Assessment of arterial stiffness variables in patients with rheumatoid arthritis: A mediation analysis

We aimed to study arterial stiffness variables in patients with rheumatoid arthritis (RA), specifically considering their associations with path model mediation analysis. We examined arterial stiffness expressed by the pulse wave velocity (PVW), augmentation index (Alx), distensibility, and clinical and biochemical characteristics in a cohort of 214 RA patients. Variable associations were analysed using multivariate linear regression analysis. We also used path model mediation analysis for PWV variable. Our results indicate that age, systolic blood pressure (SBP), and body mass index (BMI) were significantly associated with PWV, and collectively accounted for 32% of PWV variability. The parallel mediation analysis showed that SBP and BMI accounted for 21% and 7% (a total of 28%) of the total effect of age on PWV, respectively, indicating a partial mediation effect. The associated variables with Alx were age and tender joint count, while those with distensibility were BMI and sex, overall accounting for 16.5% and 4.7% of the variation in Alx and distensibility, respectively. We observed no associations of arterial stiffness with inflammatory variables, disease activity and duration, or cholesterol levels. In conclusion, in our population of RA patients, age is the most important variable that determines the increase in PWV. We have also shown that a significant proportion of the negative effects of age on PWV occurs through increases in SBP and BMI. In our study, lipid and inflammation variables were not associated with an increase in arterial stiffness.