This analysis shows that the research output of publications with respect to original data and systematic reviews from academic research divisions and institutes of general practice in Germany has greatly increased during the last decade. Cross-sectional studies are by far the most frequently used study type accounting for almost half of all publications. While most research articles had been published in German language journals without impact factor in early years, more than half of the papers now are published in English language journals. However, publications in journals with high impact factors remain rare.
Governmental funding is demanded and seen as a prerequisite for the growth of primary care research [6
]. Our results seem to support both such a demand and the success of the funding initiative of German politics mentioned in the introduction. This might be proved by our results, and it must be stated that the funding initiative of the government was successful. The increase of publication output is likely to reflect the professionalization of general practice on an academic level, which is in particular true with respect to international publications. The publication activity increased slightly at the beginning and has developed continuously since the introduction of the funding in 2002. Therefore, patience is necessary when the development of departments is monitored with respect to investment and efficiency. The funding mainly focused on four places (Frankfurt, Göttingen, Heidelberg, Marburg) with respect to the budget (more than € 1 Mio) with Heidelberg and Göttingen receiving the highest funding (> € 2 Mio), which was accompanied by the highest publication activity. Therefore, our results might reflect the direct association between funding and research productivity. At the same time it needs to be critically questioned if productivity and development will sustain as the targeted funding of primary care research is finished now in February 2012.
A welcome side-effect is the increased engagement of the academic general practice/family medicine in the development of guidelines and disease management programs. The German College of General Practitioners and Family Physicians (DEGAM) produced fifteen evidence and consensus based guidelines [7
]. These are classified as S3 guidelines, which corresponds to the highest quality with respect to the graduation of the German Working Society of Scientific Medical Disciplines (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF) [8
]. Beyond that, the DEGAM is involved in all seven national guidelines (Nationale Versorgungsleitlinie) [9
]. The existing German disease management programs for chronic diseases (coronary artery disease, diabetes, asthma, chronic obstructive pulmonary disease) have been developed with participation of academic institutes. Therefore, the academic discipline of general practice/family medicine seems to be sustainably implemented in the structure of the German health care system.
Despite the increasing professionalisation and research output in recent years, Germany’s academic family medicine still has some way to go when compared to other countries with highly developed primary care research. The frequency of cross-sectional studies in our review is remarkable. It was pointed out in the Research Agenda of the European General Practitioner Research Network (EGPRN) that descriptive, cross-sectional surveys and attitude studies will not add much knowledge in most countries and settings; and there is a call for more interventional and randomised controlled studies (RCT), respectively [10
]. Cross-sectional studies might indeed have been necessary to receive an overview of the specific primary care situation in Germany. E.g., we also have specialists working in primary care, and the contact rate in general practice is very high when compared with the UK or the Netherlands [11
]. On the other hand, high quality studies like RCTs are expensive; and more funding might be necessary to realize more such trials. This might also partly explain the low number of high impact publications, in particular when compared with the research output of the research environment of other countries [1
]. The total amount of public funding of primary care research in different countries is not easily available. Glanville et al. estimated the productivity of the primary care researchers by calculating the number of publications per billion dollar gross domestic research product spent on all research and development [1
]. Thus the relation to the direct financial investment in primary care research remains unclear. It must be stated that there is no sustainable funding strategy for primary care research in Germany. The total funding of € 13.2 Mio (=16.8 Mio US dollars) over ten years appears to be low if compared with the gross expenditure on research and development (GERD) in Germany which was around 82 billion US dollars only for 2009 according to the OECD statistics [12
]. As a consequence, German academic institutes of general practice are mostly small, in particular if compared with the Netherlands or UK. Another important barrier for international publication is the limited generalisability of the results of German health care studies to other countries.
When interpreting our findings several limitations have to be kept in mind. We did not search for and include articles by private GPs not affiliated with a medical school or research on primary care done by non-GP departments. Inclusion criteria were applied in a rather liberal manner. As a consequence, a number of articles (mainly process evaluations and developmental approaches in the area of health service research) presenting some original data have been included as primary research studies (mainly on the broad subject of health service research) for which it could be debated whether this is truly systematic research. Also, some articles included as systematic reviews used relatively vague methods. However, in all cases of ambiguity a second reviewer also assessed eligibility to ensure consistency of the selection process. A second reviewer was also involved if there were problems when categorizing a study. Due to the large number of articles and the limited resources available, the level of detail in the extraction had to be kept on a relatively low level. We could not include publications of 2011 in our review as it is very time-intensive to update our comprehensive search, obtain, select and extract an estimated number of over 200 publications. Besides that, we have not included literature which was published before 2000. However, the publication activity was low in the period before the funding by the Ministry of Education and Research, which started in 2002. As we covered a total of 11
years the three time periods compared in our analysis are not equal. While this is not optimal we believe it has little impact on the validity of our findings because the number of studies was higher in the last three years if compared with the previous four year intervals. A clear strength of our analysis is the reliance on full text articles. Borgers has repeatedly provided systematic bibliometric analyses of the publication output of Germany’s academic family medicine based on searches in the database Scopus (http://info.scopus.com/
]. He identified a total of 1130 publications in the period between 1998 and 2009, 683 of these being tagged as “original articles”. However, the bibliometric analyses rely completely on information included in Scopus and its formalized analysis options, and thus it was not checked whether an article contained original data. Therefore we had to exclude many of the articles which were identified by Borgers. Furthermore, potentially eligible publications were not only searched electronically in our study but also by direct contact with persons responsible for medical education and research on family medicine at all medical schools in Germany. Scopus searches alone missed 17% of eligible publications. For example, information on affiliation in Scopus is not regularly available for all authors, sometimes abbreviations are used (e.g. Dpt. Gen. Pract.), and in a few cases typing errors lead to missing a study. Overall, this suggests that analyses similar to ours should not exclusively rely on Scopus searches. We have used the journal impact factor as an estimate of the relevance of publications. While it is the measure most commonly used for this purpose it has several drawbacks [16
]. A particular problem regarding publications from countries speaking languages other than English is that many journals which have national relevance are not covered by this instrument. Therefore, our analyses can only provide a crude estimate of the relevance of the included research articles. It has to be stated that solely counting impact factors only reflects a distinct part of the value of an academic discipline. There is a strong debate in this context [16
], and the initiative to stratify primary care publications is important [18
]. Reflective and narrative publications could not be included in a meaningful way. However, these might sometimes also be helpful for academic development.