Elham Rahme

BACKGROUND: Empirical data on the changing epidemiology of congenital heart disease (CHD) are scant. We determined the prevalence, age distribution, and proportion of adults and children with severe and other forms of CHD in the general population from 1985 to 2000. METHODS AND RESULTS: Where healthcare access is universal, we used administrative databases that systematically recorded all diagnoses and claims. Diagnostic codes conformed to the International Classification of Disease, ninth revision. Severe CHD was defined as tetralogy of Fallot, truncus arteriosus, transposition complexes, endocardial cushion defects, and univentricular heart. Prevalence of severe and other CHD lesions was determined in 1985, 1990, 1995, and 2000 using population numbers in Quebec. Children were subjects <18 years of age. The prevalence was 4.09 per 1000 adults in the year 2000 for all CHD and 0.38 per 1000 (9%) for those with severe lesions. Female subjects accounted for 57% of the adult CHD population. The median age of all patients with severe CHD was 11 years (interquartile range, 4 to 22 years) in 1985 and 17 years (interquartile range, 10 to 28 years) in 2000 (P<0.0001). The prevalence of severe CHD increased from 1985 to 2000, but the increase in adults was significantly higher than that observed in children. In the year 2000, 49% of those alive with severe CHD were adults. CONCLUSIONS: The prevalence in adults and median age of patients with severe CHD increased in the general population from 1985 to 2000. In 2000, there were nearly equal numbers of adults and children with severe CHD.

BACKGROUND: Magnetic resonance cholangiopancreatography (MRCP) is one of many newer noninvasive tests that can image the biliary tree. PURPOSE: To precisely estimate the overall sensitivity and specificity of MRCP in suspected biliary obstruction and to evaluate clinically important subgroups. DATA SOURCES: MEDLINE search (January 1987 to March 2003) for studies in English or French, bibliographies, and subject matter experts. STUDY SELECTION: Studies were included if they allowed construction of 2x2 contingency tables of MRCP compared with a reasonable gold standard for at least 1 of the following: the presence, level, or cause of biliary obstruction. DATA EXTRACTION: Two independent observers graded study quality, which included consecutive enrollment, blinding, use of a single (versus composite) gold standard, and nonselective use of the gold standard. Logistic regression was used to examine the influence of publication year, quality score, proportion of patients having a "direct" gold standard, and clinical context on diagnostic performance. DATA SYNTHESIS: Of 498 studies identified, 67 were included (4711 patients). Mixed-effect models were used to estimate the sensitivity and specificity, and quantitative receiver-operating characteristic analysis was performed. Magnetic resonance cholangiopancreatography had a high overall pooled sensitivity (95% [+/-1.96 SD: spread of SD, 75% to 99%]) and specificity (97% [spread of SD, 86% to 99%]). The procedure was less sensitive for stones (92%; odds ratio, 0.51 [CI, 0.35 to 0.75]) and malignant conditions (88%; odds ratio, 0.28 [CI, 0.18 to 0.44]) than for the presence of obstruction. In addition, diagnostic performance was higher in studies that were larger, did not use consecutive enrollment, and did not use gold standard assessment for some patients. CONCLUSIONS: Magentic resonance cholangiopancreatography is a noninvasive imaging test with excellent overall sensitivity and specificity for demonstrating the level and presence of biliary obstruction; however, it seems less sensitive for detecting stones or differentiating malignant from benign obstruction.

The authors compared five methods of studying survival bias associated with time-to-treatment initiation in a drug effectiveness study using medical administrative databases (1996-2002) from Quebec, Canada. The first two methods illustrated how survival bias could be introduced. Three additional methods were considered to control for this bias. Methods were compared in the context of evaluating statins for secondary prevention in elderly patients post-acute myocardial infarction who initiated statins within 90 days after discharge and those who did not. Method 1 that classified patients into users and nonusers at discharge resulted in an overestimation of the benefit (38% relative risk reduction at 1 year). In method 2, following users from the time of the first prescription and nonusers from a randomly selected time between 0 and 90 days attenuated the effect toward the null (10% relative risk reduction). Method 3 controlled for survival bias by following patients from the end of the 90-day time window; however, it suffered a major loss of statistical efficiency and precision. Method 4 matched prescription time distribution between users and nonusers at cohort entry. Method 5 used a time-dependent variable for treatment initiation. Methods 4 and 5 better controlled for survival bias and yielded similar results, suggesting a 20% risk reduction of recurrent myocardial infarction or death events.

OBJECTIVES: From the Canadian Registry of patients with Upper Gastrointestinal Bleeding and Endoscopy (RUGBE), we determined clinical outcomes and explored the roles of endoscopic and pharmacologic therapies in a contemporary real-life setting. METHODS: Analysis of randomly selected patients endoscoped for nonvariceal upper gastrointestinal bleeding at 18 community and tertiary care institutions between 1999 and 2002. Covariates and outcomes were defined a priori and 30-day follow-up obtained. Logistic regression models identified predictors of outcomes. RESULTS: One thousand eight-hundred and sixty-nine patients were included (66 +/- 17 yr, 38% female, 2.5 +/- 1.6 comorbid conditions, hemoglobin, 96 +/- 27 g/L, 54% received a mean of 2.9 +/- 1.7 units of blood). Endoscopy was performed within 24 h in 76%, with ulcers (55%) most commonly noted. High-risk endoscopic stigmata and endoscopic therapy were reported in 37%. Rebleeding, surgery, and mortality rates were 14.1%, 6.5%, and 5.4%, respectively. Decreased rebleeding was significantly and independently associated with PPI use (85% of patients, mean daily dose 56 +/- 53 mg) in all patients regardless of endoscopic stigmata, (odds ratio (OR):0.53, 95% confidence interval, 95% CI:0.37-0.77) and endoscopic hemostasis in patients with high-risk stigmata (OR:0.39, 95% CI:0.25-0.61). PPI use (OR:0.18, 95% CI:0.04-0.80) and endoscopic therapy (OR:0.31, 95% CI:0.11-0.91) were also each independently associated with decreased mortality in patients with high-risk stigmata. CONCLUSIONS: These results appear to confirm the protective role of endoscopic therapy in patients with high-risk stigmata, and suggest that acute use of PPIs may be associated with a reduction of rebleeding in all patients, and lower mortality in patients with high-risk stigmata. Independent prospective validation of these observational findings is now required.

BACKGROUND: Current observational studies on warfarin use and the risk for stroke and bleeding in patients with atrial fibrillation (AF) undergoing dialysis found conflicting results. METHODS AND RESULTS: We conducted a population-based retrospective cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec and Ontario, Canada from 1998 to 2007. The AF cohort was grouped into dialysis (hemodialysis and peritoneal dialysis) and nondialysis patients and into warfarin and no-warfarin users according to the first prescription filled for warfarin within 30 days after AF hospital discharge. We determined the association between warfarin use and the risk for stroke and bleeding in dialysis and nondialysis patients. The cohort comprised 1626 dialysis patients and 204 210 nondialysis patients. Among dialysis patients, 46% (756/1626) patients were prescribed warfarin. Among dialysis patients, warfarin users had more congestive heart failure and diabetes mellitus, but fewer prior bleeding events in comparison with the no-warfarin users. Among dialysis patients, warfarin use, in comparison with no-warfarin use, was not associated with a lower risk for stroke (adjusted hazard ratio, 1.14; 95% confidence interval, 0.78-1.67) but was associated with a 44% higher risk for bleeding (adjusted hazard ratio, 1.44; 95% confidence interval, 1.13-1.85) after adjusting for potential confounders. Propensity score-adjusted analyses yielded similar results. CONCLUSIONS: Our results suggest that warfarin use is not beneficial in reducing stroke risk, but it is associated with a higher bleeding risk in patients with AF undergoing dialysis.