The presented Hazard ratios and confidence intervals are restricted to the 5% and 95% percentile of the continuous subgroup.In order to avoid convergence issues in mixed models, different structures of the covariance matrices are applied starting with the most complex one, followed by structures with decreasing complexity, i.e. the following order is applied in case of non-convergence:Unstructured, Toeplitz, Autoregressive(1).In case the model does not converge even when the simplest form of the covariance matrix is used, the last visit is dropped from the model.