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Victor Abraira

Publications and source records attributed to Victor Abraira.

10 recordsLinked to original sources
PubMed2006

Meta-DiSc: a software for meta-analysis of test accuracy data.

BACKGROUND: Systematic reviews and meta-analyses of test accuracy studies are increasingly being recognised as central in guiding clinical practice. However, there is currently no dedicated and comprehensive software for meta-analysis of diagnostic data. In this article, we present Meta-DiSc, a Windows-based, user-friendly, freely available (for academic use) software that we have developed, piloted, and validated to perform diagnostic meta-analysis. RESULTS: Meta-DiSc a) allows exploration of heterogeneity, with a variety of statistics including chi-square, I-squared and Spearman correlation tests, b) implements meta-regression techniques to explore the relationships between study characteristics and accuracy estimates, c) performs statistical pooling of sensitivities, specificities, likelihood ratios and diagnostic odds ratios using fixed and random effects models, both overall and in subgroups and d) produces high quality figures, including forest plots and summary receiver operating characteristic curves that can be exported for use in manuscripts for publication. All computational algorithms have been validated through comparison with different statistical tools and published meta-analyses. Meta-DiSc has a Graphical User Interface with roll-down menus, dialog boxes, and online help facilities. CONCLUSION: Meta-DiSc is a comprehensive and dedicated test accuracy meta-analysis software. It has already been used and cited in several meta-analyses published in high-ranking journals. The software is publicly available at http://www.hrc.es/investigacion/metadisc_en.htm.

Clinical Laboratory Techniques↗
PubMed2005

High virological failure rate in HIV patients after switching to a regimen with two nucleoside reverse transcriptase inhibitors plus tenofovir.

BACKGROUND: Regimens with two nucleoside analogue reverse transcriptase inhibitors (NRTI) plus tenofovir DF have been associated with a high failure rate when administered as first line therapy. Little is known about patients with undetectable viral loads who are switched to these regimens. METHODS: A post-hoc review of the virological outcomes at 24 weeks of patients who switched from a successful (< 50 copies/ml) highly active antiretroviral therapy regimen to a tenofovir plus two NRTI combination. RESULTS: Fifty-five patients started a two NRTI plus tenofovir regimen mostly because of previous toxicity/intolerance of the original drugs (74%). After 24 weeks, only 17 patients (31%) remained virologically suppressed. Patients with a regimen including a didanosine plus tenofovir-based regimen had significantly poorer outcomes than those on other combinations (success rate 5 versus 47.1%, P = 0.001). In contrast, patients on a regimen including zidovudine plus tenofovir showed a trend towards a better outcome (75 versus 27%, P = 0.083). Multivariate analysis confirmed the combination of didanosine plus tenofovir as the only variable associated with a higher rate of failure (odds ratio 17.7; 95% confidence interval 2.1-147; P = 0.007). Patients with previous reverse transcriptase mutations presented virological failure in all cases. At failure a new pattern, including the K65R mutation with M184V or thymidine analogue mutations, was observed. CONCLUSIONS: Even in patients with suppressed viraemia, a two NRTI plus tenofovir regimen is associated with a high virological failure rate, but significant variations are found depending on the nucleosides included.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Secular trends of candidemia in a large tertiary-care hospital from 1988 to 2000: emergence of Candida parapsilosis.

OBJECTIVE: To analyze the secular trends of candidemia in a large tertiary-care hospital to determine the overall incidence, as well as the incidence by ward and by species, and to detect the occurrence of outbreaks. DESIGN: Retrospective descriptive analysis. Secular trends were calculated using the Mantel-Haenszel test. SETTING: A large tertiary-care referral center in Spain with a pediatric intensive care unit (ICU) to which more than 500 children with congenital cardiac disease are admitted annually. PATIENTS: All patients with candidemia occurring from 1988 to 2000 were included. Cases were identified from laboratory records of blood cultures. RESULTS: There were 331 episodes of candidemia. The overall incidence of nosocomial candidemia was 0.6 episode per 1,000 admissions and remained stable throughout the study period (P = .925). The species most frequently isolated was Candida albicans, but the incidence of C. parapsilosis candidemia increased (P = .035). In the pediatric ICU, the incidence of C. parapsilosis was 5.6 episodes per 1,000 admissions and it was the predominant species. Outbreaks occurred occasionally in the pediatric ICU, suggesting nosocomial transmission. CONCLUSIONS: During this 13-year period, the incidence of candidemia remained stable in this hospital, but C. parapsilosis increased in frequency. Occasional outbreaks of candidemia suggested nosocomial transmission of Candida species.

Candida↗
PubMed2005

Scarce evidence of yogurt lactic acid bacteria in human feces after daily yogurt consumption by healthy volunteers.

In a double-blind prospective study including 114 healthy young volunteers, the presence in human feces of the yogurt organisms Lactobacillus delbrueckii and Streptococcus thermophilus after repeated yogurt consumption (15 days) was analyzed by culture, specific PCR, and DNA hybridization of total fecal DNA. Detection of yogurt lactic acid bacteria in total fecal DNA by bacterial culture and PCR assay was consistently negative. DNA compatible with yogurt bacteria was found by hybridization experiments in only 10 (10.52%) of 96 individuals after consumption of fresh yogurt and in 2 (2.10%) of 96 individuals after consumption of pasteurized yogurt (P = 0.01).

Adult↗
PubMed2003

Phenotype or virtual phenotype for choosing antiretroviral therapy after failure: a prospective, randomized study.

BACKGROUND: Resistance testing is useful in the management of virological failure patients, although the best method to be used in clinical practice has not been determined. METHODS: A prospective, randomized, double-blind, multicentre, controlled clinical trial was performed to compare the usefulness of drug resistance testing with a recombinant viral phenotype method or with a virtual phenotype, a genotyping interpretation system. Planned 300 HIV-infected adults failing their current antiretroviral therapy (HIV RNA > 1000 copies/ml) were centrally randomized 1:1 to resistance testing with a recombinant viral phenotype method or with a virtual phenotype, after stratifying according to previous drug exposure (one or two versus three drug classes). Percent of patients with HIV RNA suppression (% < 400 copies/ml) after 24 weeks was the primary outcome variable. Median HIV RNA concentration and change from baseline in HIV RNA concentration were also used to compare effectiveness. An extended analysis was performed at week 48. RESULTS: Of the 300 patients enrolled, a total of 276 patients could be analysed; 139 patients were randomized to the phenotype group and 137 patients were randomized to the virtual phenotype group. After 24 weeks of follow-up, 46.8 and 56.2% of patients had HIV RNA < 400 copies/ml (P = 0.1) in the phenotype and virtual phenotype, respectively. Mean decrease from baseline in viral load was 1.0 and 1.3 log copies/ml in the phenotype and virtual phenotype groups, respectively (P = 0.017). In a multivariate linear regression analysis, after adjusting for baseline HIV RNA and adherence to treatment, the virtual phenotype was associated with a greater mean decrease in plasma HIV RNA (P = 0.0063). The results observed at week 48 were similar. CONCLUSIONS: Virtual phenotype is at least as effective as phenotype when used to select an optimized treatment for patients who have failed one or more antiretroviral regimens.

Adult↗
PubMed2002

Effectiveness and cost-effectiveness analysis of neuroreflexotherapy for subacute and chronic low back pain in routine general practice: a cluster randomized, controlled trial.

STUDY DESIGN: A cluster randomized, controlled trial was performed. OBJECTIVES: To assess the clinical effectiveness and cost-effectiveness of adding patients' referral to neuroreflexotherapy intervention to the usual management of subacute and chronic low back pain in routine general practice. SUMMARY OF BACKGROUND DATA: Neuroreflexotherapy consists of the temporary implantation of epidermal devices in trigger points in the back and referred tender points in the ear. The efficacy of this procedure for treating subacute and chronic low back pain has been demonstrated in previous randomized, double-blind, controlled clinical trials. METHODS: Twenty-one primary care physicians working in seven primary care centers of the Spanish National Health Service in Palma de Mallorca, Spain, were randomly assigned to the intervention group (n = 11) or the control group (n = 10). The physicians recruited patients who had low back pain that had lasted for 14 or more days despite drug treatment and who did not meet criteria for surgery. The 45 patients recruited by physicians from the control group were treated according to the standard protocol, whereas the 59 patients recruited by physicians from the intervention group were, in addition, referred to neuroreflexotherapy intervention. The analysis of variables was performed taking into account that physicians, not patients, were randomly assigned. RESULTS: Patients underwent clinical evaluations at baseline and 15, 60, and 365 days later. At baseline, median intensity of pain was higher in patients undergoing neuroreflexotherapy than in control patients (visual analogue scale, 6.07; range, 4.67-8.80 vs. 5.15, range 4.11-8.00) and median duration of pain was also higher (48.1, range 28.4-211.1 vs. 17.5, range 15.0-91.5 days). At the last follow-up visit, patients treated with neuroreflexotherapy showed greater improvement than did control patients in low back pain (visual analogue scale, 5.5; range, 3.7-8.8 vs. 1.9; range, -1.2-3.0; P < 0.001); referred pain (visual analogue scale, 3.6; range, 2.7-7.3 vs. 0.6; range, -1.5-2.0; P = 0.001); and disability (Roland-Morris scale, 8.7; range, 2.0-13.3 vs. 2.0; range, -1.5-6.7; P = 0.007). Moreover, neuroreflexotherapy intervention was associated with a significantly (P < 0.035) lower number of consultations to private or public specialists, fewer indications of radiographs by primary care physicians, lower cost of drug treatment, and less duration of sick leave throughout the follow-up period. There were also differences in favor of neuroreflexotherapy intervention in the cost-effectiveness ratio for pain, disability, and quality of life that persisted in the most optimistic, the most conservative, and the average (break-even case) assumptions. CONCLUSIONS: Referral to neuroreflexotherapy intervention improves the effectiveness and cost-effectiveness of the management of nonspecific low back pain.

Acute Disease↗
PubMed2002

Validation of the spanish version of the Roland-Morris questionnaire.

STUDY DESIGN: Validation of a translated, culturally adapted questionnaire. OBJECTIVES: To translate and culturally adapt the Spanish version of the Roland-Morris Questionnaire (RMQ), and to validate its use for assessing disability in Spanish patients with low back pain (LBP). SUMMARY OF BACKGROUND DATA: The RMQ is a reliable evaluation instrument for disability, but no validated Spanish version is available. METHODS: Translation/retranslation of the English version of the RMQ was done blindly and independently by four different individuals, and adapted by a team that included five primary care physicians, three back specialists, and two methodologists. The study was done in the primary care setting in Mallorca, with 195 patients who visited their physician for acute or chronic LBP: 50 in the pilot study and 145 in the validation study. Individuals were given the RMQ and three other scales (VAS, Oswestry, and EuroQol) on their first visit and 14 days later. For the pilot study, on the first visit, patients were also given a second RMQ with the questions in a different order and they were subsequently asked for comprehension of each item of the questionnaire. RESULTS: Only 2 questions were partially rephrased after the pilot study, and no request for aid in interpretation was made during the validation study. Scores of the two RMQs on day 1 were 10.04 (SD, 5.01) and 10.9 (SD, 4.8), with an intraclass correlation coefficient of 0.874. The 95% limits of agreement by the Bland-Altman method was 0.340 +/- 4.81. Cronbach's alpha was 0.8375 (day 1) and 0.9140 (day 15) in the validation. Concurrent validity, measured by comparing RMQ responses with the results of VAS, was r = 0.347 (P = 0.0000) for day 1,and r = 0.570 (P = 0.0000) for day 15. Construct validity, tested by determining the correlation between the Spanish RMQ and the Spanish adaptation of the Oswestry Questionnaire, yielded r = 0.197 (P = 0.0061) on day 1 and r = 0.341 (P = 0.0000) on day 15. CONCLUSIONS: The Spanish version of the RMQ has good comprehensibility, internal consistency, and reliability, and is an adequate and useful instrument for the assessment of disability caused by LBP.

Adult↗
PubMed2002

Artificial anal sphincter: complications and functional results of a large personal series.

PURPOSE: This study was undertaken to evaluate the technique of artificial sphincter for fecal incontinence, with its complications and risk factors, the functional results, and which variables derived from demographic data, preoperative studies, device characteristics, technical details, perioperative findings, and complications could influence the outcome. METHODS: The Acticon Neosphincter was implanted in 53 patients (35 females), median age 46 years, with total anal incontinence not amenable to sphincter repair or after failed sphincteroplasty. In females with associated rectocele, this was synchronously corrected. Six (11 percent) patients already had a colostomy, but no proximal stoma was constructed at the time of implantation. Causes of incontinence were congenital, 13; iatrogenic, 13; obstetric, 10; neurogenic, 9; trauma, 4; idiopathic, 2; and perineal colostomy, 2. Physiologic testing before and after the operation and preoperative endosonography were done when they were available. Quality of life was assessed in 25 patients. Mean follow-up was 26.5 (range, 7-55) months. RESULTS: Perioperative events occurred in 14 (26 percent) patients: abnormal bleeding, 7; vaginal perforation, 4; rectal perforation without apparent contamination, 2; and unobserved urethral perforation, 1. Early complications were mainly related to sepsis in 8 (15 percent) patients and wound complication in 8 (15 percent). Sepsis could not be statistically associated with any of the variables studied here. Wound separation was associated with fibrosis (p = 0.003) and tension of the wound (p = 0.001). Late complications were: cuff and/or pump erosion, 9 (18 percent) patients; infection, 3 (6 percent); impaction, 11 (22 percent); pain, 4 (8 percent); and mechanical failures, 2 (4 percent). None of those complications showed a statistical association with any of the variable studied here. There were 10 (19 percent) definitive explants caused by septic or skin complications. Only 26 (60 percent) of 43 patients with the device in action use the pump (patients' decision). Normal continence was achieved in 65 percent of patients and continence to solid stool in 98 percent. The Cleveland Clinic score of incontinence (0-20, maximal incontinence) changed from 17 +/- 3 preoperatively to 4 +/- 3 postoperatively (p = 0.000). An early complication of the perianal wound influenced the functional results: postimplant score > 4 < or = 4 (p = 0.009). Resting and squeeze pressures changed significantly after activation (p = 0.000). Quality of life measured in four subscales changed significantly in all the subscales (p = 0.000). CONCLUSIONS: The artificial anal sphincter restores continence to solid stool in almost all severely incontinent patients, two-thirds of whom achieve practically normal continence. Quality of life improves significantly. Infection and skin erosion are the cause of the majority of explants. No predictable factors of functional success could be found in this study.

Adolescent↗
PubMed2002

A predictive model for mortality of bloodstream infections. Bedside analysis with the Weibull function.

This paper describes the construction and validation of a prognostic model for predicting post-bloodstream infection survival up to Day 21. A Weibull multiple regression model was adopted in a prospective cohort study of all patients diagnosed with true bacteremia or fungemia in a teaching hospital between 1991 and 1994 (training set, 1,577 patients). The final model included six variables easily detected in any institution: source of infection, underlying neoplasm, septic shock, community-acquired, age over 65, and polymicrobial bacteremia. Using this model, it is possible to obtain a graphic representation of survival probability for any combination of these risk factors. The model was tested on a second set of patients diagnosed in the same hospital between 1996 and 1997 (validation set, 952 patients), confirming its reliability in predicting survival. In conclusion, the Weibull function, together with variables easily identified at bedside, enables a precise prediction of the short-term, post-bloodstream infection mortality of a given patient.

Aged↗