Predictors of damage accrual and its impact on health-related quality of life of thrombotic antiphospholipid syndrome: Independent validation of the damage index for antiphospholipid syndrome (DIAPS)

We aim to independently assess the validity of the damage index for antiphospholipid syndrome (DIAPS) in thrombotic antiphospholipid syndrome (APS) patients by exploring the prevalence and risk factors of organ damage and evaluating its impact on health-related quality of life (HR-QoL).

Cross-sectional study including all thrombotic APS patients (Sydney criteria) attending a Portuguese tertiary centre. Damage was assessed using the DIAPS, and HR-QoL using the 3- and 5-level EuroQol HR-QoL (EQ-D5-3L and 5L), and Visual Analogue Scale (VAS) applied via a phone questionnaire. Spearman’s correlation between DIAPS and the HR-QoL scales was performed. Risk factors for damage accrual and HR-QoL impairment were explored using univariate and multivariate logistic regression.

Among the 108 patients (female, 65.7%; white, 90.7%; primary APS, 75.9%; median disease duration, 6 years), damage (DIAPS≥1) developed in 48.2% of patients (mean ± SD DIAPS, 3.08 ± 1.83). DIAPS’s neuropsychiatric domain was the most affected (24.2%), followed by the peripheral vascular domain (20.3%). No clinical, demographic nor laboratory parameters were significantly associated with damage. Regarding HR-QoL, pain/discomfort, anxiety/depression and usual activities domains were the most frequently impaired in both scales. DIAPS’s domains correlated similarly with the EQ-5D-3L and 5L scales’ individual domains. Female sex, medical disorders, secondary APS and type of presenting thrombosis (arterial) increased the risk of HR-QoL impairment. Total DIAPS was associated with higher odds of mobility, self-care and pain/discomfort impairment in both EQ-5D-3L and 5L scales but lost its independent risk in multivariable analysis.

This external validation of DIAPS reinforces the ability of the score to correlate with HR-QoL while also highlighting risk factors for HR-QoL impairment other than damage accrual.