Prevalence and associated ri̇sk faktors of sarcopenia in ankylosing spondylitis patients

Aim: AS patients are at risk for sarcopenia due to chronic inflammatory processes and physical inactivity associated with disability. Despite this, studies investigating the prevalence of sarcopenia and associated factors in patients with AS is still lacking, and the results are also contradictory. The aim of this study was to evaluate the prevalence and risk factors of sarcopenia in patients with ankylosing spondylitis. Materials and methods: A cross-sectional study was conducted involving 102 AS patients, aged 18-68, who were diagnosed according to Modified New York criteria. Muscle strength of the cases was measured with a manual hand dynamometer, values below 16 kg in women and 27 kg in men were considered abnormal. The muscle mass of the patients was evaluated by bioelectric impedance analysis (BIA) and indicated as skeletal musle mass index (SMI) (kg/m2). For the SMI value, 8.87 kg/m2 in women and 6.42 kg/m2 in men were used as recommended by the European Working Group on Sarcopenia in Older People (EWGSOP). According to these results, patients were divided into 3 groups (sarcopenic, probable sarcopenic, nonsarcopenic) and associated factors were examined. Findings: Mean age was significantly higher in sarcopenic patients (p<0.01). The mean body mass index (BMI) was lower in the sarcopenic group, but the difference was not statistically significant (p=0.061, p>0.05). No significant differences were found between the groups in terms of HLA-B27 positivity, erythrocyte sedimentation rate (ESH), C reactive protein (CRP) levels, while hemoglobin levels were significantly lower in the sarcopenic group (p<0.05). The duration of the disease was significantly higher in the group of sarcopenia and probable sarcopenia. Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), health assessment questionnaire (HAQ) scores were significantly higher in the sarcopenic and probable sarcopenic group (<0,001). Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and visual analog scale (VAS) scores were significantly higher in the probable sarcopenia group than in other groups. Although BASDAI and VAS scores were high in the sarcopenic group compared to the non-sarcopenic group, the difference was not significant. Physical activity levels were significantly lower in the sarcopenic group (p<0.001). Conclusion: 7.8% sarcopenia and 12.67% probable sarcopenia patients who should be monitored for the development of sarcopenia in the future, were identified in AS patients. Advanced age, long duration of illness, active disease that restricts functionality, and low levels of physical activity were associated with the development of sarcopenia in AS patients. Key words: sarcopenia, Ankylosing Spondylitis, disease activity, physical activity