Legg‐Calvé‐Perthes disease in the UK: Geographic and temporal trends in incidence reflecting differences in degree of deprivation in childhood

Abstract

Objective. Little is known about Legg-Calvé-Perthes disease, a common childhood precursor to osteoarthritis of the hip. This study was undertaken to analyze the incidence of Legg-Calvé-Perthes disease in the UK, with respect to geographic and temporal trends over a 19-year period.Methods. The General Practice Research database was analyzed to identify incident cases between 1990 and 2008 in children ages 0-14 years. Incidence rates were calculated by year and by region (National Health Service Strategic Health Authority regions in England, and Scotland, Wales, and Northern Ireland), and the association with regional markers of deprivation examined.Results. Over the 19-year period there was a dramatic decline in Legg-Calvé-Perthes disease incidence, with annual rates among children 0-14 years old declining from 12.2 per 100,000 to 5.7 per 100,000 (P < 0.001). There was also marked geographic variation, with incidence rates in Scotland more than twice those in London (10.39 [95% confidence interval 8.05-13.2] versus 4.6 [95% confidence interval 3.4-6.1] per 100,000 0-14-year-olds). A more rapid decline in incidence was apparent in the Northern regions compared to Southern regions. The quintile with the highest degree of deprivation had the highest disease incidence (rate ratio 1.49 [95% confidence interval 1.10-2.04]) and, with the exception of London, regional incidence showed a strong linear relationship with regional deprivation score (P < 0.01).

Unravelling the enigma of Perthes disease

“…12 London and the south east of England were least affected by Perthes disease, with a gradual increase in incidence in more northerly regions such that the incidence of Perthes disease in Scotland was more than double that in London. This geographic pattern is striking and is a common pattern seen when mapping diseases in the UK.…”

“…A investigation published in 2012 mapped Perthes disease across the UK, at a health board level. 12 This investigation used, for the first time, a community database to investigate the incidence of Perthes disease: the General Practice Research Database (GPRD). GPRD is the world's largest primary database, extensively validated and collected as part of 'routine patient care'.…”

“…12 Using deprivation markers adapted for strategic health authorities, it was shown that after excluding London, Perthes disease incidence appeared intimately related to regional deprivation. London may have differed owing to its multiethnicity and London similarly acts as an outlier in numerous deprivation-related diseases such as cardiovascular disease.…”

“…Perthes disease affects boys around four times more commonly than girls. 8,12 The age of onset of disease demonstrates a marked positive skew, meaning that most cases present between 4 and 7 years old, with a few cases still appearing late in adolescence. 12 Another well-described individual characteristic is a growth abnormality.…”

A Twin Study of Perthes Disease

“…It currently has an annual incidence of 6 cases per 100 000 children, 1 which has been steadily in decline in recent years. The etiology of LCPD is poorly understood.…”