Automated document classification can be a valuable tool for enhancing the efficiency of creating and updating systematic reviews (SRs) for evidence-based medicine. One way document classification can help is in performing work prioritization: given a set of documents, order them such that the most likely useful documents appear first. We evaluated several alternate classification feature systems including unigram, n-gram, MeSH, and natural language processing (NLP) feature sets for their usefulness on 15 SR tasks, using the area under the receiver operating curve as a measure of goodness. We also examined the impact of topic-specific training data compared to general SR inclusion data. The best feature set used a combination of n-gram and MeSH features. NLP-based features were not found to improve performance. Furthermore, topic-specific training data usually provides a significant performance gain over more general SR training.