Cross-sectional Diagnostic Accuracy Study Research Articles

Detection of Visual Field Loss in Pituitary Disease: Peripheral Kinetic Versus Central Static

Visual field assessment is an important clinical evaluation for eye disease and neurological injury. We evaluated Octopus semi-automated kinetic peripheral perimetry (SKP) and Humphrey static automated central perimetry for detection of neurological visual field loss in patients with pituitary disease. We carried out a prospective cross-sectional diagnostic accuracy study comparing Humphrey central 30-2 SITA threshold programme with a screening protocol for SKP on Octopus perimetry. Humphrey 24-2 data were extracted from 30-2 results. Results were independently graded for presence/absence of field defect plus severity of defect. Fifty patients (100 eyes) were recruited (25 males and 25 females), with mean age of 52.4 years (SD = 15.7). Order of perimeter assessment (Humphrey/Octopus first) and order of eye tested (right/left first) were randomised. The 30-2 programme detected visual field loss in 85%, the 24-2 programme in 80%, and the Octopus combined kinetic/static strategy in 100% of eyes. Peripheral visual field loss was missed by central threshold assessment. Qualitative comparison of type of visual field defect demonstrated a match between Humphrey and Octopus results in 58%, with a match for severity of defect in 50%. Tests duration was 9.34 minutes (SD = 2.02) for Humphrey 30-2 versus 10.79 minutes (SD = 4.06) for Octopus perimetry. Octopus semi-automated kinetic perimetry was found to be superior to central static testing for detection of pituitary disease-related visual field loss. Where reliant on Humphrey central static perimetry, the 30-2 programme is recommended over the 24-2 programme. Where kinetic perimetry is available, this is preferable to central static programmes for increased detection of peripheral visual field loss.

Validation of a portable monitor for the diagnosis of obstructive sleep apnea in morbidly obese patients.

We aimed to validate the diagnostic accuracy and night-to-night variability of a simple 3-channel (type IV monitor) portable sleep monitor, ApneaLink (AL), in a population of morbidly obese subjects. Cross-sectional validation and diagnostic accuracy study. Public tertiary care obesity center in Norway. A total of 105 (67 females) treatment seeking morbidly obese subjects were included, mean (SD) age 44.3 (11.4) years and BMI 43.6 (5.6) kg/m2. The patients underwent two successive nights of recordings; the first night with the AL only, and the following night with both the reference instrument Embletta (E), a type III portable somnograph, and the AL. Main outcomes were diagnostic accuracy of AL as assessed by sensitivity, specificity and area under ROC curves, and level of agreement between AL and E. AL had high diagnostic accuracy at all levels of OSA, and the Bland-Altman plots showed good agreement between AL and E. The sensitivity and specificity of the instrument were 93% and 71% at the AHI cutoff 5 events/h, and 94% and 94% at the AHI cutoff 15, respectively. The night-to-night variability was low. Our results indicate that a simple 3-channel portable sleep monitor (ApneaLink) has a high diagnostic accuracy in diagnosing OSA in morbidly obese treatment seeking patients. Accordingly, this and similar instruments might help non-specialists to diagnose OSA in morbidly obese patients, and, importantly, help non-specialists to refer patients who need specific treatment to specialist without unnecessary delay.

The relationship between history and physical examination findings and the outcome of electrodiagnostic testing in patients with sciatica referred to physical therapy.

Cross-sectional diagnostic accuracy study. To investigate the relationship between history and physical examination findings and the outcome of electrodiagnostic testing in patients with sciatica referred to physical therapy. Electrodiagnostic testing is routinely used to evaluate patients with sciatica. Recent evidence suggests that the presence of radiculopathy identified with electrodiagnostic testing may predict better functional outcomes in these patients. While some patient history and physical examination findings have been shown to predict the presence of disc herniation or neurological insult, little is known about their relationship to the results of electrodiagnostic testing. Electrodiagnostic testing was performed on 38 patients with sciatica who participated in a randomized trial that compared different physical therapy interventions. The diagnostic gold standard was the presence or absence of radiculopathy, based on the results of the needle electromyographic examination. Diagnostic sensitivity and specificity values were calculated, along with corresponding likelihood ratios, for select patient history and physical examination variables. No significant relationship was found between select patient history and physical examination findings, analyzed individually or in combination, and the outcome of electrodiagnostic testing. Diagnostic sensitivity values ranged from 0.03 (95% confidence interval [CI]: 0.00, 0.24) to a high of 0.95 (95% CI: 0.72, 0.99), and specificity values ranged from 0.10 (95% CI: 0.02, 0.34) to a high of 0.95 (95% CI: 0.72, 0.99). Positive likelihood ratios ranged from 0.15 (95% CI: 0.01, 2.87) to a high of 2.33 (95% CI: 0.71, 7.70), and negative likelihood ratios ranged from 2.00 (95% CI: 0.35, 11.48) to a low of 0.50 (95% CI: 0.03, 8.10). In this investigation, the relationship between patient history and physical examination findings and the outcome of electrodiagnostic testing among patients with sciatica was not found to be statistically significant or clinically meaningful. However, given the small sample size and corresponding large CIs, these results should be considered with caution, recognizing that some of the history and physical examination variables may prove useful in future research. These findings suggest that electrodiagnostic testing is essential to identify the subgroup of patients with sciatica who have measurable nerve injury consistent with radiculopathy, which may be an important prognostic factor for recovery. Level of Evidence Diagnosis, level 3b-. J Orthop Sports Phys Ther 2014;44(7):508-517. Epub 22 May 2014. doi:10.2519/jospt.2014.5002.

Are serum HE4 or ROMA scores useful to experienced examiners for improving characterization of adnexal masses after transvaginal ultrasonography?

To determine whether serum human-epididymis protein-4 (HE4) levels or Risk of Ovarian Malignancy Algorithm (ROMA) scores are useful second-stage tests for tumors thought to be difficult to characterize as benign or malignant on the basis of ultrasound findings by experienced examiners, and to investigate whether adding information on serum HE4 levels or ROMA scores to ultrasound findings improves diagnostic performance. This was a prospective cross-sectional diagnostic accuracy study conducted in a tertiary referral center that enrolled consecutive women with a known adnexal mass scheduled for surgery. Experienced level III examiners classified each mass as certainly or probably benign, difficult to classify, or probably or certainly malignant after preoperative ultrasound examination. Serum HE4 and CA 125 levels were measured before surgery. The final database comprised 360 women, of whom 216 (60%) had benign and 144 (40%) had malignant disease. Examiners were highly confident in 196 cases (54%), moderately confident in 135 (38%) and completely uncertain about their diagnosis in 29 (8%) cases. With a sensitivity of 67% and specificity of 70%, subjective assessment outperformed HE4 and ROMA in the subgroup of difficult tumors. Both tests had low discriminatory capacity with poor areas under the receiver-operating characteristics curve of 0.536 (95% CI, 0.302-0.771) and 0.565 (95% CI, 0.294-0.836), respectively. A strategy that incorporates sequential testing of serum HE4 or ROMA scores after transvaginal ultrasonography resulted in a deterioration in overall test performance. Measurement of serum HE4 or calculating scores using the ROMA as secondary tests does not seem useful for classifying adnexal tumors after subjective assessment with transvaginal ultrasonography.

Diagnostic accuracy of clinical tests for ankle syndesmosis injury

Objective Our aim was to investigate the diagnostic accuracy of the clinical presentation of ankle syndesmosis injury and four common clinical diagnostic tests. Design Cross-sectional diagnostic accuracy study. Setting 9 clinics in two Australian cities. Participants 87 participants (78% male) with an ankle sprain injury presenting to participating clinics within 2 weeks of injury were enrolled. Methods Clinical presentation, dorsiflexion-external rotation stress test, dorsiflexion lunge with compression test, squeeze test and ankle syndesmosis ligament palpation were compared with MRI results (read by a blinded radiologist) as a reference standard. Tests were evaluated using diagnostic accuracy, sensitivity, specificity and likelihood ratios (LRs). A backwards stepwise Cox regression model determined the combined value of the clinical tests. Results The clinical presentation of an inability to perform a single leg hop had the highest sensitivity (89%) with a negative LR of 0.37 (95% CI 0.13 to 1.03). Specificity was highest for pain out of proportion to the apparent injury (79%) with a positive LR of 3.05(95% CI 1.68 to 5.55). Of the clinical tests, the squeeze test had the highest specificity (88%) with a positive LR of 2.15 (95% CI 0.86 to 5.39). Syndesmosis ligament tenderness (92%) and the dorsiflexion-external rotation stress test (71%) had the highest sensitivity values and negative LR of 0.28 (95% CI 0.09 to 0.89) and 0.46 (95% CI 0.27 to 0.79), respectively. Syndesmosis injury was four times more likely to be present with positive syndesmosis ligament tenderness (OR 4.04, p=0.048) or a positive dorsiflexion/external rotation stress test (OR 3.9, p=0.004). Conclusions Although no single test is sufficiently accurate for diagnosis, we recommend a combination of sensitive and specific signs, symptoms and tests to confirm ankle syndesmosis involvement. An inability to hop, syndesmosis ligament tenderness and the dorsiflexion-external rotation stress test (sensitive) may be combined with pain out of proportion to injury and the squeeze test (specific).

10 PRINCIPAL RESULTS OF THE ANKLE BRACHIAL INDEX DETERMINATION BY OSCILLOMETRIC METHOD IN GENERAL PRACTICE (ABIDING) STUDY

Background: Ankle-Brachial Index (ABI) is rarely done in primary care due to the need for specialised equipment and training. ABIDING investigated the utility of a pragmatic method for ABI determination of ABI and diagnosis of peripheral arterial disease (PAD) in primary care. Design and methods: Cross-sectional validation and diagnostic accuracy study in Australian general practice in 2009-10 of 250 persons with cardiovascular disease or high risk of said. ABIs were done by a research nurse using a mercury sphygmomanometer and Doppler (conventional) and a practice nurse using an oscillometric device (pragmatic). The Bland-Altman plot between the ABI readings was used to investigate the agreement between the two procedures. Correlations between the paired readings were also calculated. The diagnostic accuracy was evaluated using ROC analysis and quantified as the C statistic. We also examined likelihood ratios. Results: There was no systematic bias between the ABI measures, difference = 0.002 (95% CI -0.024, 0.020). However, the Bland-Altman plot of ABI readings for the lowest ABI revealed poor agreement, where 95% of the readings were within ± 0.36. Multivariable C statistic for the pragmatic ABI method for PAD diagnosis in comparison to the conventional method gave: sensitivity 53% (95% CI 35-70%); specificity 97% (93-99%); positive predictive value 75% (53%-90%); negative predictive value 92% (88–95%); +LR 7.3 (4.4, 12.0); -LR 0.42 (0.30, 0.59). The C statistic of diagnosis of PAD was 0.88 (0.87). Conclusion: The +LR provides moderate evidence that a pragmatic ABI <0.9 can diagnose PAD, but low -LR suggests >0.9 won’t exclude it.

Accuracy of straight leg raise and slump tests in detecting lumbar disc herniation: a pilot study.

To determine the accuracy of the Straight Leg Raise (SLR) and slump tests in detecting Lumbar Disc Herniation (LDH). Cross-sectional diagnostic accuracy study. Two referral hospitals in Kigali, Rwanda: King Faisal Hospital and Centre Hospitalier Universitaire de Kigali. All patients aged 18 to 70 who had an MRI and who were experiencing pain in the low back, leg or low back and leg. Closed Magnetic Resonance Imaging (MRI) investigations for each patient as witnessed by a radiologist who read the image were recorded by the first researcher and blinded to other researchers. The SLR and slump tests were performed three times on each patient by independent testers who were blinded to the result of the first test. The test order was randomized for each subject and the two tests were separated by one day wash-out period. Data were analyzed using a 2x2 table to ascertain diagnostic statistics including sensitivity and specificity with 95% confidence intervals. Thirty three from a possible 37 patients mean age 41.58 ± 10 years completed all of the tests. The sensitivity of SLR was greater (0.875; CI: 0.690-0.957) than that of the slump tests (0.800; CI: 0.6087-0.911) (p = 0.01) in detecting LDH. The specificity for SLR was 0.429 (CI: 0.158-0.750) and for slump was 0.714 (CI: 0.359-0.918). Substantial agreement (K = 0.774) was obtained between the SLR and MRI. The SLR was more accurate in detecting LDH. Further validation of this pilot finding is required by studying a larger sample.

The Diagnostic Value of Physical Examination and Additional Testing in Primary Care Patients With Suspected Heart Failure

Early diagnosis of nonacute heart failure is crucial because prompt initiation of evidence-based treatment can prevent or slow down further progression. To diagnose new-onset heart failure in primary care is challenging. This is a cross-sectional diagnostic accuracy study with external validation. Seven hundred twenty-one consecutive patients suspected of new-onset heart failure underwent standardized diagnostic work-up including chest x-ray, spirometry, ECG, N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement, and echocardiography in specially equipped outpatient diagnostic heart failure clinics. The presence of heart failure was determined by an outcome panel using the initial clinical data and 6-month follow-up data, blinded to biomarker data. Of the 721 patients, 207 (28.7%) had heart failure. The combination of 3 items from history (age, coronary artery disease, and loop diuretic use) plus 6 from physical examination (pulse rate and regularity, displaced apex beat, rales, heart murmur, and increased jugular vein pressure) showed independent diagnostic value (c-statistic 0.83). NT-proBNP was the most powerful supplementary diagnostic test, increasing the c-statistic to 0.86 and resulting in net reclassification improvement of 69% (P<0.0001). A simplified diagnostic rule was applied to 2 external validation datasets, resulting in c- statistics of 0.95 and 0.88, confirming the results. In this study, we estimated the quantitative diagnostic contribution of elements of the history and physical examination in the diagnosis of heart failure in primary care outpatients, which may help to improve clinical decision making. The largest additional quantitative diagnostic contribution to those elements was provided by measurement of NT-proBNP. For daily practice, a diagnostic rule was derived that may be useful to quantify the probability of heart failure in patients with new symptoms suggestive of heart failure.

Diagnostic accuracy of FibroScan and comparison to liver fibrosis biomarkers in chronic viral hepatitis: A multicenter prospective study (the FIBROSTIC study)

The diagnostic accuracy of non-invasive liver fibrosis tests that may replace liver biopsy in patients with chronic hepatitis remains controversial. We assessed and compared the accuracy of FibroScan® and that of the main biomarkers used for predicting cirrhosis and significant fibrosis (METAVIR ≥ F2) in patients with chronic viral hepatitis. A multicenter prospective cross-sectional diagnostic accuracy study was conducted in the Hepatology departments of 23 French university hospitals. Index tests and reference standard (METAVIR fibrosis score on liver biopsy) were measured on the same day and interpreted blindly. Consecutive patients with chronic viral hepatitis (hepatitis B or C virus, including possible Human Immunodeficiency Virus co-infection) requiring liver biopsy were recruited in the study. The analysis was first conducted on the total population (1839 patients), and after excluding 532 protocol deviations, on 1307 patients (non-compliant FibroScan® examinations). The overall accuracy of FibroScan® was high (AUROC 0.89 and 0.90, respectively) and significantly higher than that of biomarkers in predicting cirrhosis (AUROC 0.77-0.86). All non-invasive methods had a moderate accuracy in predicting significant fibrosis (AUROC 0.72-0.78). Based on multilevel likelihood ratios, non-invasive tests provided a relevant gain in the likelihood of diagnosis in 0-60% of patients (cirrhosis) and 9-30% of patients (significant fibrosis). The diagnostic accuracy of non-invasive tests was high for cirrhosis, but poor for significant fibrosis. A clinically relevant gain in the likelihood of diagnosis was achieved in a low proportion of patients. Although the diagnosis of cirrhosis may rely on non-invasive tests, liver biopsy is warranted to diagnose intermediate stages of fibrosis.

Prediction of fetal anemia in pregnancies with red‐cell alloimmunization: comparison of middle cerebral artery peak systolic velocity and amniotic fluid OD450

To compare the accuracy of Doppler velocimetry (middle cerebral artery peak systolic velocity, MCA-PSV) and amniocentesis (amniotic fluid delta optical density 450 (OD450)) for the detection of fetal anemia against the gold standard of fetal blood sampling (FBS). Thirty-eight pregnancies were identified to be at risk of fetal anemia from immune causes between January 2000 and May 2002. In a cross-sectional diagnostic accuracy study, MCA-PSV and amniotic fluid delta OD450 values were plotted on reference charts and compared to an FBS obtained within the subsequent 7 days. Receiver-operating characteristics (ROC) curves were used and the area under the curve (AUC) calculated to compare the overall accuracy of the two tests. Sensitivity, specificity and likelihood ratios for positive (LR+) and negative (LR-) test results were generated for specific thresholds of MCA-PSV and delta OD450. For MCA-PSV (n = 38), the AUC was 0.71 (95% CI 0.57-0.85) and for amniotic fluid delta OD450 (n = 22) it was 0.68 (95% CI 0.49-0.87) compared with FBS within 7 days. Sensitivity, specificity and LR+, LR- for MCA-PSV were 64%, 81%, 3.4 and 0.5, respectively, and 53%, 71%, 1.9 and 0.7 for amniotic fluid OD450, respectively. MCA-PSV and OD450 have similar test accuracy in detecting fetal anemia. MCA-PSV is non-invasive and therefore presents no risk of miscarriage or preterm labor and thus is a preferable method of screening for fetal anemia.