Background The high-resolution computed tomography (HRCT) score showed correlation with % predicted Forced Vital Capacity (%pFVC) in our previous study¹. However, the correlations of the delta (Δ) HRCT scores with Δ %pFVC and Δ clinical variables have not been reported.

Objectives To evaluate the correlation of the Δ HRCT scores with Δ %pFVC, Δ Modified Rodnan Skin Score (MRSS) and Δ ESR in patients with early SSc.

Methods We used an inception cohort of early SSc patients seen at the Rheumatology clinic, Chiang Mai University, between January 2010 and June 2014. All patients underwent HRCT at study entry and every 12 months thereafter. The extent of ground glass (GG), lung fibrosis (Fib), bronchiectasis (B) and honeycombing (HC) was scored and then were aggregated to produce a total (t) HRCT score¹. Thirty-one SSc patients who underwent pulmonary function test within 12 weeks of their corresponding HRCT were identified. The Δ HRCT score (the difference between the last visit and the baseline HRCT score) along with their corresponding clinical variables were used for analysis. Data abstracted include the HRCT scores: total (t)-GG, t-Fib, t-B, t-HC and t-HRCT; %pFVC; MRSS; and ESR.

Results Mean±SD age and disease duration (from non-Raynaud's phenomenon to undergo first HRCT) were 52.2 ± 8.8 years and 11.7 ± 7.1 months, respectively. Seventeen (54.8%) patients were female and 20 (64.5%) were classified as diffuse cutaneous SSc. Mean±SD interval between the two HRCT tests was 16.0 ± 7.2 months. The mean±SD baseline t-GG, t-Fib, t-B, t-HC and t-HRCT scores were 3.2± 3.3, 4.0±3.5, 2.4±3.3, 0.7 ±2.2 and 10.3±10.3, respectively. The mean ±SD baseline %pFVC, MRSS and ESR were 69.0±15.9, 15.4±9.9 and 34.0±25.3, respectively. The mean ±SD absolute Δ HRCT scores were: t-GG, -0.5±2.1 (range -6.0 to 3.0); t-Fib, 0.3±1.9 (range -7.0 to 5.0); t-B, 0.5±1.2 (range -2.0 to 4.0); t-HC, 0.3±0.8 (range 0 to 3.0); t-HRCT, 0.7±3.8 (range-9.0 to 10.0). The mean ±SD absolute Δ clinical variables were: % of predicted FVC, 4.8 ±12.8 (range -33 to 26); MRSS, 4.9± 6.5 (range -17.0 to 8.0); ESR, -5.8 ±22.3 (range -60 to 58). Spearman rank correlations coefficient between the mean absolute ΔHRCT scores and the other variables were (N=31):

Conclusions In this study, the HRCT scores were fairly stable over the first two years of patients with early SSc; while %pFVC, MRSS and ESR showed relatively more change over the times. We found significantly negative correlation between Δ t-HC and Δ ESR. However, no significant correlations of Δ HRCT scores with Δ %pFVC and Δ MRSS were observed. Further longer study duration with larger study population is needed to confirm our findings.

1. Wangkaew S, et al. Mod Rheumatol. 2015 Dec 23:1–6.

Disclosure of Interest None declared