Effectiveness of Statins for Primary Prevention of Cardiovascular Disease in Low- and Medium-Risk Males: A Causal Inference Approach with Observational Data

In this study, we analyzed the effectiveness of statin therapy for the primary prevention of cardiovascular disease (CVD) in low- and medium-risk patients. Using observational data, we estimated effectiveness by emulating a hypothetical randomized clinical trial comparing statin initiators with statin non-initiators. Two approaches were used to adjust for potential confounding factors: matching and inverse probability weighting in marginal structural models. The estimates of effectiveness were obtained by intention-to-treat and per-protocol analysis. The intention-to-treat analysis revealed an absolute risk reduction of 7.2 (95% confidence interval (CI95%), −6.6–21.0) events per 1000 subjects treated for 5 years in the matched design, and 2.2 (CI95%, −3.9–8.2) in the marginal structural model. The per-protocol analysis revealed an absolute risk reduction of 16.7 (CI95%, −3.0–36) events per 1000 subjects treated for 5 years in the matched design and 5.8 (CI95%, 0.3–11.4) in the marginal structural model. The indication for statin treatment for primary prevention in individuals with low and medium cardiovascular risk appears to be inefficient, but improves with better adherence and in subjectvs with higher risk

A novel approach to learning through categorical variables applicable to the classification of solitary pulmonary nodule malignancy

Background: One of the main drawbacks in constructing a classification model is that some or all of the covariates are categorical variables. Classical methods either assign labels to each output of a categorical variable or are summarised measures (frequencies and percentages), which can be interpreted as probabilities. Methods: We adopted a novel mathematical procedure to construct a classification model from categorical variables based on a non-classical probability approach. More specifically, we codified the variables following the categorical data representation from the Discriminant Correspondence Analysis before constructing a non-classical probability matrix system that represents an entangled system of dependent-independent variables. We then developed a disentangled procedure to obtain an empirical density function for each representative class (minimum of two classes). Finally, we constructed our classification model using the density functions. Results: We applied the proposed procedure to build a classification model of the malignancy of Solitary Pulmonary Nodule (SPN) after five years of follow up using routine clinical data. First, with 2/3 (270) of the sample of 404 patients with SPN, we constructed the classification model, and then validated it with the remaining 1/3(134) we validated it. We tested the procedure’s stability by repeating the analysis randomly 1000 times. We obtained a model accuracy of 0.74, an F1 score of 0.58, a Cohen’s Kappa value of 0.41 and a Matthews Correlation Coefficient of 0.45. Finally, the area under the ROC curve was 0.86. Conclusion: The proposed procedure provides a machine learning classification model with an acceptable performance of a classification model of solitary pulmonary nodule malignancy constructed from routine clinical data and mainly composed of categorical variables. It provides an acceptable performance, which could be used by clinicians as a tool to classify SPN malignancy in routine clinical practice

Morphosedimentary characterization of sublittoral beds of San Andres beach (Malaga Bay) using side scan sonar

The present work contributes to the characterization and mapping of sublittoral seabed located in the nearshore of the San Andrés Beach in Malaga. This zone extends between the outer dock of the Malaga harbor and the Guadalhorce river mouth. The study was done using the description of the acoustic reflection patterns obtained with Side Scan Sonar thechniques. These patterns have been identified with lithological changes, morphological features, dimension and orientation of bedforms, underwater patrimony and evidences of the human activity on the seabe

Prognostic stratification of adult primary glioblastoma multiforme patients based on their tumor gene amplification profiles

[EN]everal classification systems have been proposed to address genomic heterogeneity of glioblastoma multiforme, but they either showed limited prognostic value and/or are difficult to implement in routine diagnostics. Here we propose a prognostic stratification model for these primary tumors based on tumor gene amplification profiles, that might be easily implemented in routine diagnostics, and potentially improve the patients management. Gene amplification profiles were prospectively evaluated in 80 primary glioblastoma multiforme tumors using singlenucleotide polymorphism arrays and the results obtained validated in publicly available data from 267/347 cases. Gene amplification was detected in 45% of patients, and chromosome 7p11.2 including the EGFR gene, was the most frequently amplified chromosomal region - either alone (18%) or in combination with amplification of DNA sequences in other chromosomal regions (10% of cases). Other frequently amplified DNA sequences included regions in chromosomes 12q(10%), 4q12(7%) and 1q32.1(4%). Based on their gene amplification profiles, glioblastomas were subdivided into: i) tumors with no gene amplification (55%); ii) tumors with chromosome 7p/EGFR gene amplification (with or without amplification of other chromosomal regions) (38%); and iii) glioblastoma multiforme with a single (11%) or multiple (6%) amplified DNA sequences in chromosomal regions other than chromosome 7p

Variability of indication criteria in knee and hip replacement: an observational study

<p>Abstract</p> <p>Background</p> <p>Total knee (TKR) and hip (THR) replacement (arthroplasty) are effective surgical procedures that relieve pain, improve patients' quality of life and increase functional capacity. Studies on variations in medical practice usually place the indications for performing these procedures to be highly variable, because surgeons appear to follow different criteria when recommending surgery in patients with different severity levels. We therefore proposed a study to evaluate inter-hospital variability in arthroplasty indication.</p> <p>Methods</p> <p>The pre-surgical condition of 1603 patients included was compared by their personal characteristics, clinical situation and self-perceived health status. Patients were asked to complete two health-related quality of life questionnaires: the generic SF-12 (Short Form) and the specific WOMAC (Western Ontario and Mcmaster Universities) scale. The type of patient undergoing primary arthroplasty was similar in the 15 different hospitals evaluated.</p> <p>The variability in baseline WOMAC score between hospitals in THR and TKR indication was described by range, mean and standard deviation (SD), mean and standard deviation weighted by the number of procedures at each hospital, high/low ratio or extremal quotient (EQ_5-95), variation coefficient (CV_5-95) and weighted variation coefficient (WCV_5-95) for 5-95 percentile range. The variability in subjective and objective signs was evaluated using median, range and WCV_5-95. The appropriateness of the procedures performed was calculated using a specific threshold proposed by Quintana et al for assessing pain and functional capacity.</p> <p>Results</p> <p>The variability expressed as WCV_5-95was very low, between 0.05 and 0.11 for all three dimensions on WOMAC scale for both types of procedure in all participating hospitals. The variability in the physical and mental SF-12 components was very low for both types of procedure (0.08 and 0.07 for hip and 0.03 and 0.07 for knee surgery patients). However, a moderate-high variability was detected in subjective-objective signs. Among all the surgeries performed, approximately a quarter of them could be considered to be inappropriate.</p> <p>Conclusions</p> <p>A greater inter-hospital variability was observed for objective than for subjective signs for both procedures, suggesting that the differences in clinical criteria followed by surgeons when indicating arthroplasty are the main responsible factors for the variation in surgery rates.</p

Trends in incidence and outcomes of revision total hip arthroplasty in Spain: A population based study

<p>Abstract</p> <p>Background</p> <p>To analyze changes in incidence and outcomes of patients undergoing revision total hip arthroplasty (RTHA) over an 8-year study period in Spain.</p> <p>Methods</p> <p>We selected all surgical admissions in individuals aged ≥ 40 years who underwent RTHA (ICD-9-CM procedure code 81.53) between 2001 and 2008 from the Spanish National Hospital Discharge Database. Age- and sex-specific incidence rates, Charlson co-morbidity index, length of stay (LOS), costs and in-hospital mortality (IHM) were estimated for each year. Multivariate analyses were conducted to asses time trends.</p> <p>Results</p> <p>32, 280 discharges of patients (13, 391 men/18, 889 women) having undergone RTHA were identified. Overall crude incidence showed a small but significant increase from 20.2 to 21.8 RTHA per 100, 000 inhabitants from 2001 to 2008 (p < 0.01).</p> <p>The incidence increased for men (17.7 to 19.8 in 2008) but did not vary for women (22.3 in 2001 and 22.2 in 2008). Greater increments were observed in patients older than 84 years and in the age group 75-84. In 2001, 19% of RTHA patients had a Charlson Index ≥ 1 and this proportion rose to 24.6% in 2008 (p < 0.001). The ratio RTHA/THA remained stable and around 20% in Spain along the entire period</p> <p>The crude overall in-hospital mortality (IHM) increased from 1.16% in 2001 to 1.77% (p = 0.025) in 2008. For both sexes the risk of death was higher with age, with the highest mortality rates found among those aged 85 or over. After multivariate analysis no change was observed in IHM over time. The mean inflation adjusted cost per patient increased by 78.3%, from 9, 375 to 16, 715 Euros from 2001 to 2008.</p> <p>After controlling for possible confounders using Poisson regression models, we observed that the incidence of RTHA hospitalizations significantly increased for men and women over the period 2001 to 2008 (IRR 1.10, 95% CI 1.03-1.18 and 1.08, 95% CI 1.02-1.14 respectively).</p> <p>Conclusions</p> <p>The crude incidence of RTHA in Spain showed a small but significant increase from 2001 to 2008 with concomitant reductions in LOS, significant increase in co-morbidities and cost per patient.</p

In-hospital mortality after stomach cancer surgery in Spain and relationship with hospital volume of interventions

<p>Abstract</p> <p>Background</p> <p>There is no consensus about the possible relation between in-hospital mortality in surgery for gastric cancer and the hospital annual volume of interventions. The objectives were to identify factors associated to greater in-hospital mortality for surgery in gastric cancer and to analyze the possible independent relation between hospital annual volume and in-hospital mortality.</p> <p>Methods</p> <p>We performed a retrospective cohort study of all patients discharged after surgery for stomach cancer during 2001–2002 in four regions of Spain using the Minimum Basic Data Set for Hospital Discharges. The overall and specific in-hospital mortality rates were estimated according to patient and hospital characteristics. We adjusted a logistic regression model in order to calculate the in-hospital mortality according to hospital volume.</p> <p>Results</p> <p>There were 3241 discharges in 144 hospitals. In-hospital mortality was 10.3% (95% CI 9.3–11.4). A statistically significant relation was observed among age, type of admission, volume, and mortality, as well as diverse secondary diagnoses or the type of intervention. Hospital annual volume was associated to Charlson score, type of admission, region, length of stay and number of secondary diagnoses registered at discharge. In the adjusted model, increased age and urgent admission were associated to increased in-hospital mortality. Likewise, partial gastrectomy (Billroth I and II) and simple excision of lymphatic structure were associated with a lower probability of in-hospital mortality. No independent association was found between hospital volume and in-hospital mortality</p> <p>Conclusion</p> <p>Despite the limitations of our study, our results corroborate the existence of patient, clinical, and intervention factors associated to greater hospital mortality, although we found no clear association between the volume of cases treated at a centre and hospital mortality.</p