Does an in-house internist at a GP practice result in reduced referrals to hospital-based specialist care?

OBJECTIVE: Consistent evidence on the effects of specialist services in the primary care setting is lacking. Therefore, this study evaluated the effects of an in-house internist at a GP practice on the number of referrals to specialist care in the hospital setting. Additionally, the involved GPs and internist were asked to share their experiences with the intervention. DESIGN: A retrospective interrupted times series study. SETTING: Two multidisciplinary general practitioner (GP) practices. INTERVENTION: An internist provided in-house patient consultations in two GP practices and participated in the multidisciplinary meetings. SUBJECTS: The referral data extracted from the electronic medical record system of the GP practices, including all referral letters from the GPs to specialist care in the hospital setting. MAIN OUTCOME MEASURES: The number of referrals to internal medicine in the hospital setting. This study used an autoregressive integrated moving average model to estimate the effect of the intervention taking account of a time trend and autocorrelation among the observations, comparing the pre-intervention period with the intervention period. RESULTS: It was found that the referrals to internal medicine did not statistically significant decrease during the intervention period. CONCLUSIONS: This small explorative study did not find any clues to support that an in-house internist at a primary care setting results in a decrease of referrals to internal medicine in the hospital setting. KEY POINTS: An in-house internist at a primary care setting did not result in a significant decrease of referrals to specialist care in the hospital setting. The GPs and internist experience a learning-effect, i.e. an increase of knowledge about internal medicine issues.