Low income scheme index: a new deprivation scale based on prescribing in general practice

To describe and validate a new deprivation index, based on the percentage of prescribed items exempt from the prescription charge under the low income scheme, at both family health services authority and practice level.

Comparison of the index with three other deprivation indices and correlation of index values with the use of drugs given for conditions with known social class gradients.

All 90 family health services authorities and 7619/9289 practices in England.

The ranking of family health services authorities on the new index correlated highly with rankings on the other indices. Values in relation to the use of drugs given for conditions with known social class gradients were in the predicted direction at both family health services authority level and practice level; correlation was highly significant at the authority level, but less significant at practice level.

The new index provides a good measure of deprivation at family health services authority level, and at practice level the results are sufficiently encouraging to warrant further research. It provides the best available instrument for relating deprivation to the use of drugs in any population that can be defined by prescribing data, but an attempt to use it in determining allocation of resources would at this stage be premature.