Hindawi International Journal of Nephrology Volume 2017, Article ID 5241482, 8 pages https://doi.org/10.1155/2017/5241482
Research Article Incidence and Risk Factors for Early Acute Kidney Injury in Nonsurgical Patients: A Cohort Study Javier Enrique Cely,1,2 Elkin José Mendoza,1,2 Carlos Roberto Olivares,2 Oscar Julián Sepúlveda,1 Juan Sebastián Acosta,1 Rafael Andrés Barón,1 and Juan José Diaztagle1,3 1
Department of Internal Medicine, Fundaci´on Universitaria de Ciencias de la Salud, San Jose Hospital, School of Medicine, Bogot´a, Colombia 2 Department of Nephrology, Dialysis and Transplantation, Fundaci´on Universitaria de Ciencias de la Salud, San Jose Hospital, School of Medicine, Bogot´a, Colombia 3 Department of Physiological Sciences, School of Medicine, Universidad Nacional de Colombia, Bogota branch, Bogot´a, Colombia Correspondence should be addressed to Javier Enrique Cely;
[email protected] Received 27 November 2016; Revised 14 March 2017; Accepted 28 March 2017; Published 11 April 2017 Academic Editor: Ziyad Al-Aly Copyright © 2017 Javier Enrique Cely et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Detecting acute kidney injury (AKI) in the first days of hospitalization could prevent potentially fatal complications. However, epidemiological data are scarce, especially on nonsurgical patients. Objectives. To determine the incidence and risk factors associated with AKI within five days of hospitalization (EAKI). Methods. Prospective cohort of patients hospitalized in the Internal Medicine Department. Results. A total of 16% of 400 patients developed EAKI. The associated risk factors were prehospital treatment with nephrotoxic drugs (2.21 OR; 95% CI 1.12–4.36, 𝑝 = 0.022), chronic kidney disease (CKD) in stages 3 to 5 (3.56 OR; 95% CI 1.55–8.18, 𝑝 < 0.003), and venous thromboembolism (VTE) at admission (5.05 OR; 95% CI 1.59–16.0, 𝑝 < 0.006). The median length of hospital stay was higher among patients who developed EAKI (8 [IQR 5–14] versus 6 [IQR 4–10], 𝑝 = 0.008) and was associated with an increased requirement for dialysis (4.87 OR 95% CI 2.54 to 8.97, 𝑝 < 0.001) and in-hospital death (3.45 OR; 95% CI 2.18 to 5.48, 𝑝 < 0.001). Conclusions. The incidence of EAKI in nonsurgical patients is similar to the worldwide incidence of AKI. The risk factors included CKD from stage 3 onwards, prehospital treatment with nephrotoxic drugs, and VTE at admission. EAKI is associated with prolonged hospital stay, increased mortality rate, and dialysis requirement.
1. Introduction Acute kidney injury (AKI) has a high impact on healthcare systems because of its high morbidity and mortality rates, length of hospital stay, and treatment costs [1–3]. Thus, prevention and early diagnosis are essential to provide measures to avoid the onset of dialysis as much as possible. Although molecular markers of early kidney damage would be ideal [4], they are, unfortunately, unavailable for routine clinical use. Therefore, variations in serum creatinine according to the Acute Kidney Injury Network (AKIN) and Kidney Disease Improve Global Outcome (KDIGO) criteria remain a valid tool for diagnosis [5, 6].
The mission of healthcare institutions is to know local epidemiology and to generate prevention strategies based on the knowledge of risk factors, which should be identified early upon hospital admission, towards eradicating in-hospital preventable deaths from AKI [7]. Such factors have already been reported in previous publications and are best known in the septic population and within intensive (ICU) and postoperative (PCU) care units, among others [8–10]. Specifically, conditions such as diabetes, proteinuria, and reduced renal function on admission have been reportedly linked to the development of AKI in patients with severe sepsis [11]. However, we do not know whether these criteria apply to other
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scenarios, including nonsurgical patients and during early hospitalization. To date, there have been no identifiable studies that evaluate variables related to the development of EAKI in this subset of nonsurgical patients who are managed by an Internal Medicine team. The importance of these studies lies in providing a useful tool for clinicians to prevent the progression of the disease and to help avoid morbid treatments such as dialysis. Therefore, the present study aims to assess the incidence and risk factors associated with the development of AKI in nonsurgical patients, including a population with CKD and at early stages of hospitalization.
2. Materials and Methods 2.1. Study Design and Patients. A prospective cohort study was performed at the San Jose Hospital in Bogota Colombia, a level-four university hospital that provides healthcare to more than 2,500 patients per year in the Internal Medicine Department and has a Nephrology and Dialysis Department and a transplantation unit. We included adult patients admitted for emergency care and hospitalized in the Internal Medicine Department for more than 48 hours from September 2015 to April 2016. Patients on chronic dialysis or meeting the criteria for urgent dialysis on admission, pregnant, of history of kidney transplantation, of community-acquired acute kidney injury (CA-AKI), or transferred to the ICU within 48 hours were excluded from the study. Creatinine levels were measured on admission, at 48 hours and on day 5 of hospital stay, to establish the presence of AKI, based on the following operational definitions. EAKI. Patient admitted with normal creatinine levels (the creatinine reference values were used according to the local clinical laboratory men ≤ 1.3 mg/dL and women ≤ 1.1 mg/dL) and with an increase in creatinine equal to or greater than 0.3 mg/dL when comparing creatinine on admission with the control at 48 hours or on day five (based on the diagnostic recommendations of the KDIGO guidelines for AKI, the criterion based on changes in urinary output was not considered) [6]. CA-AKI. Patients with increased creatinine on admission and some of the following conditions: (i) An increase ≥0.3 mg/dL creatinine on admission compared with a prehospital record of creatinine six months before admission (ii) If no previous record exists, the evaluation group was responsible for the clinical and paraclinical assessment (i.e., renal diagnostic imaging, abnormal bone mineral metabolism, or other findings suggestive of CKD) to define CA-AKI or CKD without AKI (iii) Creatinine levels at the end of hospitalization lower than the creatinine levels on admission with a difference ≥0.3 mg/dL 2.2. Source and Monitoring Methods. Data were collected from electronic medical records and were corroborated by
direct patient examination. A project coordinator was responsible for conducting the daily patient census and assessing the eligibility criteria and monitoring. In case of doubt, a medical research group formed by three nephrologists (evaluation group) performed the final patient classification. 2.3. Variables. Clinically relevant variables included history of AHT, DM, heart failure, cirrhosis, coronary heart disease, rheumatologic disease, nephrotic syndrome, and CKD. According to the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) guideline, CKD was defined as GFR ≥ 60 mL/min/1.73 m2 with structural or functional kidney abnormality (abnormal composition of urine and/or abnormal imaging studies) for ≥3 months or GFR < 60 mL/min/1.73 m2 with or without kidney damage for ≥3 months [12]. Similarly, CKD was staged from 1 to 5 according to the NFK-KDOQI guideline with the GFR estimated by the CKD-EPI equation using the creatinine on admission [13]. Stages 1 and 2 were analyzed as a single variable and stages 3, 4, and 5 as another variable for two reasons: first, the number of patients with CKD in stages 1, 4, and 5 was poor in the cohort and, secondly, the risk of AKI in patients with reduced GFR from 60 mL/min/1.73 m2 (stages 3, 4, and 5) is better known in previous publications; however, it is uncertain for stages 1 and 2 (GFR ≥ 60 mL/min/1.73 m2 with structural or functional kidney abnormality) [14]. Other variables of interest assessed included age, sepsis, hydration status on admission based on the attending physician’s criteria, main diagnosis on admission, prehospital and in-hospital treatment with nephrotoxic drugs shown in Table 1 (the operational definitions for nephrotoxic drugs are shown in Table 1 of Supplementary Material available online at https://doi.org/10.1155/2017/5241482), ICU admission after 48 hours of hospital stay, dialysis requirement, length of hospital stay (including days of ICU stay if admitted 48 hours after hospital admission), and in-hospital death. 2.4. Sample Size. Sample size calculation was performed using a logistic regression model based on a prevalence of hospital-acquired AKI of approximately 17.2% [15, 16] and expecting to obtain at least 10 events for each of the five covariates considered to be the most important risk factors: CKD at admission, administration of nephrotoxic drugs, age, history of diabetes mellitus (DM), and sepsis [10, 11, 14]. The result is a minimum required sample size of 348 patients. 2.5. Statistical Methods. A database was constructed and statistical analysis was performed using STATA 13. Descriptive statistics were used to report the absolute and relative frequencies of categorical variables, and measures of central tendency and dispersion were used for quantitative variables, considering their distribution based on the Shapiro-Wilk test. The Mann–Whitney 𝑈 test was used for quantitative variables with abnormal distribution. The incidence of EAKI was calculated. A bivariate analysis was performed to assess the relationship between independent variables (exposure) and EAKI
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3 Table 1: Population characteristics.
Variable 𝑛 (%) or median (IQR) Age (years) Sex (male) Weight (kg) Anemia History of diabetes mellitus History of AHT History of cirrhosis History of heart failure History of coronary heart disease History of rheumatologic disease CKD∗ at admission Stage 1 (>90 mL/min/1.73 m2 ) Stage 2 (60–90 mL/min/1.73 m2 ) Stage 3 (30–59 mL/min/1.73 m2 ) Stage 4 (15–29 mL/min/1.73 m2 ) Stage 5 (
