Immortal time is a span of cohort follow-up during which, because of exposure definition, the
outcome under study could not occur. Bias from immortal time was first identified in the …

… The European Medicines Agency defines a registry as “a list of patients presenting with the
same characteristic(s). This characteristic may be a disease or an outcome (disease registry) …

OBJECTIVE Time-related biases in observational studies of drug effects have been described
extensively in different therapeutic areas but less so in diabetes. Immortal time bias, time-…

Background. Morbidity and mortality from asthma appear to be increasing, and it has been
suggested that medications used to treat asthma are contributing to this trend. We …

Background Although inhaled corticosteroids are effective for the treatment of asthma, it is
uncertain whether their use can prevent death from asthma. Methods We used the …

ContextRecent reports suggest an increasing occurrence and severity of Clostridium difficile–associated
disease. We assessed whether the use of gastric acid–suppressive agents is …

… Samy Suissa was the recipient of a Research Scholar Award from the Fonds de la … Nevitt
MC, Cummings SR, Kidd S, et al. Risk factors for recurrent nonsyncopal falls: a prospective …

Background Observational studies have suggested that estrogen-replacement therapy may
reduce a woman's risk of stroke and death. Methods We conducted a randomized, double-…

Background Nephropathy and retinopathy remain important complications of type 1 diabetes.
It is unclear whether their progression is slowed by early administration of drugs that block …

… Such a gradual decay in forced expiratory volume in 1 s (FEV 1 ) inherently implies that
exacerbations interspersed within the course of disease do not necessarily alter this natural …