The number of visits to EDs decreased during the follow-up of the interventions. This decrease was most prominent in the youngest age groups. Especially, the proportions of recorded infectious diseases (Groups A, B and J) decreased. Particularly, diagnoses related to mild infections of respiratory airways decreased. Interestingly, the effects of interventions on the prevalence of different injuries varied, although generally the proportions and absolute numbers of injuries increased. The proportions and numbers of symptomatic diagnoses increased.
The decreased rate in the use of primary care EDs in the youngest people (0-19 years) is understandable. There are earlier reports suggesting that primary health care ED services are often used by the younger age groups [10–11]. Especially low acuity visits to EDs seem to be a feature of very young age groups (<10 y) and late teenagers (18-19 years) . Interestingly, social deprivation does not seem to influence this pattern of ED use . The reasons for this are many. According to a survey study with ED patients, young age groups may differ in their expectations regarding the purpose of out-of-hours services and accessibility and they may have other objectives than plain clinical urgency when they seek help . Furthermore, in a multicenter survey of patients from an urban health region, distance to a specific ED was the most important reason for choosing that ED suggesting that convenience factors play a significant role when deciding to use ED services . There is support for this view from other studies analyzing primary care out-of-hours calls and visits concerning child patients  and young adults  as well as from qualitative studies regarding treatment of small children in out-of-hours services . Altogether, previous findings have shown that if restrictions of access to primary health care EDs occur, the youngsters, who use these services a lot, reduce their ED visits more than other people.
The finding that the proportions and numbers of simple infections in the ED decreased is in line with the aims of the interventions applied [2–4]. We knew that at least about 30% of the diagnoses done in the present kind of primary care ED system and office-hours primary care were the same and that office-hours primary care might therefore have provided better continuation of treatment for these patients than the ED . Furthermore, when diagnoses in EDs and primary care doctor driven emergency systems have been compared, a higher prevalence of mild infections in primary care doctor driven emergency systems and a higher prevalence of injuries in EDs have been reported . This injury-focused activity in EDs has also been described elsewhere in all age groups [20, 21]. Thus, the present triplet of interventions seemed to shift the functions of the studied primary care ED towards the form of a standard specialized health care driven ED. Whether these low-acuity primary care services should then also be provided to the population out of office-hours is another question .
This was a retrospective study considering primary care EDs. As this study was purely register-based the subjects were not aware of their participation in the study. The present result reflects real clinical activity in this respect. As a confounding factor, electronic reminders were introduced in the electronic patient information system in 2008 to enhance recording of diagnoses and that may have altered the observed proportions of different diagnoses during the present study . For example, this intervention explains at least partially the observed increase in symptomatic diagnoses (IDC-10 group R) during this study . As a limitation, we should have been able to compare our results to a control city with a similar office-hours primary health care, demography and size. This would have strengthened our conclusions. However, such data from another city were not available for comparison. Data about possible changes in patient material or changes in ways to manage practices and diseases were not available. These factors have a considerable effect on changes in the number of visits to GPs. Data concerning these putative changes could have been obtained if we had had access to the patient information of individual patients. Unfortunately, that access we were unable to obtain.