An AE was defined as any new medical problem, or exacerbation of an existing problem, experienced by a participant while enrolled in a study , whether or not it was considered drug-related by the study physician. A treatment-emergent AE (TEAE) was defined as an AE that started after start of study drug treatment; or if the event was continuous from Baseline and was serious, study drug related, or resulted in death, discontinuation.

Safety dataset was defined as all participants who consumed at least 1 dose of study medication. Safety variables analyzed included physical examinations, laboratory tests, vital signs, ECG's and AEs.

Spot urine osmolality at trough was determined for urine samples collected immediately prior to morning dosing for Day 1 (Baseline), Months 2, 6, 12, 24, 36 for all participants. Sample was taken after the first morning's void and was provided as a mid-stream, clean catch sample. During the titration period (Weeks 1, 2, 3 and 4) and at Month 6, additional samples were collected for the preceding day immediately preceding the 2nd daily dose and at bed-time. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration. At the Month 36 visit, participants were given a urine container and brought back the specimen at Extension Day 1. All participants were fasting.

The intent-to-treat (ITT) dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. Observed cases (OC) dataset were used.

Urine osmolality at steady state (after at least 4 days of dosing) including "absolute trough" prior to the second daily dose.

Samples for this assessment were taken as closely coincident to PK blood sample as practical. During Weeks 1, 2, 3 and 4 of the Titration Period and at Month 6, additional samples were collected for the preceding day immediately preceding the second daily dose. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Urine osmolality at steady state (after at least 4 days of dosing) including "average of troughs" (the mean urine osmolality prior to bedtime).

Samples for this assessment were to be taken as closely coincident to PK blood sample as practical. During Weeks 1, 2, 3 and 4 of the Titration Period and at Month 6, additional samples were collected for the preceding day at bedtime. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Total Kidney Volume (TKV) was assessed by the central magnetic resonance imaging (MRI) rater.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

GFR was estimated using reciprocal serum creatinine formula. The formula does not adjust for body weight or height, but this may be done to normalize to body surface area. The formula for reciprocal Serum creatinine is: 1/Pcr. (Pcr = serum creatinine concentration [mg/dL]). Clinic weight scales were calibrated at least yearly.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Spot urine osmolality at trough was determined for urine samples collected immediately prior to morning dosing for Day 1 (Baseline), Months 2, 6, 12, 24, 36, Extension Day 1, and Extension Month 12 for all participants. Sample was taken after the first morning's void and was provided as a mid-stream, clean catch sample. During the titration period (Weeks 1, 2, 3 and 4) and at Month 6, additional samples were collected for the preceding day immediately preceding the 2nd daily dose and at bed-time. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration. At the Month 36 visit, participants were given a urine container and brought back the specimen at Extension Day 1. All participants were fasting.

The intent-to-treat (ITT) dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. Observed cases (OC) dataset were used.

Urine osmolality at steady state (after at least 4 days of dosing) including "absolute trough" prior to the second daily dose.

Samples for this assessment were taken as closely coincident to PK blood sample as practical. During Weeks 1, 2, 3 and 4 of the Titration Period and at Month 6, additional samples were collected for the preceding day immediately preceding the second daily dose. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Urine osmolality at steady state (after at least 4 days of dosing) including "average of troughs" (the mean urine osmolality prior to bedtime).

Samples for this assessment were to be taken as closely coincident to PK blood sample as practical. During Weeks 1, 2, 3 and 4 of the Titration Period and at Month 6, additional samples were collected for the preceding day at bedtime. These samples allowed derivation of an average nadir of spot urine osmolality concentrations at each dose level and while at steady state during extended tolvaptan administration.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

TKV was assessed by the central magnetic resonance imaging (MRI) rater.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

GFR was estimated using reciprocal serum creatinine formula. The formula does not adjust for body weight or height, but this may be done to normalize to body surface area. The formula for reciprocal Serum creatinine is: 1/Pcr. (Pcr = serum creatinine concentration [mg/dL]). Clinic weight scales were calibrated at least yearly.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participants were seated and resting systolic and diastolic BP for each scheduled assessment was recorded. At each assessment, participants were categorized (based on repeated blood pressure measurements as being normotensive (MAP < 100 mm Hg and off therapy), high normal (sBP > 129 and or dBP > 84 mm Hg off therapy) or hypertensive (sBP >140 and/or dBP > 90 mm Hg). The mean arterial pressure (MAP) was derived from these values and were not recorded (MAP = diastolic pressure + [1/3 x pulse pressure (ie systolic - diastolic pressure)] in mm Hg).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Participants were asked the question to assess the relative level of pain attributed to their kidneys. This question was, "On a scale of 0 to 10, with zero represented no pain at all and 10 represented the worst pain ever experienced, what was the worst kidney pain experienced in the last 4 months?" If the latest assessment was less than 4 months prior, the question was substituted "since your last visit" for "in the last 4 months". The same interrogator designated to this task was used throughout the study for each participant.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

Participants were asked the question to assess the relative level of pain attributed to their kidneys. This question was, "On a scale of 0 to 10, with zero represented no pain at all and 10 represented the worst pain ever experienced, what was the worst kidney pain experienced in the last 4 months?" If the latest assessment was less than 4 months prior, the question was substituted "since your last visit" for "in the last 4 months". The same interrogator designated to this task was used throughout the study for each participant.

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participant had a measurement of their abdominal girth recorded. The measurement will be taken with a tape measure extending around the abdomen at the level of the iliac crests laterally and the umbilicus anteriorly. The examiner should also palpate for each kidney and liver edge, noting presence or enlargement. (By definition if the kidneys are palpable they are enlarged, the liver edge may be palpable but not enlarged).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.

The participant had a measurement of their abdominal girth recorded. The measurement will be taken with a tape measure extending around the abdomen at the level of the iliac crests laterally and the umbilicus anteriorly. The examiner should also palpate for each kidney and liver edge, noting presence or enlargement. (By definition if the kidneys are palpable they are enlarged, the liver edge may be palpable but not enlarged).

The ITT dataset was defined as a dataset that included data from all participants who enrolled to the study with observations at Baseline and Post Baseline. OC dataset were used.