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Subgroup by treatment interaction assessments are routinely performed when analysing clinical trials and are particularly important for phase 3 trials where the results may affect regulatory labelling. Interpretation of such interactions is particularly difficult, as on one hand the subgroup finding can be due to chance, but equally such analyses are known to have a low chance of detecting differential treatment effects across subgroup levels, so may overlook important differences in therapeutic efficacy. EMA have therefore issued draft guidance on the use of subgroup analyses in this setting. Although this guidance provided clear proposals on the importance of pre‐specification of likely subgroup effects and how to use this when interpreting trial results, it is less clear which analysis methods would be reasonable, and how to interpret apparent subgroup effects in terms of whether further evaluation or action is necessary.\ud \ud A PSI/EFSPI Working Group has therefore been investigating a focused set of analysis approaches to assess treatment effect heterogeneity across subgroups in confirmatory clinical trials that take account of the number of subgroups explored and also investigating the ability of each method to detect such subgroup heterogeneity. This evaluation has shown that the plotting of standardised effects, bias‐adjusted bootstrapping method and SIDES method all perform more favourably than traditional approaches such as investigating all subgroup‐by‐treatment interactions individually or applying a global test of interaction. Therefore, these approaches should be considered to aid interpretation and provide context for observed results from subgroup analyses conducted for phase 3 clinical trials.

Estimations of mineral content of normal human skeletons using three radiological methods have led to the following conclusions: 1. Bone density of vertebral bodies increases from T.6 to L.5. Average values for thoracic and lumbar vertebrae are 0.71 and 0.88 g./cm2. 2. There is no linear correlation between the mineral content of an easily accessible peripheral bone and of the vertebrae. 3. The method for bone mineral estimation, using thulium170, which was developed in Dresden, can be used for the peripheral and central skeleton. 4. 125-photon absorption us useful for measurements on the peripheral skeleton, where it is the most elegant and accurate method. It is, however, useless for measurements of the central skeleton.