Regularity of contact with general practitioners and diabetes-related hospitalisation through a period of policy change: A retrospective cohort study.

BACKGROUND This study evaluated changes in regularity of general practitioner (GP) contact (the pattern of visits over time) and the impact of regularity on diabetes-related hospitalisation following introduction of care co-ordination incentives. METHODS Linked primary care, hospital and death records covered West Australian adults from 1991-2004. Different eras were evaluated based on incentive program changes and model fit, to assess changes in regularity. Changes in regularity, derived from the variance in the number of days between GP contacts, were evaluated using ordered logistic regression. The impact of regularity on hospitalisation rates and costs were evaluated. RESULTS Two eras prior to program introduction (1991/92-1994/9 and 1995/96-1998/99), and one after (1999/2000-2002/03) were assessed. Among 153,455 at risk of diabetes-related hospitalisation GP contact became slightly less regular in the second era, though there was no change from the second to third era. The most regular decile had 5.5% fewer hospitalisations (95% CI -0.9% to -9.9%) and lower per-patient costs (difference AU$115, CI -$63 to -$167) than the least regular. Associations were similar in each era. CONCLUSIONS Ongoing relationships between GPs and patients are important to maintaining health. Historical data provide the opportunity to assess the impact of care co-ordination incentives on relationships.