Sex-based differences in clinical features associated with the emergence of systemic lupus erythematosus: a nationwide population-based 20-year retrospective study
Ann Smith, Gwyneth A Davies, Jessica Ellis, John D PaulingAbstract
Objectives
There is no single diagnostic test for systemic lupus erythematosus (SLE) and disease onset can be insidious leading to diagnostic delay. We examined clinical events recorded in secondary care prior to SLE diagnosis, alongside sex-based differences, using nationwide population databank.
Methods
We used the Secure Advanced Data Linkage Databank in Wales to construct a national cohort of patients with SLE over 20-year period (2002-2022). We examined multi-morbidity prior to diagnosis, and the impact of social deprivation on clinical outcomes, using the Welsh Index of Multiple Deprivation (WIMD). Data was expressed using descriptive analysis, and chi-square test.
Results
A total of 2341 SLE cases (87% female) were identified. Prior utilisation of secondary care services was common (68.2% of cases); most commonly in general medicine (22%), obstetrics & gynaecology (18.6%) and general surgery (13.4%). Essential hypertension (∼15%) and circulatory disorders (∼7%) were both in the top 3 clinical codes identified in secondary care records prior to SLE diagnosis in males and females. Hypothyroidism (7%) were code only found in the top 5 for females. In contrast, idiopathic thrombocytopenic purpura was uniquely found in the top 5 codes in males. The leading recorded cause of death was chest-related infection (33%) and sepsis at 12%. Deprivation analysis showed that SLE was almost three times more common in most-deprived compared to least-deprived areas (15% vs. 6%, P < 0.001).
Conclusion
Better understanding of the demographic and clinical factors warranting secondary care services pre-dating a diagnosis of SLE may help avoid diagnostic delay.