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PubMed1997

The predictive value of cerebrospinal fluid tap-test in normal pressure hydrocephalus.

Eighteen patients (mean age of 66.5 years) with normal pressure hydrocephalus (NPH) underwent a ventriculo-peritoneal shunt surgery. Prior to operation a cerebrospinal fluid tap-test (CSF-TT) was performed with measurements of gait pattern and psychometric functions (memory, visuo-motor speed and visuo-constructive skills) before and after the removal of 50 ml CSF by lumbar puncture (LP). Fifteen patients improved and 3 were unchanged after surgery. Short duration of disease, gait disturbance preceding mental deterioration, wide temporal horns and small sulci on CT-scan were associated with good outcome after shunting. There was a good correlation between the results of CSF-TT and shunt surgery (chi 2 = 4.11, phi = 0.48, p < 0.05), with gait test showing highest correlation (r = 0.99, p = 0.01). In conclusion, this version of CSF-TT proved to be an effective test to predict improvement after shunting in patients with NPH.

Adult↗
PubMed1993

Prediction of behavior-management problems in 3-year-old children.

The aim was to determine power of nondental background factors to predict behavior-management problems at the first dental visits of 3-yr-old children. A total of 273 children from three kinds of residential area--city, town, and rural area--in Sweden took part. The parents were interviewed before the child's dental visit. The behavior of the child was rated by registering the degree of acceptance according to the method of HOLST & CROSSNER. The following steps were rated: entering the dental treatment room, mirror in mouth, probe on fingernail and tooth, air-blower on hand and in mouth, sitting in the dental chair, and examination. The behavior was then analyzed in relation to the answers of the interviews, and a logistic regression model was used to calculate the power of the variables, separately or combined, to predict behavior-management problems. Seventy-six percent of the children cooperated well at the dental examination; 13% reacted reluctantly, and 11% reacted negatively. Two interview variables had statistically significant predictive power: the parent's expectation of a negative reaction from the child in the dental situation and the child's anxiety when meeting unfamiliar people. Sixty-nine percent of child patients accepted the examination while sitting alone in the chair. Sitting alone used as a predictor for cooperation showed sensitivity 0.80, specificity 0.71, predictive value for positive test 0.44, and predictive value for negative test 0.94.

Child Behavior↗
PubMed2004

Sensitivity, specificity, positive predictive value, and negative predictive value of the dipyridamole sestamibi stress test in predicting graft occlusion or > or = 50% new native coronary artery disease in men versus women and in patients aged > or = 65 years versus < 65 years who had prior coronary artery bypass grafting.

The sensitivity, specificity, positive predictive value, and negative predictive value of the dipyridamole sestamibi stress test (DSST) in predicting graft obstruction or > or = 50% new native coronary artery disease (CAD) in 88 men compared with 56 women with prior coronary artery bypass surgery were 96% and 94% (p = NS), 30% and 67% (p = NS), 91% and 96 % (p = NS), 50% and 57% (p = NS), respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of the DSST in predicting graft obstruction or > or = 50% new native CAD in 92 patients aged < 65 years were 95% and 95% (p = NS), 50% and 40% (p = NS), 96% and 87% (p = NS), and 43% and 67% (p = NS), respectively.

Adult↗
PubMed1998

[Mathematical model for the predictive value of a test in critically ill patients studies according to APACHE II score and pathology at admission].

OBJECTIVE: To find a predictive model for mortality at four different days from the admission for critically ill patients. DESIGN: Retrospective study on two consecutive series of critically ill patients admitted in ICU. SUBJECTS: 1254 critically ill patients, subdivided into two series of 813 (561 survivors and 252 non survivors) and 441 patients (291 survivors and 150 non survivors), respectively. INTERVENTIONS: None. MEASUREMENTS: All patients had APACHE II calculated within the first 24 hours from the admission in ICU and, if the patient was still in ICU, also at the 5th, 10th and 15th day from the admission. Casistics was subdivided into two unequal series, ratio 2:1, with a random selection made on each of the 6 considered years. On the 1st series, in 1st, 5th, 10th and 15th day, for mathematical predictive models were made, using stepwise logistic regression (BMDP, Los Angeles). In the 1st day the following independent variables were utilized: APACHE II score, the specific diagnosis at admission, fitted following Knaus' diagnostic criteria, united in 6 principal categories, while for the other 3 days the variation % of APACE II score as regards the previous day. RESULTS: For each of the considered day four mathematical models have been made. These models have been validated in both series in calibration from the Hosmer-Lemeshow Goodness-of-fit test and in discrimination from the ROC curves. For each day Y (Prob.% to die) = eLogit/1 + eLogit, where Logit = beta 0 (constant) + beta 1*APACHE II + beta 2*Variat.%APACE II (difference between actual APACHE II - APACHE II of the previous day/actual APACHE II) + beta k, (coefficient pertinent to pathology). CONCLUSIONS: The mathematical model, as other models do, stratifies enough the casistics according to the risk of death. Waiting for further studies to make more precise prognostic mathematical models, this one and others can help the clinical assessment in single patient evaluation.

APACHE↗
PubMed1987

The predictive value of positive test results in screening for breast cancer by mammography in the Nijmegen programme.

After 10 years of screening for breast cancer by mammography in Nijmegen, the predictive value of positive screening results (PV+) was evaluated. The percentage of women with breast cancer in the group of referred women (PV+) for women under age 50 was 16-26%, regardless of the number of screening examinations they had. The percentage of women with breast cancer in the group of women who were biopsied was 25-40%, regardless of the number of examinations. For women aged 50 and over the predictive value was 34-57% and 58-90% respectively. It was further evaluated whether characteristics such as age, Quetelet index, parity, and Wolfe-classification could be used to increase the PV+ in women who were identified as positive by mammography. A logistic regression model analysis showed that true-positive and false-positive cases differ significantly only in terms of age and breast complaints. Although the model had a good fit, it could not be used to distinguish false-positive from true-positive test results.

Age Factors↗
PubMed1996

Antiphospholipid-protein antibodies: clinical use of laboratory test results (identification, predictive value, treatment).

Antiphospholipid-protein antibodies (APA) are a family of immunoglobulins which recognize protein-phospholipid complexes. Among the proteins implicated are: beta 2 Glycoprotein I, prothrombin, Annexin V, protein C, and protein S. Laboratory tests are used to identify, predict potential clinical complications, and manage patients with the antiphospholipid-protein syndrome (APS). Emerging evidence suggests laboratory tests can be used to stratify relative risk of patients with APA.

Antibodies, Antiphospholipid↗
PubMed2005

Predictive value of angiographic testing for tolerance to therapeutic occlusion of the carotid artery.

BACKGROUND AND PURPOSE: Controversy exists on how to assess a patient's tolerance before permanent carotid artery occlusion. We sought to determine the positive predictive value of synchronous opacification of hemispheric cortical veins at angiography of the contralateral carotid or vertebral artery as a predictor of tolerance to permanent carotid artery occlusion without development of ischemic injury. METHODS: Seventy-six angiographic test occlusions were performed in 74 consecutive patients considered for therapeutic occlusion. Angiography of collateral cerebral vessels was performed during test occlusion. Synchronous filling (a < 0.5-second delay of opacification between the cortical veins of the occluded and collateral vascular territories) was considered a predictor for tolerance to permanent occlusion. To detect clinically silent ischemic defects, MR imaging was performed before and 6-12 weeks after permanent occlusion. Positive predictive value (95% confidence interval [CI]) of synchronous venous filling for absence of ischemic deficits after permanent occlusion was calculated. RESULTS: No procedural complications of the test occlusion occurred. In 51 of 54 patients who passed the test, permanent occlusion was performed. Two patients, both in poor clinical condition after subarachnoid hemorrhage, died of diffuse vasospasm after permanent occlusion. Of the 49 surviving patients, one developed a transient discrete hemiparesis with small new hypoperfusion infarctions on MR images. All other patients remained neurologically unchanged with no new ischemic lesions on follow-up MR images. Positive predictive value of tolerance to carotid artery occlusion after passing the angiographic test was 98% (95% CI: 89-100%). CONCLUSION: The angiographic test occlusion protocol reliably predicts tolerance to therapeutic carotid artery occlusion. It is safe and easy to perform.

Adolescent↗
PubMed2001

Matching strategies for drug studies of prepulse inhibition in humans.

Prepulse inhibition (PPI), a measure of sensorimotor gating, is impaired in certain neuropsychiatric disorders. Animal studies have revealed drug effects on PPI that may be relevant to understanding the biology of gating deficits in human populations. Recent efforts have examined similarities and differences in drug effects on PPI between rodents and humans. Experimental designs are needed that most effectively translate these drug studies across species. In the course of a larger set of studies of drug effects on startle in normal human subjects, we examined the potential utility of one design element that is utilized in rodent PPI drug studies: pre-testing to diminish variability across dose groups. Startle was measured during a screening session; 7-10 days later, 20 subjects were retested after consuming a placebo pill. Acoustic and tactile startle, and unimodal and cross-modal PPI, were measured in five sessions over a period of 3 hours post-placebo. There were significant and robust correlations between levels of startle magnitude and PPI during pre-testing and testing, for both left and right eyeblink measures. Comparable correlations were evident for both unimodal and cross-modal testing. Pre-testing values were most predictive of test performance early in the 3-hour test session, and predictive strength diminished or disappeared towards the end of testing. The utility of a pre-testing design could be seen clearly by comparing groups 'matched', based on pre-test data, versus groups created by alternating or random group assignments. It is concluded that pre-test designs can effectively match groups with comparable levels of startle or PPI, and thereby diminish between-group variability in human PPI drug studies. For studies using repeated testing to assess drug time course, the predictive value of pre-testing is greatest in early test sessions.

Acoustic Stimulation↗
PubMed2006

Airway eosinophilia in children with severe asthma: predictive values of noninvasive tests.

RATIONALE: Children with severe asthma experience persistent symptoms despite maximal conventional treatment. Fraction of exhaled nitric oxide (Fe(NO)) and sputum eosinophils are used as markers of airway inflammation to guide treatment with steroids, but no data are available on how reliable they are in predicting airway eosinophilia assessed bronchoscopically in these children. OBJECTIVES: To determine how Fe(NO) and sputum eosinophils predict airway eosinophilia measured in both bronchoalveolar lavage (BAL) and endobronchial biopsy. METHODS: Twenty-seven children with moderate to severe persistent asthma attempted measurement of Fe(NO) and sputum eosinophils, followed by bronchoscopy, BAL, and endobronchial biopsy within 24 h. MAIN RESULTS: Significant correlations were found between eosinophils in sputum and both BAL eosinophils (n = 20, r = 0.45, p = 0.045) and Fe(NO) (n = 23, r = 0.42, p = 0.049). The relationship between Fe(NO) and BAL eosinophils was also significant with a stronger correlation (n = 24, r = 0.54, p = 0.006). The positive predictive value (PPV) for increased sputum eosinophil percentage (> 2.5%) to detect elevated eosinophils in BAL (> 1.19%) was 75%; the negative predictive value (NPV) was 63%. All patients with both increased sputum eosinophils and an elevated Fe(NO) value (> 23 ppb) had elevated eosinophils in BAL (PPV, 100%); the NPV of these two markers was 65%. Eight of nine patients without any sputum eosinophils had normal subepithelial eosinophil numbers (< 1.2%; NPV, 89%). However, the PPV of any sputum eosinophils for increased subepithelial eosinophilia was only 36.4%. CONCLUSIONS: There was moderate agreement between both Fe(NO) and sputum eosinophils and BAL eosinophils. There was good NPV, but only poor PPV for these markers for mucosal eosinophilia.

Adolescent↗
PubMed1999

[Gestosis: predictive value of clinoorthostatic test with ECG].

AIM: To examine value of the clinoorthostatic test (COT) with ECG conducted in pregnancy trimesters I, II and III for prediction of gestosis. MATERIALS AND METHODS: The trial included 66 healthy gravidae aged 18-26 years (mean age 19.1 +/- 2.84 years) and 135 gravidae with extragenital pathology aged 17-43 years (mean age 25.1 +/- 0.78 years) on pregnancy trimester I, II and III. Within the observation period the gravidae underwent 3-4 COT with ECG. Arterial pressure and ECG were registered in dorsal and erect positions on minute 1, 3 and 10 on pregnancy week 9-12, 16-18, 26-28. RESULTS: Most of the gravidae who subsequently developed gestosis on trimester I exhibited cardiovascular maladaptation recordable at COT with ECG. Comparison of COT results with pregnancy outcomes gave grounds for establishment of 12 prognostic tests predicting gestosis with probability 75-100% in the tests sensitivity at least 80%, specificity 89%. CONCLUSION: COT with ECG is a simple, available and informative method of predicting gestosis and can be used by obstetricians for detection of gestosis risk groups among the gravidae.

Adolescent↗
PubMed2001

Diagnosing thoracic outlet syndrome: contribution of provocative tests, ultrasonography, electrophysiology, and helical computed tomography in 48 patients.

OBJECTIVE: To evaluate the diagnostic usefulness of provocative tests, Doppler ultrasonography, electrophysiological investigations, and helical computed tomography (CT) angiography in thoracic outlet syndrome (TOS). PATIENTS AND METHODS: We prospectively evaluated 48 patients with a clinical suspicion of thoracic outlet syndrome. Standardized provocative tests, an electromyogram and somatosensory evoked responses, a Doppler ultrasonogram, and a helical CT arterial and/or venous angiogram with dynamic maneuvers were done on each patient. The final diagnosis was established by excluding all other causes based on all available data. The agreement between the results of each investigation and the final diagnosis was evaluated. RESULTS: Provocative tests had mean sensitivity and specificity values of 72% and 53%, respectively, with better values for the Adson test (positive predictive value [PPV], 85%), the hyperabduction test (PPV, 92%), and the Wright test. Using several tests in combination improved specificity. Doppler ultrasonography visualized vascular parietal abnormalities and confirmed the diagnosis in patients with at least five positive provocative tests. Electrophysiological studies were useful mainly for the differential diagnosis or for detecting concomitant abnormalities. Although helical CT angiography provided accurate information on the location and mechanism of vascular compression, the usefulness of this investigation for establishing the diagnosis of TOS and for obtaining pretherapeutic information remains unclear.

Adult↗
PubMed2003

Neuropsychologists' abilities to determine the predictive value of diagnostic tests.

The diagnostic utility of a test is relative to the base rate of the diagnosis in the population of interest. The extensive use of tests in neuropsychological assessment makes knowledge of the relevance of base rates in this context an important issue. Professional and associate members of the National Academy of Neuropsychology (NAN; n=279) answered questions involving (1) a simple use of base rates in the absence of additional diagnostic information, (2) sensitivity and specificity, and (3) positive predictive value (PPV) presented in either a probability or frequency format. Although the majority of participants answered correctly the simple base rate, sensitivity, and specificity questions, only 8.6% answered correctly the PPV question presented in a probability format versus 63.0% correct using a frequency format. These results are discussed in terms of education about the importance and application of base rate information and difficulties applying base rate information in practice.

Clinical Competence↗
PubMed1991

Predictive value of a negative exercise electrocardiogram.

Conventionally, if an exercise electrocardiogram does not show evidence of ischemia, the patient must have achieved at least 85% of the predicted maximum heart rate for that test to be considered negative. However, no documentation of the validity of this practice exists. Thus, we evaluated the exercise electrocardiograms of 164 patients who had also undergone coronary angiography within 6 months of the exercise test. The predictive value of a negative exercise electrocardiogram was determined for each percentage point between 50 and 90% of the age-predicted maximum heart rate achieved or exceeded. The predictive value was found to increase modestly between 65 and 80% of the predicted maximum heart rate with no major changes above or below this range. Thus, it appears reasonable (in the setting of a hospital-based exercise laboratory) to either consider a negative exercise electrocardiogram as a valid finding if at least 80% of the predicted maximum heart rate is achieved, or preferably to simply report the negative finding with the percent maximum heart rate attained and the proviso that the predictive value of the test is progressively improved as higher heart rates are attained.

Adult↗
PubMed2006

A single serum test for measuring early pregnancy outcome with high predictive value.

OBJECTIVES: Current testing to determine a failing pregnancy requires two separate clinic visits to measure the hCG doubling rate. Diagnosing a failing pregnancy is often done in emergency departments where simplified and accelerated testing methods are needed. Here, we investigated hyperglycosylated hCG (hCG-H) for predicting pregnancy failure. DESIGN AND METHODS: We studied two independent sets of patient samples collected in the early weeks of gestation. One set was urine samples, and the other was serum samples. In all cases, hCG and hCG-H were measured using automated chemiluminescence immunoassays. Concentrations of hCG and hCG-H were plotted on a scattergram, and levels in failing pregnancies were compared to those in continuing pregnancies. RESULTS: Data indicated that a threshold level of hCG-H (13 microg/L) in both serum and urine samples defined the concentration below where pregnancies were likely to fail. This cut-off corresponded to 73% detection of failures at a 2.9% false positive rate using serum and 75% detection at a 15% false positive rate using urine. Using an hCG cut-off that corresponded to the same false positive rates, hCG detected only 42% of failures using serum and 43% of failures using urine. CONCLUSIONS: Our data indicate that hCG-H provides a much more accurate single test than hCG for assessing pregnancy outcome. Compatible with the use of serum or urine samples, a single hCG-H test might provide simpler, faster, and more accurate results for predicting the progress of a pregnancy than standard hCG testing.

Abortion, Spontaneous↗
PubMed1992

The logistic modeling of sensitivity, specificity, and predictive value of a diagnostic test.

A method is described for modeling the sensitivity, specificity, and positive and negative predictive values of a diagnostic test. To model sensitivity and specificity, the dependent variable (Y) is defined to be the dichotomous results of the screening test, and the presence or absence of disease, as defined by the "gold standard", is included as a binary explanatory variable (X1), along with variables used to define the subgroups of interest. The sensitivity of the screening test may then be estimated using logistic regression procedures. Modeled estimates of the specificity and predictive values of the screening test may be similarly derived. Using data from a population-based study of peripheral arterial disease, the authors demonstrated empirically that this method may be useful for obtaining smoothed estimates of sensitivity, specificity, and predictive values. As an extension of this method, an approach to the modeling of the relative sensitivity of two screening tests is described, using data from a study of screening procedures for colorectal disease as an example.

Arterial Occlusive Diseases↗
PubMedDate not supplied

Predictive value of serologic tests for syphilis in otology.

Otologic syphilis (luetic inner ear disease) usually is diagnosed by positive serologic tests and by exclusion of other possible causes. Because the FTA-ABS for syphilis is exquisitely sensitive in all but early primary cases, a positive FTA-ABS result and coincident inner ear disease often are thought to be diagnostic of syphilitic inner ear disease. The result is a management dilemma: are there false-positive results in misdiagnosed cases? Over 4 years, the authors performed a prospective study with time-matched controls to determine the predictive value of serologic tests and prevalence of syphilis in otology. Thirty-one cases of otologic syphilis were diagnosed in 5,439 new (different) patients with otologic complaints. In the geographic area studied, this prevalence (570/100,000) was 25-fold greater than that of all reported cases of syphilis in the general population (22.7/100,000). The defined sensitivity of the FTA-ABS (100%) was nearly twofold greater than the measured sensitivity of the rapid plasma reagin (RPR, 55%) in otologic syphilis. Specificities were comparable; therefore, a positive FTA-ABS had higher predictive value than a positive RPR. The prevalence-related predictive value of a positive FTA-ABS (22%) was more than twice that of the RPR (9%) in otology. The predictive value of a positive FTA-ABS in otology was 11-fold greater than that of the FTA-ABS in the general population (2%). Therefore, in suspect cases the FTA-ABS should be used to screen for otologic syphilis in an otologic practice. At a prevalence of 570 cases in 100,000 patients, only 22% of otologic patients with positive FTA-ABS results actually have otologic syphilis. Because disease morbidity can be far worse than treatment morbidity, however, positive results should be considered true-positives to avoid misdiagnosis in potentially infected patients. In suspect cases with positive FTA-ABS, therefore, treatment should be recommended unless specific contraindications exist.

Adolescent↗
PubMed2003

[Predictive value of preoperative tests in facectomy].

OBJECTIVE: To establish the prevalence of abnormal results in routine preoperative tests prior to facectomies and whether they influence the occurrence of perioperative clinical complications. METHODS: This prospective study was developed in an academic medical center in Brazil. Besides a clinical evaluation, all patients were requested to undergo an electrocardiogram, complete blood work and fasting blood glucose test. Patients younger than 40 years of age who had had previous eye surgery, candidates for general anesthesia or who had suffered acute myocardial infarction up to three months before surgery were excluded from the study. Intraoperative medical events were recorded in a protocol form. Analysis was carried out using Fisher's test and ANOVA (analysis of variance). RESULTS: The sample was composed of 746 patients, 405 (54.3%) were men. The average age was 66.6+/-11.6 years. Intraoperative complications occurred in 71 (9.5%) patients. There were abnormal results in 13.5% (101 patients) of hemoglobin dosages and in 16.6% (124) of fasting blood glucose. As for electrocardiograms, abnormalities were found in 46.6% (348) of the subjects. There was a higher prevalence of electrocardiograms with abnormal values in patients who had perioperative clinical complications (p=0.02). There were no statistically significant differences between hemoglobin dosages (14.0+/-1.6 g/dL in patients without intraoperative complications and 14.3+/-1.3 g/dL in patients with complications - p=0.150) and fasting blood glucose (104+/-29 mg/dL in patients without complications and 105+/-41 mg/dL in patients with complications - p=0.850). CONCLUSIONS: Within the investigated routine of preoperative testing for facectomy, only the abnormal electrocardiogram results influenced the occurrence of complications in the perioperative period.

Aged↗