Relative risk of mortality associated with diabetes in Scotland in 2007: a nationwide record linkage study
Background
People with diabetes are known to be at increased risk of mortality compared to the general population but recent data on this association are limited. Diabetes register data are collected in Scotland in primary and secondary care for the whole population of people with diabetes and can be linked to national mortality records.
Methods
We estimated standardised mortality ratios (SMRs) for deaths from all-causes and heart disease (ICD-10 codes I00-52) identified by linkage to mortality records by type of diabetes and sex among people on the Scottish population based diabetes register in 2007 using numbers of deaths among the whole population of Scotland and 2007 mid-year population estimates for the standard.
Results
Among 209 095 people with type 1 and type 2 diabetes in Scotland in 2007 (diabetes prevalence 4.1%) there were 7803 all-cause and 2073 heart disease deaths. SMRs (95% CIs) for all-causes were 2.51 (2.24 to 2.80) and 2.79 (2.46 to 3.16) for men and women with type 1 diabetes (T1DM) and 1.27 (1.23 to 1.31) and 1.39 (1.34 to 1.43) for men and women with type 2 diabetes (T2DM) respectively. For heart disease SMRs (95% CIs) were 2.95 (2.38 to 3.65) and 4.33 (3.41 to 5.49) for men and women with T1DM and 1.52 (1.43 to 1.61) and 1.59 (1.49 to 1.71) for men and women with T2DM respectively. Further adjustment for socio-economic status made little difference to SMRs.
Conclusions
We observed similar patterns of mortality by age, sex, type of diabetes and cause of death to previous studies but lower relative mortality associated with diabetes. This latter finding may reflect differing populations and study design but might also indicate increased use of primary and secondary preventative therapies in people with diabetes. Nationwide diabetes epidemiology using routine data is now possible in Scotland.
