Prevalence, Incidence, and healthcare burden of generalised pustular psoriasis, palmoplantar pustulosis, and plaque psoriasis in England

Date of Approval
Application Number
Technical Summary

Generalised pustular psoriasis (GPP) and palmoplantar pustulosis (PPP) are two sub-classifications of pustular psoriasis. GPP is characterised by rapidly progressing diffuse erythematous patches with pustules that coalesce to form lakes of pus. Patients with GPP may experience flares which can lead to serious complications such as sepsis, and even death. In PPP, pustules are restricted to the palms of hands and soles of feet. Both GPP and PPP can occur independently of a history of psoriasis.

This retrospective descriptive cohort study will utilise primary electronic health records linked to Hospital Episodes Statistics (HES) and Office of National Statistics (ONS) datasets to quantify prevalence, incidence, mortality, and resource utilisation of GPP and PPP compared to the more commonly diagnosed psoriasis vulgaris (PV).

The primary objectives of this study include the estimation of prevalence, incidence, and patient characteristics of GPP, PPP, and PV between 1st January 2008 and 31st December 2019. The secondary objectives will estimate the all-cause mortality for each cohort using Kaplan-Maier analysis during this time period and recent healthcare resource utilisation (HCRU) during 1st January 2015 to 31st December 2019.

Patient characteristics and HCRU will be stratified by prevalent and incident cases and by patient cohort. categorical variables will be tabulated with frequencies and percentages whereas the mean/standard deviation or will be used to describe continuous variables. Prevalence, incidence, and mortality will be directly standardised by age and sex from 01st January 2008 to 31st December 2019. These rates will also be presented using negative binomial Poisson regression adjusted for age and sex.

The study design has been chosen as it is appropriate for data extracted from healthcare datasets that already have data collected retrospectively. CPRD-HES linked dataset has been chosen due to the availability of good quality data for procedures, demographics, costs, complications, readmissions and resource use.

Health Outcomes to be Measured

Primary outcomes
Prevalent cases and rate of GPP,PPP, and PV; Incident cases and rate of GPP,PPP, and PV
Secondary Outcomes:
Number of prior hospitalisations; Mortality rate (By 5-year age group and sex; directly standardised to 2019 1st July CPRD general population); healthcare utilisation: number/NHS cost of A&E visits, outpatient visits, inpatient admissions, and general practitioner (GP) visits
Exploratory Outcomes:
Number and cost of psoriasis prescriptions/treatments
Psoriasis Area Severity Index (PASI) scores

Incidence, prevalence, and mortality of GPP,PPP, and PV patients will be stratified by 5-year age groups and sex; directly standardised to 2019 1st July CPRD general population):


Smit Patel - Chief Investigator - Boehringer-Ingelheim International GmbH
Smit Patel - Corresponding Applicant - Boehringer-Ingelheim International GmbH
Christopher Griffiths - Collaborator - University of Manchester
Darren Ashcroft - Collaborator - University of Manchester
richard warren - Collaborator - University of Manchester


HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation