Age at Diagnosis of Type 2 Diabetes Mellitus and Associations With Cardiovascular and Mortality Risks
abstract
This abstract is available on the publisher's site.
Access this abstract nowBACKGROUND
Risk of cardiovascular disease (CVD) and mortality for patients with versus without type 2 diabetes mellitus (T2DM) appears to vary by the age at T2DM diagnosis, but few population studies have analyzed mortality and CVD outcomes associations across the full age range.
METHODS
With use of the Swedish National Diabetes Registry, everyone with T2DM registered in the Registry between 1998 and 2012 was included. Controls were randomly selected from the general population matched for age, sex, and county. The analysis cohort comprised 318083 patients with T2DM matched with just <1.6 million controls. Participants were followed from 1998 to 2013 for CVD outcomes and to 2014 for mortality. Outcomes of interest were total mortality, cardiovascular mortality, noncardiovascular mortality, coronary heart disease, acute myocardial infarction, stroke, heart failure, and atrial fibrillation. We also examined life expectancy by age at diagnosis. We conducted the primary analyses using Cox proportional hazards models in those with no previous CVD and repeated the work in the entire cohort.
RESULTS
Over a median follow-up period of 5.63 years, patients with T2DM diagnosed at ≤40 years had the highest excess risk for most outcomes relative to controls with adjusted hazard ratio (95% CI) of 2.05 (1.81–2.33) for total mortality, 2.72 (2.13–3.48) for cardiovascularrelated mortality, 1.95 (1.68–2.25) for noncardiovascular mortality, 4.77 (3.86–5.89) for heart failure, and 4.33 (3.82–4.91) for coronary heart disease. All risks attenuated progressively with each increasing decade at diagnostic age; by the time T2DM was diagnosed at >80 years, the adjusted hazard ratios for CVD and non-CVD mortality were <1, with excess risks for other CVD outcomes substantially attenuated. Moreover, survival in those diagnosed beyond 80 was the same as controls, whereas it was more than a decade less when T2DM was diagnosed in adolescence. Finally, hazard ratios for most outcomes were numerically greater in younger women with T2DM.
CONCLUSIONS
Age at diagnosis of T2DM is prognostically important for survival and cardiovascular risks, with implications for determining the timing and intensity of risk factor interventions for clinical decision making and for guideline-directed care. These observations amplify support for preventing/delaying T2DM onset in younger individuals.
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Additional Info
Disclosure statements are available on the authors' profiles:
Age at Diagnosis of Type 2 Diabetes Mellitus and Associations With Cardiovascular and Mortality Risks: Findings From the Swedish National Diabetes Registry
Circulation 2019 Apr 08;[EPub Ahead of Print], N Sattar, A Rawshani, S Franzén, A Rawshani, AM Svensson, A Rosengren, DK McGuire, B Eliasson, S GudbjörnsdottirFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Would You Like to Be Diagnosed With Diabetes at Age 40 or Age 80?
Intuitively, most of us would say we want to be diagnosed later. Yet, every day in our clinic when we see a young person with diabetes versus an older person with diabetes, we are more worried about the older individual having events. In fact, we spend much more time with the older individual, as well.
This paper looked at this exact question—who is at higher risk of having events compared with people without diabetes—is it the patient who is diagnosed with diabetes at age 40 years old or at age 80? Figuring this out would help us use our time and resources more effectively.
These researchers considered data from 318,083 patients from the Swedish National Diabetes Registry and matched them to almost 1.6 million people without diabetes. With these large numbers, it was possible to look at patients who had had diabetes in each decade of their life less than 40 years old all the way up to over 90 years old. This allows us to see the effect of diabetes based on the age at diagnosis.
It turns out that a diagnosis of diabetes at a younger age (≤40 years) had the higher risk compared with age-matched patients without diabetes. Total mortality had a hazard ratio (HR) of 2.05 (1.81–2.33), CV mortality had an HR of 2.72 (2.13–3.48), heart failure had an HR of 4.77 (3.86–5.89), and coronary heart disease had an HR of 4.33 (3.82–4.91). Interestingly, this difference became less and less with each increasing decade of age at diagnosis until the age of 80, when there was no more difference in events between patients with diabetes and without diabetes.
One possible explanation of this is that as we get older there are other things that can kill us; therefore, diabetes becomes a minor player as we get older.
Another possibility is that doctors take better care of older people with diabetes. Perhaps we think that older patients with diabetes are more likely to have events; hence, we see them more often and we give them more health tips. In fact, this vigilance might explain why, in the over-80 category, patients with diabetes actually had lower mortality risk; perhaps they were more likely to be on statins and RAAS blockers and get EKGs and stress tests. Whereas for 80-year-olds without diabetes, we may think that they don’t need statins or other treatments at that age. That difference in our management may explain the reduced mortality in the elderly group with diabetes.
These researchers also looked at life expectancy. They plotted life expectancy based on the age at which diabetes was diagnosed. So, a diagnosis of diabetes at age 15 meant a loss of 12 years in life compared with a 15-year-old without diabetes. A diabetes diagnosis at age 45 would mean 6 years of lost life compared with a person without diabetes. But a diagnosis at age 80 years of age would have no loss of life, and, when a person edges toward 90 years of age, there is actually a small survival benefit compared with people without diabetes.
So, we need to recalibrate our “spider senses.” Yes, elderly patients have more events, but the additional risk that diabetes causes is very minimal. However, the younger patients with diabetes lose big time compared with their non-diabetic counterparts. So, yes; we need to protect the elderly. However, more than ever, we need to focus on the younger ones because they have the most to lose, which also means that they have the most to gain if we treat them properly. So, we need to protect those younger patients from the ravages of diabetes, and give them back those 6 to 12 years of their life. A noble cause, indeed.