the study sampling frame was derived from a well - characterized population with diabetes in the kaiser permanente northern california diabetes registry ( n = ~225,000 ) ( 7 ) . kaiser permanente northern california is a fully integrated health care delivery system that provides comprehensive medical care to > 3 million members ( 30% of the catchment area ) . except for the extremes of income , the demographic characteristics of the patient population are similar to those of the overall population of the region . during 19941997 , all noninstitutionalized diabetes registry members aged > 19 years were mailed a questionnaire or contacted for a computer - assisted telephone interview in english , spanish , mandarin , or cantonese ( n = 95,953 ) . after excluding those who denied having diabetes and those who had left the health plan , we excluded another 5,511 people with unknown race / ethnicity , mixed racial / ethnic background , or those belonging to racial / ethnic groups with insufficient size for analysis ( e.g. , vietnamese , koreans , and indonesians ) , leaving a total study population of 64,211 individuals . in our analyses , we present each racial / ethnic group separately and also aggregate the four asian groups ( chinese , filipino , japanese , and south asian ) together to address our hypothesis . limited english proficiency , categorized as always or often having problems speaking and/or understanding english , was categorized using administrative records . behavioral variables included current smoking status and alcohol use and whether the subject reported using exercise to treat their diabetes at the time of the survey . bmi was calculated based on self - reported height and weight at the time of the survey . we calculated multi - interval , continuous - medication gaps , a well - validated metric of medication adherence ( percentage of time without sufficient medications ) based on pharmacy utilization for oral glucose - lowering medication . we assessed a history of hypertension using a self - reported measure and pharmacy records for antihypertensive drug use . hba1c levels , ldl cholesterol , hdl cholesterol , triglycerides , microalbuminuria , and estimated glomerular filtration rate ( egfr ) were ascertained from kaiser s regional laboratory within 1 year of baseline individual survey date . we evaluated the incidence of five diabetes complications : myocardial infarction ( mi ) , congestive heart failure ( chf ) , stroke ( ischemic or hemorrhagic ) , esrd , and nontraumatic lea over 7  3 years of follow - up . the icd-9-cm codes listed as either the primary hospitalization discharge diagnosis or the icd-10-cm code for underlying cause of death on the death certificate were used to identify mi , chf , and stroke ( supplementary data ) . esrd was identified from kaiser permanente s esrd treatment registry or defined by chronic renal failure listed as the underlying cause of death on the death certificate . emergency events serviced by non  kaiser permanente hospitals were captured via a claims reimbursement database for outside medical services . mortality and cause of death were ascertained with a validated program , the california automated mortality linkage system . we have previously reported validation studies of these end points in this population ( 7 ) . we used a direct adjustment method , with the whole diabetic cohort as the standard population to determine age- and sex - adjusted incidence densities for each outcome by race . the incidence densities are presented as the number of events per 1,000 person - years with 95% cis . we calculated age- and sex - adjusted rates and fully adjusted rate ratios comparing each ethnic group to whites using poisson regression for those with complete data . cox proportional hazards models were specified to calculate adjusted hazard ratios ( hrs ) for each ethnic minority group versus the reference category ( whites ) . we excluded individuals with a prevalent history of the same diagnosis for each of the outcomes analyzed , focusing only on incident events . we pooled the data for men and women because the interaction between ethnicity and sex was not significant for all outcomes except for mi . we specified a series of cox regression models in sequence to assess potentially explanatory variables after verifying that there were no violations of the proportionality assumption . first , we created a base model that was adjusted for sex and age ( demographic model ) . then , we added socioeconomic factors ( education , english - language proficiency , and neighborhood deprivation score ) for the second model ( ses model ) . the third model added bmi . a fourth model ( behavior model ) added smoking status , alcohol intake , self - reported use of exercise as a treatment for diabetes , and medication adherence for oral diabetes medications . the fifth and final model ( clinical model ) added characteristics specific to diabetes to the behavior model , including type of diabetes , diabetes duration , hypertension history , baseline hba1c ( < 7 , 78 , 810 , and > 10% ) , ldl cholesterol ( < 100 vs. 100 mg / dl ) , elevated urinary albumin excretion ( microalbuminuria or proteinuria vs. normoalbuminuria ) , and chronic kidney disease stages based on standard cut points for egfr . moreover , in the beginning of the study ( 1996 ) , the clinical assessments ( ldl cholesterol , hba1c , and others ) were not collected as frequently or routinely as is common today . because the analyses were restricted to complete cases , which can introduce bias if the data are not missing completely at random , we used a multiple - imputation method to replace the missing variables of our study . we used the markov chain monte carlo method ( 8) , which assumes multivariate normality to impute all missing values to make 10 complete datasets , as implemented in sas proc mi . after the 10 complete datasets were analyzed using standard sas procedures ( proc tphreg ) , the mianalyze procedure was used to generate valid statistical inferences by combining results from the 10 analyses . in addition , we performed a sensitivity analysis using observations for which no data were missing . limited english proficiency , categorized as always or often having problems speaking and/or understanding english , was categorized using administrative records . behavioral variables included current smoking status and alcohol use and whether the subject reported using exercise to treat their diabetes at the time of the survey . bmi was calculated based on self - reported height and weight at the time of the survey . we calculated multi - interval , continuous - medication gaps , a well - validated metric of medication adherence ( percentage of time without sufficient medications ) based on pharmacy utilization for oral glucose - lowering medication . we assessed a history of hypertension using a self - reported measure and pharmacy records for antihypertensive drug use . hba1c levels , ldl cholesterol , hdl cholesterol , triglycerides , microalbuminuria , and estimated glomerular filtration rate ( egfr ) were ascertained from kaiser s regional laboratory within 1 year of baseline individual survey date . we evaluated the incidence of five diabetes complications : myocardial infarction ( mi ) , congestive heart failure ( chf ) , stroke ( ischemic or hemorrhagic ) , esrd , and nontraumatic lea over 7  3 years of follow - up . the icd-9-cm codes listed as either the primary hospitalization discharge diagnosis or the icd-10-cm code for underlying cause of death on the death certificate were used to identify mi , chf , and stroke ( supplementary data ) . esrd was identified from kaiser permanente s esrd treatment registry or defined by chronic renal failure listed as the underlying cause of death on the death certificate . emergency events serviced by non  kaiser permanente hospitals were captured via a claims reimbursement database for outside medical services . mortality and cause of death were ascertained with a validated program , the california automated mortality linkage system . we have previously reported validation studies of these end points in this population ( 7 ) . we used a direct adjustment method , with the whole diabetic cohort as the standard population to determine age- and sex - adjusted incidence densities for each outcome by race . the incidence densities are presented as the number of events per 1,000 person - years with 95% cis . we calculated age- and sex - adjusted rates and fully adjusted rate ratios comparing each ethnic group to whites using poisson regression for those with complete data . cox proportional hazards models were specified to calculate adjusted hazard ratios ( hrs ) for each ethnic minority group versus the reference category ( whites ) . we excluded individuals with a prevalent history of the same diagnosis for each of the outcomes analyzed , focusing only on incident events . we pooled the data for men and women because the interaction between ethnicity and sex was not significant for all outcomes except for mi . we specified a series of cox regression models in sequence to assess potentially explanatory variables after verifying that there were no violations of the proportionality assumption . first , we created a base model that was adjusted for sex and age ( demographic model ) . then , we added socioeconomic factors ( education , english - language proficiency , and neighborhood deprivation score ) for the second model ( ses model ) . the third model added bmi . a fourth model ( behavior model ) added smoking status , alcohol intake , self - reported use of exercise as a treatment for diabetes , and medication adherence for oral diabetes medications . the fifth and final model ( clinical model ) added characteristics specific to diabetes to the behavior model , including type of diabetes , diabetes duration , hypertension history , baseline hba1c ( < 7 , 78 , 810 , and > 10% ) , ldl cholesterol ( < 100 vs. 100 mg / dl ) , elevated urinary albumin excretion ( microalbuminuria or proteinuria vs. normoalbuminuria ) , and chronic kidney disease stages based on standard cut points for egfr . moreover , in the beginning of the study ( 1996 ) , the clinical assessments ( ldl cholesterol , hba1c , and others ) were not collected as frequently or routinely as is common today . because the analyses were restricted to complete cases , which can introduce bias if the data are not missing completely at random , we used a multiple - imputation method to replace the missing variables of our study . we used the markov chain monte carlo method ( 8) , which assumes multivariate normality to impute all missing values to make 10 complete datasets , as implemented in sas proc mi . after the 10 complete datasets were analyzed using standard sas procedures ( proc tphreg ) , the mianalyze procedure was used to generate valid statistical inferences by combining results from the 10 analyses . in addition , we performed a sensitivity analysis using observations for which no data were missing . of 64,211 diabetic patients , ~63% were white , 13% were african american , 12% were latino , 6% were filipino , 3% were chinese , 1% were japanese , 1% were pacific islanders , and 1% were south asians . there were a total of 6,901 ( 11% ) asian participants in aggregate and an additional 593 ( 1% ) pacific islanders included in this analysis . the total follow - up time was ~413,500 person - years or a mean of 7.2  3.3 years from 1996 to 2006 . each of the eight ethnic groups were ~50% women , except for the chinese ( 42% women ) and south asian ( 30% women ) groups ( table 1 ) . mean age differed somewhat by ethnicity , with japanese respondents being oldest ( aged 62  11 years ) and south asians being the youngest ( aged 53  11 years ) . college graduation rates were highest among south asians ( 55% ) , filipino ( 47% ) , chinese ( 37% ) , and japanese ( 33% ) and lowest among pacific islanders ( 14% ) and latinos ( 12% ) . there were high proportions of african americans ( 47% ) and latinos ( 31% ) living in the most deprived neighborhoods . the average bmi was similar for whites , african americans , latinos , and pacific islanders ( ~30  6 kg / m for each ) and lower for the other four asian subgroups ( mean 2526 kg / m per group ) . the prevalence of smoking was highest among african americans ( 16% ) and pacific islanders ( 14% ) and lowest among the chinese and south asian ( 5% ) groups . the mean duration of diagnosed diabetes was similar for whites , african americans , latinos , and japanese ( 10  10 years for each group ) but lower for chinese ( 9  11 years ) , filipinos ( 8  8 years ) , pacific islanders ( 8  9 years ) , and south asians ( 8  7 years ) . more than half of all participants in each ethnic group were using oral hypoglycemic medications for diabetes treatment , had a family history of diabetes , and had hypertension . baseline characteristics of 64,211 participants with diabetes by race / ethnic group * * values represent % unless otherwise stated . we calculated the crude and age- and sex - adjusted incidence rates per ethnic group for each of the five diabetes complications ( table 2 ) . we also show the aggregated rates of the four asian subgroups together for comparison with the individual asian subgroups . the table shows the hr ( 95% ci ) for each ethnic group compared with whites for each of the diabetes complications . crude age- and sex - adjusted incidence rates and fully adjusted rate ratios * of each outcome by racial subgroup , distance study , 19962006 * fully adjusted rate ratio comparing the rate in each ethnic group with that of whites using a poisson regression model . there were a total of 6,088 people with incident mi during the follow - up period . the aggregated asian incidence rate ( 10.8 [ 95% ci 9.911.8 ] ) completely obscured the wide range of rates across the four asian subgroups . the highest incidence of mi occurred in pacific islanders ( 18.5 [ 14.323.5 ] per 1,000 person - years ) , and the lowest incidence was in chinese ( 9.2 [ 7.711.0 ] per 1,000 person - years ) . after age and sex adjustment , the rates were attenuated , but pacific islanders had the highest incidence of mi ( 10.1 per 1,000 person - years ) of all groups , whereas japanese ( 3.3 per 1,000 person - years ) had the lowest incidence of mi , with whites in the middle of this range ( 5.9 per 1,000 person - years ) . these differences between subgroups persisted despite multivariate adjustment for several potentially explanatory factors ( fig . compared with whites , most racial / ethnic groups had significantly lower hazards of mi . however , pacific islanders had significantly higher risk ( hr 1.29 [ 1.011.66 ] ) , and south asians were not significantly different from whites . furthermore , sex did not modify the association between ethnicity and mi risk , except for pacific islanders where women had a markedly higher risk ( 1.94 [ 1.402.68 ] ) than men ( 0.87 [ 0.591.27 ] ; p for interaction = 0.001 ) . hrs and 95% cis for each ethnic group ( vs. whites [ reference group ] ) for each diabetes complication . the total number of first - time diagnoses for chf was 5,062 during follow - up . the highest age- and sex - adjusted incidence was among african americans ( 5.2 per 1,000 person - years ) , and the lowest incidence was among chinese ( 2.5 per 1,000 person - years ) . the range of chf incidence rates among the four asian groups was narrower for chf than for mi ( from 2.4 to 3.3 ) . in fully adjusted models , there was no significant difference between african americans , filipinos , pacific islanders , and south asians compared with whites . the risk of chf was significantly lower for latinos , japanese , and chinese compared with whites . similar to chf , the age- and sex - adjusted incidence was highest among african americans , and the lowest rates occurred among japanese ( 2.8 per 1,000 person - years ) . the fully adjusted comparison with whites showed a similar pattern as chf , with latinos , japanese , chinese , and filipinos having significantly lower risk than whites and the other ethnic groups having similar risk to whites . the adjusted incidence of esrd was not uniformly higher for all ethnic minority groups compared with whites ; the incidence was lower among south asians ( 1.1 per 1,000 person - years ) and chinese ( 1.9 per 1,000 person - years ) compared with whites ( 2.4 per 1,000 person - years ) and higher among all of the other groups . aggregating all four asian groups together ( 2.9 per person - year [ 95% ci 2.04.0 ] ) obscured the wide range of esrd outcomes among each of the subgroups . however , after adjusting for all potentially explanatory groups of variables , the hazards of esrd were significantly higher for each ethnic group compared with whites , except for south asians for whom the esrd risk was similar to whites . the highest age- and sex - adjusted incidence was among african americans and pacific islanders ( 2.6 per 1,000 person - years for each ) , and the lowest rates were among chinese and filipinos ( 0.7 per 1,000 person - years for each ) . compared with whites , all four asian subgroups had significantly lower risk of leas , whereas risk for pacific islanders , african americans , and latinos was not significantly different than that in whites . restricting our cox models to those with complete data on all covariates , we found some change in risk estimates among the ethnic groups with smaller numbers of patients ( pacific islanders and south asians ) , mainly for the macrovascular disease outcomes . for mi , the risk among pacific islanders compared with whites was attenuated ( hr 1.03 [ 95% ci 0.382.81 ] ) , and the risk became somewhat stronger among south asians ( 2.00 [ 0.974.12 ] ) . for chf , the risk was strengthened among south asians ( 2.26 [ 0.915.60 ] ) . in a large , integrated , managed care organization , where participants have uniform access to health care , we found that asians and pacific islanders have substantial variation in the incidence of diabetes complications that differs significantly from whites or other ethnic minority groups . the difference in diabetes complications among the ethnic groups was not fully explained by demographic , socioeconomic , behavioral , and disease - related clinical measures . although most ethnic minority groups with diabetes have significantly lower risk of mi compared with whites , women from the pacific islands have almost twice the risk of mi compared with white women . the four asian subgroups had ~6070% lower risk of leas compared with whites or other ethnic groups . for most complications , for the three cardiovascular disease outcomes , pacific islanders and south asians had incidence similar to whites , with the exception that pacific islander women had substantively higher mi risk . mi outcomes among diabetic patients of various ethnic groups have been examined in previous studies ( 9 ) , but most have either not included several different asian subgroups or have not disaggregated data for their asian subgroups . our findings are consistent with a previous report from the kaiser diabetes registry with only 2 years of follow - up that found that all asians , blacks , and latinos had significantly lower risk of mi compared with whites after adjustment for several covariates ( 7 ) . other u.s . ( 1012 ) have compared diabetic south asians with white europeans , finding equal risk of mi complications between these two ethnic groups , consistent with our findings . singaporian studies have compared heart disease between three separate asian groups : chinese , malay , and asian indians and found that the asian indians with diabetes had higher heart disease risk than the chinese or malay ( 13 ) . little outcome data are available for diabetic pacific islanders ; studies from new zealand have reported significantly higher rates of cardiovascular risk factors , cardiovascular disease , and mortality compared with europeans ( 14 ) . similarly , native hawaiian and other pacific islanders have very high rates of cardiometabolic disease compared with other u.s . ethnic groups ( 3,15,16 ) . to our knowledge , this is the first report of significantly higher risk of mi among diabetic pacific islander women compared with all ethnic groups . higher rates of traditional cardiovascular risk factors have been reported among pacific islander women ( 16 ) , which may explain the higher mi risk . several studies have found that most ethnic minority groups have a higher risk of esrd compared with whites ( 9 ) , but there is less known about asian subgroups . studies from europe have reported that south asians have higher risk of diabetic esrd than whites in the u.k . ( 17,18 ) and in the netherlands ( 19 ) , which was not apparent in our analysis possibly as a result of the small numbers of south asians . previous studies ( 20,21 ) have identified a lower risk of diabetic foot ulcers and amputations among south asians compared with europeans , with potential explanations including better preservation of nerve function , peripheral vascular function , low smoking rates , and shorter height ( 22 ) . higher rates of diabetic foot  related complications have been reported in indigenous people of western australia compared with nonindigenous people ( 23 ) , but that study did not adjust for differences in socioeconomic , behavioral , and disease - related variables . we were limited in using data collected from a self - administered questionnaire for many covariates and to individuals who could speak english , spanish , or chinese languages . ethnicity was self - reported in narrower categories than most studies but still did not include specific nationality of origin . we did not have information about nativity , generational status , length of time since immigration to the u.s . , cultural beliefs , or acculturation to the u.s . , which may explain some of the differences in diabetes outcomes . we also did not have data on dietary patterns , stress , secondhand smoke exposure , and other environmental determinants of disease outcomes . exercise was assessed by a question asking whether the patient used exercise to treat their diabetes but did not capture intensity or frequency and may underestimate the effect of physical activity as an explanatory factor . bmi was calculated by self - reported weight and height , which may underestimate the effect of adiposity . we did not measure waist circumference , which may be a better indicator of adiposity in asians ( 24 ) . diabetes severity and control were measured at baseline using available laboratory data and self - reported measures . although all participants in this study population were enrolled in kaiser permanente and therefore had access to medical care , we did not have data on the number of primary care visits or other health care utilization measures , which may explain the differences in diabetes outcomes . however , previous studies from this health care setting have shown uniform offering of care by ethnic group ( 25 ) . limitations with using diagnostic and procedural codes for classification of our diabetes outcomes have been discussed previously ( 7 ) . misclassification of outcomes should not differ by ethnic group and would tend to bias our results toward the null . in a health care system offering uniform access to care , we found widely disparate rates of diabetes complications among the four asian groups and pacific islanders . this large , diverse cohort allowed comparison of eight racial / ethnic groups , which has not been reported previously . similar to whites , pacific islanders and south asians had high rates of all cardiovascular complications . all asian groups had significantly lower lea rates than all other groups . classifying all asian ethnic groups as a single group greatly obscures the sometimes substantial ethnic differences and may preclude identification of particularly vulnerable subgroups that deserve intensified disease management . disaggregating asian and pacific islander subgroups is imperative for disease surveillance and may enhance understanding of disease etiology .
objectiveethnic minorities with diabetes typically have lower rates of cardiovascular outcomes and higher rates of end - stage renal disease ( esrd ) compared with whites . diabetes outcomes among asian and pacific islander subgroups have not been disaggregated.research design and methodswe performed a prospective cohort study ( 19962006 ) of patients enrolled in the kaiser permanente northern california diabetes registry . 
 there were 64,211 diabetic patients , including whites ( n = 40,286 ) , blacks ( n = 8,668 ) , latinos ( n = 7,763 ) , filipinos ( n = 3,572 ) , chinese ( n = 1,823 ) , japanese ( n = 951 ) , pacific islanders ( n = 593 ) , and south asians ( n = 555 ) , enrolled in the registry . 
 we calculated incidence rates ( means  sd ; 7.2  3.3 years follow - up ) and created cox proportional hazards models adjusted for age , educational attainment , english proficiency , neighborhood deprivation , bmi , smoking , alcohol use , exercise , medication adherence , type and duration of diabetes , hba1c , hypertension , estimated glomerular filtration rate , albuminuria , and ldl cholesterol . 
 incidence of myocardial infarction ( mi ) , congestive heart failure , stroke , esrd , and lower - extremity amputation ( lea ) were age and sex adjusted.resultspacific islander women had the highest incidence of mi , whereas other ethnicities had significantly lower rates of mi than whites . 
 most nonwhite groups had higher rates of esrd than whites . 
 asians had ~60% lower incidence of lea compared with whites , african americans , or pacific islanders . 
 incidence rates in chinese , japanese , and filipinos were similar for most complications . 
 for the three macrovascular complications , pacific islanders and south asians had rates similar to whites.conclusionsincidence of complications varied dramatically among the asian subgroups and highlights the value of a more nuanced ethnic stratification for public health surveillance and etiologic research .