Life expectancy associated with different ages at diagnosis of type 2 diabetes in high-income countries: 23 million person-years of observation

BACKGROUND

The prevalence of type 2 diabetes is increasing rapidly, particularly among younger age groups. Estimates suggest that people with diabetes die, on average, 6 years earlier than people without diabetes. We aimed to provide reliable estimates of the associations between age at diagnosis of diabetes and all-cause mortality, cause-specific mortality, and reductions in life expectancy.

METHODS

For this observational study, we conducted a combined analysis of individual-participant data from 19 high-income countries using two large-scale data sources: the Emerging Risk Factors Collaboration (96 cohorts, median baseline years 1961-2007, median latest follow-up years 1980-2013) and the UK Biobank (median baseline year 2006, median latest follow-up year 2020). We calculated age-adjusted and sex-adjusted hazard ratios (HRs) for all-cause mortality according to age at diagnosis of diabetes using data from 1 515 718 participants, in whom deaths were recorded during 23·1 million person-years of follow-up. We estimated cumulative survival by applying age-specific HRs to age-specific death rates from 2015 for the USA and the EU.

FINDINGS

For participants with diabetes, we observed a linear dose-response association between earlier age at diagnosis and higher risk of all-cause mortality compared with participants without diabetes. HRs were 2·69 (95% CI 2·43-2·97) when diagnosed at 30-39 years, 2·26 (2·08-2·45) at 40-49 years, 1·84 (1·72-1·97) at 50-59 years, 1·57 (1·47-1·67) at 60-69 years, and 1·39 (1·29-1·51) at 70 years and older. HRs per decade of earlier diagnosis were similar for men and women. Using death rates from the USA, a 50-year-old individual with diabetes died on average 14 years earlier when diagnosed aged 30 years, 10 years earlier when diagnosed aged 40 years, or 6 years earlier when diagnosed aged 50 years than an individual without diabetes. Using EU death rates, the corresponding estimates were 13, 9, or 5 years earlier.

INTERPRETATION

Every decade of earlier diagnosis of diabetes was associated with about 3-4 years of lower life expectancy, highlighting the need to develop and implement interventions that prevent or delay the onset of diabetes and to intensify the treatment of risk factors among young adults diagnosed with diabetes.

FUNDING

British Heart Foundation, Medical Research Council, National Institute for Health and Care Research, and Health Data Research UK.

Stroke rates in non-anticoagulated individuals with and without atrial fibrillation and one non-sex CHA2DS2-VASc risk factor: a nationwide registry-based cohort (Atrial Fibrillation in Norway – AFNOR)

Background

Stroke prevention is fundamental in the management of atrial fibrillation (AF). However, in patients with intermediate risk of stroke (CHA2DS2-VASc score 2 in women; 1 in men) the net clinical benefit of oral anticoagulant (OAC) treatment is uncertain, as the treatment effect must be carefully balanced against the potential bleeding risk. Moreover, multiple risk factors included in the CHA2DS2-VASc score increase the risk of stroke independent of AF.

Purpose

We aimed to compare rates of ischemic and haemorrhagic stroke between non-anticoagulated individuals with and without AF in a nationwide cohort of individuals at intermediate risk of stroke.

Method

We identified a cohort of non-anticoagulated Norwegian individuals with and without non-valvular AF aged ≥18 years, with one non-sex CHA2DS2-VASc risk factor linking data from the Norwegian Population Registry, Patient Registry, Prescription Database and Cause of Death Registry. AF and comorbidities were identified with minimum three-year look-back period at study start and successively during follow up. Individuals without AF entered the study at date of first registered non-sex CHA2DS2-VASc risk factor while individuals with AF entered at the first date when both AF and first CHA2DS2-VASc risk factor were registered. Individuals with and without AF were followed from study start in 2011 until occurrence of stroke, death, emigration, OAC claim, increased CHA2DS2-VASc score or end of follow-up on December 31, 2018. Rates of ischemic and haemorrhagic stroke were calculated as the number of stroke cases per 100 person-years with 95% confidence intervals (CI).

Results

During 2011–2018, a total of 61,762 individuals with AF at intermediate risk of stroke and no previous OAC use were identified (mean age 63.2±7.6 years (SD); 37% women). In the AF population, a total of 1,304 ischemic strokes were registered during 109,881 person-years, and 127 haemorrhagic strokes during 109,559 person-years. In the corresponding intermediate risk non-AF population, 1,099,655 individuals (mean age 59.5±10.2 years (SD); 49.5% women) were identified, with a total of 6,081 ischemic strokes during 4,037,940 person-years and 3,037 haemorrhagic strokes during 4,022,952 person-years.

The rate of ischemic stroke was 1.19 (95% CI, 1.12–1.25) in AF-patients and 0.15 (95% CI, 0.15–0.15) in non-AF individuals per 100 person-years, corresponding to a rate difference of 1.04 excess stroke cases per 100 person-years in AF patients. The haemorrhagic stroke rate was 0.12 (95% CI, 0.10–0.14) in AF-patients and 0.08 (95% CI, 0.07–0.08) per 100 person-years in non-AF individuals. Similar rate differences were seen in both men and women.

Conclusion

In a nationwide population with one non-sex CHA2DS2-VASc risk factor and without OAC treatment, we found higher stroke rate in AF patients compared to the rest of the population without AF, with a stroke rate difference of ∼1% per year. Haemorrhagic stroke rates were generally low.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): South-Eastern Norway Regional Health Authority

Prevalence and incidence rates of atrial fibrillation in Denmark 2004–2018

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with substantial morbidity and mortality. Its prevalence is currently rising partly due to population ageing. However, reported trends in incidence rates are conflicting, and the comparability of existing reports is limited due to methodological inconsistencies across studies.

Purpose

The main purpose of the current study was to investigate the prevalence of AF in the Danish adult population and time trends in incidence rates from 2004 through 2018. As a secondary purpose, the prevalence and incidence were compared to corresponding Norwegian estimates from 2004 through 2014 derived using the same methodology.

Methods

A register-based study was conducted including all individuals aged ≥18 years in Denmark from 2004–2018. AF cases were identified in the National Patient Register and the Cause of Death Register, which comprise information on all hospital contacts and deaths in Denmark, respectively. The prevalence of AF was calculated as the number of individuals alive at the end of the study period with at least one registered diagnosis from 1994 through 2018 divided by the number of Danish residents aged ≥18 years. Incidence rates were calculated as the number of annual AF cases with no previous diagnosis noted in the past 10 years divided by the person-time contributed by the population free of AF on 1 January in the same calendar year. All incidence rates were standardized according to a Nordic standard population. The comparison of the Danish and Norwegian incidence estimates focused solely on AF hospitalizations and deaths from 2004 through 2014.

Results

The cumulative prevalence of AF was 3.0% in the Danish adult population. The incidence increased from 391 per 100,000 person-years in 2004 to 481 per 100,000 person-years in 2015, after which it declined to 367 per 100,000 person-years in 2018 (Figure 1). On average, the incidence increased by 1.7% annually until 2015 (IRR: 1.017 (95% CI: 1.016–1.018); p<0.001) and then declined by 8.5% (IRR: 0.915 (95% CI: 0.909–0.921); p<0.001). Although the incidence rates generally were higher among men and older individuals, a similar time trend was observed in both men and women irrespective of age. Focusing solely on AF hospitalizations and deaths did not change the interpretation of the results. The comparable Norwegian estimates will be presented at the conference.

Conclusions

The prevalence of AF is currently around 3.0% in the Danish adult population, but the incidence rate has declined steeply since 2015. The observed decline in new cases is promising from a public health perspective and its underlying causes warrant further investigation.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation Figure 1

Oral anticoagulation in atrial fibrillation patients at intermediate risk of stroke: a nationwide registry-based cohort (Atrial Fibrillation in Norway – AFNOR)

Background

The effect of oral anticoagulants (OAC) on prevention of stroke must be carefully balanced against the potential risk of bleeding in patients with atrial fibrillation (AF). The net benefit of OAC in AF patients at intermediate risk of stroke remains unclear.

Aim

We aimed to determine whether the rates of ischemic and haemorrhagic stroke differ between users and non-users of OAC in a nationwide cohort of AF patients at intermediate risk of stroke.

Method

We investigated the association between initiation of OAC treatment and rates of ischemic and haemorrhagic stroke in a cohort of Norwegian patients with non-valvular AF aged ≥18 years with one non-sex CHA2DS2-VASc risk factor registered from 2011 to 2018, linking data from the Norwegian Population Registry, Patient Registry, Prescription Database and Cause of Death Registry. Individuals using OAC at baseline were excluded. Each individual had at least a three years look-back period for identification of their first non-sex CHA2DS2-VASc risk factor, after which they entered the study cohort and were followed until occurrence of stroke, death, emigration, higher CHA2DS2-VASc score or end of follow-up on December 31, 2018. Individuals were defined as exposed to OAC from the first redeemed prescription of OAC with a reimbursement code for AF and throughout follow-up. Rates of ischemic and haemorrhagic stroke were calculated as the number of stroke cases per 100 person-years, with 95% confidence intervals (CI).

Results

During 2011–2018, a total of 61,631 individuals with AF and intermediate risk of stroke were included (mean age 63,8±7,6 years (SD); 37% women), of whom 75% initiated OAC treatment. In total, 1709 ischemic strokes (405 cases in OAC users and 1304 in non-users) were registered during 214,738 person-years, and 378 haemorrhagic strokes (251 cases in OAC users and 127 in non-users) during 213,487 person-years. The rate of ischemic stroke was 0.39 (95% CI, 0.35–0.43) and 1.19 (95% CI, 1.12–1.25) per 100 person-years in OAC users and non-users, respectively. The haemorrhagic stroke rate was 0.24 (95% CI, 0.21–0-27) and 0.12 (95% CI, 0.10–0.14) per 100 person-years in OAC users and non-users, respectively. Both ischemic and haemorrhagic stroke rates were highest among those over 65 years of age (Figure 1).

Conclusion

In a nationwide cohort of Norwegian AF patients at intermediate risk of stroke, three out of four initiated treatment with OAC. Use of OAC was associated with a considerably lower rate of ischemic stroke compared to non-OAC use. Although haemorrhagic stroke rates were increased in the OAC-users vs. non-users, the hemorrhagic stroke rates were generally low.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Vestre Viken Health Trust Figure 1. Rates of ischemic and haemorrhagic stroke per 100 person-years in AF-patients at intermediate risk of stroke (CHA2DS2-VASc score 1 in men, score 2 in women) by OAC use during 2011 to 2018. Age corresponds to age at attainment of the first non-sex CHA2DS2-VASc risk factor.

Time trends in incidence rates of atrial fibrillation-related strokes in Norway 2001–2014: a nationwide analysis using data from the cardiovascular disease in Norway (CVDNOR) project

Background

Stroke incidence rates declined in Norway during 2001 to 2014. Atrial fibrillation (AF) incidence rates were stable in the same period.

Purpose

We aimed to study time trends in incidence (first time) of acute stroke hospitalizations and stroke deaths associated with AF in Norway in the period 2001–2014.

Methods

Nationwide hospital discharge diagnoses in the Cardiovascular Disease in Norway (CVDNOR) database and in the National Patient Registry were linked to the National Cause of Death Registry. All hospitalizations with acute stroke (including ischemic stroke, intracerebral bleeding and unspecified stroke) and out-of-hospital deaths with stroke as underlying cause in individuals 25 years and older were obtained during 1994–2014. Incident stroke was defined as the first hospitalization or out-of-hospital death due to stroke with no hospitalization for acute stroke or stroke sequela the past 7 years. Stroke was defined as AF-related if AF was registered during a hospitalization the past 7 years, or as underlying or contributing cause of death up to 28 days after the stroke hospitalization. Age-standardized incidence rates with 95% confidence intervals (CIs) were calculated using direct standardization to the age-distribution in the Norwegian population per 2001. Age-adjusted average yearly incidence rate ratios (IRR) with 95% CIs were estimated by negative binomial regression analyses.

Results

From 2001 to 2014 we identified 157 580 incident stroke cases of which 38 317 were AF-related. The proportion of incident strokes that were related to AF increased from 20.6% in 2001 to 26.3% in 2014. Age-standardized incidence rates of AF-related strokes per 100,000 person years were stable at 88 (85, 92) in 2001 and 79 (76, 83) in 2014, corresponding to a 0% average yearly change, IRR 1.00 (0.99, 1.00). The age-standardized incidence rates of non-AF-related strokes per 100,000 person years decreased from 334 (328, 341) in 2001 to 214 (209, 219) in 2014, corresponding to a 3% average yearly decrease, IRR 0.97 (0.97, 0.97).

Conclusion

The favourable trend in total stroke incidence rates from 2001 to 2014 does not include AF-related strokes. This may suggest that AF has become accountable for a higher proportion of incident strokes or that AF detection improved over this period.

Figure 1. Age-standardized incidence rates of stroke hospitalizations or out-of-hospital deaths per 100,000 person years (py) by year, illustrated as all strokes (blue horizontal line) and AF-related strokes (red horizontal line/height of red area). The height of the blue area illustrates the rate for non-AF related strokes.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Vestre Viken Hospital Trust (public hospital research fund)

P1270 Systolic blood pressure at age 40 is associated with left atrial volumes at age 64

Funding Acknowledgements

Vestre Viken Hospital Trust

Background

Left atrial (LA) enlargement is associated with elevated blood pressure (BP) and with cardiovascular morbidity and mortality. In the assessment of LA size, echocardiographic guidelines recommend the use of LA end-systolic volume (LAVmax). LA end-diastolic volume (LAVmin) and LA emptying fraction (LAEF) may add valuable information in risk assessment. The knowledge of early adulthood BP and its association to LA volumes and LAEF later in life is limited.

Purpose

To explore the association between systolic BP at age 40 and LA volumes and LAEF at age 64.

Methods

We linked data from subjects who had participated in both a nationwide cardiovascular screening survey (1990-1991) at the age of 40, and the Akershus Cardiac Examination (ACE) 1950 Study (2012-2015) at the age of 64 (n = 2,597). In the ACE 1950 Study, LAVmax and LAVmin were measured with echocardiography according to the summation of discs method. LAEF was calculated as (LAVmax-LAVmin/LAVmax)x100%. The association between systolic BP at age 40 and LA volumes and LAEF at age 64 was assessed in univariate and multivariate linear regression analyses.

Results

Systolic BP at age 40 was associated with LAVmax and LAVmin but not with LAEF at age 64. In our multivariate model, a 10 mm Hg higher systolic BP at age 40 was associated with a 0.9 ml greater LA end-systolic volume and a 0.5 ml greater LA end-diastolic volume at age 64.

Conclusion

Early adulthood systolic BP is associated with LA volumes 24 years later in life.

Table. Association of systolic blood pressure at age 40 to left atrial (LA) volumes and LAEF at age 64 Univariate Multivariate* Dependent variable B (95% CI) p-value B (95% CI) p-value LAVmax (ml) 2.4 (2.0, 2.9) <0.001 0.9 (0.4, 1.4) 0.001 LAVmin (ml) 1.5 (1.1, 1.8) <0.001 0.5 (0.1, 0.9) 0.015 LAEF (%) -0.01 (-0.3, 0.3) 0.938 0.2 (-0.2, 0.5) 0.294 *Adjusted for gender, body mass index, smoking, resting heart rate and antihypertensive treatment, all assessed at age 40. B (95% CI), regression coefficient for systolic blood pressure (per 10 mm Hg) with 95% confidence interval; LAVmax, LA end-systolic volume; LAVmin LA end-diastolic volume; LAEF, LA emptying fraction

P6563Time trends in incidence rates of atrial fibrillation in Norway 2004–2014. A CVDNOR project

Background

The reported incidence and prevalence of atrial fibrillation (AF) has been inconsistent among studies.

Purpose

We aimed to study time trends in incidence (first time) of AF hospitalizations or AF deaths in Norway in the period 2004–2014 by age and sex.

Methods

Nationwide hospital discharge diagnoses in the Cardiovascular Disease in Norway (CVDNOR) database and in the National Patient Registry were linked to the National Cause of Death Registry. All hospitalizations with AF as primary or secondary diagnosis and out-of-hospital deaths with AF as underlying cause (ICD-9: 427.3 or ICD 10: I48; AF or atrial flutter) in individuals ≥18 years were obtained during 1994–2014. Incident AF was defined as first hospitalization or out-of-hospital death due to AF with no previous hospitalization for AF the past 10 years. Age-standardized incidence rates with 95% confidence intervals (CIs) were calculated using direct standardization to the age-distribution in the Norwegian population per Jan 1st 2004. Age-adjusted average yearly incidence rate ratios (IRR) with 95% CIs were estimated by Poisson regression analyses. Accumulated prevalence during 1994–2014 was assessed in Norwegian residents 18 years and older per Dec 31st 2014.

Results

During 39,865,498 person years of follow up from 2004 to 2014 we identified 175,979 incident AF cases of which 30% were registered with AF as primary diagnosis, 69% as secondary diagnosis and 1% as out-of-hospital cause of death. The age-standardized incidence rate of AF hospitalization or out-of-hospital death per 100,000 person years was stable at 433 (426–440) in 2004 and 440 (433–447) in 2014. IRR were stable or declining across age groups of both sexes, except for the youngest age group 18–44 years, where incidence rates of AF hospitalization or out-of-hospital death increased by 2% per year, IRR 1.02 (1.01, 1.03). By 2014, the prevalence of AF assessed from hospital or death records was 2.9% in the adult population 18 years and older.

Conclusion

We found overall stable incidence rates of AF from 2004 to 2014 in the adult Norwegian population. Increased incidence rates of AF in the population 18–44 years are worrying and need further investigation.

Acknowledgement/Funding

The Norwegian Atrial Fibrillation Reseach Network

The interplay between cognitive ability, alcohol consumption, and health characteristics

BACKGROUND

Higher cognitive ability is associated with favourable health characteristics. The relation between ability and alcohol consumption, and their interplay with other health characteristics, is unclear. We aimed to assess the relationship between cognitive ability and alcohol consumption and to assess whether alcohol consumption relates differently to health characteristics across strata of ability.

METHODS

For 63 120 Norwegian males, data on cognitive ability in early adulthood were linked to midlife data on alcohol consumption frequency (times per month, 0-30) and other health characteristics, including cardiovascular risk factors and mental distress. Relations were assessed using linear regression and reported as unstandardised beta coefficients [95% confidence interval (CI)].

RESULTS

The mean ± s.d. frequency of total alcohol consumption in the sample was 4.0 ± 3.8 times per month. In the low, medium, and high group of ability, the frequencies were 3.0 ± 3.3, 3.7 ± 3.5, and 4.7 ± 4.1, respectively. In the full sample, alcohol consumption was associated with physical activity, heart rate, fat mass, smoking, and mental distress. Most notably, each additional day of consumption was associated with a 0.54% (0.44-0.64) and 0.14% (0.09-0.18) increase in the probability of current smoking and mental distress, respectively. In each strata of ability (low, medium, high), estimates were 0.87% (0.57-1.17), 0.48% (0.31-0.66) and 0.49% (0.36-0.62) for current smoking, and 0.44% (0.28-0.60), 0.10% (0.02-0.18), and 0.09% (0.03-0.15) for mental distress, respectively.

CONCLUSIONS

Participants with low cognitive ability drink less frequently, but in this group, more frequent alcohol consumption is more strongly associated with adverse health characteristics.

Educational differences in cardiovascular mortality: The role of shared family factors and cardiovascular risk factors

AIMS

To explore the confounding effects of early family factors shared by siblings and cardiovascular risk factors in midlife on the educational differences in mortality from cardiovascular disease (CVD).

METHODS

Data from national and regional health surveys in Norway (1974-2003) were linked with data from the Norwegian Family Based Life Course Study, the National Educational Registry and the Cause of Death Registry. The study population consisted of participants with at least one full sibling among the health survey participants ( n=271,310). Data were available on CVD risk factors, including weight, height, blood pressure, total cholesterol and smoking.

RESULTS

The hazards ratio (HR) of CVD mortality was 3.44 (95% confidence interval (CI) 2.98-3.96) in the lowest educational group relative to the highest. The HRs were little altered in the within-sibship analyses. Adjusted for risk factors, the HR for CVD mortality in the cohort analyses was 2.05 (CI 1.77-2.37) in the lowest educational group relative to the highest. The respective HR in the within-sibship analyses was 2.46 (CI 1.48-2.24).

CONCLUSIONS

Using a sibling design, we did not find that the association between education and CVD mortality was confounded by early life factors shared by siblings, but it was explained to a large extent by CVD risk factors. These results suggest that reducing levels of CVD risk factors could have the greatest effect on mortality in less well-educated people.