Clinical Research
Incidence, Secular Trends, and Outcomes of Cardiac Surgery in Aboriginal Peoples

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Abstract

Background

Canada's Aboriginal people experience a disproportionate burden of comorbid illnesses predisposing them to higher rates of atherosclerotic disease. We set out to investigate secular rates of cardiovascular surgery (CVSx) and postsurgical outcomes in Aboriginals compared with non-Aboriginals.

Methods

All patients undergoing CVSx in Manitoba, Canada from 1995-2007 (N =12,170 [Aboriginal, 574, 4.7%; non-Aboriginal, 11,596, 95.3%]) were included in our study cohort. Race was self-identified. Age- and sex-adjusted incidence were determined using 2001 and 2006 census data. Multivariable logistic regression models were constructed to determine the association between race and the outcomes of death, infections, and a composite of adverse events.

Results

CVSx rates were significantly lower in Aboriginals compared with non-Aboriginals (all CVSx, 63.6 vs 97.7 per 10,000 population; coronary artery bypass grafting only, 46.2 vs 71.9 per 10,000 population, respectively). The lower CVSx rates were most pronounced among Aboriginals residing in urban areas (21.0 vs 78.0 per 10,000). Postoperatively, Aboriginals experienced significantly higher odds of infections (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.13-2.34; P = 0.008), in particular pneumonia (OR, 2.24; 95% CI, 1.58-3.19; P < 0.0001). There was no increase in risk of death after surgery (OR, 1.15; 95% CI, 0.63-2.08; P = 0.6) or the composite outcome (OR, 1.0; 95% CI, 0.66-1.52; P = 1.0) compared with non-Aboriginals.

Conclusions

Aboriginal peoples, particularly in the urban setting, are considerably less likely to undergo CVSx. When they do, they have postoperative mortality similar to that of non-Aboriginals. Our findings suggest an urban racial disparity in access to CVSx.

Résumé

Introduction

Les Autochtones portent un fardeau disproportionné d'affections comorbides les prédisposant à des taux plus élevés de maladies athérosclérotiques. Nous entreprenons d'examiner les taux séculaires des chirurgies cardiovasculaires (CCV) et les résultats postchirurgicaux des Autochtones par rapport aux non-Autochtones.

Méthodes

Tous les patients ayant subi une CCV au Manitoba, au Canada, de 1995 à 2007 (N = 12 170 [Autochtones, 574, 4,7 %; non-Autochtones, 11 596, 95,3 %]) ont été inclus dans notre étude de cohorte. La race a été autodéclarée. L'incidence ajustée selon l'âge et le sexe a été déterminée en utilisant les données des recensements de 2001 et de 2006. Les modèles de régression logistique multivariée ont été élaborés pour déterminer le lien entre la race et l'évolution des décès, des infections et des divers événements indésirables.

Résultats

Les taux de CCV ont été significativement plus bas chez les Autochtones comparativement aux non-Autochtones (toutes les CCV, de 63,6 vs 97,7 par population de 10 000 individus; le pontage aortocoronarien seul, de 46,2 vs 71,9 par population de 10 000 individus, respectivement). Les taux de CCV plus bas ont été plus marqués chez les Autochtones habitant en milieu urbain (21,0 vs 78,0 par 10 000 individus). Après la chirurgie, les Autochtones ont montré des risques plus élevés d’infections (ratio d’incidence approché [RIA], 1,63; intervalle de confiance [IC] à 95 %, 1,13-2,34; P = 0,008), en particulier, de pneumonie (RIA, 2,24; IC à 95 %, 1,58-3,19; P < 0,0001). Il n'y a pas eu d'augmentation du risque de décès après la chirurgie (RIA, 1,15; IC à 95 %, 0,63-2,08; P = 0,6) ou des critères de jugements combinés (RIA, 1,0; IC à 95 %, 0,66-1,52; P = 1,0) comparativement aux non-Autochtones.

Conclusions

Les Autochtones, particulièrement ceux habitant en milieu urbain, sont considérablement moins susceptibles de subir une CCV. Lorsqu’ils en subissent une, ils ont une mortalité similaire à celle des non-Autochtones. Nos conclusions montrent une disparité raciale en milieu urbain en ce qui concerne l’accès à la CCV.

Section snippets

Study population

In this retrospective study, the analytic cohort included all patients (> 15 years of age) who underwent CVSx from 1995-2007 in the province of Manitoba (population, 1.2 million). All adult cases of cardiac surgery in Manitoba were captured. This study was approved by the Research Ethics Board of the University of Manitoba, the Hospital Ethics Board at St. Boniface Hospital in Winnipeg, Manitoba, and the Assembly of Manitoba Chiefs. For additional information regarding data collection methods,

Comparison of Aboriginal and non-Aboriginal patient characteristics

Over the study period, 12,793 patients underwent CVSx. From this cohort 623 (4.9%) were missing data and excluded from the analysis, leaving 12,170 patients (574 Aboriginal; 11,596 non-Aboriginal) in the study cohort used to determine the baseline characteristics and postoperative outcomes. A further 423 patients (3.5%) were missing postal code information and 623 (5.1%) resided outside of Manitoba and were excluded from the regional analysis. There was no significant difference in missing

Discussion

In this large retrospective population-based study, Aboriginals were less likely to undergo CVSx than were non-Aboriginals. In particular, Aboriginals residing in a large urban centre had the lowest rate of CVSx, lower than those residing in the North, suggesting that remoteness and geographic barriers to care did not explain the disparate findings. These results were consistent over time and after age- and sex-adjustment. These data are concerning and suggest a racial disparity in the access

Conclusions

We have demonstrated marked cumulative and paradoxical geographic differences in the CVSx rates for Aboriginal vs non-Aboriginal patients. Further research is needed to discern whether these differences are caused by inadequate access to care or whether they reflect unmeasured differences in clinical status or patient preference. Finally, despite a higher postoperative infection rate, mortality was similar across racial groups.

Disclosures

M.M.S. has received speaker fees and has served on advisory boards for Roche, Ortho Biotech, and Sanofi. The other authors have no conflicts of interest to disclose.

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