Increased urinary orosomucoid excretion: a proposed marker for inflammation and endothelial dysfunction in patients with type 2 diabetes.

OBJECTIVE: In a previous study, urinary orosomucoid excretion rate (UOER) independently predicted cardiovascular mortality in patients with type 2 diabetes. The aim of the present study was to determine whether increased UOER is associated with cardiovascular risk factors such as inflammation, impaired left ventricular function and endothelial dysfunction in patients with type 2 diabetes. MATERIAL AND METHODS: We performed a cross-sectional study of 41 patients with type 2 diabetes (17 patients with normal UOER and 24 with increased UOER) with no history of cardiovascular disease and 21 healthy controls. Urinary orosomucoid was measured using a particle-enhanced immunoturbidimetric assay. Plasma interleukin-6 (IL-6), tissue plasminogen activator (tPA) and soluble intercellular adhesion molecule-1 (sICAM) were measured using ELISA. Endothelial function measured as vasodilatory capacity of the brachial artery and echocardiography were done in all participants. RESULTS: Patients with diabetes and increased UOER had subclinically increased serum orosomucoid (p<0.001), C-reactive protein (CRP) (p<0.001), IL-6 (p<0.001), tPA (p<0.003) and sICAM (p<0.003) compared with healthy controls. In patients with type 2 diabetes, UOER was independently associated with increasing values of IL-6 (1.43 (1.06-1.93)) and tPA (1.82 (1.20-2.77)). Measurements by echocardiography showed no signs of cardiac dysfunction. CONCLUSIONS: Asymptomatic patients with type 2 diabetes and increased UOER displayed signs of chronic low-grade inflammation and endothelial dysfunction. UOER was independently related to markers of proinflammation and endothelial dysfunction in patients with type 2 diabetes. The previously shown relation between increased UOER and cardiovascular mortality is proposed to be caused by chronic low-grade inflammation and early endothelial dysfunction.

Orosomucoid in urine is a powerful predictor of cardiovascular mortality in normoalbuminuric patients with type 2 diabetes at five years of follow-up.

AIMS/HYPOTHESIS: To study whether urinary orosomucoid excretion rate (UOER) predicts mortality in normoalbuminuric patients with diabetes at 5 years of follow-up, and to investigate the relationship between orosomucoid in serum and urine. METHODS: A cohort of 578 patients with diabetes (430 type 2, 148 type 1) was followed prospectively for an average of 5 years. UOER was measured in timed overnight urine samples. RESULTS: Eighty-two patients with type 2 diabetes and 17 patients with type 1 diabetes died. Among patients with type 2 diabetes, 251 (58%) had normoalbuminuria; increased UOER independently predicted cardiovascular mortality (OR 4.94, 95% CI 1.60-15.22; p<0.006) in those with normoalbuminuria and in the entire cohort of patients with type 2 diabetes (odds ratio 3.63, 95% CI 1.50-8.81; p<0.005). Patients with increased UOER had a higher all-cause mortality than those with normal UOER (log-rank test, p<0.001 for type 2 patients; p<0.04 for type 1 patients). In patients with type 1 diabetes, there were five cardiovascular deaths and no significant predictive value of UOER. Patients with increased UOER had a subclinical increase in serum orosomucoid. CONCLUSION/INTERPRETATION: Increased UOER was an independent, powerful predictor of cardiovascular mortality in normoalbuminuric patients with type 2 diabetes and in the entire cohort of patients with type 2 diabetes. There were indications of UOER as being a valuable marker in type 1 diabetes that showed differences in survival between patients with normal versus increased UOER. Serum orosomucoid was associated with UOER; UOER may be a marker of low-grade inflammation in patients with diabetes.

Orosomucoid in urine predicts cardiovascular and over-all mortality in patients with Type II diabetes.

AIMS/HYPOTHESIS: Urinary orosomucoid excretion rate is increased in a substantial proportion of patients with Type II (non-insulin-dependent) diabetes mellitus and normal urinary albumin excretion rate. The aim of this study was to determine whether increased urinary orosomucoid excretion rate is predictive of increased mortality in patients with Type II diabetes. METHODS: In a cohort study including 430 patients with Type II diabetes, baseline urinary samples were analysed for orosomucoid and albumin. Mean follow-up was 2.4 years. RESULTS: We found that 188 (44 %) patients had normal and 242 (56 %) patients had increased urinary orosomucoid excretion rates. During the study period 41 patients died; out of these 23 patients died of cardiovascular diseases. Odds ratio for all-cause mortality was 2.50 (95 % CI 1.00-6.22) and odds ratio for cardiovascular mortality was 9.81 (1.31-73.6) having increased urinary orosomucoid excretion rate at baseline (odds ratios adjusted for age, sex, duration of diabetes, cardiovascular diseases, weight, medication, HbA1 c, plasma creatinine and urinary albumin excretion rate). Urinary albumin excretion rate was an independent predictor of all-cause mortality when urinary orosomucoid excretion rate was not included in the analysis. Subgroup analysis revealed that 39 % of the patients with normal urinary albumin excretion rate (n = 251) had increased urinary orosomucoid excretion rates and that these patients had a higher cardiovascular mortality (p = 0.007) than patients with normal urinary albumin excretion rate and normal urinary orosomucoid excretion rates. CONCLUSION/INTERPRETATION: We found that urinary orosomucoid excretion rate predicted all-cause and cardiovascular mortality in patients with Type II diabetes independently from other risk factors.

[Evidence-based use of clinical biochemistry]. / Evidensbaseret anvendelse af klinisk biokemi.

Evidence-based use of clinical biochemistry integrates into clinical decision-making the best research evidence with the clinical expertise of the physician and the expectations and concerns of the patient. The best research evidence for the clinical use of a biochemical test should be appraised in close collaboration between clinicians and specialists in clinical biochemistry, as familiarity with both the clinical problem and the analytical performance of the test is necessary. At present, it is difficult to ensure an evidence-based use of biochemical tests. More and methodologically better studies of the clinical value of biochemical tests are needed, and methods should be developed that make it possible to assess the results of such studies by systematic reviews and meta-analyses. Clinical biochemistry is an interdisciplinary specialty, and papers on the clinical value of biochemical tests are published in a vast number of journals of different clinical specialties as well as those of clinical biochemistry. It is thus almost impossible to keep abreast of the subject. The establishment of a system for literature surveillance focusing on methodologically sound studies of the clinical value of biochemical tests would be advantageous. Lastly, training and education on how to find and assess the existing evidence for the clinical use of biochemical tests are needed.

Toward a checklist for reporting of studies of diagnostic accuracy of medical tests.

BACKGROUND: : "Diagnostic accuracy" refers to the ability of medical tests to provide accurate information about diagnosis, prognosis, risk of disease, and other clinical issues. Published reports on diagnostic accuracy of medical tests frequently fail to adhere to minimal clinical epidemiological standards, and such failures lead to overly optimistic assessments of evaluated tests. Our aim was to enumerate key items for inclusion in published reports on diagnostic accuracy, with a related aim of making the reports more useful for systematic reviews. METHODS: : We examined published reports on shortcomings of studies of diagnostic accuracy. We prepared an initial draft of a checklist to address common errors and presented it at a meeting of editors. After incorporation of comments from editors, we published a revised version in Clinical Chemistry in 1997 for comment from readers. One of us (E.M.) additionally circulated copies of the draft to methodologists and others interested in Evidence-Based Medicine. We updated the checklist with input from these sources. RESULTS: : The updated document lists items for inclusion in the title, abstract, methods, results, and discussion sections of published papers. Depending on the nature of the study, the total number of items for a single paper is approximately 40. We invite comments on this document, which is freely available at Clinical Chemistry Online, where it can accessed readily from the Table of Contents for the July 2000 issue at www. clinchem.org/content/vol46/issue7/. Comments (eLetters) can be posted there for general reading. CONCLUSIONS: : The suggested revisions incorporated in this report appear useful to ensure inclusion of additional information that can allow assessment of the validity of the conclusions and the applicability of the study in other settings. The list can be useful in formulating guidelines and a checklist, which will require testing by authors and study of their effect on published studies of diagnostic accuracy.

Albuminuria in ischemic heart disease.

Proteinuria associated with acute heart disease was studied prospectively in 160 patients admitted to the coronary care unit with suspected AMI. Series 1 comprised 150 patients, divided into the following groups: AMI, 27 UAP, 43 AP, 22 NIP and 18 excluded. Albumin and creatinine were measured in the first urine passed after admission (sample 1) and the first morning urine the following 2 days (samples 2 and 3). The ACR was significantly higher in the AMI and UAP groups than in the other patient groups (p < 0.0001). There was no significant difference of ACR between the AMI and UAP in sample 1 (p = 0.31). In the AMI, UAP and AP groups ACR was significantly higher in sample 1 than in samples 2 and 3 (p < 0.005). In the NIP group there were no significant differences between sample 1 versus samples 2 and 3 (p = 0.06). Series 2 comprised 10 patients: 8 AMI, 1 UAP and 1 AMYO. ACR were measured in all specimens voided during the period of observation. ACR can oscillate within hours between normal concentrations and concentrations well into or above the microalbuminuric range. We propose the term episodic albuminuria for this reversible, switch-like change in renal function. The albuminuric episodes lasted 90-600 minutes. Maximum values for ACR were between 133-790 mumol/mol or 78-466 mg/g. In healthy, resting individuals ACR is < 50 mumol/mol (< 30 mg/g). The rapid changes in glomerular permeability may reflect systemic changes in endothelial permeability in the affected individuals. We speculate that atrial natriuretic peptide (ANP) may be a mediator of this type of albuminuria.

Analytical quality, performance indices and laboratory service.

Faulty data lead to suboptimal diagnostics and decision making unless the flaw is known and amenable to correction. However, pure noise (added analytical variance) has only minor effects on clinically appropriate indices of diagnostic performance. This fact is illustrated by an idealized screening programme, using the preventive benefit-to-cost ratio as the index of performance. Further, this article illustrates that the effect of an unnoticed source of noise is roughly just twice the effect that the same noise will have when its magnitude is known and clinical decision limits are adjusted accordingly. Owing to the small size of these effects, however, it may be profitable to spend resources on other aspects of good laboratory service, such as timeliness, documentation and interpretative support.

Improved laboratory test selection and enhanced perception of test results as tools for cost-effective medicine.

Inconsistencies in the way physicians perceive and handle identical laboratory results have untoward effects on morbidity, mortality and cost of medical care. In this context, the selection of suitable tests to answer definite clinical questions, and the manner in which laboratory results are presented have great impact on the action taken by the clinician. This review addresses preferred methods to improve laboratory test selection, and examines methods that more effectively convey laboratory results to clinicians. It is anticipated that refined selection of tests, and presentation of the test results in a configuration that is easily perceived by the clinician, will facilitate interpretation of laboratory reports. Furthermore, any measures that promote the application of laboratory information in medical practice improve economics at the laboratory-clinical interface. The presently described methods to optimize test selection and interpretation are: likelihood ratios to provide estimates of the ability of a test to identify a clinical condition; consensus- and discriminant function-analysis to estimate the performance of tests in diagnosing a particular disease or condition; receiver operating characteristic (ROC) curves to assess discrimination capabilities. The methods which improve test result perception are expression of results as multiples of the upper normal limit, utilizing signal strength to provide prognostic probabilities, and presentation of results in graphic forms that display mutually interrelated functions, with a specific cluster of results being highly suggestive of a given condition. In addition, we discuss application of expert systems to provide rules based on knowledge and experience to analyze results of tests and suggest diagnosis and action, including additional tests when required. It is anticipated that judicious utilization of laboratory services by application of the reviewed methodologies will help to achieve medically justified responses at a lower cost and help to achieve a proper balance between cost of tests and their clinical usefulness.

Renal function after myocardial infarction and cardiac arrest in rats: role of ANP-induced albuminuria?

Renal function was measured by clearance technique before and after acute myocardial infarction (MI) induced by left coronary artery ligation in male Sprague-Dawley rats. The animals were anaesthetized with halothane-nitrous oxide, paralysed with pancuronium and artificially ventilated. All parameters were stable throughout the experiment in sham-operated time control animals (n = 8). After MI, rats developed left ventricular dysfunction with increased left ventricular end-diastolic pressure and decreased mean arterial pressure. MI produced antidiuresis and antinatriuresis without changes in glomerular filtration rate (GFR), lithium clearance or renal albumin excretion (n = 8). The antidiuretic and antinatriuretic responses to MI were similar in rats with chronic bilateral renal denervation (n = 5). Three additional rats with chronic bilateral renal denervation had cardiac arrest and were resuscitated with cardiac massage, i.v. lidocaine and intracardiac adrenaline administration. These animals showed a transient increase in urine flow rate, sodium and albumin excretion with maximum 30-60 min after resuscitation, while GFR and lithium clearance were normal. Since cardiac ischaemia and sympathetic stimulation are strong stimuli for the release of atrial natriuretic peptide (ANP), we examined if ANP (0.25, 0.50, and 1.00 microg kg(-1) min(-1), n = 8 per dose) affects urinary albumin excretion. ANP increased dose-dependently the urine/plasma concentration ratio of albumin relative to inulin, which suggests that ANP increases the glomerular permeability for albumin. We conclude that MI causes stimulation of renal tubular sodium and water reabsorption by a mechanism which is independent of intact renal innervation. MI does not produce any change in renal albumin excretion in rats, but transient albuminuria may be observed in rats following cardiac arrest and/or manoeuvres used in cardiac resuscitation. Since ANP produces albuminuria, we speculate that ANP may be an important mediator of albuminuria in states with elevated plasma concentrations of ANP.

Minimal requirements for test evaluation.

Evaluations of diagnostic (clinical) tests should be conducted so that the material can be critically assessed. The results should be reported in a manner that will allow synthesis with data from other similar investigations. Collective professional efforts to fulfil these minimal requirements comprise the continued development of recommendations on research methods and good reporting practice. This paper presents some examples of suggested requirements for good reporting practice for further consideration and discussion.

Calibration of the Ektachem Amylase method using human reference materials and the Phadebas Blue Starch method as an interim reference method.

In a multilaboratory study a consensus was established to calibrate the Ektachem Amylase method to reproduce the results of the Phadebas Blue Starch method. The calibration graph has a slope = 3.39 and intercept = 25. For the Ektachem Amylase method the reaction-rate ratio between salivary and pancreatic amylase was calculated to be 0.89, relative to that of the Phadebas Blue Starch method. A calibration value for the Nordic Amylase Calibrator to be used on Ektachem analysers was determined to be close to 469 U l-1 for the current batch. However, since the difference from the stated value of 460 U l-1 is negligible, the authors recommend the use of the stated value for this and future batches of the Nordic Amylase Calibrator. An error of around 10% introduced by the presence of salivary amylase is comparable to the methods accepted by the Scandinavian Committee on Enzymes. Introduction of a consensus calibration reduced the interlaboratory variation by up to 40% at all levels.

The MICRAL test for diabetic microalbuminuria: predictive values as a function of prevalence.

The MICRAL test is an immunospecific dipstick for detection of low concentrations of albumin in urine (microalbuminuria). The test is intended to be used for screening in an ambulatory setting. The utility of the test depends on its ability to accurately predict which patients will be classified as either microalbuminuric or normoalbuminuric by means of a standard laboratory method for determination of albumin in urine. We have analysed data from studies with a total of 2904 samples of urine from diabetic patients. The data are from our own study (190 samples) and from a selected set of 10 publications. The results from standard laboratory measurements of albumin in urine were used as " gold standards". The sensitivity and specificity as calculated from the pooled data were 83.2 and 92.3%, respectively. The predictive values were calculated using simulated changes in the prevalence of microalbuminuria (MAU). At a prevalence of MAU of 1% the predictive value of a negative test is 99.9% but that of a positive test only 9.8%. At a prevalence of MAU of 80% the positive predictive value is 97.7% and the negative predictive value 57.9%. In general, any change in the prevalence will lead to a change in the predictive values. Thus the prevalence of MAU in the given clinical setting is a decisive factor in determining the utility of the MICRAL test.

A strategy to promote the rational use of laboratory tests. International Federation of Clinical Chemistry.

These guidelines suggest how clinical chemists may promote rational laboratory use by critically evaluating the tests they offer. This may be done by documenting the clinical uses and limitations of tests in the same way that properly written up method descriptions outline analytical procedures in a particular laboratory. This information can then be promoted on result report forms, in discussion or through investigational protocols or clinical guidelines. For these to be of value they should be the result of clinical and laboratory input reflecting the local practice and facilities. They should be clearly written, easily accessible to the users and updated whenever there is a change of methodology or clinical practice. Much can be achieved by applying common sense to common knowledge and laboratories of all sizes can prepare their own material. However, national scientific societies and other professional organisations can assist local endeavour by avoiding and disseminating educational material on test evaluation, selection and use.

A strategy to promote the rational use of laboratory tests. IFCC Education and Management Division Committee on Rational Laboratory Use. International Federation of Clinical Chemistry.

The following guidelines suggest ways in which clinical chemists can promote rational laboratory use by critically evaluating the tests they offer. This may be done by documenting the clinical uses and limitations of tests in the same way that clearly written method descriptions outline analytical procedures in a particular laboratory. This information can then be disseminated on result report forms, during discussion, or through investigational protocols or clinical guidelines. For the information to be of value, it should be the result of clinical and laboratory input reflecting the local practice and facilities. The material should be clearly written, easily accessible to the users, and updated whenever there is a change in methodology or clinical practice. Much can be achieved by applying common sense to common knowledge, and laboratories of all sizes can prepare their own material. In addition, national scientific societies and other professional organizations can assist local endeavors by providing educational material on test evaluation, selection, and use.

Serum alpha-fetoprotein and alcohol consumption.

Fifty-nine persons, 23 chronic alcoholics and 36 normal healthy persons with a well described alcohol consumption, had the serum concentration of alpha-fetoprotein determined by a sensitive monoclonal immunofluorescent assay. A significant elevation in S-AFP was found in alcoholics, median 4.1 kIU/l as compared to 3.0 kIU/l in near-abstainers (< 12 g ethanol per day) (p < 0.02). This difference was not explained by differences in age. S-AFP correlated positively with age (p = 0.01). In non-alcoholics a borderline significant correlation with S-AFP was found with average daily alcohol consumption (self-reported) (p = 0.09) and a significant correlation with the serum concentration of carbohydrate-deficient transferrin (S-CDT) (p = 0.004). In 11 alcoholics 2 months of abstention from alcohol was accompanied by a median reduction of 21% in S-AFP (p < 10(-5)). In alcoholics, but not in social drinkers, S-AFP correlated with S-ASAT (p = 0.004). The increase of S-AFP with alcohol consumption may reflect reversible alcohol-induced liver affection.

Estimating and minimizing effects of biologic sources of variation by relative range when measuring the mean of serum lipids and lipoproteins.

Biologic intraindividual variation (CVb) is a major source of inaccuracy in current lipid and lipoprotein measurements. Metaanalysis has been used to estimate the average CVb of serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), and triglyceride (TG). These CVb values are larger than the National Cholesterol Education Program-accepted and -proposed analytic (CVa) goals. Measuring serial specimens reduces the error in determination of the mean concentration used in classification of the patient by cutoff points. We show (a) a convenient technique, based on the relative range, to qualitatively estimate and interpret biologic variation of TC, HDLC, LDLC, and TG, and (b) the number of serial specimens required to meet a total variation goal for measurements of mean lipid and lipoprotein values. A total variation goal has been selected that can be met by two serial specimens for a majority of individuals.