What are the risks of complications for a patient with a non-functioning kidney (Impaired renal function)?

Risks of Complications with Non-Functioning Kidney (Impaired Renal Function)

Impaired renal function significantly increases mortality risk 2- to 5-fold depending on severity, with acute kidney injury after cardiac procedures conferring an 8-fold increase in death, while also substantially elevating risks of cardiovascular disease, infections, medication toxicity, and progression to end-stage renal disease requiring dialysis. 1

Mortality and Morbidity Risks

Primary Mortality Impact:

• Moderate to severe renal impairment increases 6-year mortality risk 5-fold compared to normal renal function 1
• Mild renal impairment increases mortality risk 2-fold 1
• Acute kidney injury after cardiac surgery independently increases odds of death 8-fold 1
• Cardiovascular disease events are more common than progression to kidney failure in CKD patients, making CVD the leading cause of death 1

Hospital and Acute Care Complications:

• Impaired renal function increases intensive care unit length of stay and overall hospitalization duration 1
• Significantly increases healthcare resource expenditures 1
• Associated with higher NYHA functional class and moderate-to-severe systemic ventricular dysfunction 1

Cardiovascular Complications

The risk of cardiovascular death and events rises exponentially as GFR declines below 60 mL/min/1.73 m², with adjusted hazard ratios ranging from 1.2 to 5.1 depending on severity. 1

• Adjusted hazard ratio for cardiovascular disease occurrence: 1.4 to 3.4 across stages of renal dysfunction 1
• Renal dysfunction promotes maladaptive cardiac remodeling through loss of sodium balance, volume overload, hypertension, and anemia 1
• Increased central venous pressure—common in many cardiac conditions—plays an important role in worsening renal dysfunction 1
• Patients with CKD should be considered in the highest risk group for subsequent cardiovascular events 1

Infection Risks

Impaired renal function substantially increases susceptibility to infections, which are major causes of morbidity and mortality. 1

• Infectious complications affect approximately two-thirds of transplant patients with renal dysfunction 1
• Bacterial infections (E. coli, Enterobacter, Pseudomonas) commonly involve surgical sites, abdominal cavity, urinary tract, and bloodstream 1
• Opportunistic infections and reactivation of latent infections occur more frequently with immunosuppression 1
• Annual influenza vaccination is recommended for all adults with CKD 1
• Pneumococcal vaccination is recommended for adults with eGFR <30 mL/min/1.73 m² 1

Progression to End-Stage Renal Disease

Between 30-80% of patients with impaired kidney function develop chronic kidney disease stage 3-4, with a cumulative 5-9% risk of requiring dialysis or renal transplantation within 10 years. 1

• Risk increases with severity of baseline kidney disease 1
• Multiple factors contribute: hypertension, diabetes mellitus, cardiac dysfunction, advancing age, nephrotoxic medications, and contrast agents 1
• Calcineurin inhibitors (CNIs) are responsible for >70% of cases of end-stage renal disease in certain populations 1

Medication-Related Complications

Impaired renal function dramatically increases risks of drug toxicity and requires dose adjustments for most renally-cleared medications, with severe renal failure (CrCl <30 mL/min) contraindicating many drugs. 1, 2

Critical Medication Thresholds:

• eGFR <60 mL/min/1.73 m²: Initial consideration for dose adjustment required 2
• eGFR 30-44 mL/min/1.73 m²: Dose reduction commonly required for renally-cleared drugs 2
• eGFR <30 mL/min/1.73 m²: Many medications require substantial modification or are contraindicated 1, 2
• eGFR <15 mL/min/1.73 m²: Most medications contraindicated or require dramatic dose reduction 2

High-Risk Medications:

• Low molecular weight heparin, fondaparinux, bivalirudin, and GP IIb/IIIa inhibitors need down-titration or may be contraindicated with CrCl <30 mL/min 1
• NSAIDs should be avoided as potential nephrotoxins 3
• Contrast agents during catheterizations and CT scans pose nephrotoxicity risk 1
• Metformin must be stopped if eGFR <30 mL/min/1.73 m² 2

Bleeding Complications

Renal dysfunction is a potent independent predictor of bleeding risk in patients with acute coronary syndromes and other conditions; the more severe the dysfunction, the higher the bleeding risk. 1

• Bleeding risk increases progressively with declining renal function 1
• Unfractionated heparin does not protect against bleeding complications in severe renal failure 1

Metabolic and Systemic Complications

Patients with impaired renal function require monitoring for multiple metabolic derangements that significantly impact quality of life and outcomes. 3

• Hyperkalemia 3
• Metabolic acidosis 3
• Hyperphosphatemia 3
• Vitamin D deficiency 3
• Secondary hyperparathyroidism 3
• Anemia 1, 3
• Malnutrition 1
• Bone disease 1
• Neuropathy 1
• Decreased quality of life 1

Cancer-Related Risks

Patients with CKD have an increased risk of renal cell carcinoma, with risk increasing proportionally to severity of kidney disease. 1

• CKD is an independent risk factor for developing renal cell carcinoma 1
• Proposed mechanisms include renal fibrosis, tubular atrophy, uremia-related chronic inflammation, oxidative stress, and compromised immune function 1
• CKD is also a prognostic factor for worse outcomes in patients with existing renal cell carcinoma 1
• Nephrectomy itself is an independent risk factor for further kidney injury, especially in patients with pre-existing kidney disease 1

Acute Kidney Injury Risk

All people with CKD should be considered at increased risk of acute kidney injury during intercurrent illness or procedures. 1

• Acute kidney injury risk increases during diagnostic procedures and interventions 1
• Contrast-induced nephropathy is a growing problem with widespread use of invasive procedures 4
• Appropriate nephroprotective measures include iso-osmotic contrast agents and adequate hydration 4

Critical Monitoring Thresholds

Continuous monitoring of renal function is mandatory for early detection and management of complications, with specific surveillance requirements based on risk stratification. 1

High-Risk Patients (eGFR <30 mL/min/1.73 m²):

• Annual focused history, physical exam, and symptom assessment 1
• Annual renal function assessment 1
• Annual upper tract imaging 1
• Multichannel urodynamic studies when clinically indicated 1

Moderate-Risk Patients:

• Annual focused assessment 1
• Annual renal function assessment 1
• Upper tract imaging every 1-2 years 1

Referral Indications

Patients should be referred to specialist kidney care services when GFR <30 mL/min/1.73 m² (stages G4-G5), with progression of CKD, or with refractory complications. 1

Additional referral criteria include:

• Abrupt sustained fall in GFR 1
• Significant albuminuria (ACR ≥300 mg/g) 1
• Hypertension refractory to 4 or more antihypertensive agents 1
• Persistent potassium abnormalities 1