Differences in glycemic control and survival predict higher ESRD rates in diabetic first nations adults

Abstract

Di erences in glycemic control and survival predict higher ESRD rates in diabetic rst nations adults Abstract Purpose: Diabetic First Nations people (FN) have higher ESRD rates than other Canadians but the reasons remain unclear. We sought to better understand this disparity by comparing demographic, laboratory and survival features of diabetic FN and other Saskatchewan residents (OSK) by renal function stage.Methods: Prevalent diabetes cases in 2005/06 were identi ed in Saskatchewan's two largest health regions using administrative databases, and linked with centralized laboratory tests. ey were sub-divided into ve stages of renal function using estimated glomerular ltration rates (eGFR) that were determined in 992 of 2,321 FN (42.7%) and 14,054 of 21,886 OSK (64.2%). Age, sex, urine microalbumin (MA), glycosylated hemoglobin (A1C), low density lipoprotein cholesterol (LDL-C) and two year mortality risk was compared for all subjects.Results: Diabetic FN were younger (mean age 52.7 vs. 64.2, p<0.0001), more likely to be female (59.6% vs.45.4%, p<0.001), had increased MA (56.6% vs. 48.4%, p<0.0001) and displayed higher mean A1C levels (8.16% vs.7.36%, p<0.0001) than OSK. Despite a larger proportion having eGFR's >60 ml/min (87.0% vs.77.3%, p<0.001), FN were also more likely to have ESRD (2.3% vs.0.8%, p<0.001). Although FN with eGFR's >30 ml/min experienced higher age/sex adjusted mortality risk than OSK, the trends for both adjusted and unadjusted mortality risks for those with advanced pre-ESRD renal failure were lower for FN than for OSK.Conclusions: Elevated rates of ESRD experienced by FN with diabetes are related to poorer glycemic control at all levels of renal function, and lower age-related mortality at advanced stages of chronic kidney disease. ORIGINAL RESEARCH © 2010 CIMClin In E390 Diabetes mellitus is the most common cause of end stage renal disease (ESRD) in Canada [1] but the burden of diabetic ESRD upon indigenous peoples is of particular concern. In 1994, a disproportionate incidence of ESRD was reported among Saskatchewan First Nations (FN) people with diabetes [2] and a recent study shows that such disparities persist [3]. While the mechanisms underlying these observations are incompletely understood, there are two possibilities. First, FN with diabetes may be more prone to the initial development of diabetic glomerulosclerosis, which can lead to ESRD. is is supported by reports that diabetic FN have higher rates of microalbuminuria [4]. Second, FN with early diabetic glomerulosclerosis may progress to ESRD more frequently than others because of a more rapid course and/or lower mortality rates. Although our recent ndings that FN are diagnosed at a a younger age and experience a longer duration between diabetes and ESRD diagnoses are consistent with a di erential mortality e ect [5] other studies report lower survival rates among FN with all-cause advanced chronic kidney disease (CKD) [6].Identifying the mechanisms underlying ethnicity-based di erences in diabetic ESRD is important for understa...

Differential mortality and the excess burden of end-stage renal disease among First Nations people with diabetes mellitus: a competing-risks analysis

“…15 This phenomenon occurs in the formerly perplexing context of higher age-adjusted mortality among First Nations individuals with diabetes. 8,16,17 It also explains our earlier observation that the time from diabetes diagnosis to end-stage renal disease is significantly longer among First Nations individuals, 2 despite evidence for poorer quality of diabetes care 18,19 and a larger proportion of patients with early diabetic nephropathy. 8,20 These findings are notable because they reveal an important mechanism underlying ethnicity-based disparities in endstage renal disease that has serious long-term implications for First Nations and other indigenous populations.…”

“…6 Second, strategies to postpone type 2 diabetes should be considered: if the occurrence of diabetes can be delayed, it seems plausible that the risk of chronic complications and premature deaths will be reduced. Finally, addressing disparities in both accessibility and quality of diabetes care 8,19 is imperative to achieve therapeutic targets for glycemic, blood pressure and lipid control. 18,19 Although the reasons underlying these disparities are complicated, they are also modifiable, and substantial improvements are likely during even the early stages of resolution.…”

“…20,21 Although differences in diabetes-related incidence of end-stage renal disease have diminished between First Nations and non-First Nations popu lations in Canada 2 and between comparable populations in the United States, 22 significant ethnicity-based disparities in end-stage renal disease persist 2,22 and have remained incompletely understood. Known contributing factors include genetic 3 and other prenatal determinants, 23 envi- ronmental factors such as glycemic and blood pressure control 8,24 and social determinants such as quality of and access to health care. 18,19 We have now confirmed that an age-related survival advantage after diabetes diagnosis also contributes to the elevated risk for diabetes-related end-stage renal disease among First Nations individuals.…”

“…6 In an earlier study, we suggested that First Nations adults might be more prone to diabetic nephropathy and might experience more rapid progression to end-stage renal disease. 7 However, although albuminuria is more prevalent in this population, 8 affected individuals unexpectedly have a longer average time from diagnosis of diabetes to end-stage renal disease than people from non-First Nations populations. 2 These findings could be explained by a younger age at the time of diabetes diagnosis 6 and lower mortality among those with chronic kidney disease.…”

“…2 These findings could be explained by a younger age at the time of diabetes diagnosis 6 and lower mortality among those with chronic kidney disease. 8 An age-related survival benefit among First Nations adults with diabetes could lead to longer exposure to the metabolic consequences of diabetes and greater likelihood of end-stage renal disease.…”