Introduction

The Distance Saturation Product (DSP) is a composite index obtained during the 6-minute walk test (6MWT) and has prognostic value in several lung diseases.

Objective

The aim of our study was to evaluate the association of DSP with spirometric parameters and Diffusion Capacity for Carbon Monoxide (DLCO) in COVID-19 survivors.

Methods

It was a cross-sectional study including 311 patients referred to Pulmonary Function Tests Department, 3 months after their hospitalization for COVID-19. Measurements of Forced Vital Capacity (FVC%), Forced Expiratory Volume in the first second (FEV1%), Diffusion Capacity for Carbon Monoxide (DLCO%), 6 Minutes Walk Distance (6MWD) in meters and minimal Oxygen Saturation (mSpO2%) were performed for all patients. The DSP was calculated by multiplying 6MWD by mSpO2% during the 6MWT.

 Results

The mean age was 60 ± 13 years old. The mean values of FEV1, FVC and DLCO were 88 ± 19.39%, 85.91 ± 16.16% and 74.56 ± 17.12% respectively. DSP had a mean value   of 470.47±119.22 and     was significantly correlated with FEV1 (r=0.199; p<0.001), FVC (r=0.280; p=0.001) and DLCO (r=0.398; p>0.001). A negative correlation between DSP and length of hospital stay was also found (r= -0.236; p<0.001).

Conclusion

The DSP is a simple and reliable prognostic tool that can predict mechanical and diffusional abnormalities following hospitalization for COVID-19 pneumonia.