Relationship between digital ulcers and severity of lung function test in systemic sclerosis over a five-year period

Abstract

Background. Systemic sclerosis-related interstitial lung disease (SSc-ILD) is the leading cause of death in SSc. Predictors of the outcomes of ILD in SSc are under investigation.Objective – to assess association of the digital ulcers with dynamics of forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLco) in patients with SSc-ILD.Methods. It was a longitudinal study involving 77 pts with SSc-ILD (mean age was 46±13.2; 69% have limited subset of the disease; 93% were female). The mean duration of follow up was 58.9±11.3 months. At the end of the study a number of pts with digital ulcers (DUs) was 27 (35%). Additionally 77 pts with SSc-ILD were investigated with HRCT and were divided into 3 groups; The group 1 (16 pts) with improvement; group 2 (39 pts) without any changes and group 3 (22 pts) with worsening of fibrosis. PFT (measurement of forced vital capacity (FVC) and diffusion lung capacity (DLco)) were made.Results. 27 (35%) pts with SSc-ILD had DUs at the end of the study. The most pts with DUs was in groups 2 and 3 (14 and 9) accordingly at the end of the study. After 5 years of follow up FVC increased significantly in all pts without DUs (n=54) from 88.5±19 to 96±23% (p<0.05); in group 1 – from 92±20.5 to 106±19% (p><0.05); in group 2 – from 87±18 to 94±23.5% (p><0.05) and only in group 3 FVC was stable (88±22 and 87±24.5%) (p>0.05). The mean value of FVC in all pts with DUs didn’t change (88±14 and 86±16%; p>0.05) with tendency to decreasing in group 3 (from 83±12.5 to 74±13%; p>0.05). After 5 years of follow up DLco declined significantly in all pts with or without DUs, however in the 1st group decline of DLco wasn’t significant. The decreasing of DLCO was more prominent in group 3 than in group 2. Therefore, in group 2 in patient without DU (n=24) – from 65±16 to 60±11% (p<0.05) and in patients with DU (n=14) DLCO changed from 61±15 to 57±14% (p><0.05). In group 3 in patients without DU (n=13) DLCO decreased from 55±15 to 48±15% (p><0.05) and in patients with DU (n=9) – from 50±20 to 44.5±15% (p><0.05). Conclusions. In patients without DUs significant increasing of FVC during 5 years long follow up was observed. The worsening of fibrosis on HRCT in pts with DUs was associated with the lowest value of FVC and DLco at the entry and at the end of the study. Key words: systemic sclerosis, interstitial lung disease, digital ulcers>˂ 0.05) and in patients with DU (n=14) DLCO changed from 61±15 to 57±14% (p 0.05). In group 3 in patients without DU (n=13) DLCO decreased from 55±15 to 48±15% (p˂ 0.05) and in patients with DU (n=9) – from 50±20 to 44.5±15% (p˂ 0.05).Conclusions. In patients without DUs significant increasing of FVC during 5 years long follow up was observed. The worsening of fibrosis on HRCT in pts with DUs was associated with the lowest value of FVC and DLco at the entry and at the end of the study.