Exercise-induced desaturation as an independent predictor of the occupational chronic obstructive pulmonary disease course in combination with hypertension

Abstract

We found a significantly greater drop in the level of oxygen saturation (SpO2) during the 6-minute walk test (6MWT) in comorbid pathology compared to isolated COPD 62 (4,14±1,44 % vs. 3,39±1,31 %, p<0,05). Exercise-induced desaturation (EID), a 4 % drop in SpO2 during the 6MWT from the initial value, occurred significantly more often in comorbid pathology – in 56,5 % of patients, compared to 48,4 % in the isolated COPD group. In comorbid patients with EID, a significant (p<0,001) increase in pro-inflammatory interleukin (IL)-18 (3296,24 (2356,03; 3978,92) pg/ml vs. 2256,30 (1980,88; 2738,86) was found) pg/ml) and a decrease in anti-inflammatory IL-10 (61,12 (48,34; 79,63) pg/ml vs. 106,35 (89,45; 126,97) pg/ml) compared to patients without EID, which indicates a greater imbalance in the formation of the inflammatory response. EID in patients of the main group was associated with an increase in the right ventricular (RV) wall thickness (5,58±0,57 mm vs. 5,22±0,61, p<0,05), growth of the right atrium diameter (39,79±2,27 mm vs. 35,83±5,02 mm, p<0.05) and a decrease in the RV diameter (27,10±2,22 mm vs. 28,37±2,40 mm, p<0.05) in comparison with comorbid patients without EID. Patients with chronic obstructive pulmonary disease (COPD) and , hypertension (HT) with EID have more pronounced signs of RV pressure overload. Receiver-operating characteristic (ROC) analysis revealed the prognostic significance (p<0,001) of IL-18 level more than 3063,7 pg/ml (with a sensitivity of 61,5 % and a specificity of 90 %, area under the ROC curve (AUC) – 0,736) and the IL-18/IL-10 ratio value more than 39,9 (with a sensitivity of 76,9 % and a specificity of 83,3 %, AUC – 0,791) for EID in COPD patients combined with HT.