To the Editor. —Orthostatic hypotension due to autonomic failure is an incapacitating condition for which treatment, despite various drug interventions (eg, yohimbine, metoclopramide, β-blockers, somatostatin analog) is not yet resolved. Therefore, the encouraging results of the study of Dr Low and colleagues 1 are potentially of great importance. Although the pharmacological efficacy of midodrine, an α1-adrenoceptor agonist, is clearly demonstrated by this trial, the therapeutic effectiveness is not documented as well and is therefore less convincing. There are several important issues. First, the number of patients included in the study should allow data analysis on an intention-to-treat basis. This approach would be preferable because of the particularly high dropout rate in the midodrine group (22 [27%] of 82 subjects) when compared with the placebo group (5 [5.6%] of 89 subjects). The difference in dropout rate during the 5 weeks of the study is significant (X 2 =14.44, P