Association of microscopic hematuria with long-term mortality in patients with hypertensive crisis

Microscopic hematuria is associated with increased risk of developing chronic kidney function impairment and even death. However, data on the long-term mortality risk associated with microscopic hematuria among patients with hypertensive crisis are scarce. We hypothesized that microscopic hematuria at initial presentation in patients with hypertensive crisis would be associated with increased long-term mortality.

This retrospective study included patients admitted to the emergency department between 2016 and 2019 for hypertensive crisis (systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 110 mmHg). Microscopic hematuria was defined as ≥ 3 red blood cells per high-power field on microscopic evaluation of urine.

Among 3595 patients, 1359 (37.8%) had microscopic hematuria. The 3-year all-cause mortality in patients with and without microscopic hematuria was 25.5% and 16.3%, respectively. After adjusting for confounding variables, patients with microscopic hematuria (adjusted HR, 1.30; 95% CI 1.10-1.54) showed a significantly higher risk of 3-year all-cause mortality than patients without microscopic hematuria. In a subgroup analysis based on the presence of proteinuria, microscopic hematuria was a significant predictor of all-cause mortality in patients without proteinuria (adjusted HR, 1.61; 95% CI 1.28-2.03) but not in patients with proteinuria.

Microscopic hematuria was a significant predictor of all-cause mortality in patients with hypertensive crisis. Our study suggests that microscopic hematuria can be a useful prognostic marker and may permit early detection of patients with an increased risk of death. Clinicians in the emergency department should consider screening for kidney function using urine analysis during the initial assessment of patients with hypertensive crisis.