From the Guidelines
In a hypertensive emergency, any level of proteinuria on dipstick testing (1+ or greater) should be considered significant, especially when accompanied by elevated blood pressure. The presence of proteinuria in this context may indicate end-organ damage, specifically renal involvement, which is a hallmark of hypertensive emergency 1. Proteinuria occurs because severe hypertension damages the glomerular filtration barrier in the kidneys, allowing protein to leak into the urine. When evaluating a patient with severely elevated blood pressure, the finding of proteinuria should prompt immediate blood pressure reduction (typically by 25% in the first few hours) using intravenous antihypertensive medications such as labetalol, nicardipine, or clevidipine in a monitored setting. Other signs of end-organ damage that should be assessed include:
- Neurological symptoms
- Visual changes
- Chest pain
- Heart failure symptoms The presence of proteinuria alongside hypertension also warrants further investigation with:
- Quantitative urine protein measurements
- Serum creatinine
- Complete blood count to assess the extent of kidney damage and to distinguish between hypertensive emergency and other conditions like preeclampsia in pregnant patients or primary kidney disease 1. According to the 2024 ESC guidelines for the management of elevated blood pressure and hypertension, hypertensive emergency is defined as BP of ≥180/110 mmHg associated with acute hypertension-mediated organ damage, often in the presence of symptoms 1. Therefore, the presence of proteinuria in a patient with severely elevated blood pressure should be considered a significant indicator of end-organ damage and prompt immediate treatment to reduce blood pressure and prevent further damage.
From the Research
Proteinuria Levels and Hypertensive Emergency
- The level of proteinuria on dipstick that is significant for a hypertensive emergency is not strictly defined, but studies suggest that any level of proteinuria, even trace amounts, can be associated with increased risk of mortality and cardiovascular events 2, 3.
- A study published in the Journal of Personalized Medicine found that dipstick proteinuria was a significant predictor of all-cause mortality in patients with hypertensive crisis, and the risk of mortality increased in a dose-dependent manner according to the degree of proteinuria 2.
- Another study published in the American Journal of Kidney Diseases found that a dipstick proteinuria value of 3+ or greater had the best combination of sensitivity and specificity in predicting a protein-creatinine ratio of 1 or greater, which is often used as a threshold for diagnosing significant proteinuria 4.
- However, a study published in the American Journal of Obstetrics and Gynecology found that urinary protein dipstick values were not always reliable in predicting significant proteinuria, particularly in pregnant women with hypertension 5.
- Overall, the presence of any proteinuria on dipstick, even trace amounts, should be taken seriously and may indicate an increased risk of cardiovascular events and mortality in patients with hypertensive emergency 2, 3, 6.
Dipstick Proteinuria and Mortality Risk
- The risk of mortality associated with dipstick proteinuria is dose-dependent, with higher levels of proteinuria corresponding to increased risk of mortality 2.
- A study published in the Journal of Personalized Medicine found that the hazard ratio for all-cause mortality was 1.91 for patients with trace proteinuria, 2.32 for those with 1+ proteinuria, 2.40 for those with 2+ proteinuria, and 2.40 for those with 3+ or greater proteinuria, compared to patients with negative proteinuria 2.
- Another study published in the American Heart Journal found that patients with both moderate chronic kidney disease and dipstick proteinuria had increased risk of stent thrombosis, all-cause mortality, and nonfatal myocardial infarction or death 6.