One limitation of this study is reliance on the use of administrative claims data alone. Although there have been validation studies completed previously , there may potentially be undercounting of diagnoses for those people not seeking medical help. However, that would not be any more likely for those people living in similar geographical locations, so the differences in health status should not be affected. The Canadian universal health care system also equally applies to all, so lack of access through potential income barriers would not be as problematic as in a country without universal health care provisions. A further limitation may be in the establishment of the Métis cohort used in this study. This may have included a small number of people who are not Métis, but who were included through familial relationships using health registry data available to us (for example, if a non-Métis married a Métis, we would have classified both as Métis). If anything, this would most likely reduce the gaps in health status between Métis and all other Manitobans, so that the health inequity found in this study would be maintained or increased if a more accurate identifier were available. That being said, the Métis population count obtained through our method was similar (i.e., less than 2% difference) to that obtained through self-report of the Census.
Age- and sex-adjusted morbidity and mortality rates
Mortality and morbidity rates are, in general, higher in the Métis population of Manitoba compared to all other Manitobans when we look at age- and sex-adjusted rates. Mortality rates, whether premature mortality, total mortality, injury mortality, or potential years of life lost, all appear to be more sensitive indicators of differences than life expectancy. The former mortality indicators show elevated rates for Métis of 14% to 23%, whereas life expectancy is not significantly different for female Métis, and only 2% lower for male Métis compared to the rest of the population. In terms of morbidity, diabetes (34% higher for Métis) and ischemic heart disease (40% higher) show the biggest gap in a disease outcome for adults aged 19 and older. As well, age- and sex-adjusted diabetes-related outcomes such as lower limb amputations with diabetes comorbidity (49% higher), and dialysis initiation (35% higher) all mirror the elevated diabetes rate for the Métis.
Our research shows higher Métis life expectancies than those reported previously [9–11], and a gap of less than 2 years difference between Métis and all other Manitobans. As well, there appears to be a much smaller gap than found for Manitoba First Nations people, where life expectancy was 8 years lower than the rest of the population [24, 25].
In our study, the overall Manitoba age- and sex-adjusted prevalence of diabetes was elevated for Métis compared to all other Manitobans (11.8% vs. 8.8%; Relative Risk [RR] = 1.34). Although the prevalence of diabetes in the Métis population is elevated in Manitoba, this report did not find a doubling or tripling effect as in other Métis studies previously [10, 13, 14, 16]. This may relate to the fact that there may be underlying undiagnosed diabetes, or the rest of the Manitoba population rate is much higher than in some other provinces, or the Manitoba sample in previous studies was different than our population-based cohort that included all Manitoba Métis people. For those living with diabetes, we found an elevated risk of lower limb amputation for the Métis compared to the rest of the population (24.1 vs. 16.2 per 1000) when adjusting only for age and sex. Although a gap exists, in fact, many of the health indicators for the Métis appeared to be somewhat between those rates found for the general population and for the First Nations populations [24–26].
A more complex analysis of diabetes and amputation - regression modeling to determine factors
The main predictors of diabetes for the Métis were similar to those found in previous research studies, with older age and physical comorbidities both being strongly associated with increased likelihood (see Table 4). The sex difference in the diabetes model was not statistically significant for Métis (aOR = 1.00, 95% CI 0.94-1.07, NS), and only slightly elevated for males in the entire population model (aOR = 1.14, 95% CI 1.12-1.16). This corresponds with the finding of Janz et al. , but is contradictory to the finding of Bruce where females had a higher prevalence [13, 14].
However, the sex difference for amputation due to diabetes showed a high degree of elevated risk for males for both the entire population model (aOR = 1.94, 95% CI 1.71-2.21) and the Métis only model (aOR = 2.36, 95% CI 1.50-3.71). Although this study did not look at causes of the sex differences, it could be speculated that males have a more rapid progression of disease or may be diagnosed with diabetes at a later stage, thus being more at risk for amputation. Altenberg et al.  have demonstrated that people exhibiting lower health-conscious behavior, visiting a healthcare provider less often or showing less anxiety about their diabetes are more likely to have diabetic foot ulcers (which, in turn, could lead to greater risk of amputation). So factors such as these may be more likely in males, hence they would have an elevated risk for amputation - this needs further study in Manitoba to understand the sex differences.
For the Métis only (see Table 4), in contrast to Bruce [13, 14], a lower likelihood of having diabetes was associated with higher average household income of the neighbourhood (aOR = 0.875, 95% CI 0.86-0.89 for each $10,000 increase). As well, Métis living in the southern and mid-provincial MMF Regions had less likelihood of diabetes, but Métis living in the two northern MMF regions (The Pas MMF Region aOR = 1.22, 95% CI 1.11-1.33; Thompson MMF Region aOR = 1.66, 95% CI 1.49-1.86) were more likely to have diabetes compared to the provincial average. Bruce et al.  did not find a geographical difference, but this may have been a type 2 error due to a much smaller sample size. That study did show a trend towards higher diabetes prevalence in rural/northern compared to urban areas (7.1% vs. 5.7%, NS), albeit not statistically significant. Once again, further study is required to understand why the likelihood of diabetes is higher for Métis living in the North. This is contrary to the finding of Martens et al. , where First Nations people had a greater risk of diabetes in the southern Tribal Councils, possibly due to a longer history of colonization, stress and lifestyle changes in more urbanized areas compared to more remote areas.
Comparing the age- and sex-adjusted models with the more complex models
The regression models of diabetes and of lower limb amputation give a much more complex picture of the risk factors compared to an age- and sex-adjustment only. In Table 4, for all Manitobans, the adjusted odds ratio indicates an elevated likelihood of diabetes for the Métis compared to all other Manitobans (aOR = 1.29, 95% CI 1.25-1.34, p < .001; 29% higher), after adjusting for age, sex, geographical location, income, continuity of care, and comorbidities. This is very similar to the relative risk of 1.34 in Table 3, which is only adjusted for age and sex, showing 34% higher risk of diabetes for Métis compared to all others. Despite controlling for other factors, such as living in the North, in lower income areas, and having more physical comorbidities, there is still the persistent effect of being "Métis" and its association with a higher likelihood of having diabetes. This could possibly be genetic susceptibility of the Métis, due to their First Nations ancestry, or to unmeasured factors in our analysis such as dietary considerations  or stress levels [29, 30]. Further study would be warranted which includes more comprehensive data sources.
In contrast to the complex modeling of diabetes, the complex modeling of the likelihood of lower limb amputation for those with diabetes shows a dramatically different result when looking at the Métis effect (see Table 5). Table 3 indicates that the age- and sex-adjusted rate of amputation is 49% higher for the Métis compared to all other Manitobans (24.1 vs. 16.2 per 1000, p < .001, RR = 1.49). However, Table 5 shows the more complex regression model with factors such as geography, comorbidity and continuity of care as well as age and sex. This showed no statistically significant difference in the likelihood of lower limb amputation between Métis and all others (aOR = 1.13, 95% CI 0.90-1.40; p = 0.29, NS). Note that the model only has the power to detect an OR of 1.279, so this could be a type 2 error. However, given the dramatic decrease and the small OR after adjustment, even if this were statistically significant it would show that the ethnicity factor of being Métis is clinically not important. So this indicates that factors other than ethnicity have a significant effect on the likelihood of having an amputation once a person has diabetes. Being older or being male, living in an area of lower average household income, or in the Mid and North parts of Manitoba, and having major comorbid physical illnesses all contribute to increased likelihood of amputation. However, having continuity of care shows a beneficial association (aOR = 0.709, p < 0.001). Continuity of care may reflect the difficulties of accessing the same physician for the majority of one's healthcare, especially in rural and northern areas of the province where physician turnover rates may be high. Martens, Bartlett et al.  found that provincially, 65.4% of Metis and 69.1% of all other Manitobans received over 50% of their care from the same physician in a two-year period of time of 2005/06 to 2006/07. However, this was much lower in the North area of the province (Métis 58.7%, all other Manitobans 57.2%), and particularly in the RHA of Burntwood (Métis 47.3%, all other Manitobans 47.3%). For diabetes in particular, consistent management and follow-up may prevent adverse outcomes.
So the "Métis" effect of higher amputation rates may be explained by where the Métis live, their lower income levels, their additional burden of comorbidity, or the lower percentage receiving continuity of care. It is important to note, however, that even in the Métis-only analysis, higher average household income level was associated with lower amputation rates, so social policy must be considered. As well, knowing that Métis living in rural and northern remote areas have difficulty accessing the healthcare system, it is important to do further study into healthcare access issues. A previous ecologic study by Martens et al.  has shown that diabetes prevalence was highly associated with socioeconomic status amongst First Nations Tribal Council areas of Manitoba, but lower limb amputation was associated with lower rates of access to specialist care (and not with socioeconomic status). This study of the Métis was analyzed at the individual person level, not the aggregate area level, but we see similar findings as to the importance of the healthcare system in being associated with lower rates of amputation for people living with diabetes.