European Journal of Cardiovascular Medicine

Acute kidney injury (AKI) represents a rapid decline in kidney function that develops over hours to days and is clinically expressed by rising serum creatinine and/or reduced urine output. The condition spans a spectrum from mild, reversible impairment to severe kidney failure requiring renal replacement therapy. Pathophysiologically, AKI often reflects a convergence of renal hypoperfusion, inflammatory injury, tubular toxicity, and microvascular dysfunction, and it can evolve quickly when systemic illness is not promptly corrected. Standardized classification systems such as RIFLE and AKIN improved comparability across studies, and the KDIGO framework unified definitions and staging, facilitating consistent reporting and bedside risk stratification.[1-5]

AKI is encountered across emergency, ward, and intensive care settings, and its global burden continues to rise.[6-8] Meta-analytic evidence indicates that AKI affects a substantial proportion of hospitalized patients worldwide, with wide variation driven by case-mix, diagnostic thresholds, and access to laboratory testing.[7,8] Hospital-based studies have demonstrated that even modest acute decrements in kidney function are linked to higher short-term mortality and longer length of stay, along with increased health-care costs.[9-11] These observations underscore that AKI is not merely a biochemical diagnosis; it is a clinically meaningful syndrome that marks systemic severity and influences resource utilization.

Beyond the index admission, AKI carries prognostic implications for later chronic kidney disease and long-term mortality, reinforcing the need to document AKI episodes and ensure continuity of care after discharge.[12,13] From a practical standpoint, the earliest clinical signals in ward patients often include oliguria, fluid overload, and progressive metabolic derangements. Prevention and early reversal depend on rapid hemodynamic assessment, correction of volume status, infection control, avoidance of nephrotoxins, and careful monitoring of urine output and creatinine trends. Renal replacement therapy is reserved for accepted indications such as refractory hyperkalemia, severe metabolic acidosis, fluid overload unresponsive to diuretics, and uremic complications, and recent trial data emphasize individualized timing rather than routine early initiation.[4,5,14]

In general medicine wards, the etiological profile of AKI often reflects preventable or treatable clinical scenarios such as volume depletion, sepsis, drug exposure, and obstructive uropathy. Early recognition with prompt correction of hemodynamic and metabolic derangements can improve the likelihood of renal recovery. Nevertheless, a subset of patients progresses to advanced AKI and requires dialysis, and local data on clinical presentation, severity distribution, and short-term outcomes are essential for strengthening triage, developing unit-specific care pathways, and guiding stewardship of nephrotoxic medications.

Objectives of the study were to (i) describe the demographic and clinical profile of adults admitted with AKI, (ii) classify AKI by etiological category and KDIGO stage, (iii) document management modalities including dialysis requirement, and (iv) determine in-hospital outcomes such as recovery status, dialysis dependence at discharge, length of stay, and mortality.

Study design and setting: A hospital-based observational study was undertaken in the Department of General Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India. Patients were evaluated and managed as per routine departmental protocols with nephrology consultation when clinically indicated. Study period: The study was conducted over six months from February 2022 to July 2022. Sample size and sampling: A total of 100 consecutive adult inpatients who fulfilled the operational definition of AKI during the study period were enrolled. Consecutive sampling was adopted to reflect real-world admissions and to minimize selection bias. Eligibility criteria: Adults (aged 18 years or older) admitted under General Medicine with newly identified AKI, defined and staged using KDIGO criteria, were included.[3-5] Patients with known end-stage kidney disease on maintenance dialysis were excluded. When baseline creatinine was unavailable, the most recent documented value within the prior three months was used when present; otherwise, AKI classification relied on in-hospital trends along with clinical assessment, consistent with KDIGO guidance.[3-5] Definitions and classification: AKI severity was staged as KDIGO Stage 1, 2, or 3 using serum creatinine and urine output criteria. Etiology was categorized clinically as prerenal, intrinsic renal, or postrenal based on history, physical examination, hemodynamic assessment, urine analysis, and imaging (ultrasonography to evaluate obstruction) as per standard approaches.[4,5] Clinical evaluation and investigations: All participants underwent systematic clinical assessment including volume status, blood pressure, and urine output monitoring. Routine investigations included serum urea and creatinine, electrolytes, complete blood count, and urinalysis as clinically appropriate. Ultrasonography of kidneys, ureters, and bladder was used to support categorization of postrenal obstruction. Treatment approach: Conservative management included optimization of hemodynamics with judicious fluids, discontinuation or dose adjustment of nephrotoxic drugs, management of infections and precipitating illness, correction of electrolyte and acid–base disturbances, and monitoring of fluid balance. Renal replacement therapy (hemodialysis or peritoneal dialysis) was initiated for standard indications such as refractory hyperkalemia, severe metabolic acidosis, fluid overload with respiratory compromise, or uremic complications. Data collection: A structured case record form captured demographic variables (age, sex), comorbidities, clinical presentation, etiological category, KDIGO stage, treatment modality (conservative management, hemodialysis, peritoneal dialysis), need for ICU admission, and length of stay. Outcome measures: Primary outcomes were renal recovery status at discharge (complete recovery, partial recovery, dialysis dependence) and in-hospital mortality. Recovery status was determined by clinical improvement along with fall in creatinine and urine output normalization as documented in case records. Secondary outcomes included requirement for renal replacement therapy and duration of hospitalization. Statistical analysis: Data were entered into a spreadsheet and analyzed using descriptive statistics. Categorical variables were summarized as frequencies and percentages. Continuous variables were expressed as mean ± standard deviation. Data consistency was checked by cross-verifying source records before final analysis. Ethical considerations: The study protocol was reviewed and approved by the Institutional Ethics Committee of Prathima Institute of Medical Sciences. Written informed consent was obtained from participants or legally acceptable representatives, and confidentiality was maintained by anonymizing data prior to analysis.

A total of 100 patients diagnosed with AKI were included. The largest age-group was 41–60 years (38%), and males constituted 62% of admissions. Hypertension (46%) and diabetes mellitus (38%) were the most frequently recorded comorbidities (Table 1).

Oliguria was the commonest presenting symptom (44%), followed by pedal edema (39%) and breathlessness (28%). Vomiting/nausea (26%) and altered sensorium (16%) were also noted. Etiologically, prerenal AKI predominated (48%), followed by intrinsic renal causes (38%) and postrenal obstruction (14%) (Table 2).

Table 1. Demographic characteristics and comorbidities of patients with acute kidney injury (N = 100)

Table 2. Clinical presentation and etiological classification of acute kidney injury (N = 100)

On KDIGO staging, Stage 2 AKI accounted for 36% of patients, while Stage 1 and Stage 3 each contributed 32% (Table 3). Conservative management was instituted in 58% of cases. Renal replacement therapy was required in 34% overall, predominantly hemodialysis (30%) with a smaller fraction receiving peritoneal dialysis (4%). ICU admission was recorded in 18% of patients (Table 3).

Table 3. Severity of AKI and management modalities (N = 100)

At discharge, complete renal recovery was achieved in 54% of patients, while 26% demonstrated partial recovery. Eight percent remained dialysis-dependent at the time of discharge. The in-hospital mortality was 12%. The mean hospital stay was 8.6 ± 3.4 days (Table 4).

Table 4. Clinical outcomes of patients with acute kidney injury (N = 100)

This observational study describes the clinical profile and short-term outcomes of 100 adult inpatients with AKI admitted under General Medicine at a tertiary care teaching hospital. The cohort demonstrated a male predominance and a concentration of cases in the 41–60-year age group. Similar age and sex distributions have been reported across diverse hospital-based AKI datasets, reflecting both background comorbidity patterns and health-care utilization trends.[6-10]

Hypertension and diabetes mellitus were the most frequent comorbidities in the present cohort. These conditions predispose to reduced renal reserve and increase susceptibility to acute insults such as hypovolemia, infection, and drug-related nephrotoxicity, thereby increasing the likelihood of clinically significant AKI during hospitalization.[6,8,12] The prominence of oliguria and fluid overload manifestations (pedal edema and breathlessness) aligns with the recognized association between reduced urine output, volume dysregulation, and adverse outcomes in AKI.[4,5,11]

Prerenal AKI constituted nearly half of cases, followed by intrinsic renal causes and postrenal obstruction. This distribution is consistent with ward-based practice where hemodynamic compromise and volume depletion are common drivers, and it highlights the potential for prevention through early assessment of perfusion, targeted fluid therapy, and timely management of precipitating illness.[4-6] The staging pattern showed a substantial burden of moderate-to-severe AKI, with Stage 2 and Stage 3 together accounting for 68%. Prior studies have demonstrated a graded relationship between AKI severity and mortality, length of stay, and costs, underscoring the clinical value of standardized staging at presentation and during monitoring.[9-11,13]

Renal replacement therapy was required in approximately one-third of patients, with hemodialysis as the predominant modality. Dialysis requirement in hospital cohorts varies widely based on severity mix, availability of ICU support, and the burden of metabolic complications.[10,13,14] Evidence from randomized trials in critically ill patients suggests that an accelerated strategy for initiation of renal replacement therapy does not consistently reduce mortality compared with a standard approach, emphasizing individualized decision-making guided by conventional indications and clinical trajectory.[14]

More than half of the present cohort achieved complete renal recovery at discharge, while 12% died during hospitalization. This recovery pattern is encouraging, yet it also indicates that nearly one-third had incomplete recovery or dialysis dependence at discharge, groups that warrant close follow-up. Systematic reviews have shown that AKI survivors remain at elevated risk of later chronic kidney disease and mortality, particularly when recovery is incomplete.[12,13] Therefore, discharge planning should incorporate documentation of the AKI episode, counseling regarding avoidance of nephrotoxic exposures, medication review, and follow-up assessment of kidney function to identify non-recovery early.[12,13]

From a service perspective, the observed dialysis requirement and ICU utilization indicate a meaningful burden on renal support infrastructure in tertiary care medicine units. Implementation of AKI care bundles—early identification, standardized fluid and drug review, urine output charting, and timely escalation—can strengthen preventability and improve outcomes in similar settings.[4,5]

Limitations

This was a single-center ward-based study with a modest sample size, which limits external generalizability. Etiological categories were assigned using routine clinical criteria rather than standardized adjudication, introducing classification error. Baseline creatinine was not uniformly available for all admissions, and staging relied on in-hospital trends when prior values were absent. Detailed biochemical parameters and long-term follow-up outcomes after discharge were not evaluated.

In this tertiary care teaching hospital cohort of adults with AKI, middle-aged males formed the largest subgroup and hypertension and diabetes were the predominant comorbidities. Prerenal AKI represented the leading etiological category, and two-thirds of patients had KDIGO Stage 2 or Stage 3 disease, reflecting substantial severity at admission. Conservative management was sufficient for most patients, yet one-third required dialysis, indicating an important demand for renal support services. Despite a favorable complete recovery rate, in-hospital mortality remained notable. Strengthening early AKI recognition on medical wards, standardizing fluid and drug review, and ensuring post-discharge kidney function follow-up can improve recovery and reduce preventable adverse outcomes. Structured ward AKI bundles can help.In this tertiary care teaching hospital cohort of adults with AKI, middle-aged males formed the largest subgroup and hypertension and diabetes were the predominant comorbidities. Prerenal AKI represented the leading etiological category, and two-thirds of patients had KDIGO Stage 2 or Stage 3 disease, reflecting substantial severity at admission. Conservative management was sufficient for most patients, yet one-third required dialysis, indicating an important demand for renal support services. Despite a favorable complete recovery rate, in-hospital mortality remained notable. Strengthening early AKI recognition on medical wards, standardizing fluid and drug review, and ensuring post-discharge kidney function follow-up can improve recovery and reduce preventable adverse outcomes. Structured ward AKI bundles can help.

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10.Uchino S, Kellum JA, Bellomo R, et al; BEST Kidney Investigators. Acute renal failure in critically ill patients: a multinational, multicenter study. JAMA. 2005;294(7):813-8. doi:10.1001/jama.294.7.813.

11.Coca SG, Peixoto AJ, Garg AX, Krumholz HM, Parikh CR. The prognostic importance of a small acute decrement in kidney function in hospitalized patients: a systematic review and meta-analysis. Am J Kidney Dis. 2007;50(5):712-20. doi:10.1053/j.ajkd.2007.07.018.

12.Coca SG, Yusuf B, Shlipak MG, Garg AX, Parikh CR. Long-term risk of mortality and other adverse outcomes after acute kidney injury: a systematic review and meta-analysis. Am J Kidney Dis. 2009;53(6):961-73. doi:10.1053/j.ajkd.2008.11.034.

13.Coca SG, Singanamala S, Parikh CR. Chronic kidney disease after acute kidney injury: a systematic review and meta-analysis. Kidney Int. 2012;81(5):442-8. doi:10.1038/ki.2011.379.

14.STARRT-AKI Investigators; Canadian Critical Care Trials Group; Australian and New Zealand Intensive Care Society Clinical Trials Group; United Kingdom Critical Care Research Group; Canadian Nephrology Trials Network; Irish Critical Care Trials Group. Timing of initiation of renal-replacement therapy in acute kidney injury. N Engl J Med. 2020;383(3):240-51. doi:10.1056/NEJMoa2000741.