Illness perception and self-management behaviours in adults with multimorbidity: a systematic review protocol

Introduction Multimorbidity, characterised by the coexistence of two or more chronic conditions, represents a growing challenge for health systems, adversely affecting quality of life, self-care, treatment adherence and service utilisation. Within the context of self-regulation in health, the Common-Sense Model of Self-Regulation of Health and Illness (CSM) proposes that illness perceptions - such as beliefs about causes, control, consequences, timeline and illness identity - influence health behaviours.

Despite consolidated evidence in single-disease contexts, little is known about how these perceptions operate when multiple conditions coexist, particularly due to the need to integrate potentially conflicting representations. To date, no systematic reviews have synthesised these relationships specifically in populations with multimorbidity.

This protocol describes the methods for a systematic review aimed at examining how illness perceptions are associated with treatment adherence, self-care and indicators of chronic condition management in adults with multimorbidity. Methods and analysis This systematic review will be reported in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines.