What is the most common cause of acute kidney injury in hospitalized patients?

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Last updated: February 9, 2026 • View editorial policy

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Most Common Cause of AKI in Hospitalized Patients

Prerenal causes dominate as the most common etiology of acute kidney injury in hospitalized patients, accounting for more than 60% of cases, resulting from decreased renal perfusion without initial structural kidney damage. 1, 2

Etiologic Distribution

The breakdown of AKI causes in general hospitalized patients follows a clear hierarchy:

  • Prerenal causes: >60% of cases - These result from decreased renal perfusion without initial structural kidney damage 1, 2
  • Intrarenal causes: ~35% of cases - Primarily acute tubular necrosis from direct parenchymal damage 1, 2
  • Postrenal obstruction: <3% of cases - Urinary tract obstruction is the least common mechanism 1, 2

Key Prerenal Mechanisms in Hospitalized Patients

Volume depletion represents the dominant prerenal mechanism through multiple pathways:

  • Absolute volume depletion from hemorrhage, gastrointestinal losses, burns, or excessive diuresis 1, 2
  • Third-space fluid sequestration in pancreatitis or peritonitis 1, 2
  • Severe hypoalbuminemia from nephrotic syndrome 1, 2

Hemodynamic compromise contributes significantly:

  • Decreased cardiac output from heart failure, cardiogenic shock, or arrhythmias 1, 2
  • Systemic vasodilation from sepsis, anaphylaxis, or cirrhosis 1, 2

Medication-related causes are particularly important and often overlooked:

  • NSAIDs, diuretics, and ACE inhibitors/ARBs represent the "triple whammy" combination that dramatically increases AKI risk 1, 2
  • Each additional nephrotoxin increases AKI odds by 53%, and three or more nephrotoxins more than doubles the risk 2

Special Population Considerations

In patients with decompensated cirrhosis, prerenal AKI accounts for approximately 68% of cases, with the most common precipitating factors being:

  • Infections (most common precipitant) 1
  • Diuretic-induced excessive diuresis 1
  • Gastrointestinal bleeding 1
  • Therapeutic paracentesis without adequate volume expansion 1
  • Nephrotoxic drugs 1

Critical Diagnostic Approach

Fluid challenge with albumin at 1 g/kg (maximum 100 g/day) differentiates prerenal from intrinsic causes:

  • Hypovolemic (prerenal) AKI shows reduction in serum creatinine to within 0.3 mg/dL of baseline 1, 2
  • Patients with intrinsic AKI do not respond to fluid challenge alone 1

Common Pitfalls to Avoid

Don't assume traditional categories are discrete - Prerenal and intrinsic mechanisms frequently coexist and evolve dynamically, especially in septic patients 3

Don't overlook medication combinations - Electronic health record systems identifying patients exposed to three or more nephrotoxic drugs have led to sustained decreases in AKI incidence 2

Don't discharge without stopping diuretics - All diuretics should be discontinued irrespective of AKI stage when prerenal AKI is diagnosed 1, 2

Don't forget infection screening - Infection is the most common precipitant of hepatorenal syndrome and should be treated immediately 1

References

1
Guideline

Acute Kidney Injury Causes and Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

2
Guideline

Acute Kidney Injury Causes and Diagnostic Approach

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

3
Guideline

Prolonged Kidney Recovery from Acute Kidney Injury

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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