Symptomatic response is defined as a decrease from induction baseline in the patient reported outcome (PRO)-2 by at least 30% and at least 1 point, with either at least 1-point decrease from induction baseline in RBS or an RBS of 0 or 1. PRO-2 consists of the two components (rectal bleeding and stool frequency). The stool frequency subscale is rated as follows: 0 (normal stool frequency), 1 (1-2 stools more than normal), 2 (3-4 stools more than normal), and 3 (5 or more stools more than normal). The rectal bleeding subscale is rated as: 0 (no blood), 1 (streaks of blood less than half the time), 2 (obvious blood most of the time), and 3 (blood alone). Higher score indicates more severity in symptoms.

SFS is a component of PRO-2. The stool frequency subscale is rated as follows: 0 (normal stool frequency), 1 (1-2 stools more than normal), 2 (3-4 stools more than normal), and 3 (5 or more stools more than normal). Higher score indicates more severity in symptoms.

RBS is a component of PRO-2. The rectal bleeding subscale is rated as: 0 (no blood), 1 (streaks of blood less than half the time), 2 (obvious blood most of the time), and 3 (blood alone). Higher score indicates more severity in symptoms.

Clinical remission is defined as a partial Mayo score less than or equal to (<=) 2 with no sub-score greater than (>) 1. Partial Mayo score is a non-invasive clinical measure for determining the severity of UC. The total score falls between 0 and 9, where higher score indicates more severity.

Symptomatic remission as measured by PRO-2 is defined as a SFS of 0 or 1 and an RBS of 0, where the SFS has not increased from induction baseline. The SFS is rated as follows: 0 (normal stool frequency), 1 (1-2 stools more than normal), 2 (3-4 stools more than normal), and 3 (5 or more stools more than normal). The RBS is rated as: 0 (no blood), 1 (streaks of blood less than half the time), 2 (obvious blood most of the time), and 3 (blood alone). Higher score indicates more severity in symptoms.

Steroid-free remission is defined as clinical remission with no use of corticosteroids for at least 30 days. Clinical remission is defined as partial Mayo score <= 2 with no sub-score >1.

Sustained remission is defined as clinical remission maintenance status at post-induction (Week 12) in participants who had attained clinical remission by the end of the 12-week induction therapy.

Endoscopic improvement (healing) is defined as endoscopic remission Mayo endoscopic subscore (MES) of 0 or 1. The MES consists of 3 subscores: stool frequency, rectal bleeding and physician's global assessment, each subscore is graded from 0 (normal) to 3 (severe) with higher scores indicate more severe disease.

Endoscopic remission (normalization) is defined as an MES of 0. The MES consists of 3 subscores: stool frequency, rectal bleeding and physician's global assessment, each subscore is graded from 0 (normal) to 3 (severe) where higher scores indicate more severe disease.

Treatment discontinuation is defined as discontinuation of guselkumab treatment for any reason.

Treatment switch is defined as initiation of another medication for UC treatment after guselkumab discontinuation.

Time to treatment discontinuation is defined as the time from the guselkumab start date to the time of treatment discontinuation.

Time to treatment switch is defined as the time from the guselkumab start date to the time of initiation of a new treatment other than guselkumab.

The percentage of participants on guselkumab dosing schedules of 200mg q4w or 100 mg q8w will be assessed. For each dosing schedule, the percentage will be calculated by dividing the number of participants receiving the specific dosing regimen by the number of participants still being followed up at those time points, multiplied by 100%.

Percentage of participants having dose escalation/ de-escalation during maintenance treatment will be assessed. The percentage will be calculated by dividing the number of participants having dosage adjustment (that is, dose escalation/de-escalation) after Week 0 at any visit time point compared to his/her previous recorded administration dosage, multiplied by 100%.

IBDQ remission is defined as total IBDQ score >= 170. The IBDQ is a validated, 32-item, self-reported questionnaire for patients with inflammatory bowel disease that will be used to evaluate the disease-specific health-related quality of life (QoL) across 4 dimensional scores: bowel symptoms (loose stools, abdominal pain), systemic functions (fatigue, altered sleep pattern), social function (work attendance, need to cancel social events), and emotional function (anger, depression, irritability). Scores range from 32 to 224, with higher scores indicating better outcomes.

Change in CRP levels since guselkumab initiation will be reported.

Change in fecal calprotectin levels since guselkumab initiation will be reported.

Normalization of CRP is defined as reduction of less than or equal to 5 microgram per liter (mg/L) at weeks 12, 24 and 48 since baseline. Percentage of participants with abnormal CRP at baseline achieving CRP normalization will be reported.

Normalization of fecal calprotectin is defined as reduction of <= 250 microgram per gram (mcg/g) at weeks 12, 24 and 48 since baseline. Percentage of participants with abnormal FCP at baseline achieving fecal calprotectin normalization will be reported.