Cross-sectional study of the association between functional status and acute kidney injury in geriatric patients

A clinical score to predict recovery in end-stage kidney disease due to acute kidney injury

Background

Acute kidney injury (AKI) is a major contributor to end-stage kidney disease (ESKD). About one-third of patients with ESKD due to AKI recover kidney function. However, the inability to accurately predict recovery leads to improper triage of clinical monitoring and impacts the quality of care in ESKD.

Methods

Using data from the United States Renal Data System from 2005 to 2014 (n = 22 922), we developed a clinical score to predict kidney recovery within 90 days and within 12 months after dialysis initiation in patients with ESKD due to AKI. Multivariable logistic regressions were used to examine the effect of various covariates on the primary outcome of kidney recovery to develop the scoring system. The resulting logistic parameter estimates were transformed into integer point totals by doubling and rounding the estimates. Internal validation was performed.

Results

Twenty-four percent and 34% of patients with ESKD due to AKI recovered kidney function within 90 days and 12 months, respectively. Factors contributing to points in the two scoring systems were similar but not identical, and included age, race/ethnicity, body mass index, congestive heart failure, cancer, amputation, functional status, hemoglobin and prior nephrology care. Three score categories of increasing recovery were formed: low score (0-6), medium score (7-9) and high score (10-12), which exhibited 90-day recovery rates of 12%, 26% and 57%. For the 12-month scores, the low, medium and high groups consisted of scores 0-5, 6-8 and 9-11, with 12-month recovery rates of 16%, 33% and 62%, respectively. The internal validation assessment showed no overfitting of the models.

Conclusion

A clinical score derived from information available at incident dialysis predicts renal recovery at 90 days and 12 months in patients with presumed ESKD due to AKI. The score can help triage appropriate monitoring to facilitate recovery and begin planning long-term dialysis care for others.

Serum and Urinary Neutrophil Gelatinase-Associated Lipocalin Are Not Associated With Serum Redox Parameters in Amateur Athletes After an Ultramarathon

Objective

To evaluate the relationship between oxidative stress and NGAL levels in blood and urine of amateur athletes after participating in a 100 km ultramarathon.

Methodology

The sample was composed of seven athletes, submitted to anthropometric assessment, cardiopulmonary exercise test, collection of urine and blood, measurement of body weight. The rate of perceived exertion (RPE), competition duration, heart rate (HR), energy expenditure and oxygen consumption (V'O2") were also measured during the event. The energy consumption during the race was verified at its end. The analyses were based on the means (M) and respective standard deviations (SD), with statistical significance set at 5% (p < 0.05). Paired t-test was used for comparison between the periods before and after the competition, and Pearson's correlation coefficient was used to measure the linear correlation between quantitative variables.

Results

Body mass index (BMI) of the sample was 25.75 kg/m2 ± 3.20, body fat percentage 18.54% ± 4.35% and V'O2"max 48.87% ± 4.78. Glucose, cortisol, and neutrophil gelatinase-associated lipocalin (NGAL) (p < 0.01) as well as glutathione peroxidase (GPx) active were higher after the race when compared to basal values. Moreover, lactate, creatinine, microalbuminuria, and glomerular filtration rate (GFR) (p < 0.001) were also higher after the race. After the competition, there was a significant correlation only between serum NGAL and creatinine, which was classified as strong and positive (r: 0.77; p < 0.05). There was a significant reduction (p < 0.05) of body weight after the event (72.40 kg ± 9.78) compared to before it (73.98 kg ± 10.25). In addition, we found an increase of RPE (p < 0.001) after the race. The competition lasted 820.60 min (±117.00), with a 127.85 bpm (±12.02) HR, a 2209.72 kcal ± 951.97 energy consumption, 7837.16 kcal ± 195.71 energy expenditure, and 28.78 ml/kg/min-1 (±4.66) relative V'O2"max.

Conclusion

The lack of correlation between oxidative stress biomarkers and serum and urine NGAL suggests that NGAL is more sensitive to inflammatory processes than to ROS levels.

Restoration of dysnatremia and acute kidney injury benefits outcomes of acute geriatric inpatients

Dysnatremia and dyskalemia are common problems in acutely hospitalized elderly patients. These disorders are associated with an increased risk of mortality and functional complications that often occur concomitantly with acute kidney injury in addition to multiple comorbidities. In a single-center prospective observational study, we recruited 401 acute geriatric inpatients. In-hospital outcomes included all-cause mortality, length of stay, and changes in functional status as determined by the Activities of Daily Living (ADL) scale, Eastern Cooperative Oncology Group (ECOG) performance, and Clinical Frailty Scale (CFS). The prevalence of dysnatremia alone, dyskalemia alone, and dysnatremia plus dyskalemia during initial hospitalization were 28.4%, 14.7% and 32.4%, respectively. Patients with electrolyte imbalance exhibited higher mortality rates and longer hospital stays than those without electrolyte imbalance. Those with initial dysnatremia, or dysnatremia plus dyskalemia were associated with worse ADL scores, ECOG performance and CFS scores at discharge. Subgroup analyses showed that resolution of dysnatremia was related to reduced mortality risk and improved CFS score, whereas recovery of renal function was associated with decreased mortality and better ECOG and CFS ratings. Our data suggest that restoration of initial dysnatremia and acute kidney injury during acute geriatric care may benefit in-hospital survival and functional status at discharge.

End-stage renal disease increases risk of postoperative complications after lower extremity fracture

INTRODUCTION

End-stage renal disease (ESRD) leads to multiple systemic effects and patients suffer from multiple comorbidities including fractures. While previous studies have examined complications following hip fracture surgery in ESRD patients, there are no studies evaluating other lower extremity fractures. This study aimed to identify postoperative complication risk in patients with ESRD who had lower extremity fractures.

METHODS

Using our database from 2000 to 2015 at two level-one trauma centres, we collected data on patients over age 40, who had lower extremity fractures and surgical fixation. Diagnosis of ESRD was made before the injury. Each ESRD patient was matched by two non-ESRD patients regarding age, gender, American Society of Anaesthesiologists (ASA) score, and AO/OTA fracture classification. Postoperative outcomes were non-union, mechanical failure, and infection. The number of outcome events was compared between the ESRD and non-ESRD cohorts.

RESULTS

A total of 195 patients (65 ESRD patients matched to 130 non-ESRD patients) were identified. Median follow-up was 31 months (12-141 months). Patients with ESRD were 3.6 time more likely to have at least one postoperative complication (mechanical failure, non-union, or infection) compared to non-ESRD patients (9/65 vs. 5/130, p = 0.02). In particular, mechanical failure was eight times higher among ESRD patients compared to non-ESRD patients (8/65 vs. 2/130, p < 0.01).

CONCLUSIONS

ESRD was associated with higher rates of complications, especially mechanical failure, after lower extremity fracture surgeries.

Persistent Kidney Dysfunction after Acute Kidney Injury Predicts Short-Term Outpatient Mortality

BACKGROUND

Acute kidney injury (AKI) during hospitalization is frequent and associated with adverse outcomes. We have now evaluated the association between renal function recovery after AKI and short-term post-discharge mortality.

METHODS

This is a retrospective study of all AKI episodes codified in the electronic records of a single center in 2013 and 2014. Epidemiological data and comorbidities at baseline and laboratory values at admission and discharge were collected. Persistent kidney dysfunction after AKI was defined as a last serum creatinine equal or above 1.2-fold over baseline level. Patients were followed for 30 days after discharge.

RESULTS

Out of 1720 evaluated patients, 1541 (89%) were analyzed. Of them, 869 (56%) recovered renal function. Independent predictors of renal function recovery after AKI were lower baseline estimated glomerular filtration rate (eGFR) (p < 0.001), higher admission eGFR (p < 0.001) and hemoglobin (p = 0.016), milder AKI (p = 0.037), absence of history of heart failure (p < 0.001), and lower admission blood pressure (p < 0.001). After discharge, 46 (3%) patients died in the first 30 days. Persistent kidney dysfunction was associated (p = 0.01) to and independently predicted (OR 2.6, 95%CI (1.2-5.4), p = 0.01) short term post-discharge mortality.

CONCLUSIONS

Persistent kidney dysfunction after an AKI episode is an independent predictor of 30-day post-discharge mortality. This information may help select AKI patients who required closer follow-up and monitoring after discharge. This article is protected by copyright. All rights reserved.

[Baseline characteristics of nonagenarians hospitalised due to acute kidney injury compared to other age groups]

BACKGROUND

The increase in life expectancy leads to higher hospitalisation rates in elderly patients. The aim of this work is to study the characteristics of the population over 90 years of age that are admitted due to acute kidney injury (AKI).

MATERIAL AND METHODS

A cross-sectional study was conducted that included all patients admitted to hospital with AKI in the years 2013 and 2014. Epidemiological characteristics, comorbidity, medication and baseline analytical data were collected, and a comparison was made between patients with age over 90 years-old and the others.

RESULTS

A total of 1733 patients were included, of whom 264 (15%) were over 90 years-old. A significantly higher proportion of these patients were women. The most frequent cause of AKI in patients older than 90 years was functional (81%) (p < 0.001 compared to other age groups). The main cause of hospital admission was infection. In the group of over 90 years of age, a higher prevalence was found for arterial hypertension (p = 0.005), chronic kidney disease (p = 0.014), congestive heart failure (p = 0.006), and cognitive impairment (p < 0.0001). The baseline glomerular filtration rate by CKD-EPI was lower in the group of patients older than 90 years (p < 0.0001). Patients under 90 years admitted to hospital due to AKI, had a higher prevalence of diabetes mellitus (p < 0.001), dyslipidaemia (p < 0.001), history of neoplasia (p < 0.001), and a higher Barthel index (p < 0.0001).

CONCLUSIONS

Nonagenarians admitted due to AKI have functional aetiology as the most common factor. These patients have a higher prevalence of hypertension, heart failure, chronic kidney disease, low functional status, and more cognitive impairment.

Changing relative risk of clinical factors for hospital-acquired acute kidney injury across age groups: a retrospective cohort study

Background

Likelihood of developing acute kidney injury (AKI) increases with age. We aimed to explore whether the predictability of AKI varies between age groups and assess the volatility of risk factors using electronic medical records (EMR).

Methods

We constructed a retrospective cohort of adult patients from all inpatient units of a tertiary care academic hospital and stratified it into four age groups: 18–35, 36–55, 56–65, and > 65. Potential risk factors collected from EMR for the study cohort included demographics, vital signs, medications, laboratory values, past medical diagnoses, and admission diagnoses. AKI was defined based on the Kidney Disease Improving Global Outcomes (KDIGO) serum creatinine criteria. We analyzed relative importance of the risk factors in predicting AKI using Gradient Boosting Machine algorithm and explored the predictability of AKI across age groups using multiple machine learning models.

Results

In our cohort, older patients showed a significantly higher incidence of AKI than younger adults: 18–35 (7.29%), 36–55 (8.82%), 56–65 (10.53%), and > 65 (10.55%) (p < 0.001). However, the predictability of AKI decreased with age, where the best cross-validated area under the receiver operating characteristic curve (AUROC) achieved for age groups 18–35, 36–55, 56–65, and > 65 were 0.784 (95% CI, 0.769–0.800), 0.766 (95% CI, 0.754–0.777), 0.754 (95% CI, 0.741–0.768), and 0.725 (95% CI, 0.709–0.737), respectively. We also observed that the relative risk of AKI predictors fluctuated between age groups.

Conclusions

As complexity of the cases increases with age, it is more difficult to quantify AKI risk for older adults in inpatient population.

Frailty Predicts an Increased Risk of End-Stage Renal Disease with Risk Competition by Mortality among 165,461 Diabetic Kidney Disease Patients

To examine the effect of frailty on diabetic kidney disease patients’ risk of progression to end-stage renal disease (ESRD), mortality, and adverse episodes, as whether frailty modifies their risk of developing ESRD and other adverse outcomes remains unclear. We identified 165,461 DKD patients from the Longitudinal Cohort of Diabetes Patients in Taiwan (n=840,000) between 2004 and 2010, classifying them into those without frailty or with 1, 2 and ≥3 frailty components based on a modified version of FRAIL scale. Using Cox proportional hazard regression analysis, we examined the long-term risk of developing ESRD along with their risk of mortality, supplemented by a competing risk analysis against mortality. Among all participants, 66.2% (n=109,586), 27.2% (n=44,986), 5.9% (n=9,799), and 0.7% (n=1090) patients did not have or had 1, 2, and ≥3 frailty components, respectively. After a 4.1-year follow-up, 4.2% patients developed ESRD and 18.5% died. Cox proportional hazard modeling revealed that patients with 1, 2, and ≥3 frailty components had increased risks of developing ESRD (for 1, 2, and ≥3 components, hazard ratio [HR] 1.13, 1.18, and 1.2, respectively) and mortality (HR 1.25, 1.41, and 1.34, respectively), with. 9% and 16% risk elevations for ESRD and mortality per component increase. Competing risk analysis showed that frailty-induced ESRD risk was attenuated partially by mortality in those with moderate frailty. The receipt of palliative care did not attenuate this risk. Frailty increased the risk of ESRD based on a dose-response relationship among DKD patients with risk competition by mortality.

Age modifies the risk factor profiles for acute kidney injury among recently diagnosed type 2 diabetic patients: a population-based study

The incidence of acute kidney injury (AKI) rises with age and is associated with multiple risk factors. Here, we compared the risk factors for AKI between younger and older incident diabetic patients to examine the trends in risk alteration for individual factors across different age groups. Between 2007 and 2013, we selected all incident type 2 diabetic adults from the Taiwan National Health Insurance registry, stratified based on age: young (< 65 years), old (≥ 65 but < 75 years), and older-old (≥ 75 years). All factors with potential renal influence (e.g., comorbidities, medications, and diagnostics/procedures) were recorded during the study period, with a nested case-controlled approach utilized to identify independent risk factors for AKI in each age group. Totally, 930,709 type 2 diabetic patients were categorized as young (68.7%), old (17.7%), or older-old (13.6%). Older-old patients showed a significantly higher incidence of AKI than the old and the young groups. Cardiovascular morbidities (hypertension, atrial fibrillation, acute coronary syndrome, and cerebrovascular disease) were shown to increase the risk of AKI, although the risk declined with increasing age. Chronic obstructive pulmonary disease and receiving cardiac catheterization elevated the risk of AKI preferentially in the older-old/old and older-old group, respectively, while the administration of angiotensin-converting enzyme/α-blocker and angiotensin receptor blocker/calcium channel blocker reduced the risk of AKI preferentially in the older-old and older-old/old group, respectively. In conclusion, our findings highlight the importance of devising age-specific risk factor panels for AKI in patients with recently diagnosed type 2 diabetes.

Urinary Neutrophil Gelatinase-Associated Lipocalin Is Excellent Predictor of Acute Kidney Injury in Septic Elderly Patients

Elderly is the main age group affected by acute kidney injury (AKI). There are no studies that investigated the predictive properties of urinary (u) NGAL as an AKI marker in septic elderly population. This study aimed to evaluate the efficacy of uNGAL as predictor of AKI diagnosis and prognosis in elderly septic patients admitted to ICUs. We prospectively studied elderly patients with sepsis admitted to ICUs from October 2014 to November 2015. Assessment of renal function was performed daily by serum creatinine and urine output. The level of uNGAL was performed within the first 48 hours of the diagnosis of sepsis (NGAL1) and between 48 and 96 hours (NGAL2). The results were presented using descriptive statistics and area under the receiver operating characteristic curve (AUC-ROC) and p value was 5%. Seventy-five patients were included, 47 (62.7%) developed AKI. At logistic regression, chronic kidney disease and low mean blood pressure at admission were identified as factors associated with AKI (OR=0.05, CI=0.01-0.60, p=0.045 and OR=0.81, CI=0,13-0.47; p=0.047). The uNGAL was excellent predictor of AKI diagnosis (AUC-ROC >0.95, and sensitivity and specificity>0.89), anticipating the AKI diagnosis in 2.1±0.3 days. Factors associated with mortality in the logistic regression were presence of AKI (OR=2.14, CI=1.42-3.98, p=0.04), chronic obstructive pulmonary disease (OR = 9.37, CI =1.79-49.1, p=0.008) and vasoactive drugs (OR=2.06, CI=0.98-1.02, p=0.04). The accuracy of NGALu 1 and 2 as predictors of death was intermediate, with AUC-ROC of 0.61 and 0.62; sensitivity between 0.65 and 0.77 and specificity lower than 0.6. The uNGAL was excellent predictor of AKI in septic elderly patients in ICUs and can anticipate the diagnosis of AKI in 2.1 days.

Thrombocytopenia on the first day of emergency department visit predicts higher risk of acute kidney injury among elderly patients

Background

Few studies have addressed risk factors for acute kidney injury (AKI) in geriatric patients. We investigated whether thrombocytopenia was a risk factor for AKI in geriatric patients with medical illnesses.

Methods

A prospective cohort study was conducted, by recruiting elderly (≥65 years) patients who visited the emergency department (ED) for medical illnesses during 2014. They all received hemogram for platelet count determination, and were stratified according to the presence of thrombocytopenia (platelets, <150 K/μL) during their initial ED evaluation. They were prospectively followed up during their ED stay. We analyzed the relationship between the diagnosis of thrombocytopenia and subsequent AKI after ED stay, using Cox proportional hazard modeling, with platelet count as a continuous variable or thrombocytopenia as a categorical variable.

Results

Of 136 elderly patients (mean age of 80.7 ± 8.2 years, 40% with chronic kidney disease, and 39% with diabetes) enrolled, 22.8% presented with thrombocytopenia, without differences in baseline renal function. After a mean ED stay of 4.4 ± 2.1 days, 41.9% developed AKI (52.6% Kidney Disease Improving Global Outcomes [KDIGO] grade 1, 24.6% grade 2, and 22.8% grade 3). Patients with higher AKI severity had stepwise lower platelet counts compared to those without AKI. The Cox proportional hazard model revealed that lower platelet count as a continuous variable (hazard ratio [HR] 0.984, 95% confidence interval [CI] 0.975–0.994) and as a categorical variable (presence of thrombocytopenia) (HR 1.86, 95% CI 1.06–3.27) increased the risk of AKI. The sensitivity analyses accounting for nephrotoxic medications use, including non-steroidal anti-inflammatory drugs, vancomycin, and contrast, yielded similar results.

Discussion

Thrombocytopenia is common among ED-visiting elderly, and the potential relationship between platelet counts and the risk of AKI suggests the utility of checking hemogram for those at-risk ofdeveloping adverse renal events.

Conclusion

Thrombocytopenia on initial presentation might indicate an increased risk of AKI among elderly patients with medical illnesses.

Dipstick proteinuria level is significantly associated with pre-morbid and in-hospital functional status among hospitalized older adults: a preliminary study

Although chronic kidney disease (CKD) is associated with functional decline, whether proteinuria alone is associated with functional statuses over the course of acute illnesses independent of CKD is unclear. During 2014, we prospectively enrolled non-dialysis patients aged ≥65 years, and all participants underwent spot dipstick urinalysis on admission, divided into 3 groups according to the results (none, trace to 1 + , and 2 + or higher); functional status was evaluated using the pre-morbid and in-hospital Barthel index (BI) scores. Of 136 community-dwelling elderly patients enrolled (age 80.7 ± 8.2 years, with 19% having CKD), 17%, 57%, and 26% had no, trace to 1 + , or 2 + or higher proteinuria. Overall pre-morbid, on-admission, and on-discharge BI scores were 50.4 ± 41.9, 38.6 ± 31.8, and 38.7 ± 35.3, respectively with significant negative correlations with proteinuric severity on admission. Finally, multivariate linear stepwise regression analysis with backward variable selection found that dipstick proteinuric severity was significantly associated with pre-morbid, on-admission, and on-dischrage BI scores (p = 0.048, <0.01, and <0.01, respectively), independent of diabetes and CKD. This relationship between dipstick proteinuric levels and functional status of hospitalized elderly suggests an under-recognized association. Prospective evaluation of long-term outcome is needed.

Acute kidney injury in elderly intensive care patients from a developing country: clinical features and outcome

AIM

The elderly are at high risk of acute kidney injury (AKI) because of structural and functional degeneration over time and with the aging of the population, the demand for intensive care unit (ICU) admission for older patients has risen recently. However, data from developing countries are scarce. This study aimed to describe the incidence of AKI in elderly patients admitted to ICU from a developing country, to determine the most frequent etiologies for renal impairment and identify its risk factors and outcome.

METHODS

All patients admitted to the ICU at a Brazilian teaching hospital for 12 consecutive months were followed prospectively from the time of admission until ICU discharge. Elderly was defined as aged >60 years and AKI was defined according to the Kidney Disease Improving Global Outcomes 2012 criteria. Multivariable logistic regression was used to adjust confounding and selection bias.

RESULTS

Two hundred elderly patients were included in the study. AKI incidence was 27% and the main etiology was sepsis (48.1%). At logistic regression, baseline creatinine (odds ratio [OR]=5.17, p<0.0001), Acute Physiology and Chronic Health Evaluation (APACHE) II (OR=1.20, p<0.0001), sepsis (OR=2.96, p<0.0001), and longer ICU stay (OR=1.68, p<0.0001) were associated with AKI in elderly patients. Baseline creatinine (OR=1.97, p=0.018), APACHE II (OR=1.29, p<0.0001), sepsis (OR=1.87, p<0.0001), and AKI severity (OR=2.57, p=0.027) were identified as predictors of death.

CONCLUSION

AKI was frequent in elderly patients admitted to ICU from a developing country, and it was identified as a risk factor for death. Sepsis was an important risk factor for both AKI and mortality, similar to developed countries and in younger populations.

Performance of Edmonton Frail Scale on frailty assessment: its association with multi-dimensional geriatric conditions assessed with specific screening tools

BACKGROUND

The aim of this study was to evaluate the performance of Edmonton Frail Scale (EFS) on frailty assessment in association with multi-dimensional conditions assessed with specific screening tools and to explore the prevalence of frailty by gender.

METHODS

We enrolled 366 hospitalised patients (women\men: 251\115), mean age 81.5 years. The EFS was given to the patients to evaluate their frailty. Then we collected data concerning cognitive status through Mini-Mental State Examination (MMSE), health status (evaluated with the number of diseases), functional independence (Barthel Index and Activities Daily Living; BI, ADL, IADL), use of drugs (counting of drugs taken every day), Mini Nutritional Assessment (MNA), Geriatric Depression Scale (GDS), Skeletal Muscle Index of sarcopenia (SMI), osteoporosis and functionality (Handgrip strength).

RESULTS

According with the EFS, the 19.7% of subjects were classified as non frail, 66.4% as apparently vulnerable and 13.9% with severe frailty. The EFS scores were associated with cognition (MMSE: β = 0.980; p < 0.01), functional independence (ADL: β = -0.512; p < 0.00); (IADL: β = -0.338; p < 0.01); use of medications (β = 0.110; p < 0.01); nutrition (MNA: β = -0.413; p < 0.01); mood (GDS: β = -0.324; p < 0.01); functional performance (Handgrip: β = -0.114, p < 0.01) (BI: β = -0.037; p < 0.01), but not with number of comorbidities (β = 0.108; p = 0.052). In osteoporotic patients versus not-osteoporotic patients the mean EFS score did not differ between groups (women: p = 0.365; men: p = 0.088), whereas in Sarcopenic versus not-Sarcopenic patients, there was a significant differences in women: p < 0.05.

CONCLUSIONS

This study suggests that measuring frailty with EFS is helpful and performance tool for stratifying the state of fragility in a group of institutionalized elderly. As matter of facts the EFS has been shown to be associated with several geriatric conditions such independence, drugs assumption, mood, mental, functional and nutritional status.

The characteristics and mortality risk factors for acute kidney injury in different age groups in China-a cross sectional study

AIM

Age is an independent risk factor for acute kidney injury (AKI). The causes and outcomes of AKI in children, middle-aged, and older patients are different. The objective of this country-based study was to identify the characteristics and mortality factors for AKI in different age groups in China.

METHODS

Using data from 374,286 adult patients (≥18 years) admitted to 44 study hospitals, we investigated the characteristics and mortality risk factors for AKI in four different age groups: 18-39 years of age, 40-59 years of age, 60-79 years of age, and ≥80 years of age. The identification criteria for AKI included the 2012 KDIGO AKI definition and an expanded criterion.

RESULTS

The country-based survey included 7604 AKI patients (7604/374,286, 2.03%). The proportions of AKI in the four age groups were 11.52%, 30.79%, 41.03%, and 16.66%, respectively. In any age group, the patients with AKI stage 1 were the majority (43.4%, 42.4%, 46.4%, and 52.2%, respectively), and the most common classification of AKI was pre-renal AKI (44.3%, 51.3%, 52.3%, and 56.4%, respectively). The higher AKI peak stage occurred for the in-hospital mortality factors for AKI in all age groups; except for the AKI stage 2 patients in the 18-39 age group.

CONCLUSION

The characteristics and mortality factors for AKI vary by age in China. Elderly patients were the primary population with AKI, and the most common type of AKI was pre-renal AKI. Special caution should be taken to the old population in hospitalized patients to prevent the pre-renal AKI.

Clinical outcomes of acute kidney injury developing outside the hospital in elderly

PURPOSE

Although various studies have improved our knowledge about the clinical features and outcomes of acute kidney injury developing in the hospital (AKI-DI) in elderly subjects, data about acute kidney injury developing outside the hospital (AKI-DO) in elderly patients (age ≥ 65 years) are still extremely limited. This study was performed to investigate prevalence, clinical outcomes, hospital cost and related factors of AKI-DO in elderly and very elderly patients.

METHODS

We conducted a prospective, observational study in patients (aged ≥ 65 years) who were admitted to our center between May 01, 2012, and May 01, 2013. Subjects with AKI-DO were divided into two groups as "elderly" (group 1, 65-75 years old) and "very elderly" (group 2, >75 years old). Control group (group 3) consisted of the hospitalized patients aged 65 years and older with normal serum creatinine level. In-hospital outcomes and 6-month outcomes were recorded. Rehospitalization rate within 6 months of discharge was noted. Hospital costs and mortality rates of each group were investigated. Risk factors for AKI-DO were determined.

RESULTS

The incidence of AKI-DO that required hospitalization in elderly and very elderly patients was 5.8 % (136/2324) and 11 % (100/905), respectively (p < 0.001), with an overall incidence of 7.3 % (236/3229). Chronic kidney disease (CKD) was developed in 43.4 % of group 1 and 67 % of group 2 within the 6 months of discharge (p < 0.001). Progression to CKD was significantly lower in the control group than in groups 1 and 2 (p < 0.001). Mortality rates for groups 1, 2 and 3 were 23.5 % (n = 32), 31 % (n = 31) and 4.2 % (n = 8), respectively (p < 0.05). Rehospitalization rate within the 6 months of discharge for the groups with AKI-DO was higher than for the control group (p < 0.001). Hospital cost of groups 1 and 2 was significantly higher than that of the control group (p < 0.001). Nonsteroidal anti-inflammatory drugs (NSAIDs) (OR: 6.839, 95 % CI = 4.392-10.648), angiotensin-converting enzyme inhibitors (ACEI) (OR: 7.846, 95 % CI = 5.161-11.928), angiotensin receptor blockers (ARB) (OR: 6.466, 95 % CI = 4.813-8.917), radiocontrast agents (OR: 8.850, 95 % CI = 5.857-13.372), hypertension (OR: 4.244, 95 % CI = 2.729-6.600), diabetes mellitus (OR: 2.303, 95 % CI = 1.411-3.761), heart failure (OR: 3.647, 95 % CI = 2.276-5.844) and presence of infection (OR: 3.149, 95 % CI = 1.696-5.845) were found as the risk factors for AKI-DO in elderly patients (p < 0.001 for all). Patients with AKI-DO had higher 6-month mortality rate (HR 1.721, 95 % CI: 1.451-2.043, p < 0.001). Mortality risk increased 0.519 times at 20th day.

CONCLUSIONS

The incidence of AKI-DO requiring hospitalization is higher in very elderly patients than elderly ones, especially in male gender. Use of ACEI, ARB, NSAID and radiocontrast agents is the main risk factors for the development of AKI-DO in the elderly.