http://bmj.bmjjournals.com/cgi/reprint/321/7268/1057.pdf

"... Objectives: To calculate socioeconomic and health status measures for the primary care groups in London and to examine the association between these measures and hospital admission rates.Conclusions: It is feasible to produce a range of socioeconomic, health status, and practice measures for primary care groups for use in needs assessment and in planning and monitoring health services. These measures show that primary care groups have highly variable patient and practice characteristics and that hospital admission rates are associated with chronic illness and deprivation. These variations will need to be taken into account when assessing performance...."