Rheumatoid arthritis antirheumatic drug trials. II. Tables for calculating sample size for clinical trials of antirheumatic drugs
Bellamy, N.; Anastassiades, T.P.; Buchanan, W.W.; Davis, P.; Lee, P.; McCain, G.A.; Wells, G.A.; Campbell, J.
Journal of Rheumatology 18(12): 1901-1907
1991
ISSN/ISBN: 0315-162X PMID: 1822109 Document Number: 385214
The calculation of sample size requires knowledge of the standard deviation (SD) of index variables. Unfortunately, there are no published lists of SD and it is exceedingly difficult to locate variance estimates based on relevant populations. We used standardized procedures to determine in 60 patients with rheumatoid arthritis (RA) the SD of key outcome measures recommended in current Food and Drug Administration and European League Against Rheumatism guidelines for RA clinical trials. We anticipate that these tables will be useful to clinical researchers in selecting outcome measures as well as for calculating sample size requirements for future clinical studies in RA.