Many factors can guide clinicians in predicting the response to starting therapy with insulin analogs, but many are interdependent and thus of poor utility. The factor explaining most of the variance in HbA1c change is baseline HbA1c level, with each increase of 1.0%-units (11 mmol/mol) providing a 0.7-0.8%-units (8-9 mmol/mol) greater fall. Other factors do not explain much of the remaining variance, even when including all end-of-trial measures.