Quantity, topics, methods and findings of randomised controlled trials published by German university departments of general practice - systematic review.
BACKGROUND
Academic infrastructures and networks for clinical research in primary care receive little funding in Germany. We aimed to provide an overview of the quantity, topics, methods and findings of randomised controlled trials published by German university departments of general practice.


METHODS
We searched Scopus (last search done in April 2015), publication lists of institutes and references of included articles. We included randomised trials published between January 2000 and December 2014 with a first or last author affiliated with a German university department of general practice or family medicine. Risk of bias was assessed with the Cochrane tool, and study findings were quantified using standardised mean differences (SMDs).


RESULTS
Thirty-three trials met the inclusion criteria. Seventeen were cluster-randomised trials, with a majority investigating interventions aimed at improving processes compared with usual care. Sample sizes varied between 6 and 606 clusters and 168 and 7807 participants. The most frequent methodological problem was risk of selection bias due to recruitment of individuals after randomisation of clusters. Effects of interventions over usual care were mostly small (SMD <0.3). Sixteen trials randomising individual participants addressed a variety of treatment and educational interventions. Sample sizes varied between 20 and 1620 participants. The methodological quality of the trials was highly variable. Again, effects of experimental interventions over controls were mostly small.


CONCLUSIONS
Despite limited funding, German university institutes of general practice or family medicine are increasingly performing randomised trials. Cluster-randomised trials on practice improvement are a focus, but problems with allocation concealment are frequent.
Institute of General Practice, University Hospital rechts der Isar,Technical University Munich, Orleansstrasse 47, 81667, Munich, Germany.
Stefan
S
Heinmüller
Institute of General Practice, University Hospital rechts der Isar,Technical University Munich, Orleansstrasse 47, 81667, Munich, Germany.
Antonius
A
Schneider
Institute of General Practice, University Hospital rechts der Isar,Technical University Munich, Orleansstrasse 47, 81667, Munich, Germany. klaus.linde@tum.de.
Klaus
K
Linde
D023381:Endpoint Determination; D058006:General Practice / Q000191:economics / Q000379:methods*; D005858:Germany; D006801:Humans; D010506:Periodicals as Topic; D016032:Randomized Controlled Trials as Topic / Q000191:economics / Q000379:methods*; D012107:Research Design; D012109:Research Support as Topic; D018401:Sample Size; D015983:Selection Bias; D016896:Treatment Outcome; D014495:Universities / Q000191:economics
Academic performance; General practice; Germany; Primary care; Randomised controlled trials