Mortality Trends Among People With Type 1 and Type 2 Diabetes in Australia: 1997–2010

Abstract

OBJECTIVEWith improvements in cardiovascular disease (CVD) rates among people with diabetes, mortality rates may also be changing. However, these trends may be influenced by coding practices of CVD-related deaths on death certificates. We analyzed trends of mortality over 13 years in people with diabetes and quantified the potential misclassification of CVD mortality according to current coding methods. RESEARCH DESIGN AND METHODSA total of 1,136,617 Australians with diabetes registered on the National Diabetes Services Scheme between 1997 and 2010 were linked to the National Death Index. Excess mortality relative to the Australian population was reported as standardized mortality ratios (SMRs). Potential misclassification of CVD mortality was determined by coding CVD according to underlying cause of death (COD) and then after consideration of both the underlying and other causes listed in part I of the death certificate. RESULTSFor type 1 diabetes, the SMR decreased in males from 4.20 in 1997 to 3.08 in 2010 (P trend < 0.001) and from 3.92 to 3.46 in females (P trend < 0.01). For type 2 diabetes, the SMR decreased in males from 1.40 to 1.21 (P trend < 0.001) and from 1.56 to 1.22 in females (P trend < 0.001). CVD deaths decreased from 35.6 to 31.2% and from 31.5 to 27.2% in males and females with type 1 diabetes, respectively (P trend < 0.001 for both sexes). For type 2 diabetes, CVD decreased from 44.5 to 29.2% in males and from 45.5 to 31.6% in females (P trend < 0.001 for both sexes). Using traditional coding methods, ∼38 and 26% of CVD deaths are underestimated in type 1 diabetes and type 2 diabetes, respectively. CONCLUSIONSAll-cause and CVD mortality has decreased in diabetes. However, the total CVD mortality burden is underestimated when only underlying COD is considered. This has important ramifications for understanding mortality patterns in diabetes.

Mortality and acute complications in children and young adults diagnosed with Type 1 diabetes in Yorkshire, UK: a cohort study

“…Population-based registers have shown excess mortality for individuals with Type 1 diabetes compared with the general population [1][2][3][4][5][6][7][8][9][10]. Reduced mortality in recent years for children diagnosed with Type 1 diabetes suggests decreasing excess mortality [1,2,9,11], but few studies have examined this trend in Type 1 diabetes onset among adolescents and young adults.…”

Recent trends in life expectancy for people with type 1 diabetes in Sweden

“…There is some evidence that survival of people with type 1 diabetes relative to the general population has improved since the 1940s [6] and has continued to improve in recent years [15]. One Australian study comparing people with type 1 diabetes with the general population estimated that the standardised mortality ratio (SMR) decreased from 4.20 in 1997 to 3.08 in 2010 [16]. Similarly, LE has improved over time [5].…”

Age-Specific Trends From 2000–2011 in All-Cause and Cause-Specific Mortality in Type 1 and Type 2 Diabetes: A Cohort Study of More Than One Million People

“…We have previously reported that the proportion of deaths attributed to cancer is increasing over time, in part due to improvements in treatment of CVD. Thus, people with diabetes are surviving longer and not dying from diseases such as CVD and then develop other outcomes such as cancer (28). Cancer is now a leading COD in diabetes, accounting for 27 and 33% of all deaths in people with type 1 and type 2 diabetes, respectively (28).…”

“…Thus, people with diabetes are surviving longer and not dying from diseases such as CVD and then develop other outcomes such as cancer (28). Cancer is now a leading COD in diabetes, accounting for 27 and 33% of all deaths in people with type 1 and type 2 diabetes, respectively (28). Only one other study that we are aware of has also shown that the proportion of deaths attributed to cancer among people with type 2 diabetes has increased from 23% in 1970 to 27% in 1990 (3).…”