Determining the Disease Severity in Patients with Rheumatoid Arthritis and its Related Factors Using Generalized Estimator Equations Model

Document Type : Original Article (s)


1 Patient Safety Research Center, Department of Biostatistics and Epidemiology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran

2 Rheumatologist, Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran

3 Department of Epidemiology and Biostatistics, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran


Background: The severity of the disease is the sum of the disease activity and the damage caused by the disease, and the severity of an organ involvement may change over time. The present study aimed to determine the severity of rheumatoid arthritis and its related factors in the post-diagnosis care period using generalized estimator equations (GEE) model.Methods: In this retrospective cohort study, data were collected from 107 patients with arthritis rheumatoid who were under intensive care in Shariati Hospital, Tehran, Iran, for three years (2015-2017). The severity of the disease was calculated using the Disease Activity Score-28 (DAS28) index, as an important clinical criterion, and was introduced as an ordinal response variable.Findings: The mean age of the patients was 53.6 ± 13.12 years. 84 patients (78.5%) were women and 17 patients (15.9%) had a history of smoking. The severity of the disease had a very slow downward trend over three years, although this process was very weak. The duration of care (P = 0.004) and being men (P = 0.038) were identified as significant related factors with decreased severity of the disease.Conclusion: According to our findings, controlling the severity of the disease during the care period does not show the desired condition. In addition to continuous care, it is recommended to apply more supervision on patients.


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