Influence of self-registration on audit participants and their non-participating colleagues. A retrospective study of medical records concerning prescription patterns.

Objective: To compare participants and non-participants early in the process of an audit on treatment of respiratory tract infections (RTIs) and to analyse any effect of the actual self-registration on the prescription of antibiotics in both groups.

Design: All 80 general practitioners (GPs) at 14 health centres were invited to audit their use of antibiotics and 45 agreed to participate. There were both participants and non-participants at all centres. Data were collected retrospectively from the electronic patient records of all visits for RTI during five periods including the self-registration period. Comparisons were made over time within and between the groups.

Setting: Primary health care in Blekinge county, Southern Sweden.

Subjects: 80 GPs: 45 participants and 35 non-participants.

Main Outcome Measure: Proportion of patients with RTI who received antibiotics.

Results: At the start, the difference in prescription frequency between participants and non-participants was six percentage points (RR = 0.92; 95% CI = 0.87-0.97), and at the end seven percentage points (0.88; 0.81-0.95). The proportion of RTIs treated with antibiotics fell for both groups, (0.86; 0.80-0.92 and 0.90; 0.83-0.97, respectively).

Conclusions: GPs who chose to take part in the audit had a different prescription pattern from the non-participants right from the start. Both groups reduced their prescription of antibiotics during the study period. Either the registration had no effect on the participants or it had an effect on both the participants and the non-participants.