A systematic review of the effect of primary care-based service innovations on quality and patterns of referral to specialist secondary care.

BACKGROUND Innovations are proliferating at the primary-secondary care interface, affecting referral to secondary care and resource use. Evidence about the range of effects and implications for the healthcare system of different types of innovation have not previously been summarised. AIM To review the available evidence on initiatives affecting primary care referral to specialist secondary care. SETTING Studies of primary-secondary care interface. METHOD Systematic review of trials, using adapted Cochrane Collaboration (effective practice and organisation of care) criteria. Studies from 1980 to 2001 were identified from a wide range of sources. Strict inclusion criteria were applied, and relevant clinical, service and cost data extracted using an agreed protocol. The main outcome measures were referral rates to specialist secondary care. RESULTS Of the 139 studies initially identified. 34 met the review criteria. An updated search added a further 10 studies. Two studies provided economic analysis only. Referral was not the primary outcome of interest in the majority of included studies. Professional interventions generally had an impact on referral rates consistent with the intended change in clinician behaviour. Similarly, specialist 'outreach' or other primary care-based specialist provider schemes had at least a small effect upon referral rates to secondary care with the direction of effect being that intended or rational from a clinical and sociological perspective. Of the financial interventions, one was aimed primarily at changing the numbers or proportion of referrals from primary to specialist secondary care, and the direction of change was as expected in all cases. The quality of the reporting of the economic components of the 14 studies giving economic data was poor in many cases. When grouped by intervention type, no overall pattern of change in referral costs or total costs emerged. CONCLUSION The studies identified were extremely diverse in methodology, clinical subject, organisational form, and quality of evidence. The number of good quality evaluations of innovative schemes to enhance the existing capacity of primary care was small, but increasing. Well-evaluated service initiatives in this area should be supported. Organisational innovations in the structure of service provision need not increase total costs to the National Health Service (NHS), even though costs associated with referral may increase. This review provides limited, partial, and conditional support for current primary care-oriented NHS policy developments in the United Kingdom.