The aim of this review was to summarize population-based studies reporting prevalence and/or incidence of chronic migraine (CM) and to explore variation across studies. A systematic literature search was conducted. Relevant data were abstracted and estimates were subdivided based on the criteria used in each study. Sixteen publications representing 12 studies were accepted. None presented data on CM incidence. The prevalence of CM was 0-5.1%, with estimates typically in the range of 1.4-2.2%. Seven studies used Silberstein-Lipton criteria (or equivalent), with prevalence ranging from 0.9% to 5.1%. Three estimates used migraine that occurred ≥15 days per month, with prevalence ranging from 0 to 0.7%. Prevalence varied by World Health Organization region and gender. This review identified population-based studies of CM prevalence, although heterogeneity across studies and lack of data from certain regions leaves an incomplete picture. Future studies on CM would benefit from an International Classification of Headache Disorders consensus diagnosis that is clinically appropriate and operational in epidemiological studies.

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Bipolar disorder imposes a tremendous burden on patients and the health-care system, resulting in decreased HRQoL and increased medical and work impairment costs. Limited data suggest that appropriate management can improve HRQoL and functioning while reducing utilization and cost.

This review assessed the use of electronic medical record (EMR) systems in outcomes research. We systematically searched PubMed to identify articles published from January 2000 to January 2007 involving EMR use for outpatient-based outcomes research in the United States. EMR-based outcomes research studies (n = 126) have increased sixfold since 2000. Although chronic conditions were most common, EMRs were also used to study less common diseases, highlighting the EMRs' flexibility to examine large cohorts as well as identify patients with rare diseases. Traditional multi-variate modeling techniques were the most commonly used technique to address confounding and potential selection bias. Data validation was a component in a quarter of studies, and many evaluated the EMR's ability to achieve similar results previously achieved using other data sources. Investigators using EMR data should aim for consistent terminology, focus on adequately describing their methods, and consider appropriate statistical methods to control for confounding and treatment-selection bias.

Summary Background:  The impact of gastro‐oesophageal reflux disease on work productivity has become increasingly important, as the symptoms of gastro‐oesophageal reflux disease affect individuals in their productive years of life. Aims:  To assess the impact of gastro‐oesophageal reflux disease on reduced work productivity and to identify the predictors of reduced productivity. Methods:  A sample of employed individuals reporting chronic heartburn was selected from US household mail survey respondents. Heartburn severity and frequency were recorded using a diary, and work productivity was assessed using the Work Productivity and Activity Impairment Questionnaire for Patients with Symptoms of Gastro‐oesophageal Reflux Disease. Predictors of reduced productivity were evaluated. Results:  Over 30% of heartburn sufferers reported reduced productivity. Individuals with symptoms of gastro‐oesophageal reflux disease (n = 1003) reported 6.0% reduced productivity attributable to symptoms. Over 48% of respondents with severe symptoms reported reduced productivity, compared with 40% and 12% of respondents with moderate and mild symptoms, respectively. Using logistic regression, severity, a younger age and nocturnal symptoms were associated with increased odds of reduced productivity. In those reporting nocturnal heartburn, medication use and sleep interference increased the odds of reduced productivity. Conclusions:  Reduced work productivity is seen in a large proportion of subjects on prescription medication for gastro‐oesophageal reflux disease. Symptom severity and nocturnal heartburn are significantly associated with reduced work productivity, particularly when nocturnal heartburn interferes with sleep.