|Year : 2021 | Volume
| Issue : 3 | Page : 132-136
Acute kidney injury in intensive care unit: A clinical and outcome study
Narinder Pal Singh1, Danish Kathuria2, Neeru P Aggarwal3, Anish Kumar Gupta1, Gurleen Kaur4
1 Faculty of Medicine and Health Sciences, SGT Medical College Hospital and Research Institute, SGT University, Gurugram, Haryana, India
2 Department of Neurology, SPS Hospital, Ludhiana, Punjab, India
3 Department of Nephrology, Max Super Speciality Hospital, Ghaziabad, Uttar Pradesh, India
4 Department of Nephrology, George Washington University, NW, Washington, USA
|Date of Submission||08-Feb-2021|
|Date of Acceptance||14-Feb-2021|
|Date of Web Publication||20-Jul-2021|
Dr. Narinder Pal Singh
Faculty of Medicine and Health Sciences, SGT Medical College Hospital and Research Institute, SGT University Gurugram, Haryana
Source of Support: None, Conflict of Interest: None
Background: Acute kidney injury (AKI) has both short term as well as long-term consequences in critically ill patients. The present study is an attempt to study its etiological profile in intensive care units (ICUs) which has been only scarcely done in India. Methods: One hundred and twenty patients admitted with or developing AKI during their ICU stay were included in the prospective study and were defined as well as staged according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Patients were followed up at discharge and at 3 months to determine the outcome as either favorable (renal recovery) or adverse (residual renal dysfunction, dialysis dependence, or death). Various known risk factors, as laid down by KDIGO, were identified and analyzed with respect to their association with the outcome. Results: Out of total of 120 subjects, almost half of the subjects (47.5%) had Stage I AKI, 27.5% had Stage II AKI and the remaining quarter of subjects had Stage III AKI. One fourth had pre-existing chronic kidney disease and three-fourth subjects had developed de novo AKI of which more than half of patients had community-acquired AKI. Anemia and sepsis were the most prevalent risk factors. The highest rate of renal recovery was demonstrated in Stage I AKI. Overall mortality was 28%, highest in Stage III AKI. Conclusion: The study demonstrated increasing prevalence of the adverse outcome in a linear fashion with an increase in the severity of AKI. Sepsis was not only the most prevalent risk factor but was also strongly associated with an adverse outcome. The epidemiology of AKI in critical care in India has started to resemble high-income group countries, in terms of both age distribution as well as etiology.
Keywords: Acute kidney injury, critical illness, intensive care unit, sepsis
|How to cite this article:|
Singh NP, Kathuria D, Aggarwal NP, Gupta AK, Kaur G. Acute kidney injury in intensive care unit: A clinical and outcome study. Indian J Med Spec 2021;12:132-6
|How to cite this URL:|
Singh NP, Kathuria D, Aggarwal NP, Gupta AK, Kaur G. Acute kidney injury in intensive care unit: A clinical and outcome study. Indian J Med Spec [serial online] 2021 [cited 2021 Sep 19];12:132-6. Available from: http://www.ijms.in/text.asp?2021/12/3/132/321977
| Introduction|| |
Acute kidney injury (AKI) is characterized by an abrupt deterioration in renal function that disrupts metabolic, electrolyte, and fluid homeostasis over a period of hours to days. The incidence of AKI among critically ill patients has been increasing worldwide. The increase is attributable not only to the aging population with multiple comorbidities, polypharmacy, increasing use of contrast for diagnostic and therapeutic procedures but also to the fact that now it is being recognized more often. With the introduction of RIFLE and AKI Network criteria, emerged the concept of AKI/impairment as a syndrome that includes the whole range of acute renal dysfunction ranging from mild functional renal impairment to frank structural damage requiring renal replacement therapy (RRT). Kidney Disease: Improving Global Outcomes (KDIGO) refined this concept further and came up with a new standardized definition and staging of AKI. It defined AKI as “an increase in serum creatinine (SCr) by ≥0.3 mg/dl (≥26.5 μmol/l) within 48 h or increase in SCr by at least 1.5 times the baseline, which is known or presumed to have occurred within the prior 7 days; or urine volume <0.5 ml/kg/h for at least 6 h.”
Renal hypoperfusion and impaired renal autoregulation are the main contributors to the pathophysiology of AKI. In the last few decades, developing countries have witnessed a change in the epidemiology of AKI. It is very important to document and analyze this change to evolve our preventive strategies to counter AKI or its consequences. Our study was a small initiative in this direction.
| Methods|| |
The prospective study was conducted in 120 adult patients (age >18 years) admitted with or developing AKI in intensive care unit (ICU), staged them according to the KDIGO guidelines and then followed them at discharge and at 3 months to determine the outcome. We also tried to understand the etiological profile of AKI by identifying the various risk factors as laid down by the KDIGO guidelines-susceptibilities and exposures. All patients were given standard care of treatment.
Patients with chronic kidney disease (CKD) stage 5 or those already on some form of RRT were excluded. Patients who had AKI at the time of admission were labeled as community-acquired AKI (CA-AKI) and those who developed AKI during their ICU stay as hospital-acquired AKI (HA-AKI). The lowest SCr value in the past 7 days before admission was taken as baseline creatinine. If not available then the lowest creatinine value during hospitalization served the purpose in HA-AKI however in CA-AKI baseline creatinine was estimated using Modification of diet in renal disease formula for given age, sex, and race assuming eGFR as 75 ml/min/1.73 m2. General condition was assessed at the time of discharge and 3 months later for general wellbeing and SCr. Renal recovery was defined as SCr value that was <1.2 times the baseline value and anything more than this value was considered as residual renal dysfunction. The outcome was addressed as favorable for patients with renal recovery and as adverse for patients who died or had residual renal dysfunction or were dialysis dependent. Out of 120 subjects, at the end of 3 months follow-up, 30 patients died and 13 were lost to follow-up.
A descriptive statistical analysis based on frequency tables of categorical values was performed using a Pearson's Chi-square test. Student's t-test for independent samples was used to compare means between groups. The one-way ANOVA was used to determine any statistically significant differences between the means of three or more groups. Differences with a probability of type 1 error <5% were considered statistically significant.
The present study was conducted in a tertiary care hospital that caters to both urban and rural population in and around National Capital Region (NCR) of India. The hospital is empanelled with various private and governmental agencies, having a huge burden of critical referral cases with the aging population. The study was approved by the Ethics Committee of the Institution and patients inform consent was obtained.
| Results|| |
Out of 120 patients, about two-third of patients were males (67.5%). The mean age of males was 65.49 ± 15.42 years, which was almost similar to the mean age of females 65.53 ± 12.59 years. The majority of patients belonged to the age group older than 65 years [Figure 1].
|Figure 1: Distribution of study subjects in different age groups (n = 120)|
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In this study, febrile illness (n = 61) was the most common presentation, followed by dehydration (n = 33) and dyspnea (n = 17). Urinary retention (n = 9) and pain abdomen (n = 7) were other less common presentations, while only 3 subjects presented with multiple trauma [Figure 2].
Prevalence of risk factors – susceptibilities and exposures
Among certain risk factors relevant to the development of AKI, anemia (61.7%) and sepsis (60.8%) were most prevalent. Other risk factors are detailed in [Figure 3] and [Figure 4].
Prevalence of different acute kidney injury types, stages, and dialysis requirement among study population
Out of 120 subjects, one-fourth had preexisting CKD and three-fourth subjects had developed de novo AKI of which more than half of patients had AKI at the time of admission developed CA-AKI. Almost half of the subjects had Stage I AKI [Figure 5].
Clinical outcome at the time of discharge and at 3 months
At discharge, out of total of 120 subjects, more than a third of the subjects (44, 37%) showed complete renal recovery and another third (39,32%) had residual renal dysfunction. Fourteen subjects (12%) were dialysis-dependent and 23 subjects (19%) died during the hospital stay. At 3-month, 13 patients were lost to follow up. Out of the remaining subjects, there were 7 additional deaths, increasing the total number of deaths to 30 (mortality - 28%). At 3 months, the number of subjects with renal recovery (41, 38%) and residual dysfunction (30, 28%) was almost similar to as compared to that at discharge. The number of subjects who remained dialysis-dependent decreased to 5.6% [Figure 6].
Factors affecting outcome at discharge
Among susceptibilities, age (≥65 years), CKD, and malignancy was found to be 65.7%, 78.8%, 100%, respectively, in the adverse outcome group. Among the exposures, sepsis, and circulatory shock were found to be 75.3% and 73.4%, respectively, in the adverse outcome group. There was a similar association of gender and 63% males and 64% females were associated with the adverse outcome group.
Acute kidney injury types
There was no significant difference in outcome between CA-AKI and HA-AKI. Adverse outcomes occurred in 63.6% of patients in CA-AKI compared to 63% in HA-AKI at discharge. As compared to de novo AKI (n = 87), acute on CKD (n = 33) was more strongly associated with the adverse outcome (57.5% and 78.8%, respectively).
Acute kidney injury stages
The severity of AKI showed a linear trend with adverse outcome at discharge which was statistically significant (P = 0.025). AKI Stage-1, Stage-2 and Stage-3 was found to be 50.9%, 72.7%, and 76.7%, respectively, in adverse outcome group.
| Discussion|| |
AKI occurs in about one in every five adults during the hospital stay. The incidence in critical care is even more alarming, with more than half of the patients admitted in an ICU developing AKI of varying severity.
In the western world, an elderly with multiple comorbidities receiving a cocktail of drugs admitted with sepsis and who develops AKI during the hospital stay is a prototype patient. Where as in a country like India, the most common scenario with respect to AKI has been a young patient admitted with acute renal dysfunction which is most probably due to dehydration, tropical infection, or envenomation. However, with changing terminology of AKI (earlier acute renal failure), developing countries are also witnessing a change in its epidemiology, as suggested by the limited number of studies done, describing AKI in critical care in India.,
In the present study, a staggering majority of the subjects (58.3%) were aged more than 65 years followed by 31.7% in the age group 45–65 years. The mean age of our study population (65.5 years) was significantly higher than the mean age as described by the studies done earlier in India.,, It is probably due to the fact that unlike other studies which have concentrated on de novo AKI, our study has also included subjects who had pre-existing stable CKD. It also indicates a demographic shift toward an aging Indian population, especially in the NCR. Thus the age distribution has started to resemble the high-income group countries., Hain and Paixao describes old age and comorbidities as the perfect storm leading to AKI. In addition, our hospital is a tertiary care referral center admitting majority of the elder age population with comorbidity.
Contrary to the KDIGO guidelines, which identify female gender as a risk factor to develop AKI, we had more male subjects than females (almost 2:1). However, similar male preponderance has been seen in the multicenter study conducted by Hoste et al. (63% males) and a meta-analysis done by Susantitaphong et al. (65% males). Male gender was more commonly associated with AKI in few Indian studies as well., The reason behind this gender disparity is not clear, but considering the small size of the study population, this may just be a matter of chance.
Our study included both CA-AKI as well as HA-AKI, with the prevalence of the former (55%) slightly higher than the latter (45%). The study done by Eswarappa et al. reported a larger difference between the prevalence of the two types, HA-AKI only accounting for about one-fourth of the total cases. This relative decrease in the prevalence of CA-AKI may be attributable to improvement in the management of dehydration in the peripheral health centers and increase in the prevalence of HA-AKI which, in turn, may be due to ageing population with multiple comorbidities (higher life expectancy), increasing use of contrast agents and also recognition of slight transient changes of creatinine as AKI.
Dialysis was required in a total of 27 subjects (22.5%), maximum in AKI Stage III (16, 53.3%). Mean length of hospital stay was 12.5 days, highest in AKI Stage II (16 days) followed by Stage III (14.4 days). Shorter stay in stage III may be due to higher mortality in this subgroup. Bhadade et al. reported slightly higher proportion of dialysis requirement (29.43%) and an almost similar average length of hospital stay (10 days). The fact that severe KDIGO AKI stages were associated with higher prevalence of adverse outcomes emphasizes the early recognition of AKI and taking appropriate measures prevents its progression and possibly recovering it. Comparable mortality rates have been reported by Eswarappa et al. (37.6%) and Hoste et al. (26.9%). Mortality was highest in AKI Stage III (37%).
Contrary to previous studies, AKI Stage I in our study had relatively higher prevalence of dialysis dependence and mortality. This may be due to the fact that unlike other studies done before, we also included patients with preexisting CKD. Such patients may have a lower threshold for destabilization, even with smaller increments in SCr. Furthermore, mortality in AKI Stage I may not be attributable to AKI with patient dying due to an unrelated cause.
There was no significant difference in outcome between CA-AKI and HA-AKI in our study. This was supported by a large cohort study done by Sawhney et al. which determined outcomes at 3 months separately for community and HA-AKI. Complete renal recovery occurred in 49.2% of patients in CA-AKI compared to 45.7% in HA-AKI. Mortality in CA-AKI group was 30.5% compared to 31.8% in HA-AKI.
A systematic review by Sawhney et al. concludes that the presence of prior CKD (compared with de novo AKI) was associated with doubling of mortality and a four-fold to five-fold increase in adverse outcomes. Our study supported a significant association between pre-existing CKD and adverse outcomes.
Sepsis (60.8%) and dehydration (27.5%) were the two most common causes of AKI in our study, which is in line with the multinational study conducted by Hoste et al. Another study done in western Himalayas by Kumar et al., shows a similar prevalence of sepsis induced and prerenal AKI. Like developed countries, sepsis is emerging as the leading cause of AKI in India, especially in the tertiary care centres. This evolving trend may be explained by the increasing life expectancy leading to larger number of elderly patients who are relatively immuno-compromised due to multiple comorbid conditions such as diabetes, chronic liver, kidney and heart diseases. Use of steroids, biologicals and chemotherapeutic agents also add to the pool of immuno-compromised patients. Sepsis was not only the most prevalent etiology but was also strongly associated with an adverse outcome. Dehydration on the other hand had a relatively better outcome as compared to sepsis induced AKI.
Obstructive uropathy is less prevalent but an important cause of AKI as it is readily reversible if recognized and treated timely. We had 9 subjects (7.5%) who presented with urinary retention, of which 3 subjects completely recovered and 6 had some residual renal dysfunction. There was no mortality in this subgroup. Kumar et al. reported similar prevalence and outcome in such patients. Other less frequent but important causes include AKI associated with contrast use, nephrotoxic drugs, polytrauma, and major surgery.
Underlying malignancy was associated with high mortality. A retrospective cohort study by Juwon et al. studied the outcomes of AKI in patients with and without cancer and found higher hospital mortality in the former (42.8% vs. 22.5%). Small number of samples and shorter duration of follow-up is the limitation of the study as this is a preliminary pilot study.
| Conclusion|| |
The present study reported increasing prevalence of the adverse outcome in a linear fashion with an increase in the severity of AKI. Sepsis was not only the most prevalent risk factor but was also strongly associated with an adverse outcome. Worldwide there has been a wide heterogeneity among the studies with respect to definition and staging of AKI. KDIGO has provided a uniform platform for identifying the risk factors for AKI, its diagnosis and staging. We have attempted to use the same platform to emphasize that a country like India is witnessing a change in the spectrum of patients suffering from AKI. Better sanitation and primary health services have curbed the incidence of CA-AKI to some extent, but at the same time novel preventive strategies are required to counter the morbidity and mortality as a result of HA-AKI.
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Conflicts of interest
There are no conflicts of interest.
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