The case for differential capitation fees based on age in British general practice.

A study was performed to assess whether the existing differential capitation fees for general practitioners accurately assess differential workloads. Data from the third morbidity study in general practice were used to compare capitation fees with relative workload in differing age and sex groups. The population mix which determined the payment by capitation for the 143 principals in the study provided the basis for examining the advantage or disadvantage the general practitioner got from the existing system. Capitation fees for the elderly underestimated the increased workload by 21% for those aged 65-74 and by 54% for those aged 75 or over but overestimated the workload for male adults aged up to 65. Nevertheless, 60% of the participating general practitioners were not advantaged or disadvantaged by more than 2.5% of their capitation fees (450 pounds a year for the average practitioner with a list of 2000 patients). Similarly 88% were not advantaged or disadvantaged by more than 5%; none were advantaged or disadvantaged by more than 10%. A three scale capitation fee for the age groups 0-64, 65-74, and 75 or over should be applied in the ratio of 3:5:7 rather than in the present ratio of 3:4:5, but given the present population mix in practices there is no case for differential capitation fees by sex or differential fees for the age group 0-4 years.