Purpose: Although specialized centers are generally accepted for treatment of relatively uncommon diseases, such as cystic fibrosis, statements regarding the amount of expertise or minimum number of patients treated are increasingly included in guidelines for the treatment of other chronic diseases such as rheumatoid arthritis and diabetes mellitus.
Data sources: Medline and Embase from 1987 through March 2008 were searched.
Study selection: Studies reporting the effect of treatment in a specialized or high-volume center or by subspecialists on a clinically relevant outcome. Data extraction Two reviewers extracted the data independently and assessed the methodological quality.
Results of data synthesis: We included 22 articles. Two randomized-controlled trials and a quasi-experimental study compared the effect of outpatient team care with traditional outpatient care for patients with rheumatoid arthritis. These studies showed no difference or were inconsistent. Studies on the outcomes of care for diabetic patients (5 prospective or historical cohort studies and 10 retrospective cohort studies) were generally of poor quality. Studies comparing the subspecialist care with the care provided by general internists or primary care providers produced inconsistent results. Similar inconsistency and poor quality were found for three observational studies on cystic fibrosis.
Conclusion: The available literature suggests that among patients with rheumatoid arthritis, diabetes mellitus or cystic fibrosis, outcomes are not superior in specialized centers or with subspecialists compared with other forms of chronic illness care.