Analysis of physical performance in ankylosing spondylitis patients BY cardiopulmonary exercise test

Objective: This study aims to evaluate aerobic physical performance in ankylosing spondylitis (AS) patients by cardiopulmonary exercise test (CPET); to determine the relationship between aerobic physical performance and disease-related variables and to determine the differences with healthy controls. Materials and Methods: 40 patients who diagnosed as Ankylosing spondylitis according to modified New York criteria, aged 18-65 years, and 44 healthy controls were included in the study. We excluded the persons who had deformities that may prevent them from doing vigorous exercise, known cardiac or respiratory system disease, systemic organ involvement, neurological disease, hypertension, and those who did not want to participate in the study. Age, gender, education level, occupational status, smoking, exercise habits, disease duration, medication status, non-steroidal anti-inflammatory drug (NSAİD), and biological drug usage status were recorded for all persons. Morning stiffness duration was questioned for each patient. In order to evaluate inflammation condition, acute phase reactants (ESR, CRP) were recorded. Patient and physician global assessment scores were used to evaluate the effect on the well-being of patients with AS. In order to evaluate the axial and peripheral joint mobility of AS patients and the control group, finger to floor distance ,tragus wall distance, occiput wall distance, mouth opening, modified Schober test, intermalleolar distance, lumbar lateral flexion, cervical rotation degree, chin manubrium distance, and chest expansion measurements were done. The Bath AS disease activity scale (BASDAI) was used to evaluate disease activity in AS patients, the Bath AS functional index (BASFI) to evaluate functional status, and the Bath AS metrology index (BASMI) to evaluate axial skeleton mobility. The life quality of patients was evaluated by short form-36 (SF-36). CPET was applied to all participants in order to determine physical performance. Pulmonary function test (PFT) was done on participants before CPET. CPET was applied to the participants using the Bruce protocol on the treadmill with CortexMetalyzer 3B (MPU31-105) and SprintexCallis Z 6000 device. During CPET maximum heart rate, maximum VO2 value (ml/min/kg), respiratory exchange ratio (RER), VO2/HR (oxygen pulse), maximum time, maximum velocity reached during the test (km/h), G, VE/VO2, VE/VCO2, VT1, VT, VD/VT, VE, BF, BR, PaCO2, PetCO2, VO2/kg, VO2% norm values were recorded. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC, peak expiratory flow rate (PEF) and forced expiratory flow between %25-75% of vital capacity (FEF 25-75) values were recorded with spirometric evaluation. Results: The mean age of AS patients was 34.9±9.9 meanwhile the mean age of healthy subjects was 34.4±10.3. The mean age of two groups was similar. When the sociodemographic datas of two groups were compared drug usage, NSAİD usage, and biological treatment were significantly higher in AS patients than in healthy subjects. Apart from these, no significant difference was observed between the two groups in terms of other sociodemographic datas. While tragus wall distance and occiput wall distance were determined higher in AS patients than in healthy subjects (p<0.05), intermalleolar distance and lumbar lateral flexion measurements founded lower in AS patients than in healthy subjects (p<0.05). While VO2, VO2%, VO2/kg, TVO2, T and VT values obtained during peak cardiovascular response were found to be significantly lower in the AS group than in the control group (p<0.05); VO2maxVT1 and VO2maxVT1/kg values obtained at the first ventilatory threshold were found to be significantly higher in the AS group than in the control group (p<0.05). VT and BR% values obtained during rest were found to be significantly higher in the control group than in AS patients (p<0.05). FVC, FEV1, and PEF values were found to be significantly lower in the AS group than in the control group (p<0.05). Results obtained in CPET and PFT in AS patients were found to be higher in males compared to females. Tidal volume value obtained during rest and VO2 (ml/min/kg) value obtained at the first ventilatory threshold were found to be higher in the smoking group compared to the non-smoker group in AS patients. Heart rate obtained during rest was found to be higher in AS patients who did not use NSAİDs compared to ones using NSAİDs. It was revealed that age was negatively correlated with VO2(ml/min/kg), maximum heart rate, and RER achieved during peak cardiovascular response and with VO2 L/min and VO2 (ml/min/kg) achieved during rest in AS patients. Positive correlation was found between age and total duration. Age was negatively correlated with FEV1 and FVC values in AS patients. There was positive correlation between BASMI and disease duration in AS patients. In AS patients, positive correlation was found between VO2 (ml/min/kg) achieved at the first ventilatory threshold and BASDAI and BASFI. BASDAI showed negative correlation with VO2 (ml/min/kg) value achieved during rest in AS patients. In AS patients while BASMI showed negative correlation with FEV1, BASDAI showed negative correlation with FEF25, FEF50, and FEF25-75. Concluisons: According to CPET measurements, better results were obtained in many parameters in healthy controls compared to AS patients. VO2max value reflecting aerobic capacity was found to be significantly lower in AS patients compared to healthy controls. The reason for this decrease in aerobic exercise capacity and respiratory functions in AS patients is the involvement of the disease in various organ systems , especially in the cardiovascular, pulmonary and musculoskeletal systems. Gender was found to be an important factor affecting aerobic exercise capacity and respiratory functions in AS patients. Smoking status was found to be effective on aerobic exercise capacity measurement parameters in AS. Disease activity and functional status were not found to be effective parameters on aerobic exercise capacity and respiratory functions. Patient age in AS was found to be negatively correlated with VO2max value which reflects aerobic capacity. Further studies are needed to determine the factors affecting aerobic physical performance in ankylosing spondylitis and to determine what needs to be done to improve aerobic physical performance. Keywords: ankylosing spondylitis, aerobic capacity, physical performance, cardiopulmonary exercise test, pulmonary function