Les études de pharmacoépidémiologie consistent à étudier l’effet de médicaments en vie réelle, et sont menées de plus en plus souvent sur bases de données médico-administratives. Ce sont principalement des études observationnelles, et sont donc soumises à des biais liés à des facteurs de confusion. Ces facteurs ne sont pas toujours recueillis dans les bases de données médico-administratives qui sont implémentées à d’autres fins que la recherche. Des plans expérimentaux self-controlled designs (où le patient est son propre témoin, et dont les principaux sont le case-crossover et le self-controlled case-series) permettent d’étudier l’effet transitoire d'expositions brèves sur des évènements à début brutal. Ils sont soumis à certaines conditions d’application. Ils ont la particularité de réaliser des comparaisons sur différentes périodes plutôt que sur différents groupes de patients, permettant ainsi de prendre en compte des facteurs de confusion, y compris non mesurés, et qui ne varient pas entre les périodes observées. Ces méthodes ont montré leur utilité pour pallier l’absence de randomisation, et leur utilisation est recommandée quand leurs conditions d’application sont remplies. Nous avons étudié la fréquence d’utilisation des self-controlled designs en pharmacoépidémiologie sur bases de données, les opportunités manquées d’utilisation et leur usage approprié au regard de leurs conditions d’application, ainsi que la qualité de l’information rapportée dans les articles. Nous avons montré que leur utilisation est rare, que 15% des articles correspondent à des situations d’opportunité où ces méthodes auraient pu être implémentées, que 34% des case-crossover et 13% des self-controlled case-series étaient appliqué de façon inapproprié, et que pour 16% des articles la méthode aurait pu être adaptée pour être valide. Un usage plus approprié permettrait de contribuer à l’investigation en pharmacoépidémiologie tout en bénéficiant des avantages de ces méthodes en particulier sur bases de données de santé. / Pharmacoepidemiology consists in the study of efficacy or safety of drugs in real life, with the use more and more frequently of medico-administrative databases. Study designs are generally observational, thus they are prone to confounding bias. Confounders are not systematically collected in databases, which are implemented for other purposes than research. Self-controlled designs (mainly represented by case-crossover and self-controlled case-series, and in which the patient acts as his own control), have been developed for the study of intermittent exposure with short-term effect on abrupt onset event. They require that validity assumptions being fulfilled. They consist in the comparison over different periods, rather than different groups of patients, thus allowing for confounding factors, also if not measured, which are invariant over observed periods. Such designs have been proved useful in observational studies in the absence of randomization, and their implementation is recommended in case of validity assumptions are fulfilled. We studied their frequency of use in pharmacoepidemiology in healthcare databases, missed opportunities for use, inappropriate use with respect to validity assumptions, as well as quality of reporting. We showed that self-controlled designs are rarely used, that opportunity for use was founds in 15% of articles where such methods could have been implemented, that 34% of case-crossover and 13% of self-controlled case series were inappropriately used, and that the method could have been adapted to be valid in 16% of articles. A more appropriate use of self-controlled designs could contribute to improve investigation in pharmacoepidemiology, while beneficiating from their advantages, especially in healthcare databases.

The mortality rate for elderly pedestrians struck by vehicles is the highest of any age group, approaching 30% in several large series. Currently, there is a lack of epidemiological studies of the risk factors associated with elderly pedestrian injury; in particular, few prospective studies of elderly pedestrian injuries have been performed. The primary purpose of this project was to identify risk factors that will lead to the development and implementation of effective prevention strategies to reduce the risk of pedestrian injury in this vulnerable population. The project had three phases. In phase 1, pilot studies were performed and identified potential risk factors for elderly pedestrians and confirmed their ability to recall accident details. Risk factors identified included certain walking and street crossing behaviors, as well as the lack of use of assistive devices. In Phase 2, the relatively new case-crossover design was utilized to investigate the association of transient (proximate) triggers or exposures with elderly pedestrian injuries. The relative risk of injury if not obeying the traffic signal is five-fold (odds ratio = 5.2; 95% confidence interval = 1.8 – 15.1). Risk factors such as use of sedating or mood altering medications, or the use of alcohol did not have sufficient discordance for analysis. The behavioral findings suggested that educational programs and behavioral modification might play an important role in designing future interventions. Therefore, in Phase 3, an elderly pedestrian safety program called Safe Crossings was created and evaluated. Over 700 subjects participated in the programs, with 99% reporting they felt it was an important topic and 93% acknowledging they learned something from the program. Focus groups were also utilized to help refine the content and delivery of the program. Posters and brochures were created and distributed in English, Spanish and Creole. The program is now set for wider dissemination and validation.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / While there is consistent evidence that episodes of physical exertion are associated with an immediately higher risk of acute ischemic vascular events, the risk of placental abruption immediately following episodes of physical exertion has not been studied. In a multicenter case-crossover study, we interviewed 663 women with placental abruption at 7 Peruvian hospitals between January 2013 and August 2015. We asked women about physical exertion in the hour before symptom onset and compared this with their frequency of physical exertion over the prior week. Compared with times with light or no exertion, the risk of placental abruption was 7.8 (95% confidence interval (CI): 5.5, 11.0) times greater in the hour following moderate or heavy physical exertion. The instantaneous incidence rate ratio of placental abruption within an hour of moderate or heavy physical exertion was lower for women who habitually engaged in moderate or heavy physical activity more than 3 times per week in the year before pregnancy (rate ratio (RR) = 3.0, 95% CI: 1.6, 5.9) compared with more sedentary women (RR = 17.3, 95% CI: 11.3, 26.7; P for homogeneity < 0.001), and the rate ratio was higher among women with preeclampsia/eclampsia (RR = 13.6, 95% CI: 7.0, 26.2) than among women without (RR = 6.7, 95% CI: 4.4, 10.0; P for homogeneity = 0.07). / Revisión por pares / Revisión por pares

No description available.

Background: This study explored the differences between the seasonal mortality rates (by age and gender) between the two jurisdictions (the Republic of Ireland (RoI) and Northern Ireland (NI)). The study assessed the relationship between cold temperatures and daily mortality, and assessed for effect modification of the cold weather-mortality relationship by age and gender. Methods: Mortality rates were calculated for each cause-specific mortality group during various seasons in both jurisdictions. A time-stratified case-crossover approach was applied to examine the cold weather-mortality relationship, 1984-2007. The daily mortality risk was explored in association with exposure to daily maximum temperatures on the same day and up to 6 weeks preceding death, during the winter months and extended cold period (October-March), using distributed lag models. Model stratification by age and gender assessed for modification of the cold weather-mortality relationship. Results: The winter mortality rates were significantly greater than the summer rates. NI experienced higher mortality from cardiovascular disease, respiratory disease and stroke. The impact of cold weather in the winter months persisted up to 35 days in the RoI, with a cumulative mortality increase for all-cause of 6.4% (95%CI: 4.8%-7.9%) with regards to every 1oC drop in the daily maximum temperature with similar associations for cardiovascular disease and stroke with twice as much for respiratory diseases. The associations were less pronounced and less persistent in NI. Conclusions: The study observed excess winter mortality. The cold weather-mortality associations increased with age with some suggestion of gender differences. There were strong cold weather-mortality associations in both jurisdictions, with suggestive differences in associations by age and gender. The findings suggest the potential contribution of societal differences, and require further exploration. These findings will hopefully contribute to the current efforts to modify fuel policy and reduce winter mortality in both jurisdictions.

No description available.

No description available.

Background: Alcohol consumption has been causally related to the incidence of coronary heart disease, but the role of alcohol before the event has not been explored in depth. This study tested the hypothesis that heavy drinking (binge drinking) increases the risk of subsequent acute myocardial infarctions (AMI), whereas light to moderate drinking occasions decrease the risk. Methods: Case-crossover design of 250 incident AMI cases in Switzerland, with main hypotheses tested by conditional logistic regression. Results: Alcohol consumption 12 h before the event significantly increased the risk of AMI (OR 3.1; 95% CI 1.4–6.9). Separately, the effects of moderate and binge drinking before the event on AMI were of similar size but did not reach significance. In addition, AMI patients showed more binge drinking than comparable control subjects from the Swiss general population. Conclusions: We found no evidence that alcohol consumption before the event had protective effects on AMI. Instead, alcohol consumption increased the risk. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Background: Alcohol consumption has been causally related to the incidence of coronary heart disease, but the role of alcohol before the event has not been explored in depth. This study tested the hypothesis that heavy drinking (binge drinking) increases the risk of subsequent acute myocardial infarctions (AMI), whereas light to moderate drinking occasions decrease the risk. Methods: Case-crossover design of 250 incident AMI cases in Switzerland, with main hypotheses tested by conditional logistic regression. Results: Alcohol consumption 12 h before the event significantly increased the risk of AMI (OR 3.1; 95% CI 1.4–6.9). Separately, the effects of moderate and binge drinking before the event on AMI were of similar size but did not reach significance. In addition, AMI patients showed more binge drinking than comparable control subjects from the Swiss general population. Conclusions: We found no evidence that alcohol consumption before the event had protective effects on AMI. Instead, alcohol consumption increased the risk. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Introduction: The association between daily air pollution exposure and risk of mortality is well established. Few studies have investigated in detail the associations beyond a seven day lag. The aim of this thesis was to investigate the change in risk across longer (30 day) periods post exposure for three specific causes of death: pneumonia, chronic obstructive pulmonary disease (COPD), and ischaemic heart disease (IHD). Methods: Daily Scottish mortality data (1980-2011) was matched to measurements from local fixed site pollution (Black smoke, PM10, PM2.5, SO2, & NO2) and temperature monitors. Exposure on subjects' 'day of death' was compared with control days in a time-stratified case-crossover analysis. Exposure effects on 30 days prior to day of death were modelled using distributed lag non-linear, lag stratified, and cubic distributed lag models. Matching hospital admissions data inferred subject location during exposure, further analyses investigated extreme outliers and missing data using multiple imputation techniques. The analysis accounted for several confounders including accurately modelling temperature relationships unique for each cause of death. Results: Of the 919,301 deaths, 20% were classified as being caused by pneumonia, 9.5% as COPD, and 30% as IHD in the 'any' cause of death field. Non-linear effects for temperature and linear effects for the pollutants were present across all 30 days. Temperature-mortality was observed to be U-shaped at shorter lags. Consistently increased risk occurred for longer in cold temperatures with 1oC increase (30 days lag) = %RR -0.35% Pneumonia, -0.62% COPD, and -0.26% IHD. PM2.5 on all three outcomes, and all pollutants on COPD showed the greatest effect sizes. In general, COPD risk only occurred after a delay, peaking between 12-18 days. COPD risk due to PM2.5 was immediate (%RR (95% C.I.) = 1.05% (0.14%,2.01%)) and lasted the full 30 days. Pneumonia risk often reported the shortest lag of 10-15 days, whereas IHD risk occurred 2 days after exposure but lasted the remaining 30 days. There was some evidence especially for pneumonia of a smaller association between air pollution on mortality when subjects included were present in hospital. A simulation study indicated slight improvement in accuracy when 'multiple imputation' was performed compared to 'complete cases' analysis; though both techniques reported similarly underestimated effect estimates. Extreme outliers in the main analysis of pollution exposure did not appear to have a strong influence on the risk. However, large variability between monitor measurements of pollution exposure was present and appeared to be influencing the results. Conclusion: This study provides additional evidence on the link between air pollution, and temperature, and acute mortality. Particular focus was on three causes of death (pneumonia, COPD, and IHD) that are shown to be influenced by air pollution in subtly different ways. Results also indicated that the 'true' effect of air pollution on mortality might be greater than shown by mortality studies which do not use hospital admission location during exposure into account.