Comparison of out of hours care provided by patients' own general practitioners and commercial deputising services: a randomised controlled trial. I: The process of care.

Objective: To compare the process of out of hours care provided by general practitioners from patients' own practices and by commercial deputising services.

Design: Randomised controlled trial.

Setting: Four urban areas in Manchester, Salford, Stockport, and Leicester.

Subjects: 2152 patients who requested out of hours care, and 49 practice doctors and 183 deputising doctors (61% local principals) who responded to those requests.

Main Outcome Measures: Response to call, time to visit, prescribing, and hospital admissions.

Results: 1046 calls were dealt with by practice doctors and 1106 by deputising doctors. Practice doctors were more likely to give telephone advice (20.2% v 0.72% of calls) and to visit more quickly than deputising doctors (median delay 35 minutes v 52 minutes). Practice doctors were less likely than deputising doctors to issue a prescription (56.1% v 63.2% of patients) or to prescribe an antibiotic (43.7% v 61.3% of prescriptions issued) and more likely to prescribe genetic drugs (58.4% v 32.1% of drugs prescribed), cheaper drugs (mean cost per prescription pounds 3.28 v pounds 5.04), and drugs in a predefined out of hours formulary (49.8% v 41.1% of drugs prescribed). There was no significant difference in the number of hospital admissions.

Conclusions: By contrast with practice doctors, deputising doctors providing out of hours care less readily give telephone advice, take longer to visit at home, and have patterns of prescribing that may be less discriminating.