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Biomedical subjects

Adolfo Figueiras

Publications and source records attributed to Adolfo Figueiras.

At least 19 recordsLinked to original sources
PubMed2006

An educational intervention to improve physician reporting of adverse drug reactions: a cluster-randomized controlled trial.

CONTEXT: Data on the adverse effects of newly marketed drugs are limited. Voluntary reporting is an important part of postmarketing surveillance but is underused by physicians. OBJECTIVE: To evaluate the effectiveness of educational outreach visits for improving adverse drug reaction (ADR) reporting by physicians. DESIGN, SETTING, AND PARTICIPANTS: A cluster-randomized controlled trial covering all National Health System physicians in the north of Portugal, with intervention in March 2004 through July 2004, and 13 to 16 months of follow-up. A total of 1388 physicians were assigned in 4 spatial clusters to the intervention group, and 5063 were assigned in 11 clusters to the control group. INTERVENTION: One-hour educational outreach visits tailored to training needs identified in a previous study. MAIN OUTCOME MEASURES: Change in total number of reported ADRs and number of serious, high-causality, unexpected, and new-drug-related ADRs, using generalized linear mixed models adjusted for baseline ADR reporting, age, specialty, and work setting. RESULTS: At baseline, ADR reporting rates (per 1000 physician-years) did not differ significantly between the intervention groups and the control groups in reporting ADRs overall (7.6 vs 11.3), nor did they differ significantly by category: serious, 4.3 vs 6.0; high-causality, 5.4 vs 7.6; unexpected, 1.6 vs 3.5; and new-drug-related ADRs, 3.7 vs 3.8. (P>.05 for all comparisons). The control group had no significant increase in ADR reports during follow-up. The adjusted increase in ADR reporting rates attributable to intervention was 90.19 for total ADRs (95% confidence interval [CI], 54.51-125.87; relative risk [RR], 10.23; 95% CI, 3.81-27.51), 30.16 for serious ADRs (95% CI, 18.84-41.47; RR, 6.32; 95% CI, 2.09-19.16), 64.90 for high-causality ADRs (95% CI, 38.38-91.42; RR, 8.75; 95% CI, 3.05-25.07), 28.04 for unexpected ADRs (95% CI, 16.25-39.83; RR, 30.21; 95% CI, 4.54-200.84), and 42.17 for new-drug-related ADRs (95% CI, 21.58-62.76; RR, 8.05; 95% CI, 2.10 -30.83). The greatest difference occurred during the first 4 months after intervention, but differences remained statistically significant for 12 months. CONCLUSION: A targeted outreach program may improve high-quality reporting of ADRs among physicians.

Adult↗
PubMed2006

Effect measures in non-parametric regression with interactions between continuous exposures.

In many biomedical studies, interest is often attached to calculating effect measures in the presence of interactions between two continuous exposures. Traditional approaches based on parametric regression are limited by the degree of arbitrariness involved in transforming these exposures into categorical variables or imposing a parametric form on the regression function. In this paper, we present: (a) a flexible non-parametric method for estimating effect measures through generalized additive models including interactions; and (b) bootstrap techniques for (i) testing the significance of interaction terms, and (ii) constructing confidence intervals for effect measures. The validity of our methodology is supported by simulations, and illustrated using data from a study of possible risk factors for post-operative infection. This application revealed a hitherto unreported effect: for patients with high plasma glucose levels, increased risk is associated, not only with low, but also with high percentages of lymphocytes.

Algorithms↗
PubMed2006

Influence of pharmacists' attitudes on adverse drug reaction reporting : a case-control study in Portugal.

INTRODUCTION: Pharmacists can play a fundamental role in adverse drug reaction (ADR) reporting, although the factors that affect underreporting among these professionals are unknown. The objectives of this study were to identify (i) professional or demographic characteristics; and (ii) attitudes associated with pharmacists' ADR reporting in northern Portugal. METHODS: We conducted a case-control study on a population of pharmacists employed in hospital and community pharmacies across Portugal's Northern Regional Health Authority catchment area in 2003. Cases (n=34) comprised pharmacists who had reported at least one ADR to the northern region's drug surveillance unit, and controls (n=280) were randomly sampled from pharmacists who had never reported an ADR. All were interviewed using a mail questionnaire. Most attitudes were based on Inman's 'seven deadly sins' and were measured using a continuous visual analogue scale. Answers were recorded in a range from 0 (total disagreement) to 10 (total agreement). Logistic regression was used to determine the ADR reporting adjusted odds ratio (OR) for a change in exposure corresponding to the interquartile range for each attitude. RESULTS: The response rate was 86.8%. Reporting probability proved higher among hospital versus community pharmacists (adjusted OR 20.0; 95 CI 3.3, 125.0; p<0.001). Attitudes to ADRs were strongly associated with reporting probability. Hence, an interquartile decrease in any of the following attitudes increased the probability of reporting by (i) 223% (95% CI 51, 595; p < 0.05) for "Really serious ADRs are well documented by the time a drug is marketed"; (ii) 240% (95% CI 89, 508; p=0.002) for "I would only report an ADR if I were sure that it was related to the use of a particular drug"; (iii) 316% (95% CI 44, 1104; p=0.010) for "It is only necessary to report serious or unexpected ADRs"; and (iv) 171% (95% CI 13, 549; p=0.020) for "I do not have time to think about the involvement of the drug or other causes in ADRs". CONCLUSIONS: ADR under-reporting is strongly associated with certain attitudes, possibly indicating that under-reporting could be minimised through educational interventions targeted at changing such attitudes. Pharmacists' ADR education must be improved and educational programmes should be focused on altering attitudes identified by the study as being associated with under-reporting. Our data also indicate that community pharmacists must be a priority target for this intervention.

Adverse Drug Reaction Reporting Systems↗
PubMed2006

Residential radon and lung cancer--detailed results of a collaborative analysis of individual data on 7148 persons with lung cancer and 14,208 persons without lung cancer from 13 epidemiologic studies in Europe.

OBJECTIVES: Studies seeking direct estimates of the lung cancer risk associated with residential radon exposure lasting several decades have been conducted in many European countries. Individually these studies have not been large enough to assess moderate risks reliably. Therefore data from all 13 European studies of residential radon and lung cancer satisfying certain prespecified criteria have been brought together and analyzed. METHODS: Data were available for 7148 persons with lung cancer and 14,208 controls, all with individual smoking histories and residential radon histories determined by long-term radon gas measurements. RESULTS: The excess relative risk of lung cancer per 100 Bq/m3 increase in the observed radon concentration was 0.08 [95% confidence interval (95% CI) 0.03-0.16; P=0.0007] after control for confounding. The dose-response relationship was linear with no evidence of a threshold, and it remained significant when only persons with observed radon concentrations of <200 Bq/m3 were included. There was no evidence that the excess relative risk varied with age, sex, or smoking history. Removing the bias induced by random uncertainties related to radon exposure assessment increased the excess relative risk of lung cancer to 0.16 (95% CI 0.05-0.31) per 100 Bq/m3. With this correction, estimated risks at 0, 100, and 400 Bq/m3, relative to lifelong nonsmokers with no radon exposure, were 1.0, 1.2, and 1.6 for lifelong nonsmokers and 25.8, 29.9, and 42.3 for continuing smokers of 15-24 cigarettes/day. CONCLUSIONS: These data provide firm evidence that residential radon acts as a cause of lung cancer in the general population. They provide a solid basis for the formulation of policies with which to manage risk from radon and reduce deaths from the most common fatal cancer in Europe.

Case-Control Studies↗
PubMed2005

Non-parametric estimation of the odds ratios for continuous exposures using generalized additive models with an unknown link function.

The generalized additive, model (GAM) is a powerful and widely used tool that allows researchers to fit, non-parametrically, the effect of continuous predictors on a transformation of the mean response variable. Such a transformation is given by a so-called link function, and in GAMs this link function is assumed to be known. Nevertheless, if an incorrect choice is made for the link, the resulting GAM is misspecified and the results obtained may be misleading. In this paper, we propose a modified version of the local scoring algorithm that allows for the non-parametric estimation of the link function, by using local linear kernel smoothers. To better understand the effect that each covariate produces on the outcome, results are expressed in terms of the non-parametric odds ratio (OR) curves. Bootstrap techniques were used to correct the bias in the OR estimation and to construct point-wise confidence intervals. A simulation study was carried out to assess the behaviour of the resulting estimates. The proposed methodology was illustrated using data from the AIDS Register of Galicia (NW Spain), with a view to assessing the effect of the CD4 lymphocyte count on the probability of being AIDS-diagnosed via Tuberculosis (TB). This application shows how the link's flexibility makes it possible to obtain OR curve estimates that are less sensitive to the presence of outliers and unusual values that are often present in the extremes of the covariate distributions.

AIDS-Related Opportunistic Infections↗
PubMed2005

Analysis of case-crossover designs using longitudinal approaches: a simulation study.

BACKGROUND: Application of case-crossover designs provides an alternative to time-series analysis for analyzing the health-related effects of air pollution. Although some case-crossover studies can control for trend and seasonality by design, to date they have been analyzed as matched case-control studies. Such analyses may exhibit biases and a lower statistical efficiency than traditional time series analyzed with Poisson. METHODS: In this article, case-crossover studies are treated as cohort studies in which each subject is observed for a short period of time before and/or after the event, thus making possible analyzing with Andersen-Gill and generalized linear mixed models. We conducted a simulation study to compare the behavior of these models applied to case-crossover designs with time series analyzed with Poisson and with case-crossover analyzed by conditional logistic regression. To this end, we created a random variable that follows a Poisson distribution of low (2/day) and high mean events (22/day). This variable is a function of an unobserved confounding variable (that introduces trend and seasonality) and data on small particulate matter (PM10) from Barcelona. In addition, scenarios were created to assess the effect on exposure exerted by autocorrelation and the magnitude of the pollutant coefficient. RESULTS: The full semisymmetric design analyzed with generalized linear mixed models yields good coverage and a high statistical power for air-pollution effect magnitudes close to the real values but shows bias for high effect magnitudes. This bias seems to be attributable to autocorrelation in the exposure variable. CONCLUSIONS: Longitudinal approaches applied to case-crossover designs may prove useful for analyzing the acute effects of environmental exposures.

Air Pollutants↗
PubMed2005

A bootstrap method to avoid the effect of concurvity in generalised additive models in time series studies of air pollution.

BACKGROUND: In recent years a great number of studies have applied generalised additive models (GAMs) to time series data to estimate the short term health effects of air pollution. Lately, however, it has been found that concurvity--the non-parametric analogue of multicollinearity--might lead to underestimation of standard errors of the effects of independent variables. Underestimation of standard errors means that for concurvity levels commonly present in the data, the risk of committing type I error rises by over threefold. METHODS: This study developed a conditional bootstrap methology that consists of assuming that the outcome in any observation is conditional upon the values of the set of independent variables used. It then tested this procedure by means of a simulation study using a Poisson additive model. The response variable of this model is a function of an unobserved confounding variable (that introduces trend and seasonality), real black smoke data, and temperature. Scenarios were created with different coefficients and degrees of concurvity. RESULTS: Conditional bootstrap provides confidence intervals with coverages close to nominal (95%), irrespective of the degree of concurvity, number of variables in the model or magnitude of the coefficient to be estimated (for example, for a concurvity of 0.85, bootstrap confidence interval coverage is 95% compared with 71% in the case of the asymptotic interval obtained directly with S-plus gam function). CONCLUSIONS: The bootstrap method avoids the problem of concurvity in time series studies of air pollution, and is easily generalised to non-linear dose-risk effects. All bootstrap calculations described in this paper can be performed using S-Plus gam.boot software.

Air Pollution↗
PubMed2005

Physicians' attitudes and adverse drug reaction reporting : a case-control study in Portugal.

OBJECTIVES: Voluntary adverse drug reaction (ADR) reporting is fundamental to medical drug safety surveillance; however, substantial under-reporting exists and is the main limitation of the system. This study sought to identify the knowledge- and attitude-related factors associated with ADR reporting by physicians in Northern Portugal. METHODS: Case-control study covering a population of National Health Service medical practitioners. The 88 cases comprised physicians who had reported at least one ADR to the drug surveillance unit from the year 2000 to the date of enrolment in the study. The 771 controls were randomly selected from among the remaining physicians. All interviews were conducted using a self-administered questionnaire. Knowledge and attitudes regarding spontaneous ADR reporting were based on Inman's 'seven deadly sins'. Agreement with the questions included in the questionnaire was measured using a horizontal, continuous visual analogue scale, which was unnumbered. Recorded answers were read in a range from zero (total disagreement) to ten (total agreement). We used logistic regression to determine the ADR reporting adjusted odds ratio (ORadj) for a change in exposure corresponding to the interquartile range for each attitude. RESULTS: A total of 397 questionnaires were received from 731 eligible practitioners (54.3%). Physicians who worked in primary versus hospital care (ORadj 7.74 [95% CI 1.85, 32.30]) and in general medicine (ORadj 1.05 [95% CI 0.30, 3.69]) versus medical specialities were more likely to report ADRs. In contrast, physicians working in the medical-surgical/surgical fields were significantly less likely to report ADRs compared with medical specialists (ORadj 0.10 [95% CI 0.02, 0.46]). Attitudes to ADRs were strongly associated with reporting probability. Hence, an interquartile decrease in any of the following attitudes increased the probability of reporting by: (i) 87% (p < 0.05) for complacency (the belief that really serious ADRs are well documented by the time a drug is marketed); (ii) 109% (p < 0.01) for insecurity (the belief that it is nearly impossible to determine whether a drug is responsible for a particular adverse reaction); (iii) 143% (p < 0.001) for diffidence (the belief that one would only report an ADR if one were sure that it was related to the use of a particular drug); (iv) 220% (p < 0.001) for indifference (the belief that the one case an individual doctor might see could not contribute to medical knowledge); and (v) 71% (p < 0.05) for ignorance (the belief that it is only necessary to report serious or unexpected ADRs). CONCLUSION: This study shows that there are attitudes strongly associated with under-reporting. The implementation of purpose-designed educational interventions based on the attitudes identified in this study may serve to improve reporting substantially.

Adult↗
PubMed2004

Factors related with prescription requirement to dispense in Spain.

PURPOSE: To identify factors associated with prescription requirement to dispense. METHODS: We carried out a cross-sectional study on a sample of 166 pharmacists in North-West Spain. The following independent variables were collected through a personal interview: pharmacist's education and speciality, characteristics of the pharmacy, and its socio-economic environment. We constructed multiple regression models using as dependent variables: requirement of prescription to dispense five drugs which have to be dispensed with a prescription; and opinion on whether a prescription should be required to dispense these drugs. RESULTS: The response rate was 98.8%. A proportion of 65.9% of pharmacists dispense antibiotics without any prescription. This proportion is 83.5% for nonsteroidal anti-inflammatory drugs, 46.3% for ACE inhibitors, 13.4% for benzodiazepines and 84.8% for oral contraceptives. A higher requirement prescription was found to be associated with the antecedent of a speciality training of the pharmacist (p = 0.028) and his or her age (p < 0.001). A low prescription requirement is associated with the condition of being owner of the pharmacy (p = 0.032), with a high economic level of the population attended (p = 0.016) and with the size of the pharmacy (p = 0.045). CONCLUSIONS: The proportion of pharmacists who dispense drugs without a prescription is extremely high. Our results suggest that in order to increase quality of dispensing, it is necessary to increase pharmacist education and direct efforts of awareness primarily at pharmacists in charge, who are young and work in large pharmacies.

Adult↗
PubMed2004

Factors that influence spontaneous reporting of adverse drug reactions: a model centralized in the medical professional.

RATIONALE, AIMS AND OBJECTIVES: The spontaneous reporting of adverse drug reactions (ADRs) through the yellow card and made concrete by the knowledge and attitudes of doctors, has been rousing a great deal of bibliographical interest in recent years. However, there does not seem to be any actual revision in the theme on which the theoretical models that explain the process of decision in reporting are proposed. In this work an explanatory model of the factors that condition reporting is proposed and a revision of the literature on the subject has also been carried out. METHODS: The proposed model is centralized in the medical professional and it considers the habit of reporting as the result of the doctor's formation and his interaction with the environment. The combination of knowledge-attitudes-practices and the theory of the satisfaction of needs seemed very adequate for ADR systematization. RESULTS AND CONCLUSIONS: The results also indicate that, to improve the participation of health professionals in surveillance systems through spontaneous reporting, it might be necessary to design combined strategies that modify both intrinsic (knowledge, attitudes) and extrinsic (relationship between health professionals and their patients, the national health system and pharmaceutical companies) factors.

Adverse Drug Reaction Reporting Systems↗
PubMed2004

Correspondence re Yuan JM et al., Prediagnostic levels of serum beta-cryptoxanthin and retinol predict smoking-related lung cancer risk in Shanghai, China. 2001;10:767-73. Neuhoser ML et al., Fruits and vegetables are associated with lower lung cancer risk only in the placebo arm of the beta-carotene and retinol efficacy trial (CARET). 2002;12:350-8. Satia-Abouta J et al., Associations of micronutrients with colon cancer risk in African Americans and whites: results from the North Carolina Colon Cancer Study. 2003;12:747-54.

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Colonic Neoplasms↗
PubMed2003

Occupation and smoking as risk factors for lung cancer: a population-based case-control study.

BACKGROUND: Lung cancer is associated with occupation, but not much is known about the influence exerted on risk by length of exposure and the joint effect of occupational exposure and tobacco on risk of lung cancer. METHODS: Through a population-based case-control study, we defined risk professions as those that have been associated previously with higher risk of lung cancer. RESULTS: The relative risk seems to increase linearly and significantly with the number of years spent in risk occupations, rising significantly by 28% for every 10 years in a risk profession. Should such occupations be combined with exposure to a smoking habit, then in the case of heavy smokers, a working career spanning 20 years or more in risk occupations would mean tripling the possibility of developing lung cancer from occupation. CONCLUSIONS: The high risks observed indicate a public health problem and indicate that joint exposure to risk professions and tobacco ought to be avoided. We must stress from these results the need for effective education for all workers.

Aged↗
PubMed2003

Np.OR: an S-Plus function for pointwise nonparametric estimation of odds-ratios of continuous predictors.

Calculating odds ratios (OR) and corresponding confidence intervals (CI) for exposures that have been measured using a continuous scale, presents important limitations in the traditional practice of epidemiology. Our objective is to describe an S-Plus function, that we called np.OR, that allows the computation of the pointwise estimates of the ORs as well as their corresponding CIs of continuous predictors introduced nonlinearly in a generalised model. The function can also be generalised to compute the pointwise estimates of categorical predictors that were introduced nonlinearly. To illustrate usage of the program we analyse the relationship between ambient temperature and total mortality in Barcelona for the period 1991-1995, while controlling for observed and unobserved confounders.

Confidence Intervals↗
PubMed2002

Exposure to residential radon and lung cancer in Spain: a population-based case-control study.

Although high radon concentrations have been linked to increased risk of lung cancer by both experimental studies and investigations of underground miners, epidemiologic studies of residential radon exposure display inconsistencies. The authors therefore decided to conduct a population-based case-control study in northwest Spain to determine the risk of lung cancer associated with exposure to residential radon. The study covered a total of 163 subjects with incident lung cancer and a population sample of 241 cancer-free subjects since 1992-1994. Odds ratios for radon were estimated using logistic regression adjusted for sex, age, lifetime tobacco use, family history, and habitat. The adjusted odds ratios for the second, third, and fourth quartiles of radon (breakpoints: 37.0, 55.2, and 148.0 Bq/m(3)) were 2.73 (95% confidence interval (CI): 1.12, 5.48), 2.48 (95% CI: 1.29, 6.79), and 2.96 (95% CI: 1.29, 6.79), respectively. An additive synergic effect between radon and tobacco was found. The results from this study suggest that, even at concentrations far below official guideline levels, radon may lead to a 2.5-fold rise in the risk of lung cancer. Furthermore, the synergy found between smoking and radon may prove useful when it comes to drafting public health recommendations.

Aged↗
PubMed2002

Intake of wine, beer, and spirits and the risk of clinical common cold.

To examine whether intakes of wine, beer, spirits, and total alcohol are associated with the risk of common cold, in 1998-1999 the authors analyzed data from a cohort study carried out in a population of 4,272 faculty and staff of five Spanish universities. Usual alcohol intake was assessed at baseline by means of a standardized frequency questionnaire that was validated in a random sample of the population. The authors detected 1,353 cases of common cold. Total alcohol intake and beer and spirits consumption were not related to the occurrence of common cold, whereas consumption of wine was inversely associated with the risk of common cold. When drinkers of >14 glasses of wine per week were compared with teetotalers, the relative risk was 0.6 (95% confidence interval: 0.4, 0.8) after adjustment for age, sex, and faculty/staff status. The association was stronger for red wine. These results remained unaltered after adjustment for total alcohol intake and for other potential risk factors for common cold. Findings suggest that wine intake, especially red wine, may have a protective effect against common cold. Beer, spirits, and total alcohol intakes do not seem to affect the incidence of common cold.

Alcohol Drinking↗
PubMed2002

Data collection methods for analyzing the quality of the dispensing in pharmacies.

OBJECTIVE: To review and discuss the advantages and limitations of the different data collection methods for analyzing the dispensing quality in community pharmacies. METHODS: A bibliographic search was carried out in MEDLINE (1980-2000). Articles with Medical Subject Heading (Mesh) "pharmacies" written in English and Spanish that evaluated the quality of dispensing (structure, process or outcome) were selected. RESULTS: Various data collection methods were observed. To analyze the quality of the structure, questionnaires and pharmacist interviews were used. To analyze the quality of the process, self-completed records, external observers and simulated clients were used. For analyzing the quality of the outcome, questionnaires, client interviews, and biologic samples were collected. CONCLUSIONS: The analysis of quality of structure can be useful as a first approach, however, this method may lack sensitivity. On the other hand, the analysis of outcome may be excessively complex and difficult to use, except for experimental or observational studies with large resources. Therefore, an analysis of the quality of the process is the best option. Methods utilizing external observers and simulated clients may best conjugate both internal and external validity.

Community Pharmacy Services↗
PubMed2002

Influence of commercial information on prescription quantity in primary care.

BACKGROUND: In the last few years we have witnessed many publicly-financed health services reaching a crisis point. Thus, drug expenditure is nowadays one of the main concerns of health managers, and its containment one of the first goals of health authorities in western countries. The objective of this study is to identify the effect of the perceived quality stated in commercial information, its uses, and how physicians perceive the influence it has on prescription amounts. METHODS: A cross-sectional study of 405 primary care physicians was conducted in Galicia (north-west Spain). The independent variables physician's education and speciality, physician's perception of the quality of available drug information sources, type of practice, and number of patients were collected, through a postal questionnaire. Environmental characteristics of the practice were obtained from secondary sources. Multiple regression models were constructed using as dependent variables two indicators of prescription volume. RESULTS: The response rate was 75.2%. Prescription amounts was found to be associated with perceived credibility of information provided by medical visitors, regulated physician training, and environmental characteristics of the practice (primary care team practice, urban environment). CONCLUSIONS: The study results suggest that in order to decrease prescription amounts it is necessary to limit the role of pharmaceutical companies in physician training, improve physician education and training, and emphasize more objective sources of information.

Attitude of Health Personnel↗