Item 1 of the OHSA asked the patient to rate, using a 0-10 scale (0 meaning not bothered and 10 meaning the worst), his or her impression of the severity of dizziness, lightheadedness, feeling faint, or feeling like you might black out whenever he or she was standing and that improved when he or she sat or laid down. Higher scores indicate more severe disease.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Item 1 of the OHSA asked the patient to rate, using a 0-10 scale (0 meaning not bothered and 10 meaning the worst), his or her impression of the severity of dizziness, lightheadedness, feeling faint, or feeling like you might black out whenever he or she was standing and that improved when he or she sat or laid down. Higher scores indicate more severe disease.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement. Data for 2 sites were excluded from this re-analysis.

Items 2 through 6 of the OHSA asked the patient to rate, using a 0-10 scale (0 meaning not bothered and 10 meaning the worst), his or her impression of the severity of the following symptoms whenever he or she was standing and that improved when he or she sat down or laid down: Item 2 addresses problems with vision (blurring, seeing spots, tunnel vision, etc); Item 3, weakness; Item 4, fatigue; Item 5, trouble concentrating; and Item 6, head or neck discomfort. Symptomatology was assessed at Visit 3A (titration), Visit 5 (Period 2), and Visit 6 (study completion). A negative change from baseline indicates that symptoms have improved.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The OHSA composite symptom score was calculated by taking the average of the ratings for the symptoms present at Baseline. Participants were asked to rate symptoms by using a 0-10 scale (0 meaning not bothered and 10 meaning the worst). For subsequent visits, only those symptoms present at Baseline were scored. In this manner, a score was produced that represents the severity (and subsequent change in severity) of the patient's neurogenic OH symptoms, regardless of how many symptoms are presented at Baseline. Symptomatology was assessed at Visit 3A (titration), Visit 5 (Period 2), and Visit 6 (study completion). A negative change from baseline indicates that symptoms have improved.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The OHDAS had 4 items that asked the patient to give a graduated score from 0 (no limitation due to OH) to 10 (complete limitation due to OH). Item 1 addressed activities that required standing for a short time; Item 2, activities that required standing for a long time; Item 3, activities that required walking for a short time; and Item 4, activities that required walking for a long time. Symptomatology was assessed at Visit 3A (titration), Visit 5 (Period 2), and Visit 6 (study completion). A negative change from baseline indicates that symptoms have improved.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The OHDAS global daily activity score was calculated as the average of all daily activity item scores. The OHDAS had 4 items that asked the patient to give a graduated score from 0 (no limitation due to OH) to 10 (complete limitation due to OH) to activities that required standing for a short time, standing for a long time, walking for a short time, walking for a long time. Symptomatology was assessed at Visit 3A (titration), Visit 5 (Period 2), and Visit 6 (study completion). A negative change from baseline indicates that symptoms have improved.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The CGI-I is a 7-point scale ranging from 1 (very much improved) to 7 (very much worse). Clinical Global Impressions ratings are completed with respect to neurogenic OH symptoms. A value of 0 was used if the investigator or patient assessment was not performed. The improved category is made up of patients who were evaluated as very much improved, much improved, or slightly improved for the classification of "Overall Improvement." The CGI-I was completed at Visit 5 (Period 2) and Visit 6 (study completion).

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The CGI-I is a 7-point scale ranging from 1 (very much improved) to 7 (very much worse). Clinical Global Impressions ratings are completed with respect to neurogenic OH symptoms. A value of 0 was used if the investigator or patient assessment was not performed. The improved category is made up of patients who were evaluated as very much improved, much improved, or slightly improved for the classification of "Overall Improvement." The CGI-I was completed at Visit 5 (Period 2) and Visit 6 (study completion).

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Standing BP was measured at Visit 5 (Period 2) and Visit 6 (study completion) and compared to measurements taken at Visit 3A (titration). Standing BP was measured 3 minutes after the patient rose from the supine position or as soon as the patient indicated they needed to sit down. If the patient indicated he or she needed to sit down, the BP measurement was taken while in the standing position, before the patient sat down.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Supine BP was measured at Visit 5 (Period 2) and Visit 6 (study completion) and compared to measurements taken at Visit 3A (titration). Supine BP was measured after the patient had been in the supine position for 5 minutes.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

The SF-36 consists of 36 items in eight domains: physical functioning, general health, role-physical, bodily pain, vitality, social functioning, role-emotional, and mental health. Version 2 references "one week ago" for some questions. Raw scale scores for the SF-36 were transformed to a 0-100 scale with a higher score indicating a better quality of life. A positive change from baseline indicates that symptoms have improved. The SF-36 was completed at Visit 5 (Period 2) and Visit 6 (study completion) and compared to the score from Visit 3A (titration).

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Item 1 of the OHSA, the OHSA composite score, and the OHDAS global daily activity score were analyzed for test-retest reliability as a measure of validity. Test-retest reliability is the Pearson product-moment correlation coefficient calculated between OHQ scores at Visit 3A (baseline measure) and OHQ scores at Visit 5 for the subjects who received Placebo during Randomization Period 1.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Item 1 of the OHSA, the OHSA composite score, and the OHDAS global daily activity score were analyzed for responsiveness as a measure of validity. Assuming that subjects who received Placebo during Randomization Period 1 are stable between Visit 3A and Visit 5, and using them as the stable subjects, responsiveness was calculated as [(OH CFB in Midodrine group)-(OH CFB in Placebo group)]/(SD of OH CFB in Placebo group), where CFB is change from baseline, SD is the standard deviation of OH CFB of the stable subjects; the value reported is the quotient of this equation.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Item 1 of the OHSA and the OHSA composite score were analyzed for convergent validity with the CGI-I-Clinician scores. The change from baseline in the CGI-I scores are correlated with the OHSA Item 1 score change from baseline and the OHSA composite score change from baseline for the subjects in the ITT population. Values shown are Spearman correlation coefficients.

Intent-to-Treat, defined as all patients who were randomly assigned to treatment in the study and have at least one post-randomization OHQ measurement.

Item 1 of the OHSA asked the patient to rate, using a 0-10 scale (0 meaning not bothered and 10 meaning the worst), his or her impression of the severity of dizziness, lightheadedness, feeling faint, or feeling like you might black out whenever he or she was standing and that improved when he or she sat or laid down. The results are reported by degree of severity according to the CGI-S scale, which uses 4 categories to describe disease severity: Mild, Moderate, Marked, and Severe. The Item 1 scores reported are grouped for participants with Mild or Moderate disease severity. Higher scores indicate more severe disease.

Randomized participants enrolled at any of the 28 US sites

Item 1 of the OHSA asked the patient to rate, using a 0-10 scale (0 meaning not bothered and 10 meaning the worst), his or her impression of the severity of dizziness, lightheadedness, feeling faint, or feeling like you might black out whenever he or she was standing and that improved when he or she sat or laid down. The results are reported by degree of severity according to the CGI-S scale, which uses 4 categories to describe disease severity: Mild, Moderate, Marked, and Severe. The Item 1 scores reported are grouped for participants with Marked or Severe disease severity. Higher scores indicate more severe disease.

Randomized participants enrolled at any of the 28 US sites