Neighbourhood immigration, health care utilization and outcomes in patients with diabetes living in the Montreal metropolitan area (Canada): a population health perspective

Abstract: Background: Understanding health care utilization by neighbourhood is essential for optimal allocation of resources, but links between neighbourhood immigration and health have rarely been explored. Our objective was to understand how immigrant composition of neighbourhoods relates to health outcomes and health care utilization of individuals living with diabetes. Methods: This is a secondary analysis of administrative data using a retrospective cohort of 111,556 patients living with diabetes without previous cardiovascular diseases (CVD) and living in the metropolitan region of Montreal (Canada). A score for immigration was calculated at the neighbourhood level using a principal component analysis with six neighbourhood-level variables (% of people with maternal language other than French or English, % of people who do not speak French or English, % of immigrants with different times since immigration (<5 years, 5–10 years, 10–15 years, 15–25 years)). Dependent variables were all-cause death, all-cause hospitalization, CVD event (death or hospitalization), frequent use of emergency departments, frequent use of general practitioner care, frequent use of specialist care, and purchase of at least one antidiabetic drug. For each of these variables, adjusted odds ratios were estimated using a multilevel logistic regression. Results: Compared to patients with diabetes living in neighbourhoods with low immigration scores, those living in neighbourhoods with high immigration scores were less likely to die, to suffer a CVD event, to frequently visit general practitioners, but more likely to visit emergency departments or a specialist and to use an antidiabetic drug. These differences remained after controlling for patient-level variables such as age, sex, and comorbidities, as well as for neighbourhood attributes like material and social deprivation or living in the urban core. Conclusions: In this study, patients with diabetes living in neighbourhoods with high immigration scores had different health outcomes and health care utilizations compared to those living in neighbourhoods with low immigration scores. Although we cannot disentangle the individual versus the area-based effect of immigration, these results may have an important impact for health care planning

Characterization and consistency of interactions of triggers and substrate at the onset of paroxysmal atrial fibrillation.

Aims: Initiating mechanisms of atrial fibrillation (AF) remain poorly understood, involving complex interaction between triggers and the atrial substrate. This study sought to classify the transitional phenomena, hypothesizing that there is consistency within and between patients in trigger-substrate interaction during transition to AF. Methods and results: Non-contact left atrial (LA) mapping was performed in 17 patients undergoing ablation for paroxysmal AF. All had spontaneous ectopy. Left atrial activation from the first ectopic to established AF was examined offline to characterize the initiating and transitional sequence of activation. In 57 fully mapped spontaneous AF initiations in 8 patients, all involved interaction of pulmonary venous/LA triggers with a septopulmonary line of block (SP-LOB) also evident in sinus rhythm, by 4 different transitional mechanisms characterized by (i) continuous focal firing: AF resulted from fragmentation of each ectopic wavefront through gaps in the SP-LOB and persisted only while focal firing continued (n = 18/32%) (ii) transient focal firing, wavefront fragmentation at the SP-LOB produced wavelet re-entry that persisted after cessation of an initiating ectopic source (n = 12/21%), (iii) of two separate interacting ectopic foci (n = 15/26%), or from (iv) transiently stable macroreentry (n = 12/21%), around the SP-LOB extending to the LA roof, resulting in progressive wavefront fragmentation. It was found that 79 ± 22% of each of the initiations in individual patients showed the same triggering mechanism. Conclusion: Onset of paroxysmal AF can be described by discrete mechanistic categories, all involving interaction of ectopic activity with a common SP-LOB. Within/between-patient consistency of initiations suggests constancy of the interacting triggers and substrate, and supports the concept of mechanistically tailored treatment