CATCHMENT AREAS IN GENERAL-PRACTICE AND THEIR RELATION TO SIZE AND QUALITY OF PRACTICE AND DEPRIVATION - A DESCRIPTIVE STUDY IN ONE LONDON BOROUGH

Objective-To relate the sizes of general practice catchment areas in o ne London borough to list size, deprivation payments, medical staffing , and locally and nationally recognised measures of quality. Design-St udy of general practice catchment area maps. Setting-London borough of Lambeth. Subjects-60 out of the 71 general practices in Lambeth. Main outcome measures-Practice catchment area size with corrections for nu mbers of doctors and patients. Results-Catchment area size varied grea tly between practices, showing an almost 150-fold difference between t he largest and smallest practices. This size differential was even mor e marked when the size of the catchment area was corrected for the num ber of general practitioners in the practice, where a 300-fold differe nce was found. Substantial differences existed between practices in ea ch of the four locally assigned quality bands. The weakest practices h ad catchment areas three times as large as those of the strongest prac tices. When corrected for medical staffing, the difference was eight t imes as great. A calculated measure of patient dispersion showed that the practice population of the strongest practices was four times as d ensely clustered as that of the weakest practices, whose patients were more widely geographically dispersed. Conclusions-Large variations ex ist in the size of catchment areas of inner city practices even when c orrected for numbers of doctors and patients. These differences are as sociated with variations in quality of care.