Saudi Journal of Kidney Diseases and Transplantation

RENAL DATA FROM THE ARAB WORLD
Year
: 2021  |  Volume : 32  |  Issue : 6  |  Page : 1707--1714

Epidemiological Study of Acute Kidney Injury in Intensive Care Unit: Evolution and Prognosis


Selma Siham El Khayat1, Halima Serghini2, Zineb Filali Khattabi2, Sophia Zahid2, Nadia Boutaleb3, Mohamed Gharbi Benghanem2, Houcine Barrou4, Abdelaziz Chlilek4, Najib Elarrar4, Rachid Al Harrar4, Mohamed Mouhaoui4, Boubaker Charra4, Benyounes Ramdani2, Saïd El Antri3,  
1 Department of Biochemistry, Environment and Agrifood Laboratory (URAC36), Sciences and Technologies Faculty Mohammedia, Hassan II University; Department of Uro-Nephrology and Department of Anesthesiology and Intensive Care, Casablanca, Morocco
2 Department of Uro-Nephrology and Department of Anesthesiology and Intensive Care, Casablanca, Morocco
3 Department of Biochemistry, Environment and Agrifood Laboratory (URAC36), Sciences and Technologies Faculty Mohammedia, Hassan II University, Casablanca, Morocco
4 Department of Anesthesiology and Intensive Care, Faculty of Medicine and Pharmacy of Casablanca, Hassan II University, Casablanca, Morocco

Correspondence Address:
Selma Siham El Khayat
Department of Biochemistry, Environment and Agrifood Laboratory (URAC36), Sciences and Technologies Faculty Mohammedia, Hassan II University, Casablanca, Morocco.
Morocco

Abstract

Acute kidney injury (AKI) is very common in intensive care units (ICUs). Its complications are often fatal, life-threatening, and may lead to kidney impairment. This is a multicentric, prospective, and descriptive study, spread over a period of six months, from January 1, 2017 to June 30, 2017, including incident cases of AKI defined according to the AKI Network criteria seen in the ICUs of Ibn Rochd University Hospital of Casablanca. Their evolution was studied during the hospital stay at three, six, 12, and 24 months. A total of 102 patients were included, 52% of whom were female. The median age was 45.2 ±0 22.93 years (10 days-87 years). Clinically, 28.4% were oligo-anuric and 54.8% had a multivisceral failure, mainly neurological and respiratory. The median creatinine level was 37.6 mg/L ± 19.82 (8-230). AKI was mainly organic and functional in 43.1% and 40.2% of cases, respectively, and the main etiologies were dehydration, sepsis, and tumor obstruction. Dialysis was required in 25.5% of cases. When discharged from the hospital, mortality occurs in 35% of cases, total recovery of renal function was observed in 22%, progression to chronicity in 38%, and end-stage renal disease (ESRD) in 5% of cases. The progression to chronicity and ESRD increased in the 1st and 2nd year of followup after the first episode of AKI. The risk factors for progression to chronicity were as follows: age, hypertension, the presence of comorbidities, the presence of multivisceral failure and the severity of AKI. AKI is now considered a risk factor for chronic kidney disease and longterm mortality, hence the interest and importance of nephrological monitoring.



How to cite this article:
Khayat SE, Serghini H, Khattabi ZF, Zahid S, Boutaleb N, Benghanem MG, Barrou H, Chlilek A, Elarrar N, Harrar RA, Mouhaoui M, Charra B, Ramdani B, Antri SE. Epidemiological Study of Acute Kidney Injury in Intensive Care Unit: Evolution and Prognosis.Saudi J Kidney Dis Transpl 2021;32:1707-1714


How to cite this URL:
Khayat SE, Serghini H, Khattabi ZF, Zahid S, Boutaleb N, Benghanem MG, Barrou H, Chlilek A, Elarrar N, Harrar RA, Mouhaoui M, Charra B, Ramdani B, Antri SE. Epidemiological Study of Acute Kidney Injury in Intensive Care Unit: Evolution and Prognosis. Saudi J Kidney Dis Transpl [serial online] 2021 [cited 2022 Nov 28 ];32:1707-1714
Available from: https://www.sjkdt.org/text.asp?2021/32/6/1707/352432


Full Text



 Introduction



Acute kidney injury (AKI) is a global health problem; its incidence is clearly increasing over time. This fact is due to population aging, the frequency of its comorbidities, and the largest use of diagnostic tools and techniques.[1]

Most studies of AKI are retrospective. Few of them have demonstrated the risk of progression to chronic kidney disease (CKD), especially on an African and Arab scale.

The use of AKI Network (AKIN) and Kidney Disease Improving Global Outcomes (KDIGO) classifications has improved the comparability of studies and standardized their results.

In intensive care units (ICUs), AKI occurs in 30%-60% of patients according to the definitions used, and is responsible for a high hospital mortality exceeding 60% in patients requiring renal replacement therapy (RRT), despite recent scientific advances in understanding AKI’s pathogenesis and despite RRT techniques’ evolution.[2],[3],[4],[5]

Whatever renal function evolution immediately following an AKI episode, the risk of developing chronic renal failure and mortality remains high.[6]

The aim of this study is to describe evolving profile of AKI in ICUs to analyze risk factors for mortality and progression to CKD.

 Material and Methods



Our study is a multicentric, prospective, descriptive, and analytical study with epidemiological and prognostic aims, conducted over a six-month period, from January 1, 2017 to June 30, 2017.

This survey included all AKI patients recruited by ICUs of the Ibn Rochd University Hospital during the study period and who met the diagnostic criteria established by AKIN classification.[7]

No exclusion criteria were used. All patients were followed by nephrologists for two years to establish the course.

Studied variables were demographic characteristics of patients, diagnostic elements at admission, positive diagnosis criteria of AKI, clinical and biological characteristics at the time of AKI’s diagnosis, etiological factors, therapeutic management, and evolution during the hospital stay and after three, six, 12, and 24 months.

Following the detection of AKI, an ultrasound performed, first, made it possible to look for an obstructive etiology. Secondarily, a functional origin was sought based on clinical examination (context, signs of dehydration, or hypovolemia), and creatinine’s normalization within 48 h after normalization of blood volume. The organic origin was retained by eliminating these two first causes. No urinary biomarkers were analyzed in our study.

 Results



Study population ’s description

One hundred and two patients with AKI were treated in seven medical and surgical ICUs; 70.5% of them came from the surgical intensive care department and 29.5% from the medical intensive care department. Fifty-two percent of patients were female and the median age was 45.2 years ± 22.93 (10 days−87 years).

Clinically, 28.4% were oligo-anuric and 54.8% had a multivisceral failure, mainly neurological and respiratory distress. The median creatinine level was 37.6 mg/L ± 19.82 (8-230 mg/L).

According to the AKIN classification, 42.2% (n = 43) of patients were in Stage 1 of AKI, 26.7% (n = 27) in Stage 2, and 30.4% (n = 31) in Stage 3. AKI’s origin was essentially organic, functional, and obstructive, respectively, in 43.2%, 40.2%, and 16.6% of cases. The main causes were dehydration in 25.4% of cases, sepsis in 22.5%, and tumor obstruction in 16.6% of cases. Dialysis was required in 25.5% of patients.

Mortality

Intra-hospital mortality of patients with AKI was 35.2% (n = 36) after a median delay of two days (0-65 days) [Figure 1]. The mortality rate was 29.2% (n = 12) during functional AKI, 31.2% (n = 5) during obstructive AKI, and 44.1% (n = 19) during organic AKI.{Figure 1}

The main causes of death were a septic shock in 40.6% of cases, multiple organ failure in 21.8%, hemorrhagic shock in 12.5%, metabolic disturbances in 9.3%, and pulmonary embolism in 6.2% of cases. However, the cause of death in 9.3% of cases was unknown. The mortality rate among survivors was 3% (n= 2) in the 6th month of evolution, increased to 6.2% (n = 4) in the 12th month of evolution, and to 8.3% (n = 5) in the 2nd year of evolution.

Among the deceased patients, 66.6% were over 65 years old, 58.3% had a glomerular filtration rate (GFR) <60 mL/min/1.73 m2, and 41.6% had an associated tumor pathology.

In univariate analysis, death’s risk factors were age over 60 years, multiple organ failure, low blood pressure, shock, anuria, use of vasoactive drugs, and blood transfusion [Table 1].{Table 1}

Multivariate analysis identified independent risk factors for mortality such as age over 60 years, low blood pressure, and need for blood transfusion [Table 2].{Table 2}

Progression of renal function after the acute episode

After leaving hospital, progression was reported in survivors, accounting for 64.7% (n= 66) of patients, of which 33.3% (n = 22) recovered a normal renal function (GFR ≥60 mL/min/1.73 m2), 59% (n = 39) kept a residual renal failure (GFR between 60 and 15 mL/min/ 1.73 m2), and 7.7% (n = 5) progressed to endstage renal disease (ESRD) (DFG <15 mL/min/1.73 m2) [Figure 2].{Figure 2}

At three months, an improvement in renal function was noted compared to discharge from the hospital. About 59.1% (n = 39) of patients recovered a normal renal function (GFR ≥60 mL/min/1.73 m2), 37.9% (n = 25) maintained a residual renal insufficiency (GFR between 60 and 15 mL/min /1.73 m2), and only 3% (n = 2) evolved to ESRD (DFG <15 mL/min/1.73 m2) [Figure 2].

At six months, evolution was reported in 95% of survivors (n = 61). We noted a stabilization of renal function. About 62.8% (n = 38) of patients maintained normal renal function (GFR >60 mL/min/1.73 m2), 34.2% (n = 21) had residual renal failure (GFR between 60 and 15 mL/min/1.73 m2), and 3% (n = 2) stayed in ESRD (GFR <15 mL/min/1.73 m2) [Figure 2].

At six months, evolution was reported in 95% of survivors (n= 61). We noted a stabilization of renal function. About 62.8% (n= 38) of patients maintained normal renal function (GFR ≥60 mL/min/1.73 m2), 34.2% (n= 21) had residual renal failure (GFR between 60 and 15 mL/min/1.73 m2), and 3% (n= 2) stayed in ESRD (GFR <15 mL/min/1.73 m2) [Figure 2].

At 12 months, evolution was reported in 87% of survivors (n = 51), with a progression to CKD. About 54.9% (n = 28) of patients maintained normal renal function (GFR ≥60 mL/min/1.73 m2), 35.2% (n = 18) kept residual renal insufficiency (GFR between 60 and 15 mL/min/1.73 m2), and progression to ESRD increased to 9.9% (n = 5) IRCT (GFR <15 mL/min/1.73 m2) [Figure 2].

At 24 months, evolution was reported in 83% of survivors (n = 46), with more increased risk of progression to CKD. About 43.5% (n = 20) of patients kept a normal renal function (GFR ≥60 mL/min/1.73 m2), while 45.6% (n = 21) kept residual renal failure (60 mL/min > GFR ≥15 mL/min/1.73 m2) and 10.9% (n = 5) had ESRD stage (GFR <15 mL/min/1.73 m2) [Figure 2].

After eliminating deceased and loss of sight patients, we conducted a univariate analysis in survivors to identify risk factors for progression from AKI to CKD. The total number of patients was 66 and identified risk factors were age over 60 years, a history of high blood pressure or diabetes, an associated tumor pathology, AKI’s severity at the time of diagnosis, anuria during AKI episode, the need of diuretics, blood transfusion, and RRT [Table 3].{Table 3}

In multivariate analysis, the only risk factors that persisted for developing CKD were age over 60 years, history of diabetes or hypertension, AKI’s severity at the time of diagnosis, and the use of RRT [Table 4].{Table 4}

 Discussion



The use of the new AKIN and KDIGO classifications to define AKI by recent studies gave a uniform estimate of AKI’s incidence, which was 57.2% in ICUs.[1] However, intrahospital mortality of patients with AKI was highly variable, ranging between 15% and 60% depending on studies.[4],[7],[8],[9],[10],[11],[12],[13],[14]

Several death risk factors have been identified in patients with AKI, including age, male gender, Caucasian ethnicity, AKI’s severity (according to AKIN classification), oliguria, the use of RRT, multivisceral failures, and AKI acquired in the hospital environment.[1]

In cohort studies of patients with AKI, age appeared to be a factor of independent risk of death; it was associated with a 10% increased risk of death for every 10 years of patient age increase.[15]

Regarding males, recent studies do not confirm the increased risk death in men with AKI[4],[13],[15],[16],[17] In contrast, mortality was lower in African-American patients than Caucasian patients.[18]

Several studies have compared RIFLE and AKIN classifications,[19],[20],[21] both classifications were equivalent in terms of prognostic value. However, the risk of death was correlated with the severity of AKI.[22]

Oliguria was more common in deceased AKI patients.[7] In many studies, it was determined as an independent risk factor for mortality in AKI.[13],[17],[23],[24] This can also be explained by the increased incidence of fluid overload secondary to decreased urine output in patients with AKI and which has been shown to be associated with increased mortality.[25]

In ICUs, the mortality rate was 58% in patients requiring RRT against 43% in patients who did not need RRT.[26] Patients who required RRT were those with severe AKI, without neglecting dialysis complications, which can contribute to increased mortality.

In most studies, multivisceral failures such as coma, shock, and the use of catecholamines were associated with an increased risk of death in patients with AKI.[4],[15]

No urinary biomarkers were analyzed in our study. Recent publications have concerned new urinary biomarkers, particularly suitable for AKI in ICUs. They are based on its early detection by highlighting blood or urinary biomarkers, lesional or functional: neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, and tissue inhibitor of metallo-protease 2/insulin-like growth factor binding protein 7. These biomarkers are the subject of controversies and have not yet been validated by international guidelines.[27]

No kidney biopsy was done in these intensive care patients. Indeed, in cases where organic origin was retained, acute tubular necrosis (ATN) was most often suspected, especially in the presence of shock (septic, hypovolemic, and cardiogenic). Moreover, ATN was established as the leading cause of AKI in ICU, hence the development of RIFLE, AKIN, and KDIGO classifications which are particularly suited to this context.[28] Creatinine’s improvement over the next three weeks also argued in favor of ATN. Moreover, the hemodynamic state, hemostasis disorders, and resuscitation measures made it difficult to perform kidney biopsy.

As kidney biopsy was not performed, exact etiologic diagnosis could not be made with precision. Occurred AKIs were often of multiple origins: sepsis, hypovolemia, injection of contrast products, and heart failure.

A recent meta-analysis investigated the longterm death rate among survivors of patients with AKI and finding a one-year mortality rate of 8.9% versus 4.3% for survivors who did not have an AKI during the hospitalization’s period.

Independent risk factors for death at one year were age, initial severity assessed by APACHE II score, existence, and severity of AKI.[29]

In the literature, one year after the onset of the AKI episode, the incidence of CKD was estimated at 7.8% per year, and that of the ESRD was estimated at 4.9% per year.[30]

Recent studies have suggested that there is a link between the occurrence of an AKI and the risk of developing CKD; 63% of surviving patients regained their previous renal function. For other patients, the risk of incomplete recovery of renal function increased with the degree of severity of the AKI. The presence of comorbidities associated did not seem to have an effect.[12]

In patients treated with RRT, 70% recovered renal function and stopped dialytic therapy after three months.[31] The factors of risk of continuing dialytic therapy determined were advanced age, female gender, diabetes, the presence of preexisting CKD, the presence of comorbidities, fluid overload, and the late onset of dialytic treatment.[25],[31],[32],[33]

The risk of ESRD in patients who required dialytic therapy was three times higher than patients who received conservative treatment.[34]

A study[35] carried out over eight years confirmed that in survivors patients of an AKI episode and having a preexisting GFR ≥45 mL/min/1.73 m2, occurrence of AKI requiring dialysis was an independent factor associated with a 28 times higher risk of developing CKD Stages 4 or 5 and a doubled risk mortality during follow-up.

There are several limitations of this study: the low sampling, the monocentric nature (several ICU units in a single hospital center), and the limited biological explorations carried out, particularly in relation to urinary and blood biomarkers of AKI.

Larger studies should be done on a regional and continental scale like other great international studies, with a longer cohort’s followup. The use of new urinary biomarkers could revolutionize AKI’s early management like troponins in myocardial infarction, with the hope of lower mortality of AKI patients in ICU. Finally, the need of long-term follow-up of these patients is undeniable because of the increased risk of CKD.

Conflict of interest: None declared.

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