Impact of HRCT pattern on six-minute walk test in patients with interstitial lung disease—An observational study
Puneet Saxena, Itishree Singh, Abhishek Kumar, S Kartik, Virender Malik, Saurabh Tiwari, KR Akhil, Somali Pattanayak, Vaibhavi G. Velangi, Harsh Jain- Pulmonary and Respiratory Medicine
ABSTRACT
Background:
Forced vital capacity (FVC) and six-minute walk distance (6MWD) are robust markers in interstitial lung diseases (ILD) to assess severity and prognosis. It is unknown whether high-resolution computed tomography pattern has any independent effect on the exercise capacity in ILD. We compared six-minute walk test (6MWT) parameters between usual interstitial pneumonia (UIP) and non-UIP ILD after adjusting for FVC.
Methods:
Data from a tertiary care ILD clinic were retrospectively analysed. Based on HRCT, patients were classified as UIP and non-UIP. 6MWT parameters and FVC were recorded for enrolled patients. 6MWD, distance-saturation product (DSP) and exertional desaturation were compared between UIP and non-UIP, using analysis of covariance (ANCOVA), with per cent predicted FVC as covariate. Patients were grouped as mild (≥70%), moderate (51%–69%) and severe (≤50%) based on FVC severity.
Results:
Out of 169 patients enrolled, only patients with all three data points: spirometry, 6MWT and HRCT were included in the analysis (n = 139). UIP group comprised 56 (40.3%), while non-UIP group had 83 (59.7%) patients. More females and lesser smokers were present in non-UIP group. Mean predicted FVC% was similar between the two HRCT groups (
Conclusion:
For a similar level of lung function, exercise capacity was similar for patients with UIP and non-UIP pattern ILD.