Epidemiology and effect of psychiatric comorbidities on survival rates in patients with systemic sclerosis: A nationwide population-based cohort study

Background: Systemic sclerosis (SSc) is a chronic, disabling connective tissue disease with a considerable psychological burden. While studies suggest a higher prevalence of psychiatric disorders in SSc, most have small sample sizes. Methods: Using Taiwan's National Health Insurance Research Database, we identified 3270 SSc patients from the catastrophic illness registry and matched them 1:4 by age and sex with 13,080 controls. We compared the incidence rate ratios (IRRs) of new psychiatric disorder diagnoses between the two groups and analyzed risk factors using a Cox proportional hazards model. Kaplan-Meier analysis and log-rank test were used to compare survival in SSc patients with and without psychiatric conditions (matched at a 1:4 ratio by age, sex and CCI). We compared psychiatric disorder incidence rates. Results: The SSc group had a significantly higher incidence of psychiatric disorders than controls (IRR = 1.66, p < 0.001). In SSc patients, treatment with an oral daily steroid dose of >= 7.5 mg (hazard ratio [HR] = 1.71, p = 0.010), intravenous steroid pulse therapy (HR = 2.34, p < 0.0042), or D-penicillamine (HR = 1.60, p < 0.001) served as an independent risk factor for psychiatric comorbidities. SSc patients with psychiatric comorbidities had significantly lower survival rates than those without. Conclusions: Patients with SSc are at an increased risk of psychiatric comorbidities, which can negatively affect their survival rates. Treatment with a daily oral steroid dose of >= 7.5 mg, intravenous steroid pulse therapy, or D-penicillamine is a risk factor for psychiatric comorbidities in SSc.