Epidemiological profile of acute kidney injury in critically ill patients admitted to intensive care units: A Prospective Brazilian Cohort

Epidemiology of acute kidney injury in the clinical emergency: A prospective cohort study at a high-complexity public university hospital in São Paulo, Brazil

INTRODUCTION

Southern Hemisphere countries have been underrepresented in epidemiological studies on acute kidney injury (AKI). The objectives of this study were to determine the frequency, risk factors, and outcomes of AKI in adult hospitalized patients from the emergency department of a public high-complexity teaching hospital in the city of São Paulo, Brazil.

METHODS

Observational and prospective study. AKI was defined by the KDIGO guidelines (Kidney Disease: Improving Global Outcomes) using only serum creatinine.

RESULTS

Among the 731 patients studied (age: median 61 years, IQR 47-72 years; 55% male), 48% had hypertension and 28% had diabetes as comorbidities. The frequency of AKI was 52.1% (25.9% community-based AKI [C-AKI] and 26.3% hospital-acquired AKI [H-AKI]). Dehydration, hypotension, and edema were found in 29%, 15%, and 15% of participants, respectively, at hospital admission. The in-hospital and 12-month mortality rates of patients with vs. without AKI were 25.2% vs. 11.1% (p<0.001) and 36.7% vs. 12.9% (p<0.001), respectively. The independent risk factors for C-AKI were chronic kidney disease (CKD), chronic liver disease, age, and hospitalization for cardiovascular disease. Those for H-AKI were CKD, heart failure as comorbidities, hypotension, and edema at hospital admission. H-AKI was an independent risk factor for death in the hospital, but not at 12 months. C-AKI was not a risk factor for death.

CONCLUSIONS

AKI occurred in more than half of the admissions to the clinical emergency department of the hospital and was equally distributed between C-AKI and H-AKI. Many patients had correctable risk factors for AKI, such as dehydration and arterial hypotension (44%) at admission. The only independent risk factor for both C-AKI and H-AKI was CKD as comorbidity.

Serum bicarbonate levels and kidney outcomes in critically ill patients: a prospective cohort study

BACKGROUND

The interplay between serum bicarbonate levels and kidney outcomes is not fully understood. We conducted a prospective cohort study in three intensive care units (ICUs) to evaluate the association of serum bicarbonate levels with acute kidney injury (AKI) and kidney function recovery in critically ill patients.

METHODS

A prospective cohort study in three intensive care units (ICUs) was performed. The serum bicarbonate level in the first 24 h after ICU admission was categorized as low (< 22 mEq/L), normal (22-26 mEq/L), or high (> 26 mEq/L). Serum creatinine (SCr) levels according to the KDIGO AKI guideline were used for defining AKI within the first 7 days of ICU stay. At ICU admission, SCr ≥ 1.1 for women and ≥ 1.3 mg/dL for men were indicative of impaired kidney function. Mortality outcome was tracked up to 28 days, and kidney function recovery was assessed at hospital discharge.

RESULTS

A total of 2732 patients (66 ± 19 years and 55% men) were analyzed, with 32% having impaired kidney function at ICU admission. Overall, 26% of patients had low bicarbonate levels, while 32% had high bicarbonate levels. Notably, patients with preserved kidney function showed a lower prevalence of low bicarbonate levels compared to those with impaired kidney function (20% vs. 39%, p < 0.001), while higher rates were observed for high bicarbonate (35% vs. 24%, p < 0.001). Compared with patients with normal serum bicarbonate levels, those with low bicarbonate were 81% more likely to develop AKI (OR = 1.81; 95% CI 1.10-2.99), whereas those with high bicarbonate were 44% less likely (OR = 0.56; 95% CI 0.32-0.98) in the adjusted model for confounders. Neither those with high nor low serum bicarbonate levels were associated with an increased risk of mortality (HR = 1.03; 95% CI 0.68-1.56 and 0.99; 95% CI 0.68-1.42, respectively). In subgroup analysis, regardless of the kidney function at ICU admission, serum bicarbonate levels were not associated with the development of AKI and all-cause mortality. Regarding kidney function recovery, higher non-recovery rates were found for those with low bicarbonate.

CONCLUSION

In critically ill ICU patients, low bicarbonate levels were associated with the more likely development of AKI and subsequent non-recovery of kidney function, while high bicarbonate levels showed no such association. Therefore, low bicarbonate levels may be considered a risk factor for adverse kidney outcomes in critically ill patients.

Epidemiology, patterns of care and prognosis of acute kidney injury in critically ill patients: A multicenter study in Argentina (The EPIRA study)

BACKGROUND

Acute kidney injury (AKI) is associated with high morbidity and mortality rates in the intensive care unit (ICU). In low- and middle-income countries (LMICs), epidemiological information about this condition is still scarce. Our main objective was to characterize its epidemiology, prognosis, and its treatment.

METHODS

This multicenter prospective cohort study included 1466 patients from 35 ICUs during 6 months in Argentina in 2018. Risk factors and outcomes in patients with and without AKI, and between AKI on admission (AKIadm) and that developed during hospitalization (AKIhosp) were analyzed.

RESULTS

AKI occurred in 61.3% of patients (900/1466); 72.6% were AKIadm and 27.3% AKIhosp. Risk factors were age, BMI, arterial hypertension, cardiovascular diseases, diabetes, SOFA, APACHE II, dehydration, sepsis, vasopressor use, radiocontrast, diuresis/h and mechanical ventilation. Independent predictors for AKI were sepsis, diabetes, dehydration, vasopressors on admission, APACHE II and radiocontrast use. Renal replacement therapies (RRT) requirement in AKI patients was 14.8%. Hospital mortality in AKI vs. non-AKI was 38.7% and 23.3% (p < 0.001); and in AKIadm vs. AKIhosp, 41.2% and 37.8% (p = 0.53).

CONCLUSIONS

ICU-acquired AKI has high incidence, complications and mortality. Risk factors for AKI and RRT utilization were similar to those described in other epidemiological studies. AKIadm was more frequent than AKIhosp, but had equal prognosis.

Prognostic role of renal replacement therapy among hospitalized patients with heart failure in the Brazilian national public health system

Introduction

Data on patients hospitalized with acute heart failure in Brazil scarce.

Methods

We performed a cross-sectional, retrospective, records-based study using data retrieved from a large public database of heart failure admissions to any hospital from the Brazilian National Public Health System (SUS) (SUS Hospital Information System [SIHSUS] registry) to determine the in-hospital all-cause mortality rate, in-hospital renal replacement therapy rate and its association with outcome.

Results

In total, 910,128 hospitalizations due to heart failure were identified in the SIHSUS registry between April 2017 and August 2021, of which 106,383 (11.7%) resulted in in-hospital death. Renal replacement therapy (required by 8,179 non-survivors [7.7%] and 11,496 survivors [1.4%, p < 0.001]) was associated with a 56% increase in the risk of death in the univariate regression model (HR 1.56, 95% CI 1.52 -1.59), a more than threefold increase of the duration of hospitalization, and a 45% or greater increase of cost per day. All forms of renal replacement therapy remained independently associated with in-hospital mortality in multivariable analysis (intermittent hemodialysis: HR 1.64, 95% CI 1.60 -1.69; continuous hemodialysis: HR 1.52, 95% CI 1.42 -1.63; peritoneal dialysis: HR 1.47, 95% CI 1.20 -1.88).

Discussion

The in-hospital mortality rate of 11.7% observed among patients with acute heart failure admitted to Brazilian public hospitals was alarmingly high, exceeding that of patients admitted to North American and European institutions. This is the first report to quantify the rate of renal replacement therapy in patients hospitalized with acute heart failure in Brazil.

Association of magnesium abnormalities at intensive care unit admission with kidney outcomes and mortality: a prospective cohort study

BACKGROUND

Magnesium abnormalities have been associated with adverse kidney outcomes and mortality in critically ill patients, however, this association remains inconsistent. This study aimed to investigate the association of magnesium abnormalities at intensive care unit (ICU) admission with kidney outcomes (i.e., acute kidney injury (AKI) and kidney function recovery) and mortality risk in a large cohort of critically ill patients.

METHODS

A prospective cohort study was conducted by collecting data from three ICUs in Brazil. The ICU admission serum magnesium level was used to define hypomagnesemia (< 1.60 mg/dL) and hypermagnesemia (> 2.40 mg/dL). The Kidney Disease Improving Global Outcomes AKI Guideline was used to define AKI based on serum creatinine levels. Kidney function recovery was defined as full recovery, partial recovery, and non-recovery at ICU discharge. Mortality was screened up to 28 days during ICU stay.

RESULTS

A total of 7,042 patients was analyzed, hypomagnesemia was found in 18.4% (n = 1,299) and hypermagnesemia in 4.4% (n = 311). Patients with hypomagnesemia were 25% more likely to develop AKI after adjustment for confounding variables (OR = 1.25; 95% CI 1.08-1.46). No significant association was found for hypermagnesemia and AKI (OR = 1.18; 95% CI 0.89-1.57). Kidney function recovery was similar among groups but hypermagnesemia had lower non-recovery rates. Both hypomagnesemia and hypermagnesemia were associated with 65 and 52% higher mortality risk after adjustments for confounders, respectively (HR = 1.65; 95% CI 1.32-2.06 and 1.52; 95% CI 1.01-2.29).

CONCLUSIONS

Hypomagnesemia, but not hypermagnesemia, at ICU admission was associated with AKI development. On the other hand, both hypomagnesemia and hypermagnesemia were associated with higher mortality risks.