CARDIOPULMONARY EXERCISE TESTING AT SILICOSIS: A MODALITY TO EVALUATE WORKING PERFORMANCE

Abstract

In an examination of the relationship between silicosis and lung function, most of the studies focus on pulmonary function tests (PFT). However, no enough data can be found about cardiopulmonary exercise testing (CPET) of silicosis patients. In this study, we applied CPET to silicosis patients; as well as pulmonary function tests to see whether silicosis effects exercise capacity. Fifty-two silicosis patients, diagnosed at an occupational disease hospital, were included in our study when they admitted to a university hospital occupational disease clinic for follow-up. Informed consent was provided from the patients. CPET and PFT were performed to the patients in addition to chest X-ray and high resolution tomography (HRCT). Statistical analyses were achieved by SPSS (Version 22.0, SPSS Inc., Chicago, IL, USA). Mean +/- Standard deviation and median were used for descriptive statistics. Kruskal-Wallis Test was used to compare groups, because parametric test assumption was not provided for continuous variables. Post-hoc analysis were performed to find the source of difference. Correlation between continuous variables was analysed by Spearman's correlation coefficient. P value <0.05 was accepted as statistically significant. Peak VO2, VAT, maximum load values did not reveal significant difference between ILO category 1,2 and 3 silicosis patients. Respiratory exchange ratio (RER) differency found close to the significance between ILO categories (p=0,057). Increasing ILO categories revealed increased peak RER values at decreased maximum load (category 3 versus 2; p=0,050, r=0,635 and category 3 versus 1; p=0,023,r= - 0,529). FEV1/FVC found decreased at category 3 (p=0.488). After adjustment for smoking, decreased FEV1/FVC at category 3 found significant (p=0.025). Smoking is one of the important factors that can confound the association between silicosis and lung function. After adjustment for smoking, only FEV1/FVC was decreased with disease progression. CPET revealed no any difference between silicosis categories. According to the literature, during early categories of silicosis, pulmonary function loss is limited. Hence, cardiopulmonary exercise testing might be one of the modalities to evaluate workforce loss at silicosis patients.