Impact of age at diagnosis and duration of type 2 diabetes on mortality in Australia 1997–2011

Diabetes mellitus appears to be a risk factor for some cancers, but the effect of preexisting diabetes on all-cause mortality in newly diagnosed cancer patients is less clear. To perform a systematic review and meta-analysis comparing overall survival in cancer patients with and without preexisting diabetes. We searched MEDLINE and EMBASE through May 15, 2008, including references of qualifying articles. English-language, original investigations in humans with at least 3 months of follow-up were included. Titles, abstracts, and articles were reviewed by at least 2 independent readers. Of 7858 titles identified in our original search, 48 articles met our criteria. One reviewer performed a full abstraction and other reviewers verified accuracy. We contacted authors and obtained additional information for 3 articles with insufficient reported data. Studies reporting cumulative survival rates were summarized qualitatively. Studies reporting Cox proportional hazard ratios (HRs) or Poisson relative risks were combined in a meta-analysis. A random-effects model meta-analysis of 23 articles showed that diabetes was associated with an increased mortality HR of 1.41 (95% confidence interval [CI], 1.28-1.55) compared with normoglycemic individuals across all cancer types. Subgroup analyses by type of cancer showed increased risk for cancers of the endometrium (HR, 1.76; 95% CI, 1.34-2.31), breast (HR, 1.61; 95% CI, 1.46-1.78), and colorectum (HR, 1.32; 95% CI, 1.24-1.41). Patients diagnosed with cancer who have preexisting diabetes are at increased risk for long-term, all-cause mortality compared with those without diabetes.

Several studies have suggested that diabetes mellitus may alter the risk of developing a variety of cancers, and the associations are biologically plausible. To learn more about the relation between diabetes and cancer mortality, the authors examined associations with selected cancers in a large, prospective US cohort of 467,922 men and 588,321 women who had no reported history of cancer at enrollment in 1982. After 16 years of mortality follow-up, diabetes was significantly associated with fatal colon cancer in men (multivariate relative risk (RR) = 1.20, 95% confidence interval (CI): 1.06, 1.37) and women (RR = 1.24, 95% CI: 1.07, 1.43) and with pancreatic cancer in men (RR = 1.48, 95% CI: 1.27, 1.73) and women (RR = 1.44, 95% CI: 1.21, 1.72). For men, diabetes was significantly associated with liver cancer (RR = 2.19, 95% CI: 1.76, 2.72) and bladder cancer (RR = 1.43, 95% CI: 1.14, 1.80). In addition, diabetes was significantly associated with breast cancer in women (RR = 1.27, 95% CI: 1.11, 1.45). These associations were not explained by high body mass. Our findings suggest that diabetes is an independent predictor of mortality from cancer of the colon, pancreas, female breast, and, in men, of the liver and bladder.

The aim of the study was to describe trends in the incidence rate, prevalence and mortality rate for diabetes in Denmark. Healthcare registers at the National Board of Health were used to compile a register of diabetic patients in the Danish population (5.4 million people). Age- and sex-specific prevalence, incidence rates, mortality rates and standardised mortality ratios relative to the non-diabetic part of the population were calculated. The register contains records for about 360,000 persons with diabetes; 230,000 were alive at 1 January 2007, corresponding to an overall prevalence of 4.2%. The prevalence increased by 6% per year. In 2004 the incidence rates were 1.8 per 100,000 at age 40 years and 10.0 per 100,000 at age 70 years. The incidence rate increased 5% per year before 2004 and then stabilised. The mortality rate in the diabetic population decreased 4% per year, compared with 2% per year in the non-diabetic part of the population. The mortality rate decreased 40% during the first 3 years after inclusion in the register. The standardised mortality ratio decreased with age, from 4.0 at age 50 years to 2.5 at age 70 years and just under 2 at age 85 years, identically for men and women. The standardised mortality ratio decreased 1% per calendar year. The lifetime risk of diabetes was 30%. The prevalence of diabetes in Denmark rose in 1995-2006, but the mortality rate in diabetic patients decreased faster than that of the non-diabetic population. The mortality rate decreased markedly just after inclusion in the register. Incidence rates have shown a tendency to decrease during the last few years, but this finding should be viewed with caution.