It’s bad news for patients with newly diagnosed type 2 diabetes when they then develop heart failure during the next few years.
Dr. Bochra Zareini
Patients with incident type 2 diabetes (T2D) who soon after also had heart failure appear faced a dramatically elevated mortality risk, higher than the incremental risk from any other cardiovascular or renal comorbidity that appeared following diabetes onset, in an analysis of more than 150,000 Danish patients with incident type 2 diabetes during 1998-2015.
The 5-year risk of death in patients who developed heart failure during the first 5 years following an initial diagnosis of T2D was about 48%, about threefold higher than in patients with newly diagnosed T2D who remained free of heart failure or any of the other studied comorbidities, Bochra Zareini, MD, and associates reported in a study published in Circulation: Cardiovascular Quality and Outcomes. The studied patients had no known cardiovascular or renal disease at the time of their first T2D diagnosis.
“Our study reports not only on the absolute 5-year risk” of mortality, “but also takes into consideration when patients developed” a comorbidity. “What is surprising and worrying is the very high risk of death following heart failure and the potential life years lost when compared to T2D patients who do not develop heart failure,” said Dr. Zareini, a cardiologist at Herlev and Gentofte University Hospital in Copenhagen. “The implications of our study are to create awareness and highlight the importance of early detection of heart failure development in patients with T2D.” The results also showed that “heart failure is a common cardiovascular disease” in patients with newly diagnosed T2D, she added in an interview.
The data she and her associates reported came from a retrospective analysis of 153,403 Danish citizens in national health records who received a prescription for an antidiabetes drug for the first time during 1998-2015, excluding patients with a prior diagnosis of heart failure, ischemic heart disease (IHD), stroke, peripheral artery disease (PAD), chronic kidney disease (CKD), or gestational diabetes. They followed these patients for a median of just under 10 years, during which time 45% of the cohort had an incident diagnosis of at least one of these cardiovascular and renal conditions, based on medical-record entries from hospitalization discharges or ambulatory contacts.
Nearly two-thirds of the T2D patients with an incident comorbidity during follow-up had a single new diagnosis, a quarter had two new comorbidities appear during follow-up, and 13% developed at least three new comorbidities.
Heart failure, least common but deadliest comorbidity
The most common of the tracked comorbidities was IHD, which appeared in 8% of the T2D patients within 5 years and in 13% after 10 years. Next most common was stroke, affecting 3% of patients after 5 years and 5% after 10 years. CKD occurred in 2.2% after 5 years and in 4.0% after 10 years, PAD occurred in 2.1% after 5 years and in 3.0% at 10 years, and heart failure occurred in 1.6% at 5 years and in 2.2% after 10 years.
But despite being the least common of the studied comorbidities, heart failure was by far the most deadly, roughly tripling the 5-year mortality rate, compared with T2D patients with no comorbidities, regardless of exactly when it first appeared during the first 5 years after the initial T2D diagnosis. The next most deadly comorbidities were stroke and PAD, which each roughly doubled mortality, compared with the patients who remained free of any studied comorbidity. CKD boosted mortality by 70%-110%, depending on exactly when it appeared during the first 5 years of follow-up, and IHD, while the most frequent comorbidity was also the most benign, increasing mortality by about 30%.
The most deadly combinations of two comorbidities were when heart failure appeared with either CKD or with PAD; each of these combinations boosted mortality by 300%-400% when it occurred during the first few years after a T2D diagnosis.
The findings came from “a very big and unselected patient group of patients, making our results highly generalizable in terms of assessing the prognostic consequences of heart failure,” Dr. Zareini stressed.
Management implications
The dangerous combination of T2D and heart failure has been documented for several years, and prompted a focused statement in 2019 about best practices for managing these patients (Circulation. 2019 Aug 3;140[7]:e294-324). “Heart failure has been known for some time to predict poorer outcomes in patients with T2D. Not much surprising” in the new findings reported by Dr. Zareini and associates, commented Robert H. Eckel, MD, a cardiovascular endocrinologist at the University of Colorado at Denver, Aurora. Heart failure “rarely acts alone, but in combination with other forms of heart or renal disease,” he noted in an interview.
Dr. Robert H. Eckel
Earlier studies may have “overlooked” heart failure’s importance compared with other comorbidities because they often “only investigated one cardiovascular disease in patients with T2D,” Dr. Zareini noted. In recent years the importance of heart failure occurring in patients with T2D also gained heightened significance because of the growing role of the sodium-glucose cotransporter 2 (SGLT2) inhibitor drug class in treating patients with T2D and the documented ability of these drugs to significantly reduce hospitalizations for heart failure (J Am Coll Cardiol. 2020 Apr 28;75[16]:1956-74). Dr. Zareini and associates put it this way in their report: “Heart failure has in recent years been recognized as an important clinical endpoint ... in patients with T2D, in particular, after the results from randomized, controlled trials of SGLT2 inhibitors showed benefit on cardiovascular death and heart failure hospitalizations.”
Despite this, the new findings “do not address treatment with SGLT2 inhibitors in patients with T2D, nor can we use our data to address which patients should not be treated,” with this drug class, which instead should rely on “current evidence and expert consensus,” she said.
“Guidelines favor SGLT2 inhibitors or [glucagonlike peptide–1] receptor agonists in patients with a history of or high risk for major adverse coronary events,” and SGLT2 inhibitors are also “preferable in patients with renal disease,” Dr. Eckel noted.
Other avenues also exist for minimizing the onset of heart failure and other cardiovascular diseases in patients with T2D, Dr. Zareini said, citing modifiable risks that lead to heart failure that include hypertension, “diabetic cardiomyopathy,” and ISD. “Clinicians must treat all modifiable risk factors in patients with T2D in order to improve prognosis and limit development of cardiovascular and renal disease.”
The study received no commercial funding. Dr. Zareini and Dr. Eckel had no disclosures.
SOURCE: Zareini B et al. Circ Cardiovasc Qual Outcomes. 2020 Jun 23. doi: 10.1161/CIRCOUTCOMES.119.006260.