Does sharing care across the primary-specialty interface improve outcomes in chronic disease? A systematic review.

OBJECTIVE: To determine the effectiveness of shared care interventions designed to improve the management of chronic disease across the primary-specialty care interface. STUDY DESIGN AND METHODS: Systematic review using the Cochrane Collaboration method.
RESULTS: Twenty studies were identified, 19 of which were randomized controlled trials. The majority of studies examined complex interventions and were of short duration. Results were mixed, with no consistent improvements in physical or mental health outcomes, psychosocial outcomes, hospital admissions, default or participation rates, recording of risk factors, and satisfaction with treatment. However, there were improvements in prescribing in the studies that considered this outcome. The methodologic quality of studies varied, with only a minority of studies of high-quality design. Cost data were limited and difficult to interpret across studies.
CONCLUSIONS: At present, there is insufficient evidence to support the introduction of shared care services into clinical practice. However, methodologic shortcomings, particularly inadequate length of follow-up, may account for this lack of evidence. Further research is needed to test models of collaboration across the primary-specialty care divide both in terms of effectiveness and sustainability over longer periods of time.