title: A meta-analysis of the relative risk of mortality for type 1 diabetes patients compared to the general population: exploring temporal changes in relative mortality.
abstract: OBJECTIVE
  Type 1 diabetes has been associated with an elevated relative risk (RR) of mortality compared to the general population. To review published studies on the RR of mortality of Type 1 diabetes patients compared to the general population, we conducted a meta-analysis and examined the temporal changes in the RR of mortality over time.
  
  
  METHODS
  Systematic review of studies reporting RR of mortality for Type 1 diabetes compared to the general population. We conducted meta-analyses using a DerSimonian and Laird random effects model to obtain the average effect and the distribution of RR estimates. Sub-group meta-analyses and multivariate meta-regression analysis was performed to examine heterogeneity. Summary RR with 95% CIs was calculated using a random-effects model.
  
  
  RESULTS
  26 studies with a total of 88 subpopulations were included in the meta-analysis and overall RR of mortality was 3.82 (95% CI 3.41, 3.4.29) compared to the general population. Observations using data prior to 1971 had a much larger estimated RR (5.80 (95% CI 4.20, 8.01)) when compared to: data between; 1971 and 1980 (5.06 (95% CI 3.44, 7.45)); 1981-90 (3.59 (95% CI 3.15, 4.09)); and those after 1990 (3.11 (95% CI 2.47, 3.91)); suggesting mortality of Type 1 diabetes patients when compared to the general population have been improving over time. Similarly, females (4.54 (95% CI 3.79-5.45)) had a larger RR estimate when compared to males (3.25 (95% CI 2.82-3.73) and the meta-regression found evidence for temporal trends and sex (p<0.01) accounting for heterogeneity between studies.
  
  
  CONCLUSIONS
  Type 1 diabetes patients' mortality has declined at a faster rate than the general population. However, the largest relative improvements have occurred prior to 1990. Emphasis on intensive blood glucose control alongside blood pressure control and statin therapy may translate into further reductions in mortality in coming years.
authors.affiliation: Centre for Health Policy, Programs and Economics, School of Population Health, University of Melbourne, Melbourne, VIC 3053, Australia.
authors.forename: Tom W C
authors.initials: TW
authors.lastname: Lung
authors.affiliation: Sydney School of Public Health, Edward Ford Building (A27), The University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Hayes
authors.affiliation: The Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48105, United States of America.
authors.forename: William H
authors.initials: WH
authors.lastname: Herman
authors.affiliation: The Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia.
authors.forename: Lei
authors.initials: L
authors.lastname: Si
authors.affiliation: The Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Palmer
authors.affiliation: Centre for Health Policy, Programs and Economics, School of Population Health, University of Melbourne, Melbourne, VIC 3053, Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Clarke
mesh_terms: D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D008297:Male; D012044:Regression Analysis; D012306:Risk
chemical_list: D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors