Patients and Data Collection
The study subjects were patients diagnosed as ‘gout’ or ‘gouty
arthritis’ in the electronic medical record system, and were treated in
the inpatient department, of The First Affiliated Hospital of Zhejiang
Chinese Medical University from May 2018 to May 2020. They came from all
over Zhejiang province in China. They were deemed included if they had
fulfilled the Gout Diagnostic Criteria formulated by the American
College of Rheumatology (ACR)13 or the 2015 Gout
Classification Criteria by the American College of Rheumatology/European
League Against Rheumatism (ACR/EULAR).14 Patients
diagnosed as secondary gout that caused by kidney or myeloproliferative
diseases, or combined with other forms of arthritis such as
osteoarthritis or rheumatoid arthritis were excluded. Tophi diagnosis
was determined by rheumatologist or endocrinologist as draining or
chalk-like subcutaneous nodules under transparent skin, often with
overlying vascular and present around joints, ears, olecranon bursae,
finger pads or tendons, based on the 2015 ACR/EULAR Gout Classification
Criteria.14 For patients who had been admitted to the
hospital more than once during the study period, only the data from the
first admission were analysed. Research approval was obtained from the
hospital’s Ethics Committee (approval no.2020-KL-127-01), and all study
subjects were fully informed consents.
One hundred and fifty-eight gout patients were included in the study,
and were classified as either ‘tophi group’ or ‘non-tophi group’ for
analysis. Twenty-two variables, such as demographics and disease and
treatment characteristics of the patients, were manually collected from
the hospital’s electronic medical record system (Table 1) .
According to the result of a large sample size study of the clinical
characteristics associated with Chinese tophaceous gout patients and
previous clinical experience, we chose 45 years old, 10 years, 3 joints
and 360 umol/l as respective cut point for onset age, disease duration,
number of joint involved and serum uric acid level.2