Acute Kidney Injury in Hypertensive Emergencies: A National Inpatient Sample Analysis of Clinical Outcomes and Implications

Abstract Rationale: Severe hypertension can disrupt renal blood flow, resulting in ischemia and subsequent kidney damage. Despite the advancements in blood pressure management, the long-term prognosis for patients experiencing hypertensive emergencies remains concerning, with many at risk of adverse cardiac events or strokes within a year. We investigated morbidity, mortality, utilization of resources and cost in patients admitted with hypertensive emergency in the National Inpatient Sample (2018-2020) with and without acute kidney injury (AKI). Methods: The United States NIS (2018-2020) was queried to identify hospitalized patients with hypertensive emergency with and without AKI using ICD-10 codes. Confounders were adjusted for using multivariable logistic regression analysis. The primary outcome of our study was in-hospital mortality, while secondary outcomes included mean length of stay (LOS), mean total hospital charges (THC), and the odds of in-hospital complications including intracranial hemorrhage (including subarachnoid hemorrhage), acute coronary syndrome (STEMI and NSTEMI), acute heart failure, acute respiratory failure, cardiac arrest, mechanical ventilation, sepsis, acute pulmonary embolism, and deep venous thrombosis. Results: Out of 239,005 hospitalized patients with hypertensive emergency, 42,410 (17.74 %) had AKI, and 196,595 (82.25 %) were without AKI. Patients with hypertensive emergency and AKI were found to have a statistically significant 3-fold increase in inpatient mortality (adjusted Odds ratio [aOR] 3.10; 95% Confidence Interval [CI], 1.34-7.16; P <0.05), with an adjusted increase in mean length of stay of 1.41(95% CI, 1.17-1.64; P <0.05), and increased total hospital charges. The odds of acute coronary syndrome (both STEMI and NSTEMI), acute heart failure, acute respiratory failure, the need for mechanical ventilation, sepsis, and deep venous thrombosis was significantly greater in the AKI group (all P < 0.05). Additionally, no statistically significant differences in the rates of intracranial hemorrhage (including subarachnoid hemorrhage), acute pulmonary embolism, or cardiac arrest were observed between the two groups. Conclusions: Our study found that AKI is linked to higher mortality, longer hospital stays, and higher odds of various in-hospital complications in patients experiencing hypertensive emergencies compared to those without AKI. Acute kidney injury in these patients requires timely intervention, careful monitoring, and a multifaceted approach to address its complex challenges. It remains to be investigated through larger trials whether treating AKI enhances outcomes for these patients.