Diffusion tensor imaging-derived biomarkers performance in glioblastoma tumor regions: exploratory data analysis using zombie plots and diagnostic tests.

INTRODUCTION: Using diffusion tensor imaging (DTI), 11 biomarkers have been reported in different glioblastoma (GB) regions. OBJECTIVE: To compare the efficacy of GB biomarkers using "zombie plots". METHODS: Retrospective cohort of 29 subjects with GB who underwent 3-Tesla brain magnetic resonance imaging. DTI major, intermediate and minor eigenvalues were used to calculate biomarkers at five tumor regions: normal-appearing white matter (NAWM), proximal and distal edema, tumor tissue and necrosis. Contingency tables with true and false positive and negative results allowed the calculation of zombie plots based on the Bayes factor and previously unreported diagnostic tests. RESULTS: The MD, FA, q, L, Cl, Cp and RA biomarkers had a good performance at the optimal zone for NAWM diagnosis. The proximal and distal edema, enhancing rim and necrosis regions do not have biomarkers that identify them with an optimal performance level. CONCLUSIONS: Zombie plots allow simultaneous comparison of biomarkers based on likelihood ratios. MD, FA, q, L, Cl, Cp, RA discriminated NAWM normal brain tissue at the optimal zone, but performance for other regions was at the mediocre, diagnostic inclusion and diagnostic exclusion zones.

INTRODUCCIÓN: Han sido reportados 11 biomarcadores de imágenes con tensor de difusión (DTI) en las regiones tumorales del glioblastoma. OBJETIVO: Comparar la eficacia de biomarcadores de glioblastoma mediante gráficos de zombie, que permiten la comparación simultánea en función de razones de verosimilitud. MÉTODOS: Cohorte retrospectiva de 29 sujetos con glioblastoma a quienes se efectuó resonancia magnética cerebral de 3 T. Los eigenvalores mayor, intermedio y menor de ITD se utilizaron para calcular 11 biomarcadores en cinco regiones tumorales: sustancia blanca de apariencia normal (NAWM), edema proximal y distal, tumoral viable y necrosis. Las tablas de contingencia con resultados verdaderos y falsos positivos y negativos permitieron calcular gráficos de zombie basados en el factor de Bayes y pruebas diagnósticas previamente no reportadas. RESULTADOS: Los biomarcadores DM, AF, q, L, Cl, Cp, AR actúan en la zona óptima para el diagnóstico de NAWM. Las regiones de edema proximal y distal, tejido tumoral que se realza con contraste y necrosis no poseen biomarcadores que las identifiquen en un nivel de rendimiento óptimo. CONCLUSIONES: Los biomarcadores DM, AF, q, L, Cl, Cp, AR discriminan el tejido cerebral normal en la zona óptima, pero el rendimiento de otras regiones tumorales se ubica en las zonas de inclusión diagnóstica, exclusión diagnóstica y mediocre.

[Validation of RUDAS: A screening tool for dementia in Primary Health Care settings]. / Validación del RUDAS como instrumento de cribado de población con demencia en atención primaria.

OBJECTIVE: To validate Rowland Dementia Assessment Scale (RUDAS), as an instrument for the screening of people with dementia and cognitive impairment in Primary Health Care (PHC). RUDAS is a brief cognitive test, appropriate for people with minimum completed level of education and easily adaptable to multicultural contexts. For these reason it could be a good instrument for dementia screening in PHC. DESIGN: Cross-sectional descriptive epidemiological study with a five-year follow up. LOCATION: O Grove PHC centre, Galicia, Spain (covering a population of 10,650 individuals). OUTCOME MEASURES: RUDAS; Mini Mental State Examination; Clinical Dementia Rating; Katz, Barthel and Lawton Indexes; MMSE and Yesavage Geriatric Depression Scale. PARTICIPANTS: A total of 150 older adults (mean age 76.35±7.12years) randomly selected, from a low sociocultural and economical background and mainly rural and semirural origin. INTERVENTION: RUDAS viability in PHC was checked, and its psychometric properties assessed: reliability, sensitivity, specificity, positive and negative predictive values. RESULTS: RUDAS application was brief (7.58±2.10min) and well accepted. RUDAS area under receiver operating characteristic (ROC) curve for the detection of dementia was 0.983 (95% confidence interval (CI): 0.97-1.00) for an optimal cut-off point of 22.5, with sensitivity of 89.3%, and a specificity of 100%. Area under ROC curve for discriminating dementia from mild cognitive impairment was 0.965 (95%CI: 0.91-1.00). CONCLUSIONS: RUDAS test is fit for dementia screening in PHC and it is especially sensitive to discriminate PWD from people with MCI.

Cost-effectiveness study of the microbiological diagnosis of tuberculosis using geneXpert MTB/RIF®. / Estudio de coste-efectividad del diagnóstico microbiológico de tuberculosis mediante geneXpert MTB/RIF®.

INTRODUCTION/OBJECTIVE: To perform a cost-effectiveness analysis of a molecular biology technique for the diagnosis of tuberculosis compared to the classical diagnostic alternative. METHODS: A cost-effectiveness analysis was performed to evaluate the theoretical implementation of a molecular biology method including two alternative techniques for early detection of Mycobacterium tuberculosis Complex, and resistance to rifampicin (alternative1: one determination in selected patients; alternative2: two determinations in all the patients). Both alternatives were compared with the usual procedure for microbiological diagnosis of tuberculosis (staining and microbiological culture), and was accomplished on 1,972 patients in the period in 2008-2012. The effectiveness was measured in QALYs, and the uncertainty was assessed by univariate, multivariate and probabilistic analysis of sensitivity. RESULTS: A value of €8,588/QALYs was obtained by the usual method. Total expenditure with the alternative1 was €8,487/QALYs, whereas with alternative2, the cost-effectiveness ratio amounted to €2,960/QALYs. Greater diagnostic efficiency was observed by applying the alternative2, reaching a 75% reduction in the number of days that a patient with tuberculosis remains without an adequate treatment, and a 70% reduction in the number of days that a patient without tuberculosis remains in hospital. CONCLUSION: The implementation of a molecular microbiological technique in the diagnosis of tuberculosis is extremely cost-effective compared to the usual method. Its introduction into the routine diagnostic procedure could lead to an improvement in quality care for patients, given that it would avoid both unnecessary hospitalisations and treatments, and reflected in economic savings to the hospital.

Supervised oral HIV self-testing is accurate in rural KwaZulu-Natal, South Africa.

OBJECTIVES: To achieve UNAIDS 90-90-90 targets, alternatives to conventional HIV testing models are necessary in South Africa to increase population awareness of their HIV status. One of the alternatives is oral mucosal transudates-based HIV self-testing (OralST). This study describes implementation of counsellor-introduced supervised OralST in a high HIV prevalent rural area. METHODS: Cross-sectional study conducted in two government-run primary healthcare clinics and three Médecins Sans Frontières-run fixed-testing sites in uMlalazi municipality, KwaZulu-Natal. Lay counsellors sampled and recruited eligible participants, sought informed consent and demonstrated the use of the OraQuick(™) OralST. The participants used the OraQuick(™) in front of the counsellor and underwent a blood-based Determine(™) and a Unigold(™) rapid diagnostic test as gold standard for comparison. Primary outcomes were user error rates, inter-rater agreement, sensitivity, specificity and predictive values. RESULTS: A total of 2198 participants used the OraQuick(™) , of which 1005 were recruited at the primary healthcare clinics. Of the total, 1457 (66.3%) were women. Only two participants had to repeat their OraQuick(™) . Inter-rater agreement was 99.8% (Kappa 0.9925). Sensitivity for the OralST was 98.7% (95% CI 96.8-99.6), and specificity was 100% (95% CI 99.8-100). CONCLUSION: This study demonstrates high inter-rater agreement, and high accuracy of supervised OralST. OralST has the potential to increase uptake of HIV testing and could be offered at clinics and community testing sites in rural South Africa. Further research is necessary on the potential of unsupervised OralST to increase HIV status awareness and linkage to care.

Validation of a Spanish version of the Test Your Memory.

OBJECTIVE: To validate a Spanish version of the TYM, a self-administered cognitive screening test designed for the detection of Alzheimer's disease and mild cognitive defect. METHODS: A cross-sectional study was conducted in a neurology outpatient clinic. The TYM was administered to individuals of 50 years o more who came to the clinic for whatever the symptom. Their cognitive state was evaluated regardless of the outcome of TYM. They were categorized into 3 groups: 1) Cognitively normal (739), 2) with mild cognitive impairment (183), 3) with dementia (127). An analysis of items was made and the psychometric properties of the TYM were defined. There was a cross-validation, and the predictive validity of the TYM score, adjusted to the demographic variables, was determined by evaluating their performance in ROC curves. RESULTS: The internal consistency, interobserver reliability, short term and long-term test-retest reliability were adequate. The TYM correlated with the MMSE (r=0.779, P<.0001). The cross validation showed consistent results. With the TYM Score adjusted according to the educational level, a sensitivity of 0.86 with a specificity of 0.88 in the cut-off point of ≤40/50 was obtained to identify subjects with cognitive impairment, and a sensitivity of 0.94 with a specificity of 0.89 in the cut-off point of ≤36/50 to identify subjects with dementia. CONCLUSIONS: The TYM is a self-administered global cognitive test, possessing excellent psychometric properties and good predictive validity. It can be used as a cognitive screening test in subjects with 4 years or more of formal education.

Improving survey data on pregnancy-related deaths in low-and middle-income countries: a validation study in Senegal.

OBJECTIVE: In low- and middle-income countries (LMICs), siblings' survival histories (SSH) are often used to estimate maternal mortality, but SSH data on causes of death at reproductive ages have seldom been validated. We compared the accuracy of two SSH instruments: the standard questionnaire used during the demographic and health surveys (DHS) and the siblings' survival calendar (SSC), a new questionnaire designed to improve survey reports of deaths among women of reproductive ages. METHODS: We recruited 1189 respondents in a SSH survey in Niakhar, Senegal. Mortality records from a health and demographic surveillance system (HDSS) constituted the reference data set. Respondents were randomly assigned to an interview with the DHS or SSC questionnaires. A total of 164 respondents had a sister who died at reproductive ages over the past 15 years before the survey according to the HDSS. RESULTS: The DHS questionnaire led to selective omissions of deaths: DHS respondents were significantly more likely to report their sister's death if she had died of pregnancy-related causes than if she had died of other causes (96.4% vs. 70.9%, P < 0.007). Among reported deaths, both questionnaires had high sensitivity (>90%) in recording pregnancy-related deaths. But the DHS questionnaire had significantly lower specificity than the SSC (79.5% vs. 95.0%, P = 0.015). The DHS questionnaire overestimated the proportion of deaths due to pregnancy-related causes, whereas the SSC yielded unbiased estimates of this parameter. CONCLUSION: Statistical models informed by SSH data collected using the DHS questionnaire might exaggerate maternal mortality in Senegal and similar settings. A new questionnaire, the SSC, could permit better tracking progress towards the reduction in maternal mortality.

Digital tomosynthesis in breast cancer: A systematic review.

OBJECTIVE: To estimate and compare the diagnostic validity of tomosynthesis and digital mammography for screening and diagnosing breast cancer. MATERIAL AND METHODS: We systematically searched MedLine, EMBASE, and Web of Science for the terms breast cancer, screening, tomosynthesis, mammography, sensitivity, and specificity in publications in the period comprising June 2010 through February 2013. We included studies on diagnostic tests and systematic reviews. Two reviewers selected and evaluated the articles. We used QUADAS 2 to evaluate the risk of bias and the NICE criteria to determine the level of evidence. We compiled a narrative synthesis. RESULTS: Of the 151 original studies identified, we selected 11 that included a total of 2475 women. The overall quality was low, with a risk of bias and follow-up and limitations regarding the applicability of the results. The level of evidence was not greater than level II. The sensitivity of tomosynthesis ranged from 69% to 100% and the specificity ranged from 54% to 100%. The negative likelihood ratio was good, and this makes tomosynthesis useful as a test to confirm a diagnosis. One-view tomosynthesis was no better than two-view digital mammography, and the evidence for the superiority of two-view tomosynthesis was inconclusive. CONCLUSIONS: The results for the diagnostic validity of tomosynthesis in the diagnosis of breast cancer were inconclusive and there were no results for its use in screening.

[Critical reading of articles about diagnostic tests (part II): Analyzing results]. / Lectura crítica de artículos de pruebas diagnósticas II: análisis de resultados.

A new diagnostic test needs to be validated through comparison with a reference standard in an appropriate spectrum of patients. Diagnostic tests are not perfectly accurate; on the contrary, there can be false-positive and false-negative findings. A good diagnostic test is that which provides an acceptable proportion of positive results when a determinate condition is present in patients and an acceptable proportion of negative results when it is absent. The best measure of the usefulness of a diagnostic test is the likelihood ratio, which informs us to what degree a particular result is more likely in a person in whom a condition is present than in a person in whom the condition is absent. The present article discusses the fundamental statistical concepts necessary to interpret the results section of an article about a diagnostic test; however, the approach is clearly oriented toward clinical practice, with emphasis on concepts rather than mathematics.

[Diagnostic validity and usefulness of the Eating Attitudes Test-26 for the assessment of eating disorders risk in a Colombian female population]. / Validez y utilidad diagnóstica de la escala EAT-26 para la evaluación del riesgo de trastornos de la conducta alimentaria en población femenina de Medellín, Colombia.

OBJECTIVE: To establish diagnostic validity and usefulness of EAT-26 for the risk assessment of Eating Disorder (ED) in a female population. DESCRIPTION: Observational validation study questionnaire. SETTING: Performed in a Medellin city community care level of mixed (public and private) psychiatric consultation. SUBJECTS: Twenty five subjects aged 15 to 25 with DSM-IV-TR diagnostic criteria for anorexia and bulimia nervosa and 111 controls without ED. MAIN OUTCOMES MEASURES: The case sample was for convenience and in controls an aleatory simple one. Gold standard (structured psychiatrist interview confirming the fulfillment of ED case inclusion criteria) was compared with EAT-26 questionnaire; reliability was assessed, cultural, semantics and factorial validation was made and the best cut-off score was established with the ROC curve. RESULTS: Four domains remain in the instrument: bulimia, dieting, food preoccupation and oral control. The Cronbach's alpha was 92.1% and a score of 11 and over is the best cut-off (sensitivity 100%, and specificity 85.6%). CONCLUSIONS: This modified and abbreviated EAT-26 questionnaire is an ideal multidimensional instrument for ED screening in risk population, with excellent reliability and sensitivity values and satisfactory specificity. EAT-26 is a useful measure to be considered when strategies for ED early detection are implemented in young women.

How to detect non-institutionalized older patients at risk of malnutrition during their hospitalization? Comparison of 8 screening tools for malnutrition or nutritional risk.

BACKGROUND: The prevalence of malnutrition is high among the elderly population. Hospital admission is a window of opportunity for its detection. OBJECTIVE: To assess the concordance of different nutritional scales in hospitalized patients. METHODS: Prospective study in non-institutionalized patients over 65 years of age admitted to an internal medicine department. Five malnutrition screening surveys (MNA, MST, MUST, NRS-2000 and CONUT) and three nutritional risk screening surveys (SCREEN 3, 8 and 14) were compared. As gold standard we use the Global Malnutrition Leadership Initiative for Malnutrition (GLIM) definition of malnutrition. RESULTS: Eighty-five patients (37% female, median age 83 years) were included. Forty-eight percent (95% CI 38-59%) of patients were classified as malnourished according to GLIM criteria. The SCREEN 3 scale was the most sensitive (93%; 95% CI 87-98) and MUST the most specific (91%; CI 85-99). The most effective scale for excluding suspected malnutrition was SCREEN 3 (LR- 0.17; 95% CI 0.05-0.53) and the best for confirming it was MST (LR+ 7.08; 95% CI 3.06-16.39). Concordance between the different scales was low or very low with kappa indices between 0.082 and 0.465. CONCLUSIONS: A comprehensive approach is needed to detect malnutrition in hospitalized patients. More sensitive scales are more useful in initial screening. Nutritional risk tools could be effective at this stage. In a second step, malnutrition should be confirmed according to established criteria such as GLIM.

Performance of adenosine deaminase in synovial fluid for the diagnosis of tuberculous arthritis: A systematic review and meta-analysis.

OBJECTIVES: Adenosine deaminase (ADA) activity has shown good performance in diagnosing pleural, peritoneal, and meningeal tuberculosis. This meta-analysis aimed to evaluate the performance of measuring ADA activity in synovial fluid for the early diagnosis of joint tuberculosis. METHODS: We searched published information in MEDLINE, Embase, Cochrane Library, Web of Science, and MedRxiv databases, as well as unpublished information in the American College of Rheumatology and European League Against Rheumatism for conference abstracts (2012-2021). We also scanned the reference lists of articles. Two reviewers independently applied the criteria for selection, assessed quality, and extracted data (PROSPERO number CRD42021284472). RESULTS: Seven independent studies (N=305 subjects) that compared ADA activity in synovial fluid with a composite reference diagnostic method for tuberculosis were included. Overall, the risk of bias was judged low. Studies were classified as high quality (n=3; 148 subjects) and low quality (n=4; 157 subjects). Pooled sensitivity and specificity of ADA activity was 94% (95% confidence interval [CI], 0.89-98; I2=23%) and 88% (95% CI, 83-92; I2=83%), respectively. The random-effects model for pooled diagnostic Odds ratio was 67.1 (95%CI, 20.3-222.2; I2=30%). The receiver operating characteristic curve area was 0.96 (95% CI, 0.92-0.99). Meta-regression did not identify the quality of the study, country of publication, or the type of assay as a source of heterogeneity. CONCLUSIONS: Measuring ADA activity in synovial fluid demonstrates good performance for the early diagnosis of joint tuberculosis.

Operational characteristics of ultrasound in the diagnosis of Sjögren's syndrome.

BACKGROUND AND OBJECTIVE: To determine the operational characteristics of salivary gland ultrasound (SGU) in the diagnosis of Sjögren's syndrome (SS) in a population of colombian patients with dry symptoms. MATERIALS AND METHODS: Study of diagnostic tests in patients with dry symptoms who consecutively attended the rheumatology consultation (2018-2020). Sociodemographic and clinical data were obtained through a survey, paraclinical and ophthalmological tests, minor salivary gland biopsy, unstimulated salivary flow and SGU (score 0-6 based on De Vita) were done. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values (Stata 15®) were calculated. The receiver operating characteristics (ROC) curve was developed. RESULTS: 102 patients were included (34 SS and 68 non-SS), mean age 55.69 (±11.93) years, 94% women. Positive ultrasound (score of 2 or more) was more frequent in the SS group, (70.6% vs. 22.1%, P<0.0001). The sensitivity was the same for grade 2 and 3 (70.59%), with a higher specificity (89.71%) for grade 3 (PPV 77.42% NPV 85.92). The ROC curve from the sum of the glands by means of ultrasound was better than those of the independent glands. The ROC curve of the ultrasound presented a greater area under the curve (0.72 [0.61-0.82]) than that of the histological analysis (focus score) (0.68 [0.59-0.78]), P=0.0252. CONCLUSION: Salivary gland ultrasound is a useful and reliable method for the classification of SS. Its use could be considered in the future within the SS classification criteria.

4D-CT as a second line preoperative localization test for the evaluation of primary hyperparathyroidism.

INTRODUCTION: Four-dimensional computerized tomography (4D-CT) offers a good sensitivity for the localization of the pathological gland responsible of primary hyperparathyroidism. The aim was to evaluate its results as a second line preoperative localization test after inconclusive or discordant results of usual preoperative studies. MATERIAL AND METHODS: Observational retrospective study that included all patients intervened for primary hyperparathyroidism with 4D-CT scan as preoperative study, from 1st October 2016 to 1st October 2021, in a tertiary referral centre. The results of 4D-CT, cervical ultrasound, and Nuclear Medicine explorations (scintigraphy, SPECT and SPECT-CT) were compared with the gold standard of the surgical exploration and the pathological result. The correct lateralization and the approximate localization rates of the pathological gland were evaluated. RESULTS: A total of 64 patients were analysed, with a 93,8% (60/64) remission rate. 4DCT showed a correct lateralization in 57,8% (37/64) of the cases and revealed the approximate localization of the gland in 48,4% (31/64) of the cases. The cervical ultrasound had a rate of 31,1% (19/61) and 18% (11/61) for the correct lateralization and approximate localization, respectively, compared to 34,9% (22/63) and 28,6% (18/63) in Nuclear Medicine explorations, and 32,7% (16/49) and 24,5% (12/49) in SPECT-CT. These differences were statistically significant. CONCLUSION: 4D-CT demonstrated acceptable results for the localization of the lesions responsible of primary hyperparathyroidism, thus its use should be considered with the absence of localization in routinely studies.

Procalcitonin and C-reactive protein: markers in the early diagnosis of anastomotic leak.

OBJECTIVE: To determine the efficacy of serum procalcitonin (PCT) and C-reactive protein (CRP) in the early diagnosis of anastomotic leak (AL) in patients undergoing colorectal surgery. METHOD: Diagnostic test in a tertiary care hospital. Patients who did not have preoperative measurements of PCT and CRP were excluded. Those with postoperative infection not related to AL were eliminated. The diagnostic efficacy measures were sensitivity (Sn), specificity (Sp), positive (PPV) and negative (NPV) predictive values, positive (LR+) and negative (LR-) likelihood ratios, and area under the receiver operating characteristic curve (AUROC). RESULTS: Thirty-nine patients were analyzed; six had AL (15.4%). PCT and CRP increased on the second postoperative day, only in patients with AL. The cut-off points at the second postoperative day were 1.55 ng/mL for PCT and 11.25 mg/L for CRP. The most efficacious test was PCR at second postoperative day (AUROC: 1.00; Sn: 100%; Sp: 96.7%; PPV: 85.7%; NPV: 100%; LR+: 33.0). CONCLUSIONS: CRP at second postoperative day was the most effective test in the early diagnosis of AL in patients undergoing colorectal surgery, with a cut-off point lower than that reported in the international literature.

OBJETIVO: Determinar la eficacia de la procalcitonina (PCT) y la proteína C reactiva (PCR) séricas en el diagnóstico de fuga anastomótica (FA) en los pacientes sometidos a cirugía colorrectal. MÉTODO: Prueba diagnóstica en un hospital de tercer nivel. Se excluyeron los pacientes que no tuvieron mediciones preoperatorias de PCT y PCR. Se eliminaron los que cursaron con infección posoperatoria no relacionada con FA. Las medidas de eficacia diagnóstica fueron sensibilidad (S), especificidad (E), valores predictivos positivo (VPP) y negativo (VPN), razones de verosimilitud positiva (RV+) y negativa (RV−), y área bajo la curva característica operativa del receptor (AUROC). RESULTADOS: Se analizaron 39 pacientes, de los cuales 6 (15.4%) tuvieron FA. La PCT y la PCR aumentaron al segundo día posoperatorio solo en los pacientes con FA. Los puntos de corte al día 2 fueron 1.55 ng/ml para PCT y 11.25 mg/l para PCR. La prueba más eficaz fue la PCR al día 2 (AUROC: 1.00; S: 100%; E: 96.7%; VPP: 85.7%; VPN: 100%; RV+: 33.0). CONCLUSIONES: La PCR en el segundo día posoperatorio fue la prueba más eficaz en el diagnóstico temprano de FA en los pacientes sometidos a cirugía colorrectal, con un punto de corte inferior a lo reportado en la literatura internacional.

Diagnostic accuracy of lumbar CT and MRI in the evaluation of chronic low back pain without red flag symptoms.

BACKGROUND: Low back pain (LBP) is one of the most frequent reasons for medical consultation. Most of the patients will have nonspecific LBP, which usually are self-limited episodes. It is unclear which of the diagnostic imaging pathways is most effective and costeffective and how the imaging impacts on patient treatment. Imaging techniques are usually indicated if symptoms remain after 6 weeks. Magnetic resonance imaging (MRI) is the diagnostic imaging examination of choice in lumbar spine evaluation of low back pain; however, availability of MRI is limited. OBJECTIVES: To evaluate the diagnostic accuracy of computed tomography (CT) with MRI (as standard of reference) in the evaluation of chronic low back pain (LBP) without red flags symptoms. To compare the results obtained by two radiologists with different grades of experience. MATERIALS AND METHODS: Patients with chronic low back pain without red flags symptoms were retrospectively reviewed by two observers with different level of experience. Patients included had undergone a lumbar or abdominal CT and an MRI within a year. Once the radiological information was collected, it was then statistically reviewed. The aim of the statistical analysis is to identify the equivalence between both diagnostic techniques. To this end, sensitivity, specificity and validity index were calculated. In addition, intra and inter-observer reliability were measured by Cohen's kappa values and also using the McNemar test. RESULTS: 340 lumbar levels were evaluated from 68 adult patients with chronic low back pain or sciatica. 63.2% of them were women, with an average age of 60.3 years (SD 14.7). CT shows high values of sensitivity and specificity (>80%) in most of the items evaluated, but sensitivity was low for the evaluation of density of the disc (40%) and for the detection of disc herniation (55%). Moreover, agreement between MRI and CT in most of these items was substantial or almost perfect (Cohen's kappa-coefficient > 0'8), excluding Modic changes (kappa = 0.497), degenerative changes (kappa0.688), signal of the disc (kappa = 0.327) and disc herniation (kappa = 0.639). Finally, agreement between both observers is mostly high (kappa > 0.8). Foraminal stenosis, canal stenosis and the grade of the canal stenosis were overdiagnosed by the inexperienced observer in the evaluation of CT images. CONCLUSIONS AND SIGNIFICANCE: CT is as sensitive as lumbar MRI in the evaluation of most of the items analysed, excluding Modic changes, degenerative changes, signal of the disc and disc herniation. In addition, these results are obtained regardless the experience of the radiologist. The rising use of diagnostic medical imaging and the improvement of image quality brings the opportunity of making a second look of abdominal CT in search of causes of LBP. Thereby, inappropriate medical imaging could be avoided (2). In addition, it would allow to reduce MRI waiting list and prioritize other patients with more severe pathology than LBP.

Diagnosis of treponemal co-infection in HIV-infected West Africans.

OBJECTIVES: To evaluate the performance of two enzyme immunoassays (EIA), Murex and ICE, and the Determine TP point-of-care test (POCT) in diagnosing treponemal infection (syphilis or yaws) in patients attending a large HIV clinic in Ghana; to determine the prevalence of treponemal co-infections; and to characterise demographic and clinical features of patients with infection. METHODS: Samples were tested with EIAs and rapid plasma reagin (RPR), then POCT and reference assays for Treponema pallidum to determine prevalence of active and past infection. Sensitivity and specificity of each assay were calculated and demographic and clinical characteristics of patients compared. Data were collected from case notes of patients retrospectively. RESULTS: Overall, 45/284 patient samples (14.8%, 95% CI, 11.1-19.4%) were Treponema pallidum particle agglutination (TPPA) positive, and of these, 27 (64.3%) were RPR positive and 4 (8.9%) were treponemal IgM positive. Both EIAs and Determine TP POCT showed high sensitivities and specificities for identifying infection although RPR was less reliable. Clinical features of syphilis or yaws were rarely identified in TPPA-positive patients suggesting most had previous or late latent infection. Treatment of various intercurrent infections using short courses of antibiotics active against T. pallidum was common in the clinic. CONCLUSIONS: A high proportion of this HIV-infected cohort showed evidence of treponemal infection. Both EIAs as well as the POCT were practical and effective at diagnosing treponemal co-infection in this setting. RPR alone was unreliable at identifying active treponemal co-infection, however might be useful in some settings where treponemal-specific assays are unaffordable.

Use of predictive scales for pulmonary thromboembolism in an emergency department. / Uso de escalas predictivas de tromboembolia pulmonar en un servicio de urgencias.

BACKGROUND AND OBJECTIVE: Diagnosing pulmonary thromboembolism (PTE) is difficult. Clinical probability scales (CPS) can help. The aim is to find out which one is the best. PATIENTS AND METHODS: A retrospective cross-sectional single-center study was conducted. It evaluated four CPS (Pulmonary Embolism Rule Out Criteria [PERC], Wells, Geneva, and YEARS criteria) validity in 200 patients who underwent computerized tomography angiography of the pulmonary arteries. Their degree of use was estimated, as well as the possible correlation between them and DD (D dimer). RESULTS: The four CPS have a high sensitivity, close to 1 and without differences between them. The YEARS scale is between 2 and 4 times more specific than the others. The degree of use of the scales was estimated at 14% (95% CI: 9.19-18.81). A weak positive correlation was found between the scores on the Wells and Geneva scales and the DD. CONCLUSIONS: The YEARS scale is shown to be better than the others due to its potential greater number of imaging tests avoided and the degree of application of the CPS could be improved.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27 × 10e-4 (according to official data of new cases diagnosed by PCR) to 4.69 × 10e-4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

Utility of preoperative polymerase chain reaction testing during SARS-CoV-2 pandemic: The challenge of evolving incidence. / Utilidad de la prueba de reacción en cadena de la polimerasa preoperatoria durante la pandemia por SARS-CoV-2: el desafío de la incidencia cambiante.

INTRODUCTION: Due to its high transmissibility, measures aimed at reducing the spread of SARS CoV2 have become mandatory. Different organizations have recommended performing polymerase chain reaction tests (PCR) as part of the preoperative screening of surgical patients. We aimed to determine the performance of PCR testing to detect asymptomatic carriers. METHODS: Observational study carried out at a tertiary care center. We compared the results of preoperative real-time reverse-transcription-PCR test (RT-PCR) performed on a cohort of patients pending surgery with the results we would have expected assuming the epidemiological data released by government offices. RESULTS: We registered no positives in the 2,722 preoperative RT-PCR tests performed in our health care area between epidemiological Weeks 18 to 21, meaning a cumulative incidence trending to zero. Assuming public epidemiological data, the probabilistic projection of potential asymptomatic individuals ranged from 0.27*10e -4 (according to official data of new cases diagnosed by PCR) to 4.69*10e -4 if we assumed cases confirmed by IgG test in our province. Assuming a RT-PCR sensitivity of 95%, to obtain a positive result we should perform 38,461 and 2,028 tests respectively. CONCLUSIONS: In scenarios of very low prevalence and despite high sensitivity scores, indiscriminate preoperative RT-PCR screening is of a questionable effectiveness for detecting asymptomatic carriers. Our findings evidence the difficulty of establishing reliable predictive models for the episodic and rapidly evolving incidence of infections such as has characterized the SARS CoV2 pandemic.

[Evaluation of the diagnostic test for rapid detection of covid-19 antigen (Panbio Covid rapid test) in primary care]. / Evaluación de la prueba diagnóstica de detección rápida de antígeno de covid-19 (Panbio Covid rapid test) en atención primaria.

OBJECTIVE: COVID-19 infection requires early diagnosis, with PCR being the gold standard test. The protocols advocate the use of rapid antigenic tests that require evaluation in actual clinical practice. The objective was to evaluate the diagnostic test for rapid antigen detection, Panbio Covid rapid test, compared with PCR, in patients with symptoms of 5 or less days of evolution and with a high-suspicion of infection by COVID-19 in a health center. MATERIALS AND METHODS: 103 patients over 14 years of age who attended an urban health center located in the Usera District of Madrid, with high-suspicion of COVID-19 infection, in the first 5 days of evolution from the onset of symptoms during the month of November 2020. INTERVENTIONS: diagnostic tests for COVID-19 are performed: antigen and PCR. RESULTS: The prevalence of the disease was 24.3% according to the PCR test and 17.5% according to the rapid antigenic test. The sensitivity was 72% (95% CI: 54.3-89.6%). The specificity was 100%. The positive and negative predictive values were 100% and 91.8% respectively. In the bivariate analysis, there was no relationship between symptoms and the presence of disease, except for myalgias (p=0.030). The multivariate analysis found a relationship between cough, dyspnea, fever, myalgia, anosmia/ageusia, and ocular symptoms and the presence of disease. CONCLUSIONS: The sensitivity and specificity for the Panbio rapid antigen test are similar to other studies performed in primary care. In high-prevalence of disease and with highly suspected symptoms, positive test results can be considered definitive, but negative results will require confirmation. Myalgia, fever, dyspnea, anosmia/ageusia, and ocular symptoms may be more related to the presence of COVID-19.