Identifying type 1 and type 2 diabetic cases using administrative data: a tree-structured model

Background:

To date, few administrative diabetes mellitus (DM) registries have distinguished type 1 diabetes mellitus (T1DM) from type 2 diabetes mellitus (T2DM).

Objective:

Using a classification tree model, a prediction rule was developed to distinguish T1DM from T2DM in a large administrative database.

Methods:

The Medical Archival Retrieval System at the University of Pittsburgh Medical Center included administrative and clinical data from January 1, 2000, through September 30, 2009, for 209,647 DM patients aged ≥18 years. Probable cases (8,173 T1DM and 125,111 T2DM) were identified by applying clinical criteria to administrative data. Nonparametric classification tree models were fit using TIBCO Spotfire S+ 8.1 (TIBCO Software), with model size based on 10-fold cross validation. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of T1DM were estimated.

Results:

The main predictors that distinguished T1DM from T2DM are age <40 years; International Classification of Disease, 9th revision, codes of T1DM or T2DM diagnosis; inpatient oral hypoglycemic agent use; inpatient insulin use; and episode(s) of diabetic ketoacidosis diagnosis. Compared with a complex clinical algorithm, the tree-structured model to predict T1DM had 92.8% sensitivity, 99.3% specificity, 89.5% PPV, and 99.5% NPV.

Conclusion:

The preliminary predictive rule appears to be promising. Being able to distinguish between DM subtypes in administrative databases will allow large-scale subtype-specific analyses of medical care costs, morbidity, and mortality.     

Efficacy of multi-detector coronary computed tomography angiography in comparison with exercise electrocardiogram in the triage of patients of low risk acute chest pain

Objectives

To compare the safety and diagnostic efficacy of coronary computed tomography angiography (CTA) with exercise electrocardiography (XECG) in triaging patients of low risk acute chest pain.

Background

Noninvasive assessment of coronary stenosis by CTA may improve early and accurate triage of patients presenting with acute chest pain to the emergency department (ED).

Methods

Low risk patients of possible acute coronary syndrome (ACS) were included in the study. The patients in CTA arm with significant stenosis (≥50%) underwent catheterization, while those with no or intermediate stenosis (<50%) were discharged from ED and followed up periodically for six months for major adverse cardiovascular events (MACE). The same protocol was applied for XECG arm. Outcomes included: safety and diagnostic efficacy.

Results

A total of 81 (41 CTA and 40 XECG) patients were enrolled. In this study CTA was observed to be 100% sensitive and 95.7% specific in diagnosing MACE in low risk patients of chest pain presenting to the ED, with a PPV of 94.7% and an NPV of 100%.The overall diagnostic efficacy was 97.6%. XECG was observed to be 72.7% sensitive and 96.6% specific in diagnosing MACE with a PPV of 88.9% and NPV of 90.3% in low risk chest pain patients presenting to the ED. The overall diagnostic accuracy was 90%.

Conclusion

CTA is an excellent diagnostic tool in ED patients with low risk of ACS, with minimum time delay as compared to XECG, and also is safe for triaging such patients.     

Prediction of Advanced Fibrosis in Nonalcoholic Fatty Liver Disease: An Enhanced Model of BARD Score

Background/Aims

The BARD score is a model to detect advanced liver fibrosis in nonalcoholic fatty liver disease (NAFLD) patients. The aims of this study were to identify additional factors and then to build an enhanced version of the BARD score.

Methods

One hundred seven patients with biopsy-proven NAFLD were enrolled retrospectively. Logistic regressions were performed to identify independent risk factors for advanced liver fibrosis (stage 3 or 4). An enhanced model of the BARD score (BARDI score) was built and evaluated with a receiver operating characteristic (ROC) curve.

Results

In multivariate analysis, age (odds ratio [OR], 0.89; p=0.04), aspartate aminotransferase/alanine aminotransferase ratio (OR, 1.73; p<0.01), and international normalized ratio (INR) (OR, 8.85; p<0.01) were independently significant factors. The BARDI score was created by adding the INR to the BARD. The area under the ROC curve of the BARDI score was significantly larger than that of the BARD score (0.881 vs 0.808, p<0.01). A BARDI score of 3 or more showed a positive predictive value (PPV) of 51.0% and a negative predictive value (NPV) of 96.0%.

Conclusions

The BARDI score had an improved PPV over the BARD score and maintained an excellent NPV. Further study is warranted for its external validation and comparison with other models.     

Signal stratification of autoantibody levels in serum samples and its application to the early detection of lung cancer

Background

Further signal stratification for the EarlyCDT®-Lung test should facilitate interpretation of the test, leading to more precise interventions for particular patients.

Methods

Samples were measured for the presence of autoantibodies to seven tumor-associated antigens (TAAs) (p53, NY-ESO-1, CAGE, GBU4-5, SOX2, MAGE A4, and HuD). In addition to the current test cut-offs (determined using a previously reported Validation case-control sample set, set A; n=501), new high and low cut-offs were set in order to maximize the test’s positive and negative predictive values (PPV and NPV, respectively). All three sets of cut-offs were applied to two confirmatory datasets: (I) the case-control set B (n=751), and (II) Population-derived set C (n=883), and all three datasets combined (n=2,135).

Results

For the Validation dataset, cancer/non-cancer positivity for current cut-offs was 41%/9% (PPV =0.109, 1 in 9). The high positive stratum improved this to 25%/2% (PPV =0.274, 1 in 4). The low negative stratum improved this to 8%/23% (NPV =0.990, 1 in 105). This provides a 25-fold difference in lung cancer probability between the highest and lowest groups.The test performs equally well in subjects who fulfilled the entry risk criteria for the National Lung Screening Trial (NLST) and subjects who did not meet the NLST criteria.

Conclusions

The EarlyCDT®-Lung test has been converted to a four-stratum test by the addition of high and low sets of cut-offs: patients are thus stratified into four risk categories. This stratification will enable personalization of subsequent screening and treatment programs for high risk individuals or patients with lung nodules.KEYWORDS : Lung cancer, autoantibody (AAb), tumor-associated antigen, risk stratification     

Risk factors associated with delayed haemorrhage after pancreatic resection

Background

Delayed haemorrhage (DH) is a life-threatening complication of pancreatic resection (PR) and the mortality rate for DH is very high. However, the risk factors and prognostic factors associated with DH are rarely evaluated.

Methods

A pancreatic resection was performed on 457 patients. Delayed haemorrhage was defined as bleeding from the surgical site ≥5 days after PR. Risk factors for DH were assessed according to demographics and pathological and operative parameters. Prognostic factors after DH were evaluated for the shock index (heart rate/systolic blood pressure) and systemic inflammatory response syndrome (SIRS) scores.

Results

Of the 457 patients, 11 (2.4%) experienced DH after PR. Logistic regression analysis showed that age >60 years and a diagnosis of malignant disease were risk factors for DH. The shock index and SIRS scores at the onset of DH were significantly higher in patients who died as compared with those patients that survived (P < 0.05).

Discussion

PR-associated DH carries an increased risk for patients aged >60 years with malignant disease. Prognostic factors were a shock index score ≥0.7 and SIRS at the onset of DH.     

Automated Diabetic Retinopathy Screening and Monitoring Using Retinal Fundus Image Analysis

Background:

Diabetic retinopathy (DR)—a common complication of diabetes—is the leading cause of vision loss among the working-age population in the western world. DR is largely asymptomatic, but if detected at early stages the progression to vision loss can be significantly slowed. With the increasing diabetic population there is an urgent need for automated DR screening and monitoring. To address this growing need, in this article we discuss an automated DR screening tool and extend it for automated estimation of microaneurysm (MA) turnover, a potential biomarker for DR risk.

Methods:

The DR screening tool automatically analyzes color retinal fundus images from a patient encounter for the various DR pathologies and collates the information from all the images belonging to a patient encounter to generate a patient-level screening recommendation. The MA turnover estimation tool aligns retinal images from multiple encounters of a patient, localizes MAs, and performs MA dynamics analysis to evaluate new, persistent, and disappeared lesion maps and estimate MA turnover rates.

Results:

The DR screening tool achieves 90% sensitivity at 63.2% specificity on a data set of 40 542 images from 5084 patient encounters obtained from the EyePACS telescreening system. On a subset of 7 longitudinal pairs the MA turnover estimation tool identifies new and disappeared MAs with 100% sensitivity and average false positives of 0.43 and 1.6 respectively.

Conclusions:

The presented automated tools have the potential to address the growing need for DR screening and monitoring, thereby saving vision of millions of diabetic patients worldwide.     

Vision-Threatening Retinal Abnormalities in Chronic Kidney Disease Stages 3 to 5

Summary

Background and objectives

Retinal abnormalities are common in inherited and acquired renal disease. This study determined the prevalence of retinal abnormalities in chronic kidney disease (CKD) stages 3 to 5.

Design, setting, participants, & measurements

One hundred fifty patients with CKD stages 3 to 5 and 150 age- and gender-matched hospital patients with CKD stages 1 to 2 underwent bilateral retinal photography. These images were reviewed for incidental abnormalities, microvascular (Wong and Mitchell classification) and diabetic retinopathy (Airlie House criteria), and macular degeneration (Seddon classification).

Results

Three (2%) patients with CKD stages 3 to 5 had retinal features characteristic of inherited renal disease (atrophy in Myopathy, Encephalopathy, Lactic Acidosis, Stroke-like episodes [MELAS] syndrome; and 2 with drusen in dense deposit disease). Fifty-nine (39%) patients had moderate-severe microvascular retinopathy (hemorrhages, exudates, etc.) compared with 19 (13%) with CKD stages 1 to 2. Forty-one (28%) had moderate-severe diabetic retinopathy (microaneurysms, exudates, etc.) compared with 16 (11%) with CKD stages 1 to 2. Ten (7%) had severe macular degeneration (geographic atrophy, hemorrhage, exudates, membranes) compared with one (1%) with CKD stages 1 to 2. Renal failure was an independent risk factor for microvascular retinopathy, diabetic retinopathy, and macular degeneration. Eleven (7.3%) patients with renal failure and one (0.7%) with CKD stages 1 to 2 had previously unrecognized vision-threatening retinal abnormalities that required immediate ophthalmologic attention.

Conclusions

Retinal abnormalities are common in CKD stages 3 to 5, and are more severe and more likely to threaten vision than in hospital patients with CKD stages 1 to 2.     

P Wave Indices to Predict Atrial Fibrillation Recurrences Post Pulmonary Vein Isolation

Background

P-wave indices are appealing markers for predicting atrial fibrillation (AF) recurrences post ablation.

Objective

This study evaluates the value of P wave indices to predict recurrences post pulmonary vein isolation (PVI) in patients with paroxysmal AF.

Methods

We selected 198 patients (57 ± 8 years, 150 males) with symptomatic drug-refractory paroxysmal AF undergoing PVI in our hospital. A 12-lead electrocardiogram was used to measure P wave duration in lead II, P wave terminal force (PWTF) in lead V1, P wave axis and dispersion.

Results

During a follow-up of 9 ± 3 months, recurrences occurred in 60 (30.3%) patients. The patients that had AF recurrence had longer mean P wave duration (122.9 ± 10.3 vs 104.3 ± 14.2 ms, p < 0.001), larger P wave dispersion (40.7 ± 1.7 ms vs 36.6 ± 3.2 ms, p < 0.001). P wave duration ≥ 125 ms has 60% sensitivity, 90% specificity, positive predictive value (PPV) of 72% and negative predictive value (NPV) of 83.7%, whereas P wave dispersion ≥ 40 ms has 78% sensitivity, 67% specificity, PPV of 51% and NPV of 87.6% 48/66 (72.7%) patients with PWTF ≤ - 0.04 mm/second vs 12/132(9%) with PWTF > -0.04 mm/second showed recurrence of AF (p < 0.001). P wave axis was not different between two groups. On multivariate analysis, P wave indices were not independent from left atrial size and age.

Conclusions

P wave duration ≥ 125 ms, P wave dispersion ≥ 40 ms and PWTF in V1 ≤ - 0.04 mm/sec are good clinical predictors of AF recurrences post PVI in patients with paroxysmal atrial fibrillation; however they were not independent from left atrial size and age.     

DrishtiCare: a telescreening platform for diabetic retinopathy powered with fundus image analysis

Objective:

Diabetic retinopathy is the leading cause of blindness in urban populations. Early diagnosis through regular screening and timely treatment has been shown to prevent visual loss and blindness. It is very difficult to cater to this vast set of diabetes patients, primarily because of high costs in reaching out to patients and a scarcity of skilled personnel. Telescreening offers a cost-effective solution to reach out to patients but is still inadequate due to an insufficient number of experts who serve the diabetes population. Developments toward fundus image analysis have shown promise in addressing the scarcity of skilled personnel for large-scale screening. This article aims at addressing the underlying issues in traditional telescreening to develop a solution that leverages the developments carried out in fundus image analysis.

Method

We propose a novel Web-based telescreening solution (called DrishtiCare) integrating various value-added fundus image analysis components. A Web-based platform on the software as a service (SaaS) delivery model is chosen to make the service cost-effective, easy to use, and scalable. A server-based prescreening system is employed to scrutinize the fundus images of patients and to refer them to the experts. An automatic quality assessment module ensures transfer of fundus images that meet grading standards. An easy-to-use interface, enabled with new visualization features, is designed for case examination by experts.

Results

Three local primary eye hospitals have participated and used DrishtiCare’s telescreening service. A preliminary evaluation of the proposed platform is performed on a set of 119 patients, of which 23% are identified with the sight-threatening retinopathy. Currently, evaluation at a larger scale is under process, and a total of 450 patients have been enrolled.

Conclusion:

The proposed approach provides an innovative way of integrating automated fundus image analysis in the telescreening framework to address well-known challenges in large-scale disease screening. It offers a low-cost, effective, and easily adoptable screening solution to primary care providers.     

Comparison of the diagnostic accuracy of ischemia-modified albumin and echocardiography in patients with acute chest pain

BACKGROUND:

Several imaging tests and biomarkers have been proposed for the identification of patients with unstable angina among those presenting to the emergency department with acute chest pain. Preliminary data suggest that ischemia-modified albumin (IMA) may represent a potentially useful biomarker in these patients.

OBJECTIVE:

To compare IMA and echocardiography in excluding unstable angina in patients with acute chest pain.

METHODS:

Thirty-three patients (mean [± SD] age 59.8±10.8 years; 28 men) presenting to the emergency department with acute chest pain lasting <3 h suggestive of acute coronary syndrome, with normal or non-diagnostic electrocardiograms, and creatine kinase MB and troponin levels within the normal range, were included in the present study.

RESULTS:

After further diagnostic evaluation, five patients (15.2%) were diagnosed with unstable angina. The sensitivity, specificity, positive predictive value and negative predictive (NPV) value of echocardiography for diagnosing unstable angina was 60.0%, 89.3%, 50.0% and 92.6%, respectively. The area under the ROC curve for diagnosing unstable angina based on the serum IMA levels was 0.193 (95% CI 0.047 to 0.339; P<0.05). Based on ROC curve analysis, serum IMA levels ≥31.95 IU/mL yielded the optimal combination of sensitivity and specificity for diagnosing unstable angina. The sensitivity, specificity, positive predictive value and NPV of serum IMA levels ≥31.95 IU/mL for diagnosing unstable angina was 40.0%, 28.6%, 9.1% and 72.7%, respectively.

CONCLUSIONS:

Measurement of serum IMA levels appears to represent a useful tool for excluding unstable angina in patients presenting to the emergency department with acute chest pain. Moreover, IMA shows an NPV that is comparable with echocardiography.     

BNP was Associated with Ischemic Myocardial Scintigraphy and Death in Patients at Chest Pain Unit

Background

Recent studies have suggested that B-type Natriuretic Peptide (BNP) is an important predictor of ischemia and death in patients with suspected acute coronary syndrome. Increased levels of BNP are seen after episodes of myocardial ischemia and may be related to future adverse events.

Objectives

To determine the prognostic value of BNP for major cardiac events and to evaluate its association with ischemic myocardial perfusion scintigraphy (MPS).

Methods

This study included retrospectively 125 patients admitted to the chest pain unit between 2002 and 2006, who had their BNP levels measured on admission and underwent CPM for risk stratification. BNP values were compared with the results of the MPS. The chi-square test was used for qualitative variables and the Student t test, for quantitative variables. Survival curves were adjusted using the Kaplan-Meier method and analyzed by using Cox regression. The significance level was 5%.

Results

The mean age was 63.9 ± 13.8 years, and the male sex represented 51.2% of the sample. Ischemia was found in 44% of the MPS. The mean BNP level was higher in patients with ischemia compared to patients with non-ischemic MPS (188.3 ± 208.7 versus 131.8 ± 88.6; p = 0.003). A BNP level greater than 80 pg/mL was the strongest predictor of ischemia on MPS (sensitivity = 60%, specificity = 70%, accuracy = 66%, PPV = 61%, NPV = 70%), and could predict medium-term mortality (RR = 7.29, 95% CI: 0.90-58.6; p = 0.045) independently of the presence of ischemia.

Conclusions

BNP levels are associated with ischemic MPS findings and adverse prognosis in patients presenting with acute chest pain to the emergency room, thus, providing important prognostic information for an unfavorable clinical outcome.     

Role of endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of solid pancreatic and peripancreatic lesions: is onsite cytopathology necessary?

Objectives:

The reported median diagnostic yield from endoscopic ultrasound (EUS) fine-needle aspiration (FNA) cytology is 78% (range 39–93%). The aim of this study is to describe a single-centre experience in the diagnostic work-up of solid pancreatic and peripancreatic masses without the benefit of an onsite cytopathologist.

Methods:

In a consecutive series of 429 EUS examinations performed over a 12-month period by a single operator, 108 were on non-cystic pancreatic or biliary lesions. Data were collected prospectively and the accuracy of FNA was assessed retrospectively using either surgery or repeat imaging as the benchmark in the presence or absence of malignancy.

Results:

Of the 108 FNAs, 102 (94%) were diagnostic, four were falsely negative (FN) and two were atypical and considered equivocal. There were 78 pancreatic lesions, of which 65 were true positives (TP), 11 true negatives (TN) and two FN, giving an overall accuracy of 97% (76/78). Of nine periampullary lesions, two were TP, six were TN and one was FN, giving an overall accuracy of 89% (8/9). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of EUS-FNA for pancreatic and periampullary lesions combined were 96%, 100%, 100% [95% confidence interval (CI) 95–100%], 85% (95% CI 62–97%) and 97%, respectively. There were 21 bile duct lesions, of which 10 were TP, eight TN, two atypical and one FN, giving an overall accuracy of 86% (18/21). The sensitivity, specificity, PPV, NPV and accuracy of EUS-FNA for biliary lesions were 91%, 100%, 100% (95% CI 69–100%), 91% (95% CI 59–100%) and 95%, respectively.

Conclusions:

The diagnostic accuracy of EUS-FNA for pancreatic lesions in our series was 97% and the PPV for the three subgroups of lesion type was 100%; these figures are comparable with the best rates reported in the literature, despite the absence of onsite cytopathology. These rates are potentially a direct result of high-volume practice, dedicated endosonography and cytopathology. These results show that it is possible to achieve high rates of accuracy in places where logistical issues make it impossible to maintain a cytopathologist in the endoscopy suite. In addition, our results contribute to the limited, collective global experience on the effectiveness of EUS-FNA in periampullary and biliary lesions.     

External validation of a prediction model for pathologic N2 among patients with a negative mediastinum by positron emission tomography

Background

A prediction model for pathologic N2 (pN2) among lung cancer patients with a negative mediastinum by positron emission tomography (PET) was recently internally validated. Our study sought to determine the external validity of that model.

Methods

A cohort study [2005-2013] was performed of lung cancer patients with a negative mediastinum by PET. Previously published model coefficients were used to estimate the probability of pN2 based on tumor location and size, nodal enlargement by computed tomography (CT), maximum standardized uptake value (SUV_max) of the primary tumor, N1 disease by PET, and pretreatment histology.

Results

Among 239 patients, 18 had pN2 [7.5%, 95% confidence interval (CI): 4.5-12%]. Model discrimination was excellent (c-statistic 0.80, 95% CI: 0.75-0.85) and the model fit the data well (P=0.191). The accuracy of the model was as follows: sensitivity 100%, 95% CI: 81-100%; specificity 49%, 95% CI: 42-56%; positive predictive value (PPV) 14%, 95% CI: 8-21%, and negative predictive value (NPV) 100%, 95% CI: 97-100%. CI inspection revealed a significantly higher c-statistic in this external validation cohort compared to the internal validation cohort. The model’s apparently poor specificity for patient selection is in fact significantly better than usual care (i.e., aggressive but allowable guideline concordant staging) and minimum guideline mandated selection criteria for invasive staging.

Conclusions

A prediction model for pN2 is externally valid. The high NPV of this model may allow pulmonologists and thoracic surgeons to more comfortably minimize the number of invasive procedures performed among patients with a negative mediastinum by PET.     

Using a Single Item to Measure Burnout in Primary Care Staff: A Psychometric Evaluation

Background

Burnout affects nearly half of all U.S. nurses and physicians, and has been linked to poor outcomes such as worse patient safety. The most common measure of burnout is the well-validated Maslach Burnout Inventory (MBI). However, the MBI is proprietary and carries licensing fees, posing challenges to routine or repeated assessment.

Objective

To compare a non-proprietary, single-item burnout measure to a single item from the MBI Emotional Exhaustion (MBI:EE) subscale that has been validated as a standalone burnout measure.

Design

Cross-sectional online survey.

Participants

A sample of primary care providers (PCPs), registered nurses, clinical associates (e.g., licensed practical nurses (LPNs), medical technicians), and administrative clerks in the Veterans Health Administration surveyed in 2012.

Main Methods

We compared a validated one-item version of the MBI:EE and a non-proprietary single-item burnout measure used in the Physician Work Life Study. We calculated kappa statistics, sensitivity and specificity, positive predictive (PPV) and negative predictive values (NPV), and area under the receiver operator curve (AUC). We conducted analyses stratified by occupation to determine the stability of the correlation between the two measures.

Key Results

We analyzed responses from 5,404 participants, including 1,769 providers and 1,380 registered nurses. The prevalence of burnout was 36.7 % as measured on the single MBI:EE item and 38.5 % as measured on the non-proprietary single-item measure. Relative to the MBI:EE, the non-proprietary single-item measure had a correlation of 0.79, sensitivity of 83.2 %, specificity of 87.4 %, and AUC of 0.93 (se = 0.004). Results were similar when stratified by respondent occupation.

Conclusions

A non-proprietary single-item measure served as a reliable substitute for the MBI:EE across occupations. Because it is non-proprietary and easy to interpret, it has logistical advantages over the one-item MBI.

Electronic supplementary material

The online version of this article (doi:10.1007/s11606-014-3112-6) contains supplementary material, which is available to authorized users.Key words: Workforce, Psychometrics, Physician satisfaction     

The value of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in identifying clinically relevant bacteria: a comparison with automated microbiology system

Background

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been developed as a new-type soft ionization mass spectrometry in the recent year. Increasing number of clinical microbiological laboratories consider it as an innovate approach for bacterial identification.

Methods

A total of 876 clinical strains, comprising 52 species in 27 genus, were obtained from Fudan University Affiliated Zhongshan Hospital. We compared the identification accuracy of the Vitek MS system (bioMerieux, Marcy l’Etoile) to other conventional methods for bacterial identification. 16S rRNA gene sequencing was performed as a reference identification method in cases of discrepant results.

Results

The Vitek MS system consistently produced accurate results within minutes of loading, while conventional methods required several hours to produce identification results. Among the 876 isolates, the overall performance of Vitek MS was significantly better than the conventional method both for correct species identification (830, 94.7% vs. 746, 85.2%, respectively, P=0.000).

Conclusions

Compared to traditional identification methods, MALDI-TOF MS is a rapid, accurate and economical technique to enhance the clinical value of microorganism identification.     

Telemedicine Process Used to Implement an Effective and Functional Screening Program for Diabetic Retinopathy

Background

Diabetic retinopathy, damage to the blood vessels in the retina, is the leading cause of blindness in adults 20–74 years of age. Nearly 300 million people worldwide have diabetes and nearly half of all people with diabetes will develop some degree of diabetic retinopathy during their lifetime. It has been estimated that blindness from diabetic retinopathy is preventable in at least 65% of cases, if detected early. The aim of the project was to develop a flexible, modular, mobile method for screening individuals that could be used effectively in a variety of medical and community settings.

Methods

Our project created software to support a simple, effective retinal screening process for people with diabetes. The system included four separate software components: registration, imaging, grading, and tracking/reporting. The imaging component consisted of customized software running on a computer attached to a camera that drives retinal image acquisition.

Results

Seven hundred and six subjects with diabetes were successfully consented, registered, imaged, and had their eye images graded. The mean time for subjects to be registered, imaged, and have eye images graded was 00:12:53. Seventy-six percent of the sample was instructed to follow-up with their eye doctor in 1 year (had no retinopathy or microaneurysms). Only six patients (0.8 %) were asked to see their eye doctor within 6 weeks (proliferative retinopathy or diabetic maculopathy).

Conclusion

Our project successfully demonstrated that the retinal screening software and workflow process can be used to overcome challenges of providing adequate screening and diagnostic services for people at risk for diabetic retinopathy.     

Validity of chronic obstructive pulmonary disease diagnoses in a large administrative database

BACKGROUND:

Administrative databases are often used for research purposes, with minimal attention devoted to the validity of the included diagnoses.

AIMS:

To determine whether the principal diagnoses of chronic obstructive pulmonary disease (COPD) made in hospitalized patients and recorded in a large administrative database are valid.

METHODS:

The medical charts of 1221 patients hospitalized in 40 acute care centres in Quebec and discharged between April 1, 2003 and March 31, 2004, with a principal discharge diagnosis of COPD (International Classification of Diseases, Ninth Revision codes 491, 492 or 496) were reviewed. The diagnosis of COPD was independently adjudicated by two pulmonologists using clinical history (including smoking status) and spirometry. The primary outcome measure was the positive predictive value (PPV) of the database for the diagnosis of COPD (ie, the proportion of patients with an accurate diagnosis of COPD corroborated by clinical history and spirometry).

RESULTS:

The diagnosis of COPD was validated in 616 patients (PPV 50.4% [95% CI 47.7% to 53.3%]), with 372 patients (30.5%) classified as ‘indeterminate’. Older age and female sex were associated with a lower probability of an accurate diagnosis of COPD. Hospitalization in a teaching institution was associated with a twofold increase in the probability of a correct diagnosis.

CONCLUSIONS:

The results support the routine ascertainment of the validity of diagnoses before using administrative databases in clinical and health services research.     

How efficient is acoustic radiation force impulse elastography for the evaluation of liver stiffness?

Background

In chronic liver diseases, a correct estimation of the severity of liver fibrosis is important for recommendations regarding the treatment. Nowadays, evaluation of fibrosis is done by noninvasive methods such as biochemical scores and transient elastography instead of liver biopsy. The lack of sensitivity to detect fibrosis, because of its heterogeneity is a drawback of liver biopsy (LB).

Objectives

To compare transient elastography (TE) and acoustic radiation force impulse (ARFI) for the evaluation of liver stiffness (LS), against percutaneous LB.

Patients and Methods

Our study comprised of 223 subjects; 52 without fibrosis (38 volunteers and 14 patients with F0 on LB), 36 with F1, 40 with F2, 26 with F3 and 69 with liver cirrhosis (46 with LB and 23 with signs of cirrhosis). For each patient we performed in the same session 10 TE and 5 ARFI measurements. The median values were calculated.

Results

A strong linear correlation (Spearman rho = 0.870) was found between TE and fibrosis (P < 0.0001); there was also a weaker correlation between ARFI and fibrosis (Spearman rho = 0.646; P < 0.0001). TE measurements were also correlated with ARFI measurements (Spearman rho = 0.733, P < 0.0001). The best test for predicting significant fibrosis (F ≥ 2) was TE with a cut-off value of 7.1 kPa (AUROC 0.953). For ARFI, the cut-off value was 1.27 m/s-area under ROC curve (AUROC): 0.890, sensitivity (Se) of 88.7%, specificity (Sp) of 67.5%, positive predictive value (PPV) of 64.5%, and negative predictive value (NPV) of 90% (P = 0.0044). For predicting cirrhosis (F = 4), the optimum cut-off values were 14.4 kPa for TE (AUROC: 0.985, Se: 95.6%, Sp: 94.7%, PPV: 89.2%, NPV: 98%) and 1.7 m/s for ARFI (AUROC: 0.931, Se: 93%, Sp: 86.7%, PPV: 73.6%, NPV: 96.9%) (P = 0.0102).

Conclusions

LS evaluation by means of ARFI is not superior to TE for the assessment of liver fibrosis. ARFI is an accurate test for the diagnosis of cirrhosis.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the identification of beta-hemolytic streptococci

Objective

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as promising technology for species identification. The purpose of this investigation was to compare the performance of MS and the traditional method for identification of beta-hemolytic streptococci (BHS).

Methods

Clinical BHS isolates were identified by the BD Phoenix SMIC/ID Streptococcal panels, and two MALDI-TOF MS platforms: the VITEK MS and the Bruker MALDI Biotyper systems respectively. In case of discordant results, 16sRNA sequencing was performed to provide the reference ID.

Results

A total of 96 isolates of BHS were analyzed. Thirty-six isolates (20.8%) were re-tested by BD Phoenix for identification failure; and four isolates (4.2%) were rerun on the Bruker system for low identification score. No isolate need a second run for identification by Vitek MS system. Overall, BD Phoenix, BioTyper and Vitek MS automated system accurately identified 76 strains (79.2%), 91 (94.7%) strains and 92 (95.8%) strains, respectively.

Conclusions

Our study suggests that MALDI-TOF MS is a superior method to conventional phenotypic methods for BHS identification.