Interval Confidence Research Articles

On the Superiority of the Negative Binomial Test Over the Binomial Test for Estimating the Bit Error Rate

This paper examines the binomial and negative binomial tests for estimating the bit error rate using Monte Carlo simulations. Whereas the estimator error variances and simulation times do not recommend one test over the other, confidence interval analysis and test design criteria recommend the negative binomial test for estimating a small bit error rate based on a limited number of error events. The Clopper-Pearson interval length is much more consistent for the negative binomial test in the small bit error rate case. The logarithmically centered confidence interval is introduced and analyzed. For a given confidence interval length and confidence probability, the negative binomial test requires fewer error events than the binomial test. The asymptotic analyses of the Clopper-Pearson and logarithmically-centered confidence intervals yield useful design criteria for the negative binomial test in a way that is not possible for the binomial test.

Consistency of the Automatic Algorithm in Detecting Complex Fractionated Electrograms using an Electroanatomical Navigation System

The different settings of the automatic algorithm in the Carto system (Carto XP, Biosense Webster, Diamond Bar, CA, USA) used for detecting complex fractionated electrograms (CFEs) during atrial fibrillation (AF) may influence the identification of the fragmented electrograms. We aimed to evaluate the impact of the different parameters on the detection of CFEs and the efficacy of the substrate modification after pulmonary vein isolation (PVI). A total of 1,159 electrograms were analyzed from 11 consecutive patients (age = 56 ± 12 years). The effect of the different algorithm factors, such as the high-voltage thresholds (0.12, 0.25, 0.5, 20 mV), detection algorithms (average complex interval [ACI] vs interval confidence level), and recording duration (2.5 seconds vs 5 seconds), on the disparities of the CFEs was investigated. The proportion of the different grades of CFEs depended on the detection algorithm and recording duration. The high-voltage threshold would not affect the consistency of the CFEs irrespective of the different settings of the detection algorithm or recording duration. High-grade CFEs were most consistent with an ACI algorithm and recording duration of 5 seconds (Cronbach's alpha = 0.952). Ablation consisting of a PVI and high-grade CFE sites converted AF directly to sinus rhythm in eight of 11 patients or into atrial tachycardia in one of 11. The distribution and consistency of the CFE detection depended on the detection algorithm and recording duration, but not on the high-voltage threshold. Under the ACI algorithm and a recording duration of 5 seconds, high-grade CFE sites remained highest consistency.

In defense of adolescents: They really do use braces for the hours prescribed, if good help is provided. Results from a prospective everyday clinic cohort using thermobrace

BackgroundThe effectiveness of bracing relies on the quality of the brace, compliance of the patient, and some disease factors. Patients and parents tend to overestimate adherence, so an objective assessment of compliance has been developed through the use of heat sensors. In 2010 we started the everyday clinical use of a temperature sensor, and the aim of this study is to present our initial results.MethodsPopulation: A prospective cohort of 68 scoliosis patients that finished at least 4 months of brace treatment on March 31, 2011: 48 at their first evaluation (79% females, age 14.2±2.4) and 20 already in treatment.Treatment: Bracing (SPoRT concept); physiotherapic specific exercises (SEAS School); team approach according to the SOSORT Bracing Management Guidelines.Methods. A heat sensor, “Thermobrace” (TB), has been validated and applied to the brace. The real (measured by TB) and referred (reported by the patient) compliances were calculated.Statistics. The distribution was not normal, hence median and 95% interval confidence (IC95) and non-parametric tests had to be used.ResultsAverage TB use: 5.5±1.5 months. Brace prescription was 23 hours/day (h/d) (IC95 18–23), with a referred compliance of 100% (IC95 70.7-100%) and a real one of 91.7% (IC95 56.6-101.7%), corresponding to 20 h/d (IC95 11–23). The more the brace was prescribed, the more compliant the patient was (94.8% in 23 h/d vs. 73.2% in 18 h/d, P < 0.05). Sixty percent of the patients had at least 90% compliance, and 45% remained within 1 hour of what had been prescribed. Non-wearing days were 0 (IC95 0–12.95), and involved 29% of patients.ConclusionThis is the first study using a TB in a setting of respect for the SOSORT criteria for bracing, and it states that it is possible to achieve a very good compliance, even with a full time prescription, and better than what was previously reported (80% maximum). We hypothesize that the treating team (SOSORT criteria) plays a major role in our results. This study suggests that compliance is neither due to the type of treatment only nor to the patient alone. According to our experience, TB offers valuable insights and do not undermine the relationship with the patients.

Statistical Inferences for Lomax Distribution Based on Record Values (Bayesian and Classical)

A maximum likelihood estimation (MLE) based on records is obtained and a proper prior distribution to attain a Bayes estimation (both informative and non-informative) based on records for quadratic loss and squared error loss functions is also calculated. The study considers the shortest confidence interval and Highest Posterior Distribution confidence interval based on records, and using Mean Square Error MSE criteria for point estimation and length criteria for interval estimation, their appropriateness to each other is examined.

Estimating the Trunk Transverse Surface Area to Assess Swimmer's Drag Force Based on their Competitive Level

The aim of this study was to compute and validate trunk transverse surface area (TTSA) estimation equations to be used assessing the swimmer’s drag force according to competitive level by gender. One group of 130 swimmers (54 females and 76 males) was used to compute the TTSA estimation equations and another group of 132 swimmers (56 females and 76 males) were used for its validations. Swimmers were photographed in the transverse plane from above, on land, in the upright and hydrodynamic position. The TTSA was measured from the swimmer’s photo with specific software. It was also measured the height, body mass, biacromial diameter, chest sagital diameter (CSD) and the chest perimeter (CP). With the first group of swimmers it was computed the TTSA estimation equations based on stepwise multiple regression models from the selected anthropometrical variables. The TTSA prediction equations were significant and with a prediction level qualitatively considered as moderate. All equations included only the CP and the CSD in the final models. In all prediction models there were no significant differences between assessed and estimated mean TTSA. Coefficients of determination for the linear regression models between assessed and estimated TTSA were moderate and significant. More than 80% of the plots were within the 95% interval confidence for the Bland-Altman analysis in both genders. So, TTSA estimation equations that are easy to be computed by coached and researchers were developed. All equations accomplished the validation criteria adopted.

Yield‐Related Process Capability Indices for Processes of Multiple Quality Characteristics

Process capability indices (PCIs) have been widely used in industries for assessing the capability of manufacturing processes. Castagliola and Castellanos (Quality Technology and Quantitative Management 2005, 2(2):201–220), viewing that there were no clear links between the definition of the existing multivariate PCIs and theoretical proportion of nonconforming product items, defined a bivariate Cpk and Cp (denoted by BCpk and BCp, respectively) based on the proportions of nonconforming product items over four convex polygons for bivariate normal processes with a rectangular specification region. In this paper, we extend their definitions to MCpk and MCp for multivariate normal processes with flexible specification regions. To link the index to the yield, we establish a ‘reachable’ lower bound for the process yield as a function of MCpk. An algorithm suitable for such processes is developed to compute the natural estimate of MCpk from process data. Furthermore, we construct via the bootstrap approach the lower confidence bound of MCpk, a measure often used by producers for quality assurance to consumers. As for BCp, we first modify the original definition with a simple preprocessing step to make BCp scale‐invariant. A very efficient algorithm is developed for computing a natural estimator of BCp. This new approach of BCp can be easily extended to MCp for multivariate processes. For BCp, we further derive an approximate normal distribution for , which enables us to construct procedures for making statistical inferences about process capability based on data, including the hypothesis testing, confidence interval, and lower confidence bound. Finally, the proposed procedures are demonstrated with three real data sets. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Quantifying uncertainty of emission estimates in National Greenhouse Gas Inventories using bootstrap confidence intervals

Greenhouse gas (GHG) emissions have exacerbated global warming, and consequently are the focus of worldwide reduction efforts. Reducing emissions involves accurately estimating GHG emissions and the uncertainty associated with such estimates. The uncertainty of GHG emission estimates is often assessed using the 95% confidence interval. Given a small sample size and non-normal distribution of the underlying population, the uncertainty estimate obtained using the 95% confidence interval may lead to significant bias. Bootstrap confidence interval is an effective means of reducing bias. This work presents a procedure for estimating the uncertainty of GHG emission estimation using bootstrap confidence intervals. Numerical simulation is performed for GHG emission estimates under three distributions (namely normal, log-normal and uniform) to find the 95% confidence intervals and bootstrap confidence intervals. Finally, the accuracy and sensitivity of the uncertainty of various interval estimations are examined by comparing the coverage performance, interval mean and interval standard deviation. Simulation results indicate that the bootstrap intervals are more applicable than the 95% confidence interval given non-normal dataset and small sample size. Moreover, when sample size n is less than 30, the bootstrap confidence interval has a smaller interval length with a smaller deviation than that of the classical 95% confidence interval regardless of whether the data distribution is normal or non-normal. This study recommends a sample size greater than or equal to 9 for estimating the uncertainty of emission estimates. When the sample size n exceeds 30, either the normality-based 95% confidence interval or bootstrap confidence intervals may be used regardless of whether the data distribution is normal or non-normal. A case study of carbon stock from Taiwan demonstrates the feasibility of the proposed procedure.

Generalizing the standardized hazard ratio to multivariate proportional hazards regression, with an application to clinical~genomic studies

The standardized hazard ratio for univariate proportional hazards regression is generalized as a scalar to multivariate proportional hazards regression. Estimators of the standardized log hazard ratio are developed, with corrections for bias and for regression to the mean in high-dimensional analyses. Tests of point and interval null hypotheses and confidence intervals are constructed. Cohort sampling study designs, commonly used in prospective–retrospective clinical genomic studies, are accommodated.

Evaluation of an Immunofluorescence Antibody Assay for the Detection of Antibodies Against Toxoplasma gondii in Meat Juice Samples from Finishing Pigs

Serum and meat juice analyses for the detection of Toxoplasma gondii antibodies by an immunofluorescence antibody assay were compared in 100 seropositive and 100 seronegative slaughtered heavy swine. Meat juice was obtained from diaphragm and gracilis muscles of the serologically tested animals. Seventy-two diaphragmatic meat juice samples (36%, 95% interval confidence [IC] 29.4%-43.1%) and 63 gracilis meat juice samples (31.5%, 95% IC 25.1%-38.4%) tested positive for T. gondii antibodies. The average concordance between serum and meat juice derived from both muscles was "substantial" (K=0.6-0.8). The K-value was 1 when considering serum samples showing a titer >1/16, whereas it decreased to 0.62 and to 0.49 when considering serum samples with a 1/16 titer in meat juice from diaphragm and gracilis muscle, respectively.

Is the Insurance Cost-of-Capital Fair?

This paper aims to present the insurance cost-of-capital computation issue. It highlights two methodologies introduced by Chief Risk Officer Forum (2008) to perform the cost-of-capital rate and which more or less justify the risk premium adopted by supervisory authorities. These strategies are based either on market return of insurance companies or on the modelling of insurance business profit and loss. We estimate a cost-of-capital rate corresponding to these basic methodologies and point out the benefits and drawbacks of each method. We show that the risk premium adopted by the supervisory authorities is inside the interval confidence given either by market data or by the modelling: thus it would correspond to a fair cost-of-capital rate. In addition to that we discuss the fact that this rate is quite low and allows to adopt a relative conservative strategy.

Performance of Glycated Hemoglobin and a Risk Model for Detection of Unknown Diabetes in Coronary Patients

Introduction and objectives Traditionally, the oral glucose tolerance test has been useful to diagnose unknown diabetes. Recently, the American Diabetes Association committee has accepted glycated hemoglobin ≥6.5% as a criterion for unknown diabetes. The aim was to determine the benefit of glycated hemoglobin for diagnosing unknown diabetes and also create a predictive model that adjusts the indication for oral glucose tolerance test in coronary patients. Methods We examined the glycemic profile of 338 coronary patients without previous diagnosis of diabetes, applying 2010 American Diabetes Association criteria. A unknown diabetes risk predictive model was developed using logistic regression analysis, and then validated in another cohort. Results Using the glycated hemoglobin criteria and/or fasting plasma glucose, unknown diabetes was diagnosed in 26 patients. The remaining patients were classified according to oral glucose tolerance test as follows: unknown diabetes 53 (17%), prediabetes 144 (46.2%), and normoglycemic 115 (36.8%). The diagnostic method for unknown diabetes was fasting plasma glucose in 25.3%, glycated hemoglobin in 7.6%, and oral glucose tolerance test in 67.1%. A risk model including fasting plasma glucose, glycated hemoglobin, left ventricular ejection fraction, age, and noncoronary vascular disease was shown to effectively predict unknown diabetes after oral glucose tolerance test: area under the ROC curve 0.8 (95% interval confidence: 0.74-0.87). When the oral glucose tolerance test is restricted to patients with a risk score >6 (31% of our sample) we properly identify 83% of unknown diabetes cases (sensitivity: 75%, specificity: 73%, positive predictive value: 40%, negative predictive value: 93%). The model was adequately validated in another cohort of 115 patients (area under the ROC curve 0.84 [95% interval confidence: 0.74-0.95]). Conclusions In coronary patients, glycated hemoglobin alone failed to detect many cases of unknown diabetes. However, its inclusion in a risk prediction model leads to optimizing the usefulness of oral glucose tolerance test.

Morbilidad materna extrema en cuidados intensivos obstétricos. Cartagena (Colombia) 2006 - 2008

Objetivo: el presente estudio tiene como objetivo establecer la incidencia de la morbilidad materna extrema (MME), sus características clínicas y hacer una primera aproximación a los indicadores de calidad de la atención obstétrica en la unidad de cuidados intensivos (UCI).Materiales y métodos: estudio de cohorte, retrospectivo de pacientes obstétricas con MME que ingresaron a la UCI de la Clínica de Maternidad Rafael Calvo de Cartagena entre el período del 1 de enero de 2006 al 31 de diciembre de 2008. Se registraron las características sociodemográficas, ginecoobstétricas, criterios de MME y los indicadores de calidad de la atención obstétrica. Para el análisis de resultados se utilizaron medidas de tendencia central y dispersión, porcentajes, tablas de frecuencia y razones estandarizadas de morbilidad con intervalos de confianza (IC) al 95%.Resultados: la incidencia de MME fue de 12,1 por 1000 nacimientos. El 27,2% (88 pacientes) eran adolescentes y el 61,6% multigestantes (199 pacientes). El principal diagnóstico asociado a la MME fue el trastorno hipertensivo del embarazo, 49,5% (160 pacientes), seguido por las hemorragias del embarazo, 22,6% (73 pacientes). Las principales disfunciones orgánicas fueron respiratorias, 38,1% (123 casos), hepáticas, 15,2% (49 casos) e inmunológicas, 14,6% (47 casos). La transfusión fue la intervención más común, 22,6% (73 pacientes). Durante los años de estudio la incidencia de MME y la razón de casos de MME: muerte materna (MM) aumentaron, mientras que el índice de mortalidad disminuyó.Conclusiones: se encontró una incidencia de MME del 12,1 por 1000 nacimientos. Se presentaron los indicadores de calidad como medición basal, lo que servirá de comparación para futuras mediciones.

Morphometric Study for Estimation and Validation of Trunk Transverse Surface Area To Assess Human Drag Force on Water

The aim of this study was to compute and validate estimation equations for the trunk transverse surface area (TTSA) to be used in assessing the swimmer’s drag force in both genders. One group of 133 swimmers (56 females, 77 males) was used to compute the estimation equations and another group of 131 swimmers (56 females, 75 males) was used for its validations. Swimmers were photographed in the transverse plane from above, on land, in the upright and hydrodynamic position. The TTSA was measured from the swimmer’s photo with specific software. Also measured was the height, body mass, biacromial diameter, chest sagital diameter (CSD) and the chest perimeter (CP). With the first group of swimmers, it was computed the TTSA estimation equations based on stepwise multiple regression models from the selected anthropometrical variables. For males TTSA=6.662*CP+17.019*CSD-210.708 (R2=0.32; Ra2=0.30; P<0.01) and for females TTSA=7.002*CP+15.382*CSD-255.70 (R2=0.34; Ra2=0.31; P<0.01). For both genders there were no significant differences between assessed and estimated mean TTSA. Coefficients of determination for the linear regression models between assessed and estimated TTSA were R2=0.39 for males and R2=0.55 for females. More than 80% of the plots were within the 95% interval confidence for the Bland-Altman analysis in both genders.

Autonomic modulation of complex fractionated atrial electrograms in patients with paroxysmal atrial fibrillation

In patients with atrial fibrillation (AF), complex fractionated atrial electrograms (CFAE) have been shown to be located at the anatomic sites of ganglionated plexi (GP). This study aimed at investigating the contribution of parasympathetic activity to formation of CFAE. Twelve patients (aged 55 ± 11years, five females) with paroxysmal AF were studied. Following electroanatomical mapping of the left atrium, GP were identified by high frequency stimulation (HFS), 12-24V in a conscious state, and assessment of CFAE during AF was performed with the use of dedicated software. Fractionated activity was measured at each GP site by interval confidence levels (ICL) and average complex interval (ACI), and was compared to measurements obtained 1min after intravenous administration of 1mg of atropine. In total, 30 out of 48 GP could be identified by HFS. CFAE were detected at all sites where GP were found. ICL was significantly lower after atropine administration only at ARGP (5.4 ± 2.7 vs. 2.8 ± 2.1, p = 0.028), whereas no significant difference was detected pre- or post-atropine at any GP in ACI. Considering all fractionation values from the four GP, a statistically significant reduction of the ICL score was observed (4.6 ± 3.4 vs. 5.8 ± 2.9, p = 0.03) after atropine administration, whereas no significant differences were observed in the ACI score (144.5 ± 24.0 post-atropine vs. 146.7 ± 27.7 pre-atropine, p = 0.620). The average RR interval became significantly shorter post-atropine (575.8 ± 139.1 vs. 637.2 ± 158.7, p = 0.004). Our data do not support the hypothesis that parasympathetic activity plays the dominant role in electrogram fractionation.

Confidence Distributions and a Unifying Framework for Meta-Analysis

This article develops a unifying framework, as well as robust meta-analysis approaches, for combining studies from independent sources. The device used in this combination is a confidence distribution (CD), which uses a distribution function, instead of a point (point estimator) or an interval (confidence interval), to estimate a parameter of interest. A CD function contains a wealth of information for inferences, and it is a useful device for combining studies from different sources. The proposed combining framework not only unifies most existing meta-analysis approaches, but also leads to development of new approaches. We illustrate in this article that this combining framework can include both the classical methods of combining p-values and modern model-based meta-analysis approaches. We also develop, under the unifying framework, two new robust meta-analysis approaches, with supporting asymptotic theory. In one approach each study size goes to infinity, and in the other approach the number of studies goes to infinity. Our theoretical development suggests that both these robust meta-analysis approaches have high breakdown points and are highly efficient for normal models. The new methodologies are applied to study-level data from publications on prophylactic use of lidocaine in heart attacks and a treatment of stomach ulcers. The robust methods performed well when data are contaminated and have realistic sample sizes and number of studies.

P02-200 - Drug-induced psychiatric disoders in prisoners

IntroductionThe prevalence of psychiatric disorders in prison populations showed in other European countries has not been replicated in Spain.ObjectivesThe aim of the study was to estimate the lifetime and last month prevalence of mental disorders in a Spanish prison population sample. In this posetr we look a drug induced psychiatryc disorders found in this study.MethodThis is a descriptive cross-sectional epidemiological study. 783 male inmates were included in the study. Mental disorders were assessed with Structured Clinical Interview (SCID 1) for DSM-IV Axis 1 Disorders, clinical version and personality disorders were assessed by the Spanish version of the International Personality Disorders Examination.ResultsThe lifetime prevalence of mental disorder was 84.4%. Substance use disorder (abuse and dependence) was the most frequent disorder (76,2%): When look at substance induced diosder we found Mood induced disoder had lifetime prevalence of 15,8%(,13,2–18,5) and a last month prevalence of 2,8% (1,6–4,1), anxiety disoders were 16,1% (13,4–18,8) in lifetime prevalence and 5,9 (4,2–7,7) for last month prevalence and for subtance induce psychotic disoder lifetime prevalence was 7,1%(5,2–9,0) and last month prevalence was 2.0 (1.0–3.0). There is a 95 interval confidence on all these data.ConclusionsThe high prevalence of mental disorder and substance misuse is relevant both for the planning of health resource use in the prison environment and the prevention and approach to these disorders.

A General Model for Start-Up Demonstration Tests

The commonly known consecutive successes total failures (CSTF) start-up demonstration test procedure is generalized to a total successes consecutive successes total failures consecutive failures (TSCSTFCF) procedure. Accordingly, a unit under test is accepted when either a total number of successful tests or a specified number of consecutive successes of tests are observed before both a total number of failures and any run of specified length of failures; otherwise the unit is rejected. The waiting time until termination (the length of the set of tests) of the general procedure is evaluated. A correct choice of parameters (e.g. the number of successes required for acceptance, or the length of a run of failures causing rejection) may yield a significantly shorter waiting time than that of the relevant CSTF procedure. Also, the new procedure is less sensitive to parameter changes, which is an obvious improvement in case the parameter values are miss-specified. We provide interval confidence bounds for the estimation of the reliability for the start-up demonstration test, which is based on maximum likelihood estimators. Then, we determine the minimum sample size needed in a demonstration test to achieve a certain precision of this reliability at a specified confidence level.

The Contrast between the Area of the Ganglionated Plexi and Complex Fractionated Atrial Electrograms

The Ganglionated Plexi (GP) and complex fractionated atrial electrograms (CFAE) play the important role as the perpetuator of atrial fibrillation (AF). GP ablation is known as alternative procedure for AF. The aim of this study was to evaluate the contrast between the area of the GP and CFAE. Method: Ten consecutive patients with AF were studied. For patients with sinus rhythm, AF was induced by rapid atrial pacing. The geometry of Left atrium (LA) was reconstructed with electroanatomical mapping system (CARTO XP). Bipolar electrograms recorded during 2.5 second were analyzed using CFAE software module. The algorism was customized to demonstrate the classification as follows in Interval confidence level (ICL) map. Sites with continuous or transient fractionated atrial potentials were colored red. Sites with irregular amplitude, polarity, cycle length but not rapid were colored green. Sites with slow organized atrial potential were purple. The sites where vagal response was evoked by high-frequency stimulation were identified as GP sites and marked on the geometry. Result: A total of 1,107 points were taken in LA. Among a total of 197 GP points, 139 (77.2%) points were in colored red and categorized as in CFAE area. GP points in colored purple categorized as in slow organized area were only 4 points (2.3%). Conclusion: The Ganglionated Plexi is strongly related to CFAE.

Estimation of a Time Varying NAIRU for France

Among the several concepts encompassed by the idea of an equilibrium rate of unemployment (labour mismatch, unemployment trend, non inflationary unemployment, structural unemployment), the NAIRU appears as the more interesting one for a central bank since it focuses directly on inflation. Thus, the paper considers the reduced Phillips equation, assuming a stable relationship between inflation and some kind of demand desequilibrium index, as the most promising starting point to estimate an equilibrium rate of unemployment. We adopt a semi-structural method based on a combination of an economic and a statistical approach. The Phillips equation we consider is very close to the so-called triangle suggested by Gordon, where inflation rate is determined by three factors (hence the triangle) : adaptive expectations and inertia, excess demand or shortage - estimated by the gap between the actual unemployment rate and the NAIRU - and supply shock variables. We regard the NAIRU as a time-varying parameter and estimate a state space model composed of a random walk process that describes its variations over time and of a Phillips equation. Under reasonable assumptions on the innovations to the NAIRU equation, the estimation of the state-space model (using Kalman filter techniques) yields empirical results for France that appear quite convincing: the time varying NAIRU we obtain accounts for the steady increase in the actual unemployment rate during the 1970s and the 1980s and offers the appropriate degree of smoothness. Working on the sample 1986-1999 the time varying NAIRU amounts to 10% in the second quarter of 1999 (with an interval confidence between 9% and 11%). The estimation of the model since 1970 gives information on the path followed by the NAIRU during the last decades. Whereas the NAIRU increased by 2.7 points between 1977 and 1988, its steady rise seems to slow down somewhat since the second part of the 1980s, exhibiting two main deceleration periods: first during the second part of the 1980s and second in the mid-1990s. Though this method exploits the set of information contained in the Phillips curve and provides fairly robust measures of the NAIRU, it gives little insight regarding its underlying determinants. It must therefore be completed by the analysis of the recent developments in French labour market. In the second part of this paper, we provide strong evidence that the changes in the NAIRU in France during these two episodes may be linked to significant shifts in the demographic composition of the workforce together with a break in the evolution of the fiscal-social wedge. Several other factors (such as threshold effects in unemployment benefits or individual abilities) play probably a major role in unemployment variation.

Estudio de prevalencia de la enfermedad arterial periférica en las unidades médicas de corta estancia en España. Estudio UCEs

The Medical Short Stay Units (UMCE) have an area of preferred on an elderly population and multipathological patients whose most common diagnoses for admission usually are high prevalence diseases. They coincide in a high presence of cardiovascular disease, whether known or not. Peripheral arterial disease (PAD) is one manifestation of arteriosclerosis that is defined by an obstruction of the arterial blood flow in the lower extremities. A high percentage of patients do not exhibit any symptoms and others have a difficult diagnosis. The detection of the PAD through the Ankle–Brachial Index Measurement (ITB) is a non-invasive method, the scope of clinical, highly efficient in the detection of subclinical vascular injury. Objectives This technique offers a high sensitivity and specificity for stenosis ≥50% in arteries of the lower limbs. Patients and methods This is an epidemiological cross-national multicentre study with 813 patients included, 50 and older admitted for various causes that gave consent for the execution of an ITB during its income, analyzing themselves the data of 744 with ITB <1.3; considered pathological figures < 0.9. Results The prevalence of an ITB decreased in admitted subjects was 46.91% (interval confidence [CI] 95%: 43.32%–50.49%). Factors associated with significant differences were age, smoking/people who smoked, hypertension and a history of cardiovascular disease. Conclusion The prevalence of PAD as determined by a fallen ITB is high in the UMCEs in Spain, being increased with age, the presence of hypertension and smoking/people who smoked and the prior existence of cardiovascular diseases.