Descriptive epidemiology of hospitalisation for psoriasis

Background: The epidemiology and outcome of people hospitalised with a primary diagnosis of psoriasis has never been characterised previously in the United Kingdom. The aim of the study was to characterise the epidemiology of people admitted to hospital with a primary diagnosis of psoriasis. Methods: Routine hospital data from a large urban area of South Wales, UK (with a population of approximately 435 000) were record-linked using probability matching algorithms to mortality data from the Office of National Statistics (1991–2005). Relative survival was compared using Cox proportional hazards models. Patients were selected with a primary diagnosis of psoriasis. Admission rates were calculated as a proportion (%) of admissions and a crude population rate. Results: It was possible to identify 1935 hospital admissions from 1038 subjects; 49% male. The mean age at first admission was 44 years (SD 20). The minimum, crude prevalence of people hospitalised with psoriasis at some time was 0.23%. These admissions represented 0.13% of all hospital admissions. The crude admission rate with a primary diagnosis of psoriasis was 2.9 per 10 000 population per year. The proportion of subjects who had only one admission ranged between 65% and 77%. The median time between the first admission and the second admission was 1.4 years (IQR 0.5–3.1). The mean length of hospital stay was 16.8 days (median 15; IQR 8–23). There were 55 deaths in total in this group. Ten year survival was 92.7%. Following standardisation, people admitted more than once had increased risk of all cause mortality (hazard ratio 2.71; 95% CI 1.39–5.31). Conclusion: This study provides useful background intelligence on the most severe psoriasis patients identified by their admission to hospital with the condition. The proportion of psoriasis patients admitted was estimated to be about one in six people. Those with more than one admission with psoriasis – greater psoriasis severity – were associated with increased risk of all-cause mortality