The effects on GP prescribing of joining a commissioning group

It is not known to what extent general practitioners (GP) can change their prescribing upon joining a commissioning group and what features of a commissioning group may promote prescribing change. The opportunity to study potential prescribing change arose with the formation of a limited number of Primary Care Commissioning Groups (PCCGs), a precursor of Primary Care Groups (PCGs) and Primary Care Trusts (PCTs).

This was a controlled study of general practice prescribing costs. All practices (n=24) within one inner city PCCG were compared with matched controls that were not part of a PCCG. Cross sectional survey data was collected from the PCCG practices to determine possible reasons for prescribing change.

The total annual prescribing cost rose by 4.0% in the PCCG practices and by 6.9% in controls (P=0.01). Significant cost containment was found for gastrointestinal prescribing (P=0.03), attributable to differences in the cost of proton pump inhibitors (PPIs) which fell by 0.7% in the PCCG but rose by 7.3% in controls (P=0.03). Total relative savings in the PCCG practices amounted to around pound 220,000. General practitioners making the greater savings in PPI costs within the PCCG, were more likely to report being influenced by information from the prescribing adviser.

General practice prescribing costs were contained to a greater degree in practices participating in the PCCG. The differences in gastrointestinal prescribing were most marked for PPIs which were specifically targeted by the prescribing adviser. The GPs themselves attributed their own prescribing change to information provided by the prescribing adviser. Other factors operating within the PCCG may also have influenced prescribing such as a more locally based management system, different financial incentives and a greater degree of co-operative working amongst GPs.