Treatment Adherence, Psychosocial Factors, and Clinical Outcomes in Repeatedly Hospitalized Patients with Rheumatoid Arthritis and Ankylosing Spondylitis: An Exploratory Mid-Term Longitudinal Mixed-Effects Study.

backgroundRheumatoid arthritis (RA) and ankylosing spondylitis (AS) are chronic inflammatory rheumatic diseases associated with impaired quality of life, persistent disease burden, and increased healthcare utilization. Treatment adherence and psychosocial factors may influence outcomes, but their longitudinal associations in real-world hospitalized populations remain insufficiently characterized.

methodsWe conducted a single-center, retrospective, mid-term longitudinal observational study including 50 adults with RA or AS who experienced repeated hospitalizations over a four-year period. The final dataset comprised 196 hospitalization episodes analyzed as repeated observations nested within individual patients. Disease activity was assessed using DAS28 in RA and ASDAS and/or BASDAI in AS, according to data availability and routine clinical practice. Treatment adherence, quality of life, anxiety, social isolation, patient-provider communication, dietary support, inflammatory markers, and hospitalization-related outcomes were extracted from medical records and structured inpatient assessments. Linear mixed-effects models were used for continuous outcomes, and ordinal mixed-effects models were used for ordered categorical outcomes, with adjustment for age, sex, and time where appropriate.

resultsIn RA, higher treatment adherence was associated with lower disease activity over time. In AS, comparable associations were not detected, possibly reflecting disease-specific factors, limited variability in adherence, and reduced statistical power in the smaller AS subgroup. Better patient-provider communication was associated with higher adherence and lower anxiety, whereas greater social isolation was associated with poorer quality of life. More favorable dietary support was associated with better adherence, although the magnitude of this association should be interpreted cautiously because of sparse categories and wide confidence intervals. Lower inflammatory burden, particularly lower CRP over time, was associated with lower hospitalization-related costs.

conclusionsIn this selected cohort of repeatedly hospitalized patients with RA or AS, treatment adherence, psychosocial factors, and supportive care indicators were associated with clinically relevant longitudinal outcomes. The findings support a multidisciplinary, patient-centered approach to inflammatory rheumatic disease care. However, because of the retrospective design, modest sample size, selected inpatient population, non-standardized assessment of several variables, and possible instability of some ordinal model estimates, the results should be interpreted as exploratory and confirmed in larger prospective cohorts.