Background

Acute kidney injury results in devastating outcomes to affected patients and is reported to contribute to high morbidity and mortality rates disproportionately in lower- and middle-income countries (LMIC). [1, 2] The global burden of AKI is high and at one time it was estimated to be 13.3 million cases per year, with 85% of these being in LIMIC. [3] The aetiology of AKI in LMIC was predominantly community acquired in contrast to developed world, however with improved critical care facilities there is trend towards hospital acquired AKI in developing countries. [4, 5, 6] In 2015 International Society of Nephrology (ISN) declared AKI to be a human right problem and called for reduction of deaths attributable to AKI by 2025 through an initiative dubbed 0 by 25 initiative [7]. Despite the scarcity of information on the burden of AKI in sub-Saharan Africa which hamper efforts in reducing its impact on morbidity and mortality, it is reported to be common with devastating outcome. In Malawi, Evans et al reported AKI incidence of 17.2% among admitted medical patients with mortality of 44.4% [8]. Similar findings were reported by Halle et al in a study conducted in Cameroun with AKI incidence of 22.3% among patients admitted in internal medicine ward and ICU at Douala General Hospital [6]. Outcome of AKI in sub-Saharan African is reported to be poor with mortality of up to 86% when renal replacement therapy is required and not offered [9]. This study was carried out in Tanzania aiming at determining the burden of AKI among patients admitted in the ICU at Muhimbili National Hospital, which is the largest referral hospital. Tanzania like many other countries in the region is faced with difficulties of providing nephrology services despite some remarkable improvement in nephrology services [10,11].

Methods

Study design and study area

This was a retrospective chart review of patients admitted to the Intensive Care Unit at Muhimbili National Hospital (MNH) from 2009 to 2012. MNH is the largest tertiary hospital in Tanzania and is also teaching hospital for Muhimbili University of Health and Allied Sciences (MUHAS). MNH is in Dar es Salaam city which has a population of approximately 8 million people. MNH has more than 1500 beds and at the time of this study, the ICU had 8 beds with no renal replacement therapy in form of hemodialysis. The staffing in ICU included 34 registered nurses who run 2-3 shifts a day with 4 in-house doctors, all of whom are qualified anesthesiologists. About 2-25 patients were admitted to the ICU monthly, these included medical, surgical, obstetrics/ gynaecological and paediatric patients.

Study Population

All adult patients (aged 18 years and above) admitted in ICU between 1 ^st January 2009 and 31^st December 2012 were eligible for this study. All charts of patients admitted in ICU were reviewed and those with filled clinical and laboratory data were included in this study.

Data Collection

Data collection was carried out by one of the investigators and a trained research assistant; these were obtained from patients’ charts retrieved from medical records and recorded into a pre-tested research tool. Recorded information included; demographic data like age, sex, and address. Others included duration of illness, ICU admission and discharge dates, admission and final diagnoses, ICU outcome (death/survival at discharge), any co-morbidities, mode of treatment including mechanical ventilation and Renal replacement therapy like hemodialysis. Vital signs (blood pressure, respiratory rate, temperature, oxygen saturation, urine output) and laboratory tests including serum creatinine, urea, and electrolytes, complete blood counts and liver function tests were also recorded. AKI was defined based on AKIN criteria with two serum creatinine values separated by a time duration of at least 48 hours with an increase in serum creatinine of ≥0.3mg/dl (26.4µmol/l) and/ or a urine output of <0.5mls/kg/hr.

Data Analysis

Data were coded and entered data into epi data version 3.1 and was exported to STATA version 12 (Stata Corp. STATA 12.0, College Station, Texas 77845 USA) for analysis. Descriptive statistics were used to summarize the characteristics of the patients. Continuous variables were summarized into means, medians and ranges. Categorical data were summarized as frequencies and percentages. Comparisons of AKI patients according to AKIN classification were based on chi-square test or Fisher’s exact test for categorical data. A p-value of <0.05 was considered statistically significant.

Ethical Consideration

This study was approved by MUHAS ethical committee with ethical approval number MU/PGS/SAEC/Vol. IV. Permission to conduct this study at MNH was granted by the Hospital administration. None of the patients’ identifying information including registration number and names was recorded and access to data was only provided to research team.

Results

Seven hundred and sixty-eight patients were admitted in ICU between January 2009 and December 2012, of these 233 (30%) met the inclusion criteria and were included in the final analysis. Five hundred and thirty-five (535) patients were excluded because of age <18 years (136), missing files from the medical records department (207), and incompletely filled files (192) Figure 1.

Discussion

This was a retrospective cross-sectional study which was carried out among patients admitted in ICU at Muhimbili National Hospital between January 2009 and December 2012, to determine occurrence and outcome of AKI. AKI occurrence among critically ill patients was noted to be common and 135/ 233 (57.9) had AKI, among these 52% had severe AKI defined as AKIN stage 3. This finding is quite high and is in line with other studies which have reported high burden of AKI in ICU. Ya-Wen et al reported a similar prevalence of AKI (59%) from a study conducted among medical ICU patients in Taiwan [12]. Burden of AKI in ICU reported from developed countries varies (19.2% -74.5%), depending on defining criteria of AKI [13]. At the time of this study no renal replacement therapy was offered in ICU at MNH which may account for the finding of more than 50% of patients with AKI having AKIN stage 3 and the extremely high mortality outcome.

Sepsis is a predominant risk factor and cause of AKI for patients admitted in ICU, in our study 67.4% of patients with AKI were recorded as having sepsis, out of which 15.5% had septic shock. In a multicentre retrospective study conducted by Bagshaw et al among patients admitted in 57 ICUs across Australia, sepsis accounted for 32.4% of all patients with AKI [14]. Sepsis among patients in ICU is reported to result in severe form of septic AKI which result in adverse outcome including failure of recovery of AKI and mortality [14-17]. Glomerulonephritis which is an important cause of AKI was reported with small contribution of only 2%, this shows native kidney diseases may also contribute to AKI and should not be underestimated. Yousif et al reported glomerulonephritis as the predominant cause among patients who received haemodialysis for AKI in Sudan [18].

Overall mortality in this study was 93.1%, this mortality was noted to be significantly higher among patients who had AKI as compared to those without, showing the significant contribution of AKI to mortality. This high mortality reflects the absence of renal replacement therapy in the ICU at MNH when study participants were admitted. This finding is in line with what was reported by Olowu et al in systematic review of studies on outcome of AKI in sub-Saharan Africa reporting mortality as high as 86% when dialysis was needed but was not offered. [9]. From the mortality curve comparing the two groups (Figure 2), it was observed that though mortality was significantly high in both groups, AKI patients died faster within the first 2-3 weeks as compared to those without AKI. This could probably be explained by the fatal acute complications of AKI like fluid overload, electrolyte abnormalities like hyperkalaemia, metabolic acidosis that require prompt diagnosis and quick management including renal replacement therapy which was not available in the ICU. Need for mechanical ventilation was noted to be associated with mortality in our study which is in agreement with many other similar studies conducted in ICU settings both in high income and low-income countries [16,19-22].

This is one of few studies indicating the burden of AKI in intensive care unit in Tanzania, being a retrospective study and hospital based, there are several limitations which are attributed to missing information and generalizability of the findings of this study. Nevertheless, the findings highlight the high burden of morbidity and mortality faced by health facilities in limited resourced settings. Additionally, this study highlights the need for timely accessibility of renal replacement therapy in low-income countries like Tanzania especially in the intensive care units that manage critically ill patients.

Conclusions

High prevalence of AKI of 57.9% (135/233) was noted for ICU patients at MNH. Mortality among those with AKI was 94.1% (127/135) while the overall cause mortality of the study patients during the four-year 93.1%. Need for mechanical ventilation was found to be significantly associated with increased risk of mortality among our study patients. Among patients with AKI, sepsis and septic shock, 67.4% and 15.5% respectively, were the most common underlying diagnoses for ICU patients.

Disclaimer

The findings from this study have since changed due to major improvements at the Muhimbili National Hospital including renal transplant currently being done. The findings from our study highlighted challenges then when renal replacement therapy was unavailable in the ICU, this has however since changed

References

1. Susantitaphong P, Cruz DN, Cerda J, Abulfaraj M, Alqahtani F, et al. (2013) World Incidence of AKI: A Meta-Analysis. CJASN 8: 1482-1493.
2. Lameire NH, Bagga A, Cruz D, Maeseneer JD, Endre Z, et al. (2013) Acute kidney injury: an increasing global concern. Lancet 382: 170
3. Lewington AJ, Cerda J, Mehta RL (2013) Raising awareness of acute kidney injury: a global perspective of a silent killer. Kidney Int 84: 457
4. Wonnacott A, Meran S, Amphlett B, Talabani B, Phillips A (2013) Epidemiology and Outcomes in Community-Acquired Versus HospitalAcquired AKI. Clin J Am Soc Nephrol 9: 1007-1014.
5. Yousif DE, Topping AR, Osman MF, Raimann GJ, Osman EM, et al. (2018) Acute Kidney Injury in Sub-Sahara Africa: A Single-Center Experience from Khartoum, Sudan. Blood Purif 45: 201-207.
6. Marie Patrice E. Halle MPE, Chipekam NMC, Beyiha G, Fouda H, et al. (2018) Incidence, characteristics and prognosis of acute kidney injury in Cameroon: a prospective study at the Douala General Hospital. Ren Fail 40: 30-37.
7. Mehta RL, Cerdá J, Burdmann EA, Tonelli M, García-García G, et al. (2015) International Society of Nephrology’s 0by25 initiative for acute kidney injury (zero preventable deaths by 2025): a human rights case for nephrology. Lancet 385: 2616-2643.
8. Evans RDR, Hemmilä U, Craik A, Mtekateka M, Hamilton F, et al. (2017) Incidence, aetiology and outcome of community-acquired acute kidney injury in medical admissions in Malawi. BMC Nephrology 18: 21.
9. Olowu WA, Niang A, Osafo C, Ashuntantang G, Arogundade FA, et al. (2016) Outcomes of acute kidney injury in children and adults in subSaharan Africa: a systematic review. Lancet Glob Health 4: e242-250.
10. Fredrick FF, Ruggajo PJ, Basu G, Svarstad E, Langeland N (2015)

Global collaboration bears fruit: Tanzania report. Kidney Int 88: 12111214.

11. Janmohamed M, Fredrick F, Bhandari S (2018) Nephrology in developing and developed nations: worlds apart but many similarities. British Journal of Renal Medicine 23: 92-96.
12. Ya-Wen Yang, Che-Hsiung Wu, Wen-Je Ko, VIN-Cent Wu, Jin-Shing Chen, et al. (2012) Prevalence of Acute Kidney Injury and Prognostic Significance in Patients with Acute Myocarditis. PLoS One 7: e48055.
13. Bellomo R, Ronco C, Mehta RL, Asfar P, Boisramé-Helms J, et al. (2017) Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference. Ann. Intensive Care 7: 49.
14. Bagshaw SM, George C, Bellomo R (2008) Early acute kidney injury and sepsis: a multicentre evaluation. Crit Care 12: R47.
15. Vikrant S, Gupta D, Singh M (2018) Epidemiology and outcome of acute kidney injury from a tertiary care hospital in India. Saudi J Kidney Dis Transpl 29: 956-966.
16. Uchino S (2005) Acute renal failure in critically Ill patients: a multinational, multicentre study. JAMA 294: 813-818.
17. Cruz MG, Dantas JGAO, Levi TM, Rocha MS, de Souza SP, et al. (2014) Septic versus non-septic acute kidney injury in critically ill patients: characteristics and clinical outcomes. Rev Bras Ter Intensiva 26: 384-391.
18. Yousif DE, Topping AR, Osman MF, Raimann JG, Osman EM, et al. (2018) A Single-Center Experience from Khartoum, Sudan. Blood Purif 45: 201-207.
19. Liano F, Junco E, Pascual J (1998) The spectrum of acute renal failure in the intensive care unit compared with that seen in other settings. The Madrid Acute Renal Failure Study Group. Kidney Int Suppl 66: S16-24.
20. Friedericksen DV, Van der Merwe L, Hattingh TL (2009) Acute renal failure in the medical Intensive care unit still predictive of high mortality. S Afr Med J 99: 873-875.
21. Xue JL, Daniels F, Star RA (2006) Incidence and mortality of acute renal failure in Medicare beneficiaries, 1992 to 2001. J Am Soc Nephrol 17: 1135-1142.
22. Bagshaw SM, George C, Bellomo R (2007) Changes in the incidence and outcome for early acute kidney injury in a cohort of Australian intensive care units. Crit Care 11: R68.