency of the FOI measure using interrater reliability. METHODS: The FOI measure was developed, its scoring system modified and the rating criteria defined. Thematic framework analysis was conducted to content validate the FOI measure using nine intervention discussions between four specialist cancer nurses and four breast cancer patients, and one simulated breast cancer patient. Intraclass-correlation was conducted to assess interrater reliability. RESULTS: The qualitative findings suggested that the Mini-AFTERc FOI measure has content validity as it was able to measure all five components of the Mini-AFTERc intervention. The interrater reliability suggested a moderate to excellent degree of reliability among three raters, r ICC = 0.84, 95% CI [0.51, 0.96]. CONCLUSION: The study has illustrated the steps that an FOI measure can be developed through a systematic approach applied to the Mini-AFTERc intervention. The FOI measure was found to have content validity and was consistently applied, independently, by three researchers familiar with the Mini-AFTERc intervention. Future studies should determine whether similar levels of interrater reliability can be obtained by distributing written and/or video instructions to researchers who are unfamiliar with the FOI measure, using a larger sample. Employing developed and validated FOI measures such as the one presented for the Mini-AFTERc would facilitate implementation of interventions in the FCR field in clinical practice as intended. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier: NCT03763825.