Table 1.

Selected publications comparing CVD in type 1 and type 2 diabetes

Publication	Setting and participant selection	Population characteristics	Findings	Comment
Constantino et al [67]	Records from the Royal Prince Alfred Hospital Diabetes Clinical Database matched with the Australian National Death Index to establish mortality outcomes from 1986 until June 2011. Clinical and mortality outcomes in individuals with T2DM (n=354), age of onset 15–30 years, were compared with those with T1DM, primarily with T1DM individuals (n=470) with a similar age of onset.	Age of diabetes onset: T2DM, 25.6 years; T1DM, 22.0 years. Duration of diabetes: T2DM, 11.6 years; T1DM, 14.7 years. Age at baseline: T2DM, 40.4 years; T1DM, 38.9 years.	After median observation period of >20 years, young-onset T2DM found to be more lethal diabetes phenotype and was associated with greater mortality, mostly driven by CVD mortality, more complications and unfavourable CVD risk factors vs T1DM.
Eppens et al [68]	Clinic-based cross-sectional study of individuals with T1DM (n=1433) and T2DM (n=68), aged <18 years, from New South Wales, Australia.	Mean age: T1DM, 15.7 years; T2DM, 15.3 years. Mean diabetes duration: T1DM, 6.8 years; T2DM, 1.3 years. HbA1c: T1DM, 8.5% (69 mmol/mol); T2DM, 7.3% (56 mmol/mol).	Microalbuminuria and hypertension significantly more common in T2DM vs T1DM. Despite shorter diabetes duration, microalbuminuria found in >25% of T2DM vs 6% of T1DM.	Cross-sectional study, no prospective data.
Dabelea et al [69]	Observational study from 2002 to 2015 in 5 US locations, including participants with T1DM (n=1746) and T2DM (n=272) diagnosed at <20 years old.	Mean diabetes onset: T1DM, 10.0 years; T2DM, 14.2 years. Age: T1DM, 17.9 years; T2DM, 22.1 years. Major difference prevalence of obesity: T1DM, 14.3%; T2DM, 72.1%.	Prevalence of each outcome estimated at age 21 years by diabetes type. After adjustment for established risk factors, T2DM group had significantly higher odds of DKD, retinopathy and peripheral neuropathy vs T1DM, but no significant difference in odds of arterial stiffness, hypertension, or autonomic neuropathy.	No CV outcomes.
Hockett et al [72]	A US and an Indian registry dataset with demographic and clinical data were harmonised. Key characteristics from youth with T1DM and T2DM, aged <20 years and newly diagnosed between 2006 and 2010 were compared.	There were 1899 US youth with T1DM and 384 with T2DM who completed a baseline research visit. There were 2104 Indian youth with T1DM and 227 with T2DM who completed a baseline visit.	US vs. Indian patients were diagnosed at younger ages for T1DM and T2DM (10.1 vs 10.5 years, p<0.001 and 14.7 vs 16.1 years, p<0.001, respectively). For T2DM, the US database had a higher proportion of people with low SES than in India. For T1DM and T2DM, US youth had a higher BMI, lower BP, and lower HbA1c than Indian youth.
Luk et al [73]	N=2323 Chinese individuals (T1DM, n=209; normal-weight T2DM, n=636; overweight T2DM, n=1478) from the Hong Kong Diabetes Registry underwent detailed clinical assessment during 1995–2004.	Mean age: T1DM, 27.8 years; normal-weight T2DM, 41.9 years; overweight T2DM, 40.8 years. Time since diabetes diagnosis: T1DM, 8 years; normal-weight T2DM, 7 years; overweight T2DM, 5 years.	Over median follow-up of 9.3 years, overweight T2DM had highest incidence of CVD, followed by normal-weight T2DM group. Compared with T1DM, overweight T2DM group had greater hazard of progression to CVD (HR 15.3 [95% CI 2.1, 112.4]) following adjustment for age, sex and disease duration. The association became nonsignificant upon additional adjustment for CVD risk factors.	The number of events was limited, particularly in the T1DM cohort. CIs for the estimates were very wide, precluding firm conclusions.
Juutilainen et al [75]	Cohort study of individuals with T1DM (n=173) and T2DM (n=834), aged 45–64 years at baseline and free of CVD, identified from drug reimbursement registry in Finland. Age of diabetes onset was >30 years in both diabetes groups. Nondiabetic participants (n=1294) from a random sample were invited for comparison.	Population baseline characteristics not tabulated. Compared with T2DM, T1DM group stated to be younger, leaner, with lower prevalence of hypertension, lower BP, higher HDL-c, lower TG, longer diabetes duration and lower estimated creatinine clearance.	After 18 years follow-up, impact of T1DM and T2DM on CVD-related mortality was similar. Effect of increasing hyperglycaemia on risk of CVD mortality more pronounced in T1DM vs T2DM.	Compared only maturity-onset diabetes.
Allemann et al [76]	Cohort study of T1DM (n=225) and T2DM (n=308) participants recruited from 231 Swiss local practitioners. Participants followed for 30 years.	Mean age at baseline: T1DM, 43.0 years; T2DM, 46.8 years. Mean diabetes duration: T1DM, 15.5 years; T2DM, 9.2 years.	Compared with general Swiss population, T1DM and T2DM groups had increased risk of CVD mortality (SMR 5.6 [95% CI 4.8, 6.6]) but SMRs did not significantly differ between T1DM and T2DM.	Not clear how patients were selected.
Amutha et al [77]	Individuals with T1DM (n=108) and T2DM (n=90) were recruited from a tertiary diabetes centre in Chennai, India. Participants were diagnosed at 10–25 years old and did not have any evidence of diabetes complications at diagnosis.	Mean age at diagnosis: T1DM, 17.1±4.2 years; T2DM 21.6±3.6 years.	In Cox regression analysis, after adjustment for age, HbA1c, BP and serum cholesterol, T2DM group had 2.11 times (95% CI 1.27, 3.51) higher risk of developing any diabetes complication vs T1DM, indicating that young-onset T2DM has a more aggressive disease course than T1DM.	Not powered for separate CV outcomes.
Kiss et al [78]	Young adults with T1DM recorded in the Hungarian National Health Insurance Fund between 2001 and 2014 (n=11,863) and a similar age T2DM population (n=47,931).	Mean age: T1DM, 21.6 years; T2DM, 33.5 years. Mean follow-up: T1DM, 6.5 years; T2DM, 6.6 years.	HRs (T1DM vs T2DM): all-cause mortality, 2.17 (95% CI 1.95, 2.41); MI, 0.90 (95% CI 0.70, 1.13); stroke, 1.06 (95% CI 0.87, 1.29).	No data on diabetes duration or glycaemic control.
Lee et al [79]	Korean adults with T1DM (n=9397) vs those without diabetes (n=18.5 million) or with T2DM (n=1.9 million), using Korean National Health Insurance Service datasets. T1DM accounted for 0.5% of all diabetes.	Mean age: no diabetes, 45.9 years; T1DM, 56.2 years; T2DM, 57.8 years. Mean follow-up: 4.6 years. Mean BMI: T1DM, 24.1 kg/m2; T2DM, 25.1 kg/m2.	Fully adjusted HRs (95% CIs) for incident MI (1.68 [1.49, 1.89]), hospitalised HF (2.11 [1.90, 2.33]), AF (1.61 [1.41, 1.83]) and all-cause death (1.88 [1.76, 2.01]) within mean follow-up of 4.6 years higher in T1DM vs T2DM.	Diabetes duration was dichotomously categorised as <5 years and ≥5 years because complete determination of diabetes duration was not feasible for those diagnosed >5 years before the baseline since past data were unavailable.

AF, atrial fibrillation; CV, cardiovascular; DKD, diabetic kidney disease; HDL-c, HDL-cholesterol; HF, heart failure; MI, myocardial infarction; SES, socioeconomic status; SMR, standardised mortality ratio; T1DM, type 1 diabetes; T2DM, type 2 diabetes; TG, triglycerides