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<div><p>Acute Severe Hypertension (ASH), presenting as a Hypertensive Emergency (HE) or Hypertensive Urgency (HU), is a frequent reason for emergency department (ED) admissions. This study sought to assess the prevalence of ASH among adult ED patients in Pakistan and investigate all-cause mortality and hospitalization rates over six months. We conducted a prospective single-center cohort study in Karachi, Pakistan, from June 3, 2019, to September 22, 2020. We enrolled all adult male and non-pregnant female patients presenting to the emergency department with a systolic blood pressure of ≥180 mm Hg or diastolic blood pressure of ≥120 mm Hg. Telephonic follow-ups were conducted at one, three-, and six months post-discharge from the hospital. The Cox Regression Model was used to identify the risk factors for mortality. <b>O</b>f 49,431 ED visits during the study period, 1,525 (3.1%) met the inclusion criteria, and 1,161 (76.2%) were enrolled. A total of 356 patients (30.6%) were diagnosed with HE, and 805 (69.2%) with HU. Among follow-up patients, 14.6% with HE and 4.7% with HU experienced mortality within six months. Notably, the risk of mortality was higher in patients aged >65 years (aRR = 1.90, 95% CI = 1.20 to 3.02) and those suffering from stroke (aRR = 2.09, 95% CI = 1.21 to 3.61) or acute kidney injury (aRR = 1.82, 95% CI = 1.09 to 3.04). Conversely, regular blood pressure monitoring (aRR = 0.08, 95% CI = 0.03-0.19) and adherence to antihypertensive medications (aRR = 0.23, 95% CI = 0.09-0.56) significantly lowered the risk HE resulted in heightened mortality at six months, while HU, traditionally deemed benign, also led to substantial morbidity and mortality. This underscores the ED visit for ASH as a crucial opportunity for preventing short-term and longer-term health complications.</p></div>