Comparative analysis of the frequency of comorbid diseases in axial psoriatic arthritis and other variants of axial spondyloarthritis. Data from a hospital cohort

Objective : to compare the frequency of comorbid diseases in axial psoriatic arthritis (axSpA) and in other variants (OV) of axial spondyloarthritis (axSpA). Material and methods . We studied 60 patients, 30 with axPsA (15 men and 15 women, mean age – 49.1±10.4 years, disease duration – 12.6±6.9 years) and 30 with OV axSpA (16 men and 14 women, mean age – 42.9±9.7 years, disease duration – 16.30±8.3 years). All patients underwent a standard rheumatological examination. The diagnosis of comorbid diseases was confirmed using ICD-10 codes. The Cumulative Illness Rating Scale (CIRS), Charlson comorbidity index (CCI) and the weighted version of Functional Comorbidity Index (w-FCI) were used to assess comorbidity. Results and discussion . Comparative analysis of the two groups revealed that axPsA patients were older than OV axSpA patients (p <0.05). Occurrence of back pain before the age of 40 was observed in 60% of axPsA cases, compared to 86.7% in OV axSpA (p<0.05). The limitation of spinal and hip mobility was less severe in axPSA than in OV axSpA. The median side flexion was 12.3 [10; 15] and 9.5 [8; 11] cm, the Schober test was 4.2 [3; 5] and 3.0 [2; 4] cm and intermalleolar distance was 95.9 [86; 102] and 83.0 [75; 100] cm, respectively (p<0.05). Patients with axPsA were more likely to have peripheral arthritis compared to patients with OV axSpA: 27 (90%) and 11 (36.7%) cases, respectively (p<0.05) and higher laboratory indices of activity: median ESR, 31.9 [10; 38] and 20.4 [5; 14] mm/h, and CRP, 20.5 [2.8; 20.7] and 13.6 [0.9; 12.0] mg/L, respectively (p<0.05). In the axPsA and OV axSpA groups, circulatory system diseases were found in 50 and 50% of patients, metabolic disorders in 76.6 and 76.6%, and gastrointestinal diseases in 46.7 and 70 %. Obesity was more common in axPsA than in OV axSpA – in 40 and 16.7% of patients, respectively (p<0.05). Conclusion. A high frequency of comorbidities, mainly cardiovascular and metabolic diseases, was found in both groups. These data should be considered in the choice of therapy and optimization of existing treatment algorithms.