The primary-secondary care interface: does provision of more services in primary care reduce referrals to medical specialists?

Great variation in referral rates between primary care physicians has been the main reason to influence physician's referral behaviour, by for example, stimulating extra services. This study investigated the extent to which the number of therapeutic and diagnostic services performed by primary care physicians influenced referrals. Data was derived from electronic medical records of 70 general practices for the period 2006 until 2010. For the total patient population (N=651,089 patient years) and specific patients groups for whom specific services were performed mostly (28 groups; 10 services), logistic multilevel regression analyses were conducted to determine associations between the number of services performed in a practice and referrals to medical specialists. The total number of services performed in a practice was not associated with the referral rate (OR: 1.00). Only for two specific services was a significant association found: a lower referral rate for minor surgery for patient with sebaceous cysts (OR: 0.98) and a higher rate for Doppler diagnostic tests for patients with other peripheral arterial diseases (OR: 1.04). As the number of services in general practice was rarely associated with referrals, other measures might be more effective in changing referral behaviour. Another explanation for our results could be that certain preconditions have not been met.