Don’t Forget our Patients with Type 1 Diabetes

Cardiovascular and renal disease burdens also occur in type 1 diabetes.

Over 463 million patients worldwide are living with diabetes. The prevalence keeps rising over the years even though more treatment and resources are available to control them. While heart diseases are the leading cause of death in adults, having diabetes can increase that risk even more. On one side, type 2 diabetes is associated with metabolic syndrome, obesity, insulin resistance, hypertension, and dyslipidemia, contributing to cardiovascular events. On the other side, diabetic nephropathy is a common complication in patients with diabetes. Over the years, researchers had studied the link between cardiovascular diseases and type 2 diabetes, but more studies are needed to understand the risk in those with type 1 diabetes.

A recent cohort study investigated the populations with type 1 and 2 diabetes from Sweden and Norway to evaluate cardiovascular and renal disease risk. In this study, they included 543,572 patients aged 18-84 years. These participants were followed up for a mean period of 2.6 years. For this study, type 1 diabetes was defined as having received at least one prescription of short-acting insulin from treatment start or within six months after starting basal insulin treatment and having a hospital diagnosis of type 1 diabetes. On the other hand, type 2 diabetes was defined as having any prescribed antidiabetic drug dispensed by a pharmacy. The index date was December 31, 2013, for both Sweden and Norway. The follow-up period for Norway was December 31, 2015 (2 years), while the follow-up for Sweden was December 31, 2016 (3 years). The baseline comorbidities and baseline drug treatments were searched in registries one year before the index date for these participants. These participants were followed in the national patient and cause of death registries until the end of the follow-up period or death. They obtained information from outcomes from hospital records. The clinicians looked for specific events like all-cause death, myocardial infarction, heart failure, chronic kidney disease, cardiovascular-renal disease, and cardiovascular and all-cause death. Since this study included participants from 2 countries, baseline characteristics were calculated separately. They used Cox regression models for statistical tests to determine hazard ratios (HR) and 95% CI. Clinicians also performed baseline assessments for the presence of cardiovascular diseases or events.

Form the 543,572 participants, 59,331 were diagnosed with type 1 diabetes and 484,241 with type 2 diabetes. Of those with type 2 diabetes, 87.5% were on antidiabetic medication, while the rest started some treatment but stopped at some point before the baseline date. Clinicians observed that patients with type 1 diabetes were younger than those with type 2 diabetes (mean age 45.8 vs. 64.1 years). They also found that comparing type 1 versus type 2 patients, type 1 had a lower overall prevalence of cardiovascular diseases (13.3% vs. 26.2%), had a higher incidence of chronic kidney disease (4.3% vs. 3.3%), and more frequent microvascular complications (76.6% vs. 27.8%). In general, those patients >40 years had a higher prevalence of cardiovascular events regardless of which type of diabetes they had. Clinicians did not observe any age difference for MI, HF, and stroke. On the other hand, there was an age-dependent increase in the prevalence of having chronic kidney disease in patients with type 1 diabetes compared to patients with type 2 diabetes.

During this study, those <40 years reported fewer cardiovascular and renal events compared to older patients. Heart failure events were higher for patients with type 1 diabetes in those aged 65-79 years (HR: 1.31-1.39), while myocardial infarction showed similar findings for patients aged 55-79 years (HR:1.30-1.79). Also, they found that stroke rates were higher in patients with type 1 diabetes aged 40-54 years (HR: 1.35-1.72). Furthermore, the incidence of chronic kidney disease was higher for participants with type 1 diabetes at all ages than those with type 2 diabetes. Overall, the risk of having a cardiovascular, renal disease was higher in patients with type 1 diabetes (HR: 1.20-1.60). Also, cardiovascular mortality rates were higher in patients with type 1 diabetes (HR: 1.37-1.71). Clinicians also performed sensitivity analysis where they compared those with cardiovascular-renal diseases and those without them. They found that patients with type 1 diabetes aged 70-79 years had higher rates of myocardial infarction (HR:1.41-1.70) and cardiovascular mortality at 75-79 years (HR: 1.78).

This cohort study was the first to address cardiovascular disease in patients with type 1 and type 2 diabetes. Even though researchers did not adjust for renal impairment, which is one of the limitations, they found that participants with type 1 diabetes had a higher incidence and prevalence. Overall, they noticed that patients with type 1 diabetes had less, or no, drugs in their therapy to prevent cardiovascular diseases, like statins and antiplatelet drugs. Thus, this study provided some clinically relevant findings using a large population from 2 countries. On the other hand, some limitations reported can be evaluated and included in future studies. For example, scientists did not determine the duration of treatment for all patients with type 2 diabetes, so they did not adjust the data for this factor. Also, they did not include a control population for this study. Moreover, they missed some critical data to assess the risk factors associated with cardiovascular-renal diseases. For example, clinicians did not consider the socioeconomic status or lifestyle risk factors that are essential for outcomes.

Practice Pearls:

• Drugs for preventing cardiovascular diseases were less prescribed in type 1 patients than in patients with type 2 diabetes.
• Cardiovascular-renal disease burden is equally heavy in patients with type 1 and 2 diabetes.
• The presence of chronic kidney disease is an essential factor for cardiovascular morbidity and mortality.

References

Kirstofi, R, et al. Cardiovascular and Renal Disease Burden in Type 1 Compared with Type 2 Diabetes: A Two-Country Nationwide Observational Study. Diabetes Care (2021). doi:10.2337/dc20-2839. https://care.diabetesjournals.org/content/early/2021/03/02/dc20-2839

Laura Martínez López, PharmD. Candidate 2021, Lake Erie College of Osteopathic Medicine, College of Pharmacy

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