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 Table of Contents  
Year : 2016  |  Volume : 2  |  Issue : 2  |  Page : 102-108

Characteristics of acute kidney injury in adult patients in a tertiary health facility in northern Nigeria

Department of Medicine, Nephrology Unit, Ahmadu Bello University, Zaria, Nigeria

Date of Submission06-Jan-2016
Date of Acceptance10-Oct-2016
Date of Web Publication13-Jan-2017

Correspondence Address:
Istifanus Bala Bosan
Department of Medicine, Nephrology Unit, Ahmadu Bello University, Zaria
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2455-3069.198377

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Introduction: Acute kidney injury (AKI) is a complex renal disorder with multiple etiologies and manifestations which vary widely between regions and populations and it is associated with an increased mortality. It is defined by abrupt rise in serum creatinine and/or decrease in urine output to below 0.5 ml/kg/h.
Materials and Methods: Patients' records from January 2013 to December 2014 were reviewed retrospectively, and data from those who satisfied the definition of AKI were extracted for analysis using the Statistical Package for Social Sciences software version 17. Results were presented as means, frequencies, and percentages, and the significance of relationships was investigated using t-test or Chi-square test as appropriate.
Results: Three hundred and twenty patients, 2.3% of the total hospital adult admissions and 12.5% of adult medical admissions, had AKI. There were 162 (50.6%) males with a mean age of 38.51 ± 16.574 years and 158 (49.4%) females with a mean age of 31.22 ± 13.471 years. The most common causes of AKI were sepsis (37.2%), diarrhea and vomiting (27.5%), and hemorrhage (16.9%). Of those who had sepsis, 70/119 (58.8%) were females while 70/88 (79.5%) of those with diarrhea and vomiting were males. Most patients (58.1%) presented with Stage 3 injuries which had a significant influence on renal outcome and mortality. Anemia was more common in females, i.e., 85/158 (53.8%) than males, i.e., 11/162 (6.8%), but it did not have a significant influence on the severity of injury and the overall outcome. We conclude that AKI is not uncommon in our environment and the outcome depends on the etiology and severity of injury. Hemodialysis treatment given when indicated improved the overall outcome.

Keywords: Acute kidney injury, characteristics, etiology, outcome, severity

How to cite this article:
Bosan IB, Ibrahim A, Oguche SM, Tuko MT, Abdulrasheed MM. Characteristics of acute kidney injury in adult patients in a tertiary health facility in northern Nigeria. J Curr Res Sci Med 2016;2:102-8

How to cite this URL:
Bosan IB, Ibrahim A, Oguche SM, Tuko MT, Abdulrasheed MM. Characteristics of acute kidney injury in adult patients in a tertiary health facility in northern Nigeria. J Curr Res Sci Med [serial online] 2016 [cited 2023 May 29];2:102-8. Available from: https://www.jcrsmed.org/text.asp?2016/2/2/102/198377

  Introduction Top

Acute kidney injury (AKI) is a complex renal disorder that is associated with an increased mortality, especially in the critically ill and Intensive Care Units.[1],[2]

AKI has multiple etiologies and manifestations which vary between regions, countries, and localities.[3],[4],[5],[6],[7] AKI presents with oliguria or anuria which may be masked or accompanied by a wide spectrum of symptoms and signs from the multiple etiologies which vary depending on the prevailing risk factors and the population studied.[8]

AKI is defined as an abrupt decline in glomerular filtration rate (GFR) that is sustained leading to the accumulation of urea and other chemicals in the blood.[1] Biochemically, it is characterized by the elevation in serum creatinine > 0.5 mg/dl (45 µmol/L) from baseline (either known or presumed to have occurred within the previous 7 days) or >0.3 mg/dl (26.5 µmol/L) in 48 h. Alternatively, it is defined by urine output <0.5 ml/kg/h.[1] It also presents with varying levels of severity as was classified by the Kidney Disease Improving Global Outcome/National Kidney Foundation into five stages (Risk, Injury, Failure, Loss of Function, and End-stage Failure [RIFLE]) modified by the Acute Kidney Injury Network (AKIN) into three stages for ease of recognition and management planning.[1]

The following table attempts to combine the RIFLE and AKIN modified classification [Table 1].
Table 1: RIFLE and AKIN classifications for acute kidney injury

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Early diagnosis and appropriate supportive care halt progression to more severe injury and reduce mortality and risk of subsequent chronic kidney disease.[5]

Knowledge of the characteristics of AKI in most parts of Africa is poor.[4] In a meta-analysis evaluating the world incidence of AKI in 2012, the authors found the incidence of AKI to be 21.6% in adults and 33.7% in children and a mortality of 23.9% in adults and 13.8% in children.[9] The mortality was inversely related to the country's income and the percentage of gross domestic product spent on health. Most of the studies were retrospective with very little information coming from Africa and Asia.[9]

The incidence of AKI in Africa is not well known, but Barsoum in 2004 estimated an incidence of 150/million population.[10] In a 2008 review of major causes of AKI in Africa, the authors reported a wide variability between regions.[4] More recent studies from Burkina Faso,[11] Senegal, and Nigeria [12],[13],[14],[15] confirm the variability in incidence, etiology, and outcome between centers and populations.

So far, there has been no report from the Savannah region with peculiar climatic conditions and environmental risk factors for AKI. The tertiary health facility where this study took place is situated within the Guinea Savannah region with a referral catchment area spanning the entire Guinea Savannah of the middle belt Nigeria through the Sudan Savannah of the northwest to the Sahel region of the far north and Niger Republic. We chose to review cases that presented to the hospital with clear features that satisfied the internationally accepted definition of AKI from January 2013 to December 2014.

  Materials and Methods Top

All available records of patients seen and managed by the adult nephrology team of the tertiary health facility from January 2013 to December 2014 were reviewed. These included patients admitted into the medical wards, the obstetrics and gynecology wards, oncology wards, surgical wards, and Intensive Care Units, for which consultation of the nephrology team was requested. Some of the patients were also seen at the emergency unit and others referred from other units to the nephrology clinic. Patient's records were included in the study if the available records satisfied the serum creatinine/GFR or urine output criteria for AKI or both, as defined in the introduction above. The following characteristics were extracted from the case files; age, gender, etiology, severity of injury, comorbidity, renal outcome, all-cause mortality within 3 months of diagnosis, and whether dialysis treatment was offered or not. Data so obtained were recorded in a specially designed study data sheet (pro forma). For the analysis, the SPSS Inc. SPSS Statistics for Windows, Version 17.0. (Chicago, USA) for Windows was used. Results were expressed as means with standard deviations, frequencies, and percentages in parentheses, as appropriate. Mean ages for males and females were compared using one-sample t-test for significance and cross tabulations using Chi-square (χ2) test, and asymptotic correlation matrix was used to determine the significance of relationships of the study parameters with each other. At 95% confidence level, P < 0.05 was considered statistically significant.

  Results Top

Three hundred and twenty patients fit the diagnostic criteria for AKI and were 2.3% (320/13,914) of the total hospital adult admissions and 12.5% (320/2560) of adult medical admissions. The number of males and females was 162 (50.6%) and 158 (49.4%), respectively.

The ages ranged from 16 to 75 years, but the females were relatively younger with a mean age of 31.22 ± 13.471 years while the mean age for the males was 38.51 ± 16.574 years. The age group of 16–35 years formed 56.9% of the patients with AKI [Table 2] with significantly more females aged 16–25 years than men and more males aged 56–75 years (P = 0.007). Over 91% (91.9%) of our patients acquired AKI from the community with only 8.1% in the hospital [Table 2].
Table 2: Characteristics of patients with acute kidney injury showing the differences between males and females

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Sepsis and malaria accounted for 119 (37.2%) cases which were associated with puerperal infections, postabortion sepsis, urinary tract infections in obstructive uropathy/malignancies, and the critically ill. Other causes of AKI were diarrhea and vomiting in 88 (27.5%) cases, hemorrhage from trauma, gastrointestinal hemorrhage, and obstetric complications accounted for 54 cases (16.9%) while chronic heart failure and decompensate liver cirrhosis accounted for 38 (11.9%) cases, obstructive uropathy in nine cases, hypertensive crisis in six, acute glomerulonephritis in four, and the critically ill with multiple organ failure in two cases [Table 2]. More number of females had sepsis/malaria (70/119 [58.8%] [34 of them from abortion or puerperal sepsis]), males had sepsis in 49/119 cases (41.2%). Females had hemorrhage in 43/54 (79.6%) (30 of them from complications of abortion or child birth) compared to 11/54 (20.4%) males mainly from trauma and gastrointestinal bleeding. Overall, 64/320 (20%) cases had AKI from complications of abortion or child birth. Those with diarrhea and vomiting were 70/88 (79.5%) males against 18/88 (20.5%) females [Table 2].

Large proportions (58.1%) of our AKI patients were diagnosed with AKIN Stage 3 severity while 31.3% with AKIN Stage 1 and 10.6% with AKIN Stage 2 [Table 2]. There was no significant gender difference with regard to severity of injury (χ2 = 0.249, two-sided asymptotic significance = 0.883) and no significant differences in the severity of injury between the age groups (χ2 = 0.16, two-sided asymptotic significance = 0.194) [Table 2]. Some etiologic factors presented with early stages of the disease while others were only recognized at more severe stages [Table 3]. The time to diagnosis could not be determined from the records available.
Table 3: Frequencies of etiological factors with the severity of injury

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Patients with obstructive uropathy, acute glomerulonephritis, and multi-organ failure had AKIN Stage 3 in more than 80% of the cases while the corresponding severity for sepsis and hemorrhage was 58% and 68.5%, respectively. AKIN Stage 3 severity in patients with diarrhea and vomiting accounted for 46.6% while that chronic heart failure and liver cirrhosis accounted for 52% [Table 3].

Diabetes mellitus, hypertension, heart and liver disease, trauma, and urinary tract obstruction were present without significant gender differences; nevertheless, anemia was found in 32.8% of the patients; 85 (31.2%) females and only 20 (1.6%) males (χ2 = 102.887, two-sided asymptotic significance = 0.002).

Anemia did not significantly influence the severity of acute injury; 30.5% of those with anemia had AKIN Stage 1 and 37.1% AKIN Stage 3 compared to the complete series with 31.3% AKIN Stage 1 and 58.1% AKIN Stage 3. Of the 105 cases with anemia, 61 patients (58%) were associated with sepsis; 44 females and 17 males while 38 patients (36%) were associated with hemorrhage; 37 females and 1 male.

Renal outcome was reported as complete recovery in 51.9%, partial recovery in 28.8%, and no recovery in 19.4% of the patients [Table 2]. Renal outcome was influenced by the etiology of AKI [Table 4]. All patients who had acute hemorrhage had complete renal recovery; also complete recovery occurred in 63.6% (56/88) of those with diarrhea and vomiting, while those with sepsis had complete recovery accounting for 43.7% (52/119). None of the patients with heart failure, liver cirrhosis, or multiple organ failure had complete renal recovery [Table 4]. Patients with AKIN Stage 1 severity had complete recovery accounting for 66% (66/100) while 53.7% (100/186) of those with AKIN Stage 3 severity had complete recovery (χ2 = 81.679, P = 0.000) [Table 5].
Table 4: Frequency of etiological factors and their renal outcome for patients with acute kidney injury

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Table 5: Renal outcome by severity of injury

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Patients without comorbidity had complete renal recovery accounting to 67.8% (97/143); those with anemia in 61.9% (65/105) with 74% (63/85) of the females achieving complete recovery while 90% (18/20) of the males had only partial recovery. Patients with prostatic disease and cervical cancer had complete renal recovery in only 20% while all those with diabetes mellitus, hypertension, and heart or liver disease had either partial or no renal recovery at all [Table 6].
Table 6: Renal outcome by associated comorbidity

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Fifty of the 320 patients (15.6%) benefited from hemodialysis; 25/50 (50%) of them had AKI associated with sepsis, 6/50 (12%) associated with diarrhea and vomiting, 6/50 (12%) from hemorrhage, 4/50 (8%) from hypertensive emergency, and the others from obstructive uropathy, acute glomerulonephritis, and cardiac failure/liver cirrhosis. All patients who had renal support with hemodialysis had AKIN Stage 3 severity and 32/50 (64%) of them had complete renal recovery compared to 134/270 (49.6%) in those with all stages of severity who were not benefited from hemodialysis and 36.6% (68/186) of all those with Stage 3 severity. However, there was no renal recovery in 20% of those who had hemodialysis compared with 19.3% for all stages of severity and 23.7% for Stage 3 severity. Ten (20%) of those dialyzed died within 3 months of AKI diagnosis compared to 22.1% in those with similar severity who were not dialyzed. Three of those dialyzed who died had AKI associated with sepsis, two each associated with liver cirrhosis, critically ill, and cancers causing urinary obstruction.

Sixty-two of the 320 patients (19.4%) died within the first 3 months of diagnosis from all-cause mortality and all of them had no renal recovery at all. Forty-two (42/158) (26.6%) females died and 20/162 (12.3%) males died. All the males who died were aged 56 years and above while 22 females died at ages 26–35 years while 16 died at ages 46–55 years. The two age groups made up over 90% of the female deaths [Table 7]. Based on etiology, 21/119 (17.6%) of those associated with sepsis died while 36/38 (94.7%) of those with heart failure and liver cirrhosis died within 3 months. No death was recorded among those with diarrhea and vomiting, hemorrhage, or hypertension.
Table 7: All-cause mortality by age group and sex

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  Discussion Top

The results of our study have shown that AKI is not uncommon in our practice. The incidence of 2.3% of all hospital admissions is higher than 1.9% reported by earlier authors [5] but <4.5%–40% reported by other West African authors.[12] We wish to acknowledge that being a retrospective study we might have missed out some records and also that some patients might have not been able to reach us because of the lack of geographical or economic access. What we are reporting may just be a “tip of the iceberg” of the true incidence of AKI in our environment.

Although our hospital attends to more women than men at the outpatient clinics, more men were admitted into the medical wards than females, so our patients had more male preponderance although the difference was not statistically significant. Most of our patients had community-acquired AKI, but in the developed countries, AKI is mostly hospital acquired.[4] This is likely because our primary and secondary health-care systems are poorly developed, critical care medicine is almost nonexistent, and we do not carry out major cardiothoracic surgeries in our center which constitute major risk factors for AKI in the developed countries.

Interestingly, we found the females to be of younger age group than the males with significant differences in the etiological factors. Sepsis was found in 119 patients (70 females and 49 males) which was the most common cause of AKI (37.2%), with a statistically significant gender difference. Sepsis in this series was associated with septic abortion, puerperal infections, urinary tract infections in obstructive uropathy, cancer, and diabetes mellitus. Other authors in the West African subregion have reported sepsis and malaria to be the most common cause of AKI. Authors from Burkina Faso reported sepsis in 47.9% of their cases,[11] and from Ilorin, Nigeria, 26% was reported with sepsis as the leading cause.[12] However, in Lagos, Nigeria, authors reported primary kidney disease to be the most common cause of AKI in children between 1 month and 16 years, but another review by the same authors in 2015 reported sepsis as the most common cause.[14],[15] In a review of major causes of AKI in Africa, the authors reported a wide variability between regions in Africa, but sepsis and malaria were the leading causes in almost all the regions.[4]

In our study, diarrhea and vomiting was the second most common cause in 88/320 patients (27.5%) with 70/320 (21.9%) males and 18/320 (5.6%) females. This gender difference may reflect greater exposure of males in this population to alimentary infections as they eat in public eateries when they are out during the day looking for their daily income while most women prefer to pack their lunch from home.

Hemorrhage was the third most common cause of AKI (16.9%) in our series with 43 females (30 of these bled from obstetric/gynecologic complications) and 11 males mostly from gastrointestinal bleeding and trauma. Overall, 64/320 (20%) of our cases had AKI related to obstetric and gynecologic complications. In Burkina Faso, authors reported obstetric and gynecologic causes in 17.3% of their 121 cases.[11] It is plausible that the younger female preponderance in our study reflects the peculiarities of this female population to early marriages which confer vulnerabilities to obstetric/gynecologic causes of AKI.

The severity of disease in our study was influenced mainly by the etiology. More severe disease was seen with multiple organ failure, acute glomerulonephritis, and obstructive uropathy while hemorrhage, heart failure, and liver cirrhosis had higher proportions with AKIN Stage 1 disease [Table 3]. Etiology was also observed to influence the renal outcome independent of the severity of disease. Patients with hemorrhage who had a significant proportion of AKIN Stage 3 had complete renal recovery in all and those with diarrhea and vomiting also had significant numbers with AKIN Stage 3 severity but with better renal outcome than those with heart failure and liver cirrhosis who had large proportion of AKIN Stage 1 disease and had no complete recovery at all [Table 4]. These may be related to the persistent impact of the failed major extrarenal organs on the kidneys.

The presence of anemia did not significantly influence the severity of disease or renal outcome in our series. Thirty-two of 105 patients (30.5%) of those with anemia had AKIN Stage 1 compared with 100/320 patients (31.3%) in the whole series and only 39/105 patients (37.1%) with AKIN Stage 3 compared with 186/320 patients (58.1%) overall. In addition, 65/105 patients (61.9%) of those with anemia recovered completely compared with 166/320 patients (51.9%) overall. The differences in outcome between males and females with anemia are most likely due to the differences in etiology.

Our patients had complete renal recovery in 51.9%, partial recovery in 28.8%, and no renal recovery in 19.4% of the patients. This outcome is a little better than that reported by authors from Senegal in 2011 with 45.9% complete recovery, 24% partial recovery, and 30.1% with no renal recovery (conference abstract). We also found that independent of etiology, the less severe the injury, the more the chance of complete renal recovery and the less the chance of dying within the first 3 months of AKI diagnosis [Table 5]. This agrees with earlier reports of increasing mortality with increasing severity of disease.[5]

All of our fifty patients who had hemodialysis treatment had AKIN Stage 3 severity of injury but had complete recovery in 32/50 (64%) compared with 49.6% for all stages of severity who did not have the hemodialysis treatment and 36.6% for AKIN Stage 3 severity. Only ten (20%) of those who had hemodialysis treatment died within 3 months of AKI diagnosis compared to 22.1% of those who had similar severity of injury but did not have dialysis treatment. AKI was associated with sepsis in 25/50 (50%) of those dialyzed but only 3 (12%) died compared with 21/98 (21.4%) of all those with AKI associated with sepsis. Other causes of AKI among those who had dialysis but died within 3 months were liver cirrhosis in two, critically ill in two, cancer with obstructive uropathy in two, and one associated with acute glomerulonephritis. These highly suggest that hemodialysis treatment in those with severe injury will enhance renal recovery and reduce mortality.

The all-cause mortality was 19.4% in our series which is within the worldwide mortality range of 19%–83%[8],[16],[17] Authors in Burkina Faso reported 24%, others in Senegal and in Ilorin reported 23.3% and 13.3% mortality, respectively.[11],[12] In North Africa, 21.5% mortality was reported while 37.5% was reported in Ethiopia.[10]

Our study has confirmed some similarities and also differences in the incidence, etiology, and outcome of AKI between our center and centers in other regions of Africa and other parts of the world. These differences may be due to variations in the incidence of the different causes of AKI. Time and fluids are the only effective therapies for AKI currently.[18] However, our study could neither capture the time before diagnosis nor could we determine the effectiveness or otherwise of the available modalities of management other than hemodialysis.

In general, we conclude that AKI is not uncommon in our environment and that the outcome depends on the etiology and severity of injury. We therefore recommend further research for strategies to enhance the early recognition of AKI in resource-constrained settings and the appropriate supportive care, especially at the primary care level to prevent or reduce progression of injury. Furthermore, it is pertinent to address the vulnerabilities of young women to AKI in this population, as the etiological factors are highly preventable.

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Conflicts of interest

There are no conflicts of interest.

  References Top

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Naicker S, Aboud O, Gharbi MB. Epidemiology of acute kidney injury in Africa. Semin Nephrol 2008;28:348-53.  Back to cited text no. 4
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Harel Z, Wald R, Bargman JM, Mamdani M, Etchells E, Garg AX, et al. Nephrologist follow-up improves all-cause mortality of severe acute kidney injury survivors. Kidney Int 2013;83:901-8.  Back to cited text no. 17
Zarbock A, Schmidt C, Van Aken H, Wempe C, Martens S, Zahn PK, et al. Effect of remote ischemic preconditioning on kidney injury among high-risk patients undergoing cardiac surgery: A randomized clinical trial. JAMA 2015;313:2133-41.  Back to cited text no. 18


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]

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