Sex influence on outcomes of patients with systemic sclerosis-associated interstitial lung disease: a EUSTAR database analysis

Objective Interstitial lung disease (ILD) is the leading cause of morbidity and mortality in systemic sclerosis (SSc) patients. We aimed to investigate the impact of sex on SSc-ILD. Methods EUSTAR SSc patients with radiologically confirmed ILD and available percentage predicted forced vital capacity (%pFVC) were included. Demographics and disease features were recorded. A change in %pFVC over 12 months (s.d. 6) (cohort 1) was classified into stable (<= 4%), mild (5-9%) and large progression (>= 10%). In those with 2-year longitudinal %pFVC (cohort 2), the %pFVC change at each 12-month (s.d. 6) interval was calculated. Logistic regression analyses [odds ratio (OR) and 95% CI] and Cox proportional hazards models adjusted for age and %pFVC were applied. Results A total of 1136 male and 5253 female SSc-ILD patients were identified. Males were significantly younger, had a shorter disease duration, had a higher prevalence of CRP elevation and frequently had diffuse cutaneous involvement. In cohort 1 (1655 females and 390 males), a higher percentage of males had stable ILD (74.4% vs 69.4%, P = 0.056). In multivariable analysis, disease duration and %pFVC [OR 0.99 (95% CI 0.98, 0.99) and OR 0.97 (95% CI 0.95, 0.99), respectively] in males and age, %pFVC and anti-centromere [OR 1.02 (95% CI 1.00, 1.04), OR 0.97 (95% CI 0.96, 0.98) and OR 0.39 (95% CI 0.245, 0.63), respectively] in females were associated with large progression. The 1-year mortality rate was higher in males (5.1% vs 2.5%, P = 0.013). In cohort 2 (849 females and 209 males), a higher percentage of females showed periods of large progression (11.7% vs 7.7%, P = 0.023), the percentage of patients with none, one or two periods of worsening was not different. The overall death rate was 30.9% for males and 20.4% in females (P < 0.001). In the survival analysis, male sex was a predictor of mortality [OR 1.95 (95% CI 1.66, 2.28)]. Conclusions Male SSc-ILD patients have a poorer prognosis and sex-specific predictors exist in SSc-ILD.