it is well established that patients with diabetes mellitus ( dm ) have a higher short - term mortality after acute myocardial infarction ( ami ) than patients without dm . several recent studies have found that hospital , 28-day and 1-year mortality after ami was approximately 1.52  times higher in diabetic patients [ 13 ] . as it is known that most patients survive beyond this period , it is important to study the difference in long - term survival after an ami between diabetic and nondiabetic patients as well . survival after an ami may be particularly worsened beyond the poorer prognosis already conferred by the presence of dm itself , as diabetic patients with an ami may experience more severe coronary heart disease and more complications ( left ventricular dysfunction and heart failure , significant ventricular arrhythmias ) than nondiabetic patients with an ami [ 2 , 3 ] . there are relatively few recent studies that address differences in long - term prognosis after an ami between diabetic and nondiabetic patients with follow - up lasting through the second half of the 1990s [ 48 ] . moreover , data largely originate from clinical trials or single centers [ 4 , 5 , 7 ] . these studies reported that dm is independently associated with long - term mortality [ 48 ] . the aim of the present study was to compare short- and long - term mortality after a first hospitalized ami in patients with and without dm encompassing the entire country by using data from linked national registers . the study methods , including enrollment of the study population , have recently been described in detail . in brief , cases of first hospitalized ami in the netherlands in 1995 were identified by linkage of the dutch national hospital discharge register and the dutch population register . thus , the study included a total of 21,565 patients hospitalized for a first ami in 1995 . information about demographic characteristics , medical history and hospital outcomes was obtained from the hospital register and the population register . all general and academic hospitals and most specialty hospitals participate in the hospital register . for each hospital admission a new record is created in the hospital register , including the following information : date of birth , gender , numeric part of postal code , hospital - specific patient identification code , type of hospital , admission date and principal and secondary diagnoses of the admission . the principal diagnosis is determined at discharge and is in retrospect the main reason for admission . the diagnoses are coded using the ninth revision and clinical modification of the international classification of diseases ( icd-9-cm ) . the population register contains information on all registered persons living in the netherlands , including date of birth , gender , current address , postal code , nationality , native country ( both of registered person and his / her parents ) , date of death and date of emigration . patients were classified as having a history of cardiovascular disease or having dm when cardiovascular disease ( icd-9-cm   codes 390459 and subcategories , principal diagnoses ) or dm ( icd-9-cm   code 250 and subcategories , principal and secondary diagnoses ) was registered during previous hospital admissions in 19911995 and in case of dm also during the index admission in 1995 . data on mortality of the patients were derived by linking their records with the population register and the cause of death certificates . in the population register , linkage of the population register with the cause of death certificates yielded information on primary causes of death . survival time was calculated as the time from the initial ami admission date in 1995 to the date of death from any cause , or a patient was censored at the date of loss to follow - up in the population register ( 4% of patients , e.g. in case of emigration ) or the end of study at december 31 , 2000 , whichever came first . crude short - term ( 28-day ) , 1-year and long - term ( 5-year ) mortality risks were computed for diabetic and nondiabetic patients . cox proportional hazard analyses were used to examine the association between dm and overall survival in men and women . dm ( yes / no ) and other predictors , including age ( continuous ) , previous cardiovascular disease ( yes / no ) and ethnic origin ( native or non - native dutch ) were included in the models . furthermore , cox proportional hazards models were used to determine whether gender , age , previous cardiovascular disease and ethnic origin were independently associated with overall survival in patients with dm and patients without dm . interaction terms were included in the models to assess the interaction of gender with dm , age with dm and age with gender . the study methods , including enrollment of the study population , have recently been described in detail . in brief , cases of first hospitalized ami in the netherlands in 1995 were identified by linkage of the dutch national hospital discharge register and the dutch population register . thus , the study included a total of 21,565 patients hospitalized for a first ami in 1995 . information about demographic characteristics , medical history and hospital outcomes was obtained from the hospital register and the population register . all general and academic hospitals and most specialty hospitals participate in the hospital register . for each hospital admission a new record is created in the hospital register , including the following information : date of birth , gender , numeric part of postal code , hospital - specific patient identification code , type of hospital , admission date and principal and secondary diagnoses of the admission . the principal diagnosis is determined at discharge and is in retrospect the main reason for admission . the diagnoses are coded using the ninth revision and clinical modification of the international classification of diseases ( icd-9-cm ) . the population register contains information on all registered persons living in the netherlands , including date of birth , gender , current address , postal code , nationality , native country ( both of registered person and his / her parents ) , date of death and date of emigration . patients were classified as having a history of cardiovascular disease or having dm when cardiovascular disease ( icd-9-cm   codes 390459 and subcategories , principal diagnoses ) or dm ( icd-9-cm   code 250 and subcategories , principal and secondary diagnoses ) was registered during previous hospital admissions in 19911995 and in case of dm also during the index admission in 1995 . data on mortality of the patients were derived by linking their records with the population register and the cause of death certificates . in the population register , linkage of the population register with the cause of death certificates yielded information on primary causes of death . survival time was calculated as the time from the initial ami admission date in 1995 to the date of death from any cause , or a patient was censored at the date of loss to follow - up in the population register ( 4% of patients , e.g. in case of emigration ) or the end of study at december 31 , 2000 , whichever came first . crude short - term ( 28-day ) , 1-year and long - term ( 5-year ) mortality risks were computed for diabetic and nondiabetic patients . cox proportional hazard analyses were used to examine the association between dm and overall survival in men and women . dm ( yes / no ) and other predictors , including age ( continuous ) , previous cardiovascular disease ( yes / no ) and ethnic origin ( native or non - native dutch ) were included in the models . furthermore , cox proportional hazards models were used to determine whether gender , age , previous cardiovascular disease and ethnic origin were independently associated with overall survival in patients with dm and patients without dm . interaction terms were included in the models to assess the interaction of gender with dm , age with dm and age with gender . the characteristics of the diabetic and nondiabetic patients with a first ami are presented in table  1 . most of the diabetic patients were women ( 52% ) , whereas most of the nondiabetic patients were men ( 69% ) . in both diabetic and nondiabetic patients , women were older and had a longer duration of hospital stay than men . diabetic patients were older and more likely to have previous cardiovascular disease ( excluding ami ) compared to nondiabetic patients . table  1characteristics of first acute myocardial infarction patients with and without diabetes mellituspatients with diabetes mellituspatients without diabetes mellitusmenwomenmenwomennumber of patients9691,04913,4946,053age at admission ( years )  mean ( standard deviation)68.7 ( 11.0)73.2 ( 10.3)64.0 ( 12.3)71.6 ( 12.0)prior admission for cvd ( % ) 31.731.016.816.3type of hospital ( % )  academic6.76.16.25.7  general93.393.993.894.3length of stay ( days )  mean ( standard deviation)11.1 ( 8.5)12.5 ( 11.8)9.7 ( 7.4)10.6 ( 9.7 )  median10.010.09.09.0  p25p757.013.06.016.06.012.06.013.0native ethnic origin ( % ) 87.088.090.090.0cvd  =  cardiovascular disease , excluding acute myocardial infarction25th and 75th percentile characteristics of first acute myocardial infarction patients with and without diabetes mellitus cvd  =  cardiovascular disease , excluding acute myocardial infarction 25th and 75th percentile during admission , 18% of the diabetic patients ( men 16% , women 20% ) and 13% of the nondiabetic patients ( men 11% , women 18% ) died . in both diabetic and nondiabetic patients , ami was the most frequent cause of death ( during hospitalization 71 and 82% , respectively , and during 5  years of follow - up 39 and 45% , respectively ) . table  2 shows the higher absolute short- and long - term mortality risks for diabetic patients compared to nondiabetic patients in men and women . table  2short- and long - term mortality in patients with a first hospitalized acute myocardial infarction ( ami ) in the netherlands in 1995 stratified by gender and presence of diabetes mellitusmendiabetic patients ( n  =  969)non - diabetic patients ( n  =  13,494)deaths ( n)deaths ( % ) deaths ( n)deaths ( % ) at 28  days17017.5 ( 15.119.9)1,55511.5 ( 11.012.1)at 1  year28929.8 ( 26.932.7)2,31617.2 ( 16.517.8)at 5  years51653.3 ( 50.156.4)4,11630.5 ( 29.731.3)womendiabetic patients ( n  =  1,049)non - diabetic patients ( n  =  6,053)deaths ( n)deaths ( % ) deaths ( n)deaths ( % ) at 28  days23522.4 ( 19.924.9)1,15219.0 ( 18.020.0)at 1  year36835.1 ( 32.238.0)1,62626.9 ( 25.728.0)at 5  years61158.2 ( 55.361.2)2,53841.9 ( 40.743.2)figures are numbers and percentages of deaths ( 95% confidence intervals in brackets ) based on actuarial life table method short- and long - term mortality in patients with a first hospitalized acute myocardial infarction ( ami ) in the netherlands in 1995 stratified by gender and presence of diabetes mellitus figures are numbers and percentages of deaths ( 95% confidence intervals in brackets ) based on actuarial life table method crude short- and long - term mortality was significantly higher in diabetic patients than in nondiabetic patients in both men ( 28-day hazard ratio ( hr ) 1.55 ; 95% confidence interval ( ci ) 1.321.81 , 5-year hr 2.01 ; 95% ci 1.842.21 ) and women ( 28-day hr 1.19 ; 95% ci 1.031.37 , 5-year hr 1.53 ; 95% ci 1.401.67 ) . when differences in age and other covariates between diabetic and nondiabetic patients were taken into account , risk differences became nonsignificant at 28  days , but dm was still associated with a significantly higher long - term mortality in both men and women ( table  3 ) . the interaction between gender and dm for 28-day , 1-year and 5-year mortality did not reach significance in the analyses , indicating that risks are equally elevated among men and women . table  3multivariate analysis of the association between diabetes mellitus and short- and long - term mortality in first acute myocardial infarction patients ( n  =  21,565 ) by gender and ageage ( years)follow - up duration28  days1  year5  yearsmen<601.41 ( 0.792.53)1.38 ( 0.862.23)1.83 ( 1.342.51)60691.46 ( 1.022.08 ) 1.73 ( 1.312.28)1.80 ( 1.462.21)70791.04 ( 0.801.36)1.16 ( 0.941.42)1.42 ( 1.231.65)801.11 ( 0.821.50)1.32 ( 1.041.66)1.37 ( 1.141.65)all ages1.16 ( 0.991.36)1.33 ( 1.171.50)1.49 ( 1.361.64)women<602.06 ( 1.093.88)2.16 ( 1.253.75)2.13 ( 1.403.25)60691.38 ( 0.922.06)1.65 ( 1.192.29)1.99 ( 1.572.54)70790.94 ( 0.721.22)1.12 ( 0.921.37)1.38 ( 1.191.60)801.15 ( 0.941.42)1.18 ( 0.991.40)1.25 ( 1.091.44)all ages1.12 ( 0.971.28)1.23 ( 1.091.37)1.39 ( 1.271.52)totalall ages1.13 ( 1.021.26)1.27 ( 1.171.38)1.44 ( 1.351.53)figures are hazard ratios ( 95% confidence intervals in brackets ) with nondiabetic patients representing the reference groupresults from cox proportional hazards analyses with diabetes mellitus , previous cardiovascular disease and ethnic origin ( age- and gender - specific hazard ratios ) and age ( gender - specific overall hazard ratios ) and gender ( overall hazard ratios ) included in the model multivariate analysis of the association between diabetes mellitus and short- and long - term mortality in first acute myocardial infarction patients ( n  =  21,565 ) by gender and age figures are hazard ratios ( 95% confidence intervals in brackets ) with nondiabetic patients representing the reference group results from cox proportional hazards analyses with diabetes mellitus , previous cardiovascular disease and ethnic origin ( age- and gender - specific hazard ratios ) and age ( gender - specific overall hazard ratios ) and gender ( overall hazard ratios ) included in the model in the multivariate analyses , gender differences in mortality in nondiabetic patients varied over time with a higher mortality in women at 28  days and a higher mortality in men at 5  years ( 28-day hr 1.11 ; 95% ci 1.031.20 , 5-year hr 0.93 ; 95% ci 0.880.98 ) . largely comparable , yet not significant , gender differences in mortality were found in diabetic patients ( 28-day hr 1.09 ; 95% ci 0.891.34 , 5-year hr 0.93 ; 95% ci 0.821.04 ) . our study provides nationwide estimates of the difference in mortality after a first hospitalized ami between diabetic and nondiabetic patients . long - term mortality was significantly higher in diabetic patients than in nondiabetic patients . yet some aspects of the study need to be addressed . in our study , the presence of dm was merely based on information from hospital admissions and on a retrospective period of maximal 5  years . as a result , the estimate of the effect of dm is likely an overestimate due to selection of the more severe cases ( those hospitalized with or due to dm ) , while a fairly limited number of people with less severe stages of dm ( not requiring hospital care ) will be diluted in the large group of people who truly did not have dm . in our study , we were able to jointly evaluate a number of predictors of mortality using information from the hospital register . however , we were unable to examine the contribution of other predictors on our outcomes , including other risk factors , comorbidity and treatment , as registration in the hospital register is limited . yet , this does not invalidate the finding that dm is related to a worse long - term prognosis in patients with a first ami , as confounding is not an issue in descriptive ( prognostic ) research . however , if cofactors such as the presence of poorly treated hypertension or dyslipidemia become the focus of investigation , the lack of more detailed information from the hospital register renders such analyses impossible . in our study , the percentage patients with a cardiovascular history ( other than ami ) was about 2  times higher in diabetic patients than in nondiabetic patients . to be sure that the worse prognosis of diabetic patients compared to nondiabetic patients was real and not merely a reflection of the difference in cardiovascular history , we repeated the analyses in diabetic and nondiabetic patients without a cardiovascular history . a substantial and possibly selective mortality with regard to dm might have preceded the baseline of our study , e.g. if dm were more prone to out - of - hospital death   then this may result in less clear differences over the rest of the first 28  days , because the early deaths were not recorded . therefore , the study population does not represent ( the diabetes distribution of ) all first ami patients in the netherlands , but specifically hospitalized first ami patients , and results might differ from population - based studies , which usually manage to include the out - of - hospital deaths . as data on patients without an ami were not available , we were not able to compare the effect of dm on mortality in patients without an ami with the effect in patients with an ami , i.e. whether survival after an ami is particularly worsened beyond the poorer prognosis already conferred by the presence of dm itself . the strength of our study lies in the validity of the registries and linkage methods , the large size and lack of selection of the cohort and the long duration of follow - up . recently , it was shown that 99% of the personal , admission and discharge data and 84% of the principal diagnoses ( validated through medical record review by medical specialists ) were correctly registered in a random sample of all hospital admissions registered in the hospital register . furthermore , over 97% of the uniquely linked hospital admissions resulting from linkage of the hospital register with the population register were shown to be correctly linked . results from different studies regarding differences in mortality between diabetic and nondiabetic patients are conflicting . consistent with our findings , it has been reported that dm has no independent predictive value on short - term mortality . yet , several other recent studies showed that short - term ( < 1  year ) mortality after ami was significantly higher ( approximately 1.5 to 2  times ) in diabetic patients compared with nondiabetic patients [ 13 , 15 ] . .   found a significant higher 1-year mortality in diabetic men ( odds ratio ( or ) 1.5 ; 95% ci 1.21.9 ) , but no significant association in women . recent studies regarding differences in long - term mortality ( follow - up ranging from 4 to 10  years ) after ami showed an approximately 1.52.5 higher risk of dying in diabetic patients [ 48 , 17 ] . .   showed that dm was an independent predictor of 10-year mortality in patients with single vessel disease ( or 1.81 ; 95% ci 1.272.54 ) , but in patients with multivessel disease the influence of dm was nonsignificant ( or 1.17 ; 95% ci 0.851.60 ) . melchior et  al .   reported that the difference in mortality after ami between diabetic and nondiabetic patients increased with time ( relative risk ranging from 1.03 [ 95% ci 0.811.31 ] at 30  days to 1.43 [ 95% 1.241.66 ] at 2  months-3  years and 1.74 [ 95% ci 1.362.23 ] at 79  years in patients admitted between 1990 and 1992 ) . we found no significant differences in short- and long - term mortality after a first ami between men and women in diabetic patients . a few other studies examined gender differences in mortality after an ami in diabetic patients . .   found that women with dm were at increased risk of hospital death compared to men ( or 1.37 ; 95% ci 1.081.75 ) , but no significant gender difference in 1-year mortality ( hr 1.25 ; 95% ci 0.991.58 ) and 10-year mortality ( hazard ratio 1.00 ; 95% 0.991.58 ) was found . two other studies showed a higher short - term ( hospital or 28-day ) mortality in women [ 2 , 20 ] . the higher risk of long - term mortality in first ami patients with dm reinforces the importance of vigorous preventive measures by lifestyle advice and drugs in these patients . currently , achievement of lifestyle and risk factor goals for reducing mortality in diabetic patients with ami is poor , as illustrated by pyorala et  al .   who reported that 20% of diabetic patients continued to smoke , 43% were obese , 57% had hypertension and 55% had hypercholesterolemia at least 6  months after hospitalization for coronary heart disease . a long - term , intensive approach consisting of behavior modification and pharmacologic therapy aimed at multiple risk factors is necessary , as it has been shown that this results in an impressive reduction in cardiovascular complications in patients with dm . in conclusion , our findings in an unselected cohort covering a complete nation show that diabetic patients are at an increased risk of long - term mortality after a first acute myocardial infarction . yet these results stress the importance of secondary prevention by lifestyle advice and drugs in diabetic patients after a first ami .
aims to compare short- and long - term mortality after a first acute myocardial infarction ( ami ) in patients with and without diabetes mellitus . 
 methods and results a nationwide cohort of 2,018 diabetic and 19,547 nondiabetic patients with a first hospitalized ami in 1995 was identified through linkage of the national hospital discharge register and the population register . 
 follow - up for mortality lasted until the end of 2000 . at 28  days and 5  years respectively , absolute mortality risks were 18 and 53% in diabetic men , 12 and 31% in nondiabetic men , 22 and 58% in diabetic women , and 19 and 42% in nondiabetic women . 
 crude mortality was significantly higher in diabetic patients than in nondiabetic patients in both men ( 28-day hazard ratio ( hr ) 1.55 ; 95% confidence interval ( ci ) 1.321.81 , 5-year hr 2.01 ; 95% ci 1.842.21 ) and women ( 28-day hr 1.19 ; 95% ci 1.031.37 , 5-year hr 1.53 ; 95% ci 1.401.67 ) . 
 after multivariate adjustment , risk differences became nonsignificant at 28  days , but diabetes was still associated with a significantly higher long - term mortality in both men ( 28-day hr 1.16 ; 95% ci 0.991.36 , 5-year hr 1.49 ; 95% ci 1.361.64 ) and women ( 28-day hr 1.12 ; 95% ci 0.971.28 , 5-year hr 1.39 ; 95% ci 1.271.52 ) . 
 the interaction between diabetes mellitus and gender did not reach significance in the analyses . 
 conclusion our findings in an unselected cohort covering a complete nation show a significantly higher long - term mortality after a first acute myocardial infarction in diabetic patients . yet , short - term mortality is not significantly higher in diabetic patients . 
 risks appear to be equally elevated in men and women .