Direct and Indirect Relationships Between Physical Activity, Fitness Level, Kinesiophobia, and Health-Related Quality of Life in Patients with Rheumatic and Musculoskeletal Diseases: A Network Analysis

INTRODUCTION: Using a network analysis, the present study investigated the extent to which physical activity (PA), objective fitness level, kinesiophobia, and health-related quality of life (HRQoL) interact in patients with rheumatic and musculoskeletal diseases. The objectives were twofold: 1) to clarify the direct and indirect relationships between these variables while controlling for the shared variance between them, and 2) to establish a potential ranking of influence among them. METHODS: This cross-sectional design study involved patients recruited from a rheumatology unit. One hundred and twenty patients completed self-reported measures of PA, the Tampa scale of kinesiophobia and the 36-item Short-Form Health Survey, and ninety-seven of those patients performed the six-minute walking test and the thirty-second sit-to-stand test. Network analyses were conducted using bootnet and qgraph packages. RESULTS: Weekly time spent on PA, as well as physical fitness measures, were directly linked to kinesiophobia and the HRQoL physical dimension, but indirectly linked to HRQoL mental dimension through the mediation of kinesiophobia. Specifically, weekly PA time had direct relationships to physical functioning, vitality, and role limitations due to physical and emotional problems. Fitness measures had direct relationships with physical functioning, bodily pain, and mental health. The analyses did not clearly highlight one variable as the most influential in the network. DISCUSSION: The study highlights the complexities of direct and indirect biopsychosocial relationships that are at the core of patients’ daily functioning. Measurement of PA, use of a longitudinal design, and interventions are discussed.