Early detection of individuals at risk for severe AKI & poor outcomes is still difficult, despite advancements in supportive care. The most widely used indicator of kidney function, serum creatinine, is constrained by non-renal variables & a delayed rise. Finding biomarkers that represent underlying pathophysiological processes like inflammation is therefore of increasing interest [3–5].

Regardless of the cause, inflammation is crucial to the pathophysiology of AKI. Tubular & vascular damage is caused by endothelial dysfunction, cytokine release, leukocyte activation, & oxidative stress. An acute-phase reactant produced by the liver in reaction to interleukin-6, C-reactive protein (CRP) is a sensitive indicator of tissue damage & systemic inflammation.

Despite being often employed in clinical practice, CRP's function in AKI is still unclear. A higher inflammatory burden & more serious renal damage may be indicated by elevated CRP. The purpose of this study is to evaluate the connection between hospitalized patients' clinical outcomes, AKI severity, & CRP levels [6].

Elevated serum levels of the inflammatory marker C-reactive protein (CRP) have been linked to a higher risk of cardiovascular events & mortality in both the general population & kidney disease patients [7]. It was first shown that consecutive patients could benefit from repeated CRP measures in predicting outcomes from PD-associated peritonitis.

The magnitude of the CRP response correlated with the severity of the episode, patients who resolved with antibiotics showed a prompt fall in CRP towards normal, & patients in whom the serum CRP value remained raised had a complicated course; however, the association between CRP & hard end points, such as mortality & recurrent peritonitis events, has not been examined.

Objectives

1. To measure CRP levels in patients with acute kidney injury
2. To assess the association between CRP levels & AKI severity
3. To evaluate the relationship between CRP & clinical outcomes including:
   • Renal replacement therapy
   • Length of hospital stay
   • Renal recovery
   • In-hospital mortality

Study Population: The study included 100 adult patients admitted to a tertiary care hospital & diagnosed with AKI between January 2024 & December 2024.

Inclusion Criteria:

• Age ≥ 18 years
• Diagnosis of AKI as per KDIGO criteria
• Availability of CRP measurement at AKI diagnosis

Exclusion Criteria:

• End-stage renal disease on maintenance dialysis
• Known chronic inflammatory or autoimmune diseases
• Active malignancy
• Pregnancy

Data Collection: Demographic data, comorbidities, baseline renal function, AKI etiology, & laboratory parameters were recorded. Serum CRP was measured at the time of AKI diagnosis (Day 0) & repeated on Day 3 & Day 7. AKI severity was classified using KDIGO staging.

Outcome Measures:

• AKI stage
• Requirement of renal replacement therapy (RRT)
• Length of hospital stay
• Renal recovery at discharge
• In-hospital mortality

Statistical Analysis:

Continuous variables were expressed as mean ± standard deviation or median (interquartile range). Categorical variables were expressed as percentages. Comparisons were performed using chi-square test or ANOVA where appropriate. A p-value <0.05 was considered statistically significant

Table 1. Baseline Characteristics of AKI Patients (n = 100)

Among the 100 patients, the mean age was 60.8 ± 14.2 years, with male predominance. Hypertension & diabetes mellitus were the most common comorbidities.

Table 2. CRP Levels According to AKI Stage

CRP Levels & AKI Severity

CRP levels increased significantly with increasing AKI stage.

Table 3. Clinical Outcomes by CRP Quartiles

Patients with higher CRP levels had worse clinical outcomes.

Table 4. Association of CRP with Adverse Outcomes

Higher CRP levels were independently associated with RRT requirement & mortality.

The severity of AKI & unfavorable clinical outcomes are strongly correlated with higher CRP levels, according to this study. Increased mortality, prolonged hospital stays, severe AKI, & the need for renal replacement treatment were all associated with higher CRP levels [8].

The gradual increase in CRP across KDIGO stages implies that the degree of renal damage is correlated with systemic inflammation. Continuous inflammatory processes that hinder renal recovery may be reflected in persistently elevated CRP.

CRP is a useful diagnostic for early risk categorization in AKI since it is affordable, widely accessible, & simple to interpret [9]. Monitoring the course of the illness & the effectiveness of treatment may be aided by serial CRP tests.

Hemodynamic instability, sepsis, nephrotoxic exposure, & pre-existing comorbidities are all part of the complex pathophysiology of AKI & the progression to RRT in ICU patients. In this regard, physiological disturbance is measured & prognostication is guided by sickness severity scoring systems like SOFA & APACHE II [10]. These scores are frequently used as reference standards when evaluating the risk of organ failure, particularly renal dysfunction, due to their comprehensive character. In the context of AKI & RRT risk, our study sought to determine if the CAR, a straightforward inflammation-based biomarker, complements or enhances the predictive power of these well-established instruments.

These findings underscore that established scoring systems remain indispensable for risk stratification in critical illness, often outperforming single biomarkers. Basile‑Filho et al. reported that composite ICU scores like APACHE II & SOFA had better discrimination for mortality than the CAR or its components alone. Similarly, we observed that adding CAR did not improve prediction of RRT once APACHE/SOFA were accounted for[11-12]. Indeed, CAR appears to track with overall illness severity—APACHE II correlates positively with CRP/ albumin levels in ICU patients—so patients with high CAR usually already have high severity scores.

Limitations

• Single-center study
• Relatively small sample size
• CRP is a non-specific inflammatory marker
• Long-term renal outcomes were not assessed

Elevated CRP levels are significantly associated with increased severity of acute kidney injury & poorer clinical outcomes. CRP may serve as a valuable adjunctive biomarker for prognostication & management of AKI patients.

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