Sample size calculations for the two-sample problem using the multiplicative intensity model.
In this paper we propose formulae for calculating the expected number of events or, alternatively, the required trial duration, for clinical trials involving two treatment groups in which patients may potentially experience multiple events and the data will be analysed using a multiplicative intensity (MI) model. We use a partial likelihood-based approach and examine in detail two MI models: one that includes a binary treatment variable as the only covariate and a three-state Markov process model in which a binary time-varying covariate is added to the previous model. For the simpler model, our formula coincides with those derived by Cook using full likelihood methods. We present applications of the derived formulae to chronic granulomatous disease and breast cancer data sets.
Department of Biostatistics, Harvard School of Public Health, USA. bernardo@hsph.harvard.edu
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Bernardo
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Harrington
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy; D002648:Child; D003520:Cyclophosphamide / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D005474:Fluoxymesterone / Q000627:therapeutic use; D006105:Granulomatous Disease, Chronic / Q000188:drug therapy; D006801:Humans; D007371:Interferon-gamma / Q000627:therapeutic use; D016013:Likelihood Functions; D008390:Markov Chains; D008727:Methotrexate / Q000627:therapeutic use; D008954:Models, Biological; D011241:Prednisone / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D018401:Sample Size; D013629:Tamoxifen / Q000627:therapeutic use
D013629:Tamoxifen; D007371:Interferon-gamma; D003520:Cyclophosphamide; D005474:Fluoxymesterone; D005472:Fluorouracil; D011241:Prednisone; D008727:Methotrexate