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Abstract #10232 Published in IGR 6-1
Dropout rates for intent-to-treat and per protocol analyses
William C. Stewart WC; Jackson AL; Jenkins JNAmerican Journal of Ophthalmology 2004; 137: 639-645
PURPOSE: To describe dropout rates for the intent-to-treat and per protocol analyses from prospective clinical trials. METHODS: Review of prospective multi-center parallel studies of 100 patients or more from 1996 onwards. RESULTS: The authors identified 33 articles (70 treatment arms) that fit the criteria for this study. No statistical differences in dropout rates were observed among drug classes for either the intent-to-treat (p = 0.075) or per protocol analyses (p = 0.40). A difference was observed in the percentage dropout rate for the intent-to-treat analyses decreasing with the length of the study (p < 0.0001). This finding was not observed by the number of study visits (p = 0.44). However, a statistically greater percentage dropout rate was observed for the per protocol analyses increasing with the length of the study (p = 0.034) and number of study visits (p = 0.01). No statistical differences were observed or with increasing sample size of the study for either the intent-to-treat or per protocol analyses (p > 0.05). CONCLUSIONS: Known discontinuation rates for per protocol and intent-to-treat analyses may help in planning sample sizes for future clinical trials.
