Clinical Trials

Clinical Trials: A Practical Guide ■❚❙❘reports/reporting, 363–452, 435baseline data, 385–390components, 386–388example data, 387imbalances, 389importance, 386significance tests, 388–389CONSORT statement, 369–371allocated treatment, 371coherence and clarity, 371defined outcome, 369randomization, 369sample size, 369contents, 370–371critical appraisal of, 427–437format of randomized trial reports, 435formats, 435implications, 436influence of patient selection, 430limitations, 436negative trials, 432–433outcome measures, 433–435power and sample size, 433publication type, 428–429quality of evidence guidelines, 428recruitment rate and timing, 430–431relevance, 429systematic bias and confounding, 431–432figures see figuresinterpretation, 368–369press releases, 373–374problem areas, 372–373structure, 366–368tables see tablestrial profiles see trial profiletypes of report, 366residual, definition, 276results section, 367, 370risk difference, two-arm trial, 226–230, 249risk factor, definition, 456risk ratiodefinition, 455two-arm trial, 226–227, 249rounding, tables, 402Ssample, significance tests, 186sample size, 81–87calculation, 84, 85cluster randomized trials, 144–145CONSORT statement, 369critical appraisal of reports, 433definition, 82determining factors, 82–83, 85example, 83–85expected event rate calculation, 83null hypothesis rejection, 83significance level determination, 83study design, 83subject dropout, 85treatment effect detection, 83type II error rate, 84factorial design, 104–105, 110methodologies, 87negative results, 85–86noninferiority trials, 135–137, 136parallel trials vs crossover trials, 95, 96power choice, 84protocol development, 31–32purpose, 82treatment effect vs, 86sampling period, 125–126, 126sampling times, 125scatter plots, 418, 419, 423secondary endpoints, 38secondary hypothesis, protocol development, 29selection see patient selectionselection bias, 56–58cluster randomized trials, 143randomization, 57sensitivity analysis, cluster randomized trials, 147significance level determination, sample sizeand power, 83significance tests, 185–195baseline data presentation, 388–389confidence intervals, 191–192, 193, 194examples, 193–194hypothesis testing, 186–191, 191alternative hypothesis, 187calculating test statistics, 187–188determine P-value, 189–190method choice, 187–188null hypothesis, 186–187significance level definition, 189significance level specification, 188statistical inference, 190type I (alpha) errors, 190–191, 192type II (beta) errors, 190–191, 192477