What is the association between laboratory markers (platelet count, transaminases (liver enzymes), albumin, C-Reactive Protein (CRP)) and Acute Kidney Injury (AKI) severity in patients with Tropical Acute Febrile Illness?

Association of Laboratory Markers with AKI Severity in Tropical Acute Febrile Illness

Laboratory markers including low platelet count, elevated transaminases, hypoalbuminemia, and increased CRP are significantly associated with increased severity of AKI in tropical acute febrile illness, with the CRP/prealbumin ratio being the strongest independent predictor of mortality. 1, 2, 3

Key Laboratory Markers and Their Association with AKI Severity

Platelet Count

• Low platelet count serves as both a diagnostic and prognostic marker in TAFI-associated AKI, with lower counts associated with higher mortality and increased need for renal replacement therapy (RRT) 1
• Thrombocytopenia is present in approximately 70% of patients with dengue fever, with more severe thrombocytopenia correlating with increased risk of AKI development 4

Transaminases (Liver Enzymes)

• Severe transaminitis is significantly associated with AKI in TAFI patients, with higher SGPT (ALT) levels observed in patients who develop AKI (450 U/L vs. 144 U/L in non-AKI patients, p=0.001) 4
• Hyperbilirubinemia is an independent risk factor for TAFI-associated AKI with an adjusted odds ratio of 2.4 (95% CI 1.1-4.9) 2

Albumin

• Hypoalbuminemia is significantly associated with AKI development in TAFI, with lower albumin levels seen in AKI patients compared to non-AKI patients (2.65 g/dL vs. 3.09 g/dL, p<0.001) 4
• In the context of acute illness, albumin primarily reflects the inflammatory state rather than nutritional status 1

C-Reactive Protein (CRP)

• Elevated CRP levels are significantly higher in AKI patients who die within 28 days compared to survivors 3
• The ratio of CRP to prealbumin is independently associated with mortality in AKI patients after adjustment for age, gender, sepsis, and sequential organ failure assessment (SOFA) score 3
• Patients in the highest quartile of CRP/prealbumin ratio have a hazard ratio of 3.89 for mortality compared to the lowest quartile 3

Integrated Assessment and Risk Stratification

Combined Biomarker Approach

• The Acute Disease Quality Initiative (ADQI) consensus recommends combining clinical assessment with biomarkers to optimize patient triage and intervention timing 1
• A combination of damage and functional biomarkers, along with clinical information, improves diagnostic accuracy of AKI and helps assess severity 1
• The CRP/prealbumin ratio is a particularly valuable predictor, with increasing quartiles showing hazard ratios of 1.00 (reference), 1.85,2.25, and 3.89 for mortality (p=0.01 for trend) 3

Risk Factors for AKI Development and Progression

• Male gender (AOR 3.1; 95% CI 1.3-7.4), respiratory failure (AOR 4.6; 95% CI 1.5-14.1), hyperbilirubinemia (AOR 2.4; 95% CI 1.1-4.9), and obesity (AOR 2.9; 95% CI 1.4-6) are independent risk factors for TAFI-associated AKI 2
• Patients with leptospirosis have the highest risk of developing severe AKI (stage 2-3) and requiring RRT 5
• The presence of hypotension, coexisting viral hepatitis, sepsis, and multiple organ dysfunction syndrome (MODS) are significantly associated with AKI development in dengue fever 4

Clinical Implications and Management Considerations

Early Detection and Monitoring

• Serial monitoring of platelet count, transaminases, albumin, and CRP is recommended for early detection of AKI in TAFI patients 1, 2
• Patients with abnormal laboratory markers (leukocytosis, severe transaminitis, hypoalbuminemia, metabolic acidosis, and proteinuria) should be closely monitored for AKI development 2

Prognostic Value and Treatment Decisions

• The RIFLE and KDIGO classifications are valid and applicable in TAFI-related AKI, with incremental risk of mortality and dialysis requirement across increasing AKI stages 6
• Approximately 10.2% of AKI patients require RRT initiation, with leptospirosis being the most common cause 5
• AKI is associated with significantly increased mortality in TAFI patients (p=0.005), with all reported deaths occurring in the AKI group in some studies 2, 4

Common Pitfalls and Caveats

• Relying on a single biomarker may lead to missed or delayed diagnosis of AKI in TAFI patients 1
• The etiology of TAFI varies geographically, with malaria being the most common cause in some regions and leptospirosis being the most nephrotoxic 5
• Not all TAFI patients with abnormal laboratory markers will develop AKI, but the combination of multiple abnormal markers significantly increases the risk 2
• The CRP/prealbumin ratio may be a more valuable predictor than individual markers alone and should be considered in risk assessment 3