Microalbuminuria as predictor of outcome. Shows promise but large prospective trials are needed

Association of Urinary Albumin:Creatinine Ratio with Outcome of Children with Sepsis

Objective

The aim of the study was to investigate the association of urinary albumin:creatinine ratio (ACR) with regard to the outcome of sepsis patients and to study the trends of ACR with severity of disease, organ dysfunction, microcirculation status, the use of inotrope, and mechanical ventilation use, and length of pediatric intensive care unit (PICU) stay.

Materials and methods

In the prospective observational study, the patients with varying categories of sepsis admitted in the PICU with stay >24 hours were enrolled consecutively. Urine samples were collected at the time of admission (ACR1), 12 hours (ACR2), and 24 hours (ACR3).

Results

One hundred and thirty-eight patients including 56 cases of sepsis, 31 of severe sepsis, 22 of septic shock, and 29 of multiorgan dysfunction syndrome (MODS) cases were analyzed. There were 29 (21%) deaths. ACR (median, IQR) was significantly higher in nonsurvivors [ACR1 198.9 (111.2–329.4) vs 124.5 (59.37–294.5), p 0.03], [ACR2 213.8 (112.5–350) vs 117.8 (62.6–211.9) p 0.008], [ACR3 231.8 (99.9–441.2 vs 114.4 (44.1–240.3), p 0.005]. The ACR is increased progressively with the increasing severity of sepsis (p < 0.001). The performance of ACR operative characteristics was compared with that of PRISM and PELOD scores. In deceased, ACR was significantly correlated with blood pH, lactate, and base deficit. A cutoff value of ACR 102.7 mg/g had sensitivity 86.2%, specificity 40.4%, positive predictive value 27.8%, and negative predictive value 91.7%. The use of inotropes, mechanical ventilation (>48 hours), and mortality was significantly higher in patients with ACR >102 mg/g. The probability of death varied from 17.6 to 19% in the first 24 hours of admission. ACR was significantly cheaper as compared to PRISM score and PELOD score estimations.

Conclusion

Urinary ACR, a cost-effective tool, correlates with the severity of sepsis and associated morbidity and mortality in children.

How to cite this article

Sachdev A, Raheja K, Gupta N, Chugh P. Association of Urinary Albumin:Creatinine Ratio with Outcome of Children with Sepsis. Indian J Crit Care Med 2020;24(6):465–472.

Microalbuminuria: An inexpensive, non invasive bedside tool to predict outcome in critically ill patients

This study was conducted to evaluate whether microalbuminuria on admission and after 24 hrs of admission to intensive care unit (ICU) predicts outcome as well as the Acute Physiology and Chronic Health Evaluation (APACHE) II severity illness score, the current accepted method of doing so. The study was carried out in a 20 bed mixed medical-surgical ICU of a tertiary care hospital. Of 525 consecutive adult patients with ICU stay of more than 24 hrs, 238 were included for the study. Patients with pregnancy, menstruation, anuria, macroscopic hematuria, urinary tract infection, marked proteinuria due to renal and post-renal structural diseases, were excluded. Spot urine samples were collected on admission to ICU and 24 hrs thereafter. Urine albumincreatinine ratio (ACR) was measured on ICU admission (ACR1) and after 24 hrs (ACR2) and expressed in mg/g. Patient demographics were noted on admission. For disease severity scoring, APACHE II scores were calculated. Each patient was followed up throughout their ICU stay for a maximum of 28 days and the following outcome data were obtained: ICU length of stay and ICU mortality. Of the 238 patients, 196 survived while 42 patients died in the ICU. Non-survivors had a significantly higher median ACR2 [162.7 mg/g (IQR 69.5-344.3)] in comparison to the survivors who had a median ACR2 = 54.4 mg/g (IQR 19.0-129.1) (P< 0.0001). The median ACR1 [161.0 mg/g (IQR 29.0-369.3)] of non-survivors was higher than the median ACR1 [80.4 mg/g (IQR 35.1-167.6)] of survivors but failed to reach statistical significance (P= 0.0948). In a receiver operating characteristic curve (ROC) analysis, ACR2 emerged as the best indicator of mortality [(area under curve (AUC) of ACR2 = 0.71 > AUC (ACR1) =0.58 > AUC (ΔACR) =0.55] similar to the currently used APACHE II scores (AUC = 0.78) (P=0.3). At a cutoff of 101 mg/g, ACR2 had a sensitivity of 69%, specificity of 67%, positive predictive value of 31% and a negative predictive value of 91% for predicting mortality in the critically ill patients. Absence of significant microalbuminuria at 24 hrs of ICU admission may help to predict survival in the ICU.

Albuminuria, intermittent hyperfiltration and salt wasting in patients with stroke: a pilot study

OBJECTIVE

To investigate whether different types of stroke influence renal excretion of albumin, major electrolytes and water.

MATERIAL AND METHODS

Timed urine collections were started shortly after admission in 5 patients with haemorrhagic stroke (group A), 5 with ischaemic stroke (group Bx), 6 with presumed ischaemic stroke (groups By/z) and 6 with subarachnoid haemorrhage (group C). Albuminuria was also investigated in four patients undergoing elective abdominal surgery.

RESULTS

Increased levels of albuminuria were observed in all patients in groups A and B, but were found to decline with observation time and appeared to be related to outcome in group B. In group C, albuminuria was detected in 4 out of 6 patients. Elective surgery did not affect albumin excretion. In a setting with high urinary osmolality, high excretion rates for creatinine, urea, sodium, potassium and large diuresis were intermittently observed in groups A, B and C. None of these patients was in steady-state condition.

CONCLUSIONS

Different types of stroke elicit a complex change in renal function which resembles the response to a hypervolaemic and hyperosmolar signal, possibly mediated by a breakdown of renal autoregulation of blood flow in the presence of high vasopressin activity. Acute changes in excretion of albumin might be an indicator of prognosis in stroke. The findings point to the existence of unrecognized pathways between the central nervous system and the kidneys. Further studies on the mechanisms underlying alterations in renal function in stroke and their implication for treatment and outcome are indicated.

Prognostic value of postoperative proteinuria in cardiac surgery: a pilot study

BACKGROUND

Proteinuria is a non-specific marker of inflammation that may reflect the glomerular component of systemic capillary leak. The objective of this pilot study was to determine if postoperative proteinuria is associated with adverse outcomes following cardiac surgery with cardiopulmonary bypass.

METHODS

Eligible patients were individuals undergoing cardiac surgery with cardiopulmonary bypass who did not have severe pre-existing renal dysfunction. Urine was collected after induction of anesthesia (baseline) and two to four hours after arrival to the intensive care unit (ICU). Proteinuria was measured as random protein creatinine ratio in g.mol(-1). Adverse events were defined a priori as prolonged ICU stay (> or = 90th percentile) and organ dysfunction. The relationship between proteinuria and adverse events was assessed by bivariate (Chi-square or Fisher's exact tests) and multivariable (multiple logistic regression) analyses.

RESULTS

The study included 197 (of 243 eligible) patients. Postoperative proteinuria (protein creatinine ratio > or = 30 g.mol(-1)) was associated with prolonged (> or = four days) ICU stay [odds ratio (OR) 7.0; 95% confidence interval (CI) 2.8-17.1] and organ dysfunction (OR 3.9; CI 1.9-8.1). After adjustment for confounders, proteinuria was associated with a 3.2-fold increase in the odds of both prolonged ICU stay (CI 1.1-9.7) and organ dysfunction (CI 1.4-7.0).

CONCLUSIONS

Proteinuria two to four hours after cardiac surgery with cardiopulmonary bypass may be a useful marker for systemic capillary leak and adverse postoperative events. Large prospective studies are needed to confirm these findings.

Microalbuminuria in the intensive care unit: Clinical correlates and association with outcomes in 431 patients*

OBJECTIVE

Comparison of urine albumin within 6 hrs of intensive care unit (ICU) admission with demography, clinical classification, outcome, inotrope/vasopressor requirement, clinical assessment of mortality risk, and Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation (APACHE) II scores.

DESIGN

Urine albumin-creatinine ratio (ACR) was measured on ICU admission (ACR 1) and after 4-6 hrs (ACR 2).

SETTING

A 17-bed general ICU in a university teaching hospital.

PATIENTS

Unselected medical (206) and surgical (225) patients recruited prospectively.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Bedside urine ACR was measured by nurses using a Bayer DCA 2000 analyzer and expressed in mg/mmol (reference range <2.3). ACR 1 in medical and surgical patients was 15.5 (12.4-19.5) and 8.2 (5.9-11.1) mg/mmol, respectively (p = .0002), and ACR 2 was 9.0 (5.8-12.5) and 4.6 (3.6-5.3), respectively (p < .0001). For all patients, median (95% confidence interval) ACR fell from 11.2 (8.7-13.2) to 5.4 (4.7-6.8) mg/mmol 4-6 hrs after ICU admission (p < .0001). ACR 1 for nonsurvivors (n = 90) and survivors (n = 341) was 16.1 (11.2-21.3) and 8.8 (6.9-11.9), respectively (p = .0002) and ACR 2, 12.4 (8.2-18.9) and 4.8 (3.9-5.4), respectively (p < .0001). In both medical and surgical patients who died on the ICU, median ACR failed to decrease significantly following admission. ACR1 and ACR 2 were higher in patients who required inotropic or vasopressor support and correlated with duration of therapy. ACR 1 and 2 were inversely correlated with mean Po2/Fio2 ratio 48 hrs after ICU admission and positively correlated with duration of mechanical ventilation and ACR 1 with ICU stay. ACR 2 predicted mortality and ACR 1 inotrope requirement independent of clinical mortality risk assessment and APACHE II and SOFA scores.

CONCLUSIONS

Urine albumin changes rapidly within the first 6 hrs following ICU admission and predicts ICU mortality and inotrope requirement as well as or better than APACHE II and SOFA scores. Serial urine albumin measurement may provide a means of monitoring the microvascular effects of systemic inflammation.

Does microalbuminuria predict illness severity in critically ill patients on the intensive care unit? A systematic review

CONTEXT

Studies assessing the accuracy of microalbuminuria to predict illness severity on the intensive care unit have produced inconsistent results.

OBJECTIVE

To determine the diagnostic accuracy of microalbuminuria to predict illness severity in critically ill patients on the intensive care unit.

DATA SOURCE

MEDLINE (1951 to September 2004) and EMBASE (1980 to September 2004) electronic databases were searched for relevant studies. Reference lists of all abstracts were manually searched to identify studies not included in the electronic database.

STUDY SELECTION

Studies that prospectively evaluated the accuracy of microalbuminuria to predict illness severity and/or mortality probability in adult patients on the intensive care unit were selected.

DATA EXTRACTION

We included nine studies in the review. Data to evaluate methodological quality and results were abstracted.

DATA SYNTHESIS

The methodological quality of a number of studies was poor. Significant heterogeneity in the design and conduct of the studies circumvented the data being subjected to meta-analysis. Studies also differed in the timing of the index test, in the methods of quantifying microalbuminuria, and in the cutoff values used.

CONCLUSIONS

This descriptive analysis reveals that microalbuminuria may hold promise as a predictor of illness severity and mortality on the intensive care unit. However, future epidemiologic studies need to be conducted to determine the optimal timing as well as the threshold reference value for the urine albumin creatinine ratio in the adult intensive care unit population. Thereafter, multiple-center prospective epidemiologic studies must be conducted to confirm and validate the findings of these preliminary studies. Future studies should conform to the Standards for Reporting of Diagnostic Accuracy checklist in terms of study design, conduct, and reporting. Presently there is no evidence to warrant the use of this tool on the intensive care unit.

The Effect of Acute Normovolaemic Haemodilution on the Inflammatory Response and Clinical Outcome in Abdominal Aortic Aneurysm Repair—Results of a Pilot Trial

OBJECTIVES

To determine the effect of acute normovolaemic haemodilution (ANH) on the inflammatory response and clinical outcome in elective open abdominal aortic aneurysm (AAA) repair.

DESIGN

Randomised controlled clinical trial.

METHODS

Thirty-six patients were randomised to undergo ANH or act as controls. Cell salvage was permitted in both groups. Heterologous blood was transfused according to pre-determined triggers. Outcome measures were markers of the systemic inflammatory response in serum and urine observed at multiple time points, and clinical recovery.

RESULTS

Median 890 (range 670-1620) ml of blood was removed at ANH in 16 patients. There were no differences in peri-operative changes in neutrophil count ( P = 0.13), serum C-reactive protein ( P = 0.38), interleukin-6 ( P = 0.50), total antioxidant capacity ( P = 0.73), urinary secretion of albumin ( P = 0.97) or retinol binding protein ( P = 0.41). There were no differences in the mortality and morbidity rates, systemic inflammatory response syndrome, ITU or hospital stay.

CONCLUSIONS

ANH, when used in combination with cell salvage, made no impact on systemic inflammatory response and clinical outcome when compared to cell salvage alone after AAA repair. ANH cannot be recommended for routine use in patients undergoing abdominal aortic aneurysm surgery when cell salvage is available.

Microalbuminuria testing in diabetes: is a dipstick as effective as laboratory tests?

The National Service Framework (NSF) for Diabetes (Department of Health, 2002) aims to improve care for people with diabetes. Primary care trusts need to demonstrate the provision of cost-effective and evidence based care. The National Institute for Clinical Excellence guidelines (NICE, 2002) recommend that microalbuminuria is tested annually in people with diabetes, either by a dipstick method or by a laboratory method. A mini systematic review was undertaken to establish whether a dipstick method of detecting microalbuminuria is as effective as a laboratory method. Four databases were searched and studies comparing dipstick and laboratory methods were included. A hand search was also included. The review was further limited to the Micral test II compared to a reference laboratory standard. Four studies met the inclusion criteria and it was concluded that the Micral test II has a high sensitivity but not very high specificity with lower positive predictive value; it was therefore found to be adequate as a screening tool but not as a diagnostic tool. Therefore the Micral II test is not as effective as a laboratory comparator.

Mortality prediction at admission to intensive care: a comparison of microalbuminuria with acute physiology scores after 24 hours

OBJECTIVE

To compare low level albumin excretion (microalbuminuria), a marker of systemic capillary permeability, with mortality, Acute Physiologic And Chronic Health Evaluation (APACHE II) score, the Simplified Acute Physiologic (SAP II) score, and their derived mortality probabilities in patients admitted to a general intensive care unit.

DESIGN

Prospective observational study.

SETTING

A 14-bed intensive care unit in a university teaching hospital.

PATIENTS

A total of 140 consecutive patients (59 surgical, 48 medical, 22 trauma, and 11 burns).

INTERVENTIONS

Urine collection within 15 mins of intensive care unit admission for assessment of microalbuminuria.

MEASUREMENTS AND MAIN RESULTS

Microalbuminuria, expressed as the albumin-creatinine ratio (ACR: normal, <2.3 mg/mmol), was compared with mortality, APACHE II and SAP II scores and their derived mortality probabilities after 24 hrs, intensive care unit stay, and markers of organ function and inflammation. Median (95% confidence interval) ACR at admission for survivors (n = 115) and nonsurvivors (n = 25) were 4.2 (3.6-6.5) and 17.8 (8.0-40.8) mg/mmol, respectively (p =.0002 Mann Whitney). For 92 surgical, trauma, and burn patients, of whom 81 survived, ACR of >5.9 mg/mmol gave a sensitivity for death of 100%, specificity of 59%, positive predictive value of 25%, and negative predictive value of 100%. Mortality probability receiver operator characteristic curve areas for ACR, APACHE II, and SAP II were 0.843 (p <.0001), 0.793 (p =.0004), and 0.770 (p =.0017), respectively. ACR was associated with intensive care unit stay (p =.0021) and highest serum C-reactive protein (p =.0002), serum creatinine (p <.0001), and bilirubin (p =.0009). For 48 medical patients, of whom 34 survived, admission ACRs for survivors and nonsurvivors were 8.3 (5.7-10.8) and 10.7 (4.1-48.2) mg/mmol, respectively (p =.32). SAP II, but not APACHE II, score was significantly higher for nonsurvivors.

CONCLUSIONS

For surgical, trauma, and burn patients, but not medical patients, microalbuminuria within 15 mins of intensive care unit admission predicted death as well as APACHE II and SAP II scores calculated after 24 hrs, and it shows promise as a predictor of outcome.

Does microalbuminuria predict diabetic nephropathy?

OBJECTIVE

To describe risk factors associated with microalbuminuria (MA) in subjects with diabetes, investigate the predictive value of MA as a marker of risk for diabetic nephropathy (DN), and define risk factors associated with the development and progression of MA.

RESEARCH DESIGN AND METHODS

We conducted a prospective longitudinal study of 23 diabetic subjects with persistent MA and 209 diabetic subjects without MA who attended diabetes clinics at the University of Michigan Medical Center in 1989 and 1990. Both groups were examined at baseline and after 7 years. At baseline, urinary albumin-to-creatinine ratios were studied in random, first morning, and 24-h urine samples. At follow-up, a 12-h overnight urine sample was collected and analyzed for albumin and creatinine. At baseline, MA was defined by at least two separate urine specimens with albumin-to-creatinine ratios between 30 and 299 microg albumin per milligram of creatinine.

RESULTS

MA regressed in 56% of subjects with baseline MA without systematic application of corrective measures and developed in 16% of subjects without baseline MA. The predictive value positive of MA as a marker of risk for DN was 43%, and the predictive value negative was 77%. In the combined cohort, the incidence and progression of MA were significantly associated with poor glycemic control and duration of diabetes between 10 and 14 years.

CONCLUSIONS

MA may not be as sensitive and specific a predictor of DN as previously suggested. Other markers of risk for DN are needed for optimal clinical management.

Review of feline pancreatitis part two: clinical signs, diagnosis and treatment

In the past decade pancreatitis has become recognised as a significant disease in the cat. Chronic, mild pancreatitis is often associated with more commonly diagnosed diseases such as inflammatory bowel disease or cholangitis/cholangiohepatitis. Furthermore, acute pancreatitis with similar complications to those seen in dogs is now diagnosed more frequently in cats. Unfortunately, the clinical signs and clinicopathological findings in cats with pancreatitis are often non-specific and vague. The lack of specific signs often results in a diagnosis being made only when the veterinary surgeon has a strong index of suspicion for pancreatitis and vigorously pursues that diagnosis. Pancreatitis is an important disease in cats, has been implicated as a potential cause of diabetes mellitus, and when present complicates the treatment of diabetes and other intra-abdominal diseases in cats.

Relationship between plasma sialic acid concentration and microvascular and macrovascular complications in type 1 diabetes: the EURODIAB Complications Study

OBJECTIVE

To test the hypothesis that an increased plasma concentration of sialic acid, a marker of the acute-phase response, is related to the presence of diabetic micro- and macrovascular complications in type 1 diabetes.

RESEARCH DESIGN AND METHODS

We investigated the relationship between plasma sialic acid concentration and nephropathy, retinopathy, neuropathy, and coronary heart disease (CHD) in a cross-sectional survey of 1,369 people with type 1 diabetes. Subjects were participants in the EURODIAB IDDM Complications Study, which involved 31 centers in 16 European countries.

RESULTS

There was a significantly increasing trend of plasma sialic acid with severity of retinopathy (P < 0.001 in men) and with degree of urinary albumin excretion (P < 0.001 men, P < 0.01 women). Plasma sialic acid correlated with increasing plasma creatinine concentration (P < 0.009 men, P < 0.0002 women), and men with neuropathy had a higher plasma sialic acid concentration than those without (P < 0.006). There was no significant correlation between plasma sialic acid and CHD in either sex. Elevated plasma sialic acid concentrations were also associated with several risk factors for diabetic vascular disease: diabetes duration, HbA1c, plasma triglyceride and cholesterol concentrations, waist-to-hip ratio, hypertension and smoking (in men), and low physical exercise (in women). In multiple logistic regression analysis, plasma sialic acid was independently related to proliferative retinopathy and urinary albumin excretion rate in men.

CONCLUSIONS

We conclude that an elevated plasma sialic concentration is strongly related to the presence of microvascular complications in type 1 diabetes, especially retinopathy and nephropathy. Further study of acute-phase response markers and mediators as indicators or predictors of diabetic microvascular complications is therefore justified.