Population-based cohort study of hospital delivery volume, geographic accessibility, and obstetric outcomes.

OBJECTIVE: To determine associations between geographic accessibility, delivery volume, and obstetric outcomes. METHODS: Population-based cohort study of linked hospital administrative, census, and geospatial data (2006-2009) from all Canadian jurisdictions except Quebec. Perinatal mortality and major maternal morbidity/mortality were compared across categories of road distance and hospital delivery volume. RESULTS: Among 820 761 mothers delivering 827 504 neonates, travel distance had minimal effect on perinatal mortality. Compared with mothers travelling 0-9 km, the odds of adverse maternal outcomes was decreased for women travelling modest distances (20-49 km, odds ratio, 0.80 [95% confidence interval, 0.75-0.86]), and increased thereafter (50-99 km, 0.99 [0.89-1.10]; 200-299 km, 1.44 [1.10-1.87]; >400 km, 2.22 [1.06-4.63]). Relative to high-volume hospitals (>2500 deliveries/year), adverse maternal outcomes were less likely for hospitals with 1000-2499 (0.90 [0.86-0.95]), and roughly equivalent for hospitals with 200-499 (1.34 [1.22-1.48]) and 500-999 (1.27 [1.17-1.39]) deliveries/year. Odds of perinatal mortality ranged from 1.04 (0.73-1.49; 100-199 deliveries/year) to 1.50 (1.04-2.16; 50-99 deliveries/year); the pattern did not suggest causality. CONCLUSION: Maternal outcomes worsen when travel distance is greater than 200 km, and improve when delivery volume exceeds 1000 deliveries per year.

Genetic associations in community context: a mixed model approach identifies a functional variant in the RBP4 gene associated with HDL-C dyslipidemia.

BACKGROUND: The objective of this study was to examine individual and community factors that influence high-density lipoprotein cholesterol (HDL-C) dyslipidemia in Newfoundland and Labrador (NL), a genetically isolated population in Canada with a high prevalence of HDL-C dyslipidemia. METHODS: First, a group of single nucleotide polymorphisms from 10 metabolic trait candidate genes was tested using a multivariate logistic regression model. The significant SNPs were entered into the second phase, where a mixed logistic model incorporated the community disease risk factors together with the individual factors as the fixed part of the model and the geographic region as a random effect. RESULTS: Analysis of 1489 subjects (26.9% HDL-C dyslipidemia) identified rs3758539, a non-coding variant in the 5'UTR of RBP4, to be associated with HDL-C dyslipidemia (odds ratio = 1.45, 95% confidence interval = 1.08-1.97, p = 0.01). The association remained significant, and the effect size did not change after the incorporation of individual and community risk factors from 17 geographic regions (odds ratio: 1.41, 95% confidence interval = 1.03-1.93, p = 0.03) in NL. Besides this variant, sex, BMI, and smoking also showed significant associations with HDL-C dyslipidemia, whereas no role was identified for the community factors. CONCLUSIONS: This study demonstrates the use of community-level data in a genetic association testing. It reports a functional variant in the promoter of RBP4, a gene directly involved in lipoprotein metabolism, to be associated with HDL-C dyslipidemia. These findings indicate that individual factors are the main reason for a higher prevalence of HDL-C dyslipidemia in the NL population.

Outcomes of deliveries by family physicians or obstetricians: a population-based cohort study using an instrumental variable.

BACKGROUND: Previous research has suggested that obstetric outcomes are similar for deliveries by family physicians and obstetricians, but many of these studies were small, and none of them adjusted for unmeasured selection bias. We compared obstetric outcomes between these provider types using an econometric method designed to adjust for unobserved confounding. METHODS: We performed a retrospective population-based cohort study of all Canadian (except Quebec) hospital births with delivery by family physicians and obstetricians at more than 20 weeks gestational age, with birth weight greater than 500 g, between Apr. 1, 2006, and Mar. 31, 2009. The primary outcomes were the relative risks of in-hospital perinatal death and a composite of maternal mortality and major morbidity assessed with multivariable logistic regression and instrumental variable-adjusted multivariable regression. RESULTS: After exclusions, there were 3600 perinatal deaths and 14,394 cases of maternal morbidity among 799,823 infants and 793,053 mothers at 390 hospitals. For deliveries by family physicians v. obstetricians, the relative risk of perinatal mortality was 0.98 (95% confidence interval [CI] 0.85-1.14) and of maternal morbidity was 0.81 (95% CI 0.70-0.94) according to logistic regression. The respective relative risks were 0.97 (95% CI 0.58-1.64) and 1.13 (95% CI 0.65-1.95) according to instrumental variable methods. INTERPRETATION: After adjusting for both observed and unobserved confounders, we found a similar risk of perinatal mortality and adverse maternal outcome for obstetric deliveries by family physicians and obstetricians. Whether there are differences between these groups for other outcomes remains to be seen.

Challenges and opportunities for using administrative data to explore changes in health status: a study of the closure of the Newfoundland cod fishery.

The closure of the cod fishery in Newfoundland and Labrador has had dramatic social and economic impacts on fishing communities in the province. Following a limited closure in 1992, a more extensive closure followed in 1994, which is still in force today, although income support provided to displaced fishery workers ended in 1999. A population-based study was conducted in 2004/2005 using 7 different sources of administrative and survey data to investigate a range of social, demographic, and health changes in fishing communities affected by the closure of the cod fishery from the period 1991 to 2001. Findings of this study extend our understanding of the impact of the fishing moratorium in Newfoundland. This article also presents both the challenges to and opportunities for using administrative and survey data to explore the impact of the fishery closure on the health and well-being of Newfoundland fishing communities. One of the most significant challenges to using administrative and survey databases was the inconsistencies in how communities were identified across the various databases. Although not without limitations, administrative data is a cost-effective means to explore the impact of socioeconomic change on a population's health status.