Pagets disease is a disorder of bone which can result in pain and bone deformity. Population surveys conducted in the 1970s and 1990s suggested that the frequency declined significantly during that time. We do not know whether or not the disease continues to decline or whether the incidence has levelled off. Research has also suggested that the disease is more frequent in Lancashire than other parts of the UK, however, the reason for this has never been fully explained. Also we know little about the impact of the disease on subsequent health care behaviour including visits to general practice. The aim of this research study is to examine the primary care records of patients to see how the occurrence of Pagets disease has changed over time, whether or not the disease is more common in certain regions of the UK and also whether or not differences in frequency can be explained by differences in levels of deprivation. We will also look at whether there is any increased mortality linked with the disease and also the impact of the disease on adverse health outcomes including lower limb joint replacement surgery (hip / knees) and fractures. We will look also at health care utilisation including attendances at primary care. The research is important in that it may help provide further clues about the causes of the disease and also help better define the clinical and public health impact of the disease.
Our broad aim is to determine temporal and geographic trends in the incidence of clinically diagnosed Pagets disease. A secondary aim is to examine health impact including mortality and health care utilisation following clinical diagnosis.
Age-, sex-, geographic- and Index of Multiple Deprivation (IMD)- specific incidence rates will be calculated by dividing the number of new cases by the total person timeof follow-up. This will be calculated as the sum of the number of patients registered in the database on January 1st of each year. Trends in incidence rates over time (grouped into 5 year intervals) will be examined using Poisson regression. We will test for any significant geographic effects on occurrence, and any significant impact of deprivation and whether this is able to explain any observed regional effects.
Health care outcomes and health care utilisation will be characterised using descriptive statistics. Poisson regression will be used to compare health care utilisation between Pagets patients and controls, adjusting for age, gender, IMD and comorbidity (Charlson Index). Given the potential that analysis of secondary care contacts may be affected by over dispersion we will analyse this data using a negative binomial model. We will look also at the crude occurrence of significant health outcomes including hip and knee arthroplasty in those with Pagets compared to controls.
All cause mortality will be determined using data from CPRD. Participants with Pagets disease will be matched to up to 5 controls at the date of Pagets diagnosis. Cases will be matched to controls on age, sex, and practice. Survival will be compared between cases and controls using Kaplan-Meir curves. Cox proportional hazards will be used to determine whether there is any excess mortality in those with the disease compared to the controls.
Incidence of Pagets disease (new clinical diagnoses of Pagets disease in GP records); number of GP visits; number of hospital admissions. Also, all-cause mortality, hip and knee arthroplasty and major fractures.
Terence O'Neill - Chief Investigator - University of Manchester
Terence O'Neill - Corresponding Applicant - University of Manchester
Darren Ashcroft - Collaborator - University of Manchester
Michael Cook - Collaborator - University of Manchester
Stephen Pye - Collaborator - University of Manchester
William Dixon - Collaborator - University of Manchester
HES Admitted Patient Care;Practice Level Index of Multiple Deprivation