The rising prevalence of asthma: true increase, diagnostic exchange or diagnostic accuracy?

In the midst of frequent reports about "the asthma epidemic," results from a number of studies by the manitoba centre for health policy have shown stable or decreasing prevalence of an overall indicator of respiratory diseases which includes asthma. To resolve these apparently contrary findings, we conducted a time trend analysis using administrative data. results revealed significant potential for diagnostic exchange: asthma prevalence increased, but that of bronchitis decreased.

Dementia and depression with ischemic heart disease: a population-based longitudinal study comparing interventional approaches to medical management.

BACKGROUND: We compared the proportion of ischemic heart disease (IHD) patients newly diagnosed with dementia and depression across three treatment groups: percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) and medical management alone (IHD-medical). METHODS AND FINDINGS: De-identified, individual-level administrative records of health service use for the population of Manitoba, Canada (approximately 1.1 million) were examined. From April 1, 1993 to March 31, 1998, patients were identified with a diagnosis of IHD (ICD-9-CM codes). Index events of CABG or PCI were identified from April 1, 1998 to March 31, 2003. Outcomes were depression or dementia after the index event. Patients were followed forward to March 31, 2006 or until censored. Proportional hazards regression analysis was undertaken. Independent variables examined were age, sex, diabetes, hypertension and income quintile, medical management alone for IHD, or intervention by PCI or CABG. Age, sex, diabetes, and presence of hypertension were all strongly associated with the diagnosis of depression and dementia. There was no association with income quintile. Dementia was less frequent with PCI compared to medical management; (HR = 0.65; p = 0.017). CABG did not provide the same protective effect compared to medical management (HR = 0.90; p = 0.372). New diagnosis depression was more frequent with interventional approaches: PCI (n = 626; hazard ratio = 1.25; p = 0.028) and CABG (n = 1124, HR = 1.32; p = 0.0001) than non-interventional patients (n = 34,508). Subsequent CABG was nearly 16-fold higher (p<0.0001) and subsequent PCI was 22-fold higher (p<0.0001) for PCI-managed than CABG-managed patients. CONCLUSIONS: Patients managed with PCI had the lowest likelihood of dementia-only 65% of the risk for medical management alone. Both interventional approaches were associated with a higher risk of new diagnosed depression compared to medical management. Long-term myocardial revascularization was superior with CABG. These findings suggest that PCI may confer a long-term protective effect from dementia. The mechanism(s) of dementia protection requires elucidation.

Age difference explains gender difference in cardiac intervention rates after acute myocardial infarction.

Many investigators have reported higher rates of cardiac procedures for males than females after acute myocardial infarction (AMI), suggesting that men are treated more aggressively than women. However, others have reported no significant differences after controlling for age, resulting in uncertainty about the existence of a true gender bias in cardiac care. In this study, a population-based cohort approach was used to calculate age-specific procedure rates by sex from administrative data. Chi-square tests and generalized linear modelling were used to assess gender differences and interactions. For all four procedures studied, rates were significantly higher for males than females (p<0.01). However, age-specific rates revealed few significant differences by gender and a sharp decrease in intervention rates with age for both males and females. Generalized linear modelling confirmed that patient age was a significant predictor of intervention rates, whereas sex was not. The significant gender difference in overall rates was completely confounded by the older age profile of female AMI patients compared to their male counterparts.

How health status affects progress and performance in school: a population-based study.

OBJECTIVE: To assess the effects of health status at birth and health status in the preschool years on educational outcomes to age 9 in a population-based birth cohort. METHODS: Administrative data were used to follow all children born to Winnipeg mothers in 1990, and remaining in Manitoba until September 2004 (N = 5,873). A structural equation model was used, incorporating latent variables to represent Health Status at Birth, Major Illness and Minor Illness during the preschool years. The model also included the child's sex and exact age, along with a number of social, economic, and demographic characteristics of the child's family. The outcome was a combination of marks on Grade 3 Standards Tests and enrollment in the appropriate grade for age. RESULTS: Major Illness in the preschool years had a significant influence on progress and performance in school (p = 0.0003), predicting 1.26% of the variation in the outcome. Minor Illness was weaker but still significant (p < 0.01). Health Status at Birth was not directly related to the outcome; its effect was mediated by Major and Minor Illness in childhood. Overall, the strongest predictors were the child's age and the area-level income, followed by the mother's age, family receipt of income assistance, the sex of the child, breastfeeding initiation (all p < 0.0001), and Major Illness. CONCLUSIONS: Health status plays a statistically significant but substantively small role in explaining progress and performance in school among a population-based cohort. Major Illness was more important than Minor Illness, and these two factors completely mediated the influence of Health Status at Birth on the outcome. The strength of the social, economic, and demographic variables underscores the importance of the broader factors that affect both health and educational outcomes.