Insulin Pump Use Cuts Cardiovascular Deaths Compared With Pens

September 17, 2014

The largest prospective observational study to date to compare hard clinical end points among patients with type 1 diabetes using insulin pumps vs those using multiple daily insulin pen injections has shown a large reduction, an almost halving, of fatal cardiovascular events among those using the pump.

Lead author of the study, Soffia Gudbjörnsdottir, MD, of the University of Gothenburg, Sweden, told Medscape Medical News: "This is by far the largest study [to date] on end points. We saw that the main effect was on fatal cardiovascular disease."

Dr. Gudbjörnsdottir presented her findings during a press conference here at the European Association for the Study of Diabetes (EASD) 2014 Meeting, and she will also present them during an oral session tomorrow.

Dr. Soffia Gudbjörnsdottir

"The results are quite dramatic," she said. "For fatal cardiovascular disease, the hazard ratio is 0.56 and for total mortality 0.71, so 30% less risk [of any death] if you are treated with the pump."

However, she cautioned that the patients using pen injections were different from those using pumps: the former had a slightly lower educational level, were slightly older, had a longer duration of diabetes, higher blood pressure, and more previous cardiovascular disease, although the same HbA1c. Although they used propensity-scoring to balance the 2 groups and compare them fairly, they may not have eliminated all confounding, she noted.

Asked if she thought the pump itself saves lives, she said: "I don't think it's the pump per se; it's everything that comes with the pump. In our country, pump users are invited to diabetic school when they start the pump, and it's easier to contact a doctor or nurse on weekends, so you have better care."

EASD president Andrew Boulton, MD, of the University of Manchester, United Kingdom, who chaired the press conference, said: "This is an observational study, it isn't a randomized controlled trial, so it's difficult to draw true conclusions. But I think that pump-delivered insulin is the best form of therapy we have today. Nevertheless there are still safety concerns — there are problems occurring with pumps, but these can be picked up by the patient if they have been educated."

Dr. Gudbjörnsdottir presented her findings during a press conference in which the safety of new devices, such as insulin pumps, in diabetes was discussed, with a focus on the lack of regulation regarding approval of these in the European Union. Even in the United States, although the Food and Drug Administration has the MAUDE database for reporting of adverse events with devices, it's still difficult to drill down into the reasons these occur, doctors at the briefing said. Indeed, the EASD and American Diabetes Association intend to issue a joint statement on insulin pumps here at the meeting, and the American Association of Clinical Endocrinologists has called for better training of both patients and providers in the use of insulin pumps.

Dr. Gudbjörnsdottir told Medscape Medical News that "in Sweden, patients are carefully selected for pumps."

"This is reassuring," she continued. "As patients are selected today [in my country], it seems to be a safe treatment and even saves lives."

Insulin-Pump Users: 1 in 4 Women and 1 in 5 Men

The observational study conducted by Dr. Gudbjörnsdottir and colleagues included all patients in the Swedish National Diabetes Registry, which started in 1996 and now includes all hospital clinics for diabetes in the country, covering more than 95% of all known type 1 diabetes patients, she explained.

The data show that 1 in every 4 women with type 1 diabetes in Sweden has an insulin pump and 1 in 5 men. "Among children, pumps are much more common, with over half of all children with type 1 diabetes using an insulin pump," she noted.

"The aim of this study was to look at those treated with an insulin pump and to compare them with those treated with the insulin pen for mortality and cardiovascular diseases," she explained.

They cross-linked the diabetes registry to the Causes of Death Register, the National In-Patient Register, and the Education Register (statistics in Sweden for education and income level, etc).

Just over 18,000 people with type 1 diabetes were assessed, and of these there were 2441 patients with the pump throughout the whole study period, compared with 15,727 patients who used insulin pens throughout the whole study.

Follow-up was almost 7 years, from 2005 to 2012, which "you might say is a short study, but it's as good as it gets today," Dr. Gudbjörnsdottir commented.

Reporting the results, she noted there were differences throughout the study period between the insulin-pump and injection groups: "The survival is higher in the pump group, even after adjusting for all the covariates that we know of."

Outcomes for 18,168 Type 1 Diabetes Patients Followed for 7 Years, 2005­–2012

Outcome Events (%) Events/1000 person-years Hazard Ratio P
Fatal/nonfatal CHD
Injection 6.7 10.7 1.0  
Pump 4.0 6.2 0.82 0.06
Fatal/nonfatal CVD
Injection 8.2 13.1 1.0  
Pump 5.3 8.3 0.89 0.3
Fatal CVD
Injection 3.3 5.1 1.0  
Pump 1.2 1.8 0.56 0.003
Total mortality
Injection 7.1 11 1.0  
Pump 3.4 5.3 0.71 0.003
Non-CVD mortality
Injection 3.8 5.9 1.0  
Pump 2.2 3.5 0.82 0.2

Choosing Right the Right Patients for the Pump Is Key

Asked by Medscape Medical News what she thinks the results mean for type 1 diabetes patients and their doctors, Dr. Gudbjörnsdottir said: "My thinking now, as a clinician, is, 'Do I have more patients like those I am already treating, who would like to have a pump?' If so, then I should not hesitate to start this treatment."

But it's also important "to know that not all people want to have the pump," she said. "Adults have to know that they have to learn about all the technical details and so on. It would not help them to have the pump and not be interested in it.

"We should work on creating interest about these devices and know that we have the possibility to help our patients even more, and not just to say it's good enough with pens. Pens are good enough for some people, but not for all; some would do better with a better device. If the patient is interested, you should not be restrictive."

She also reiterated, however, that those with pumps seem to receive better care, at least in Sweden, which may have played a role in their findings. "There are a lot of good things that come with the pump treatment, and it's just a shame we haven't had the time to do things the same way with everybody — the [pump patients] are fast-tracked to the doctor, to the nurse, and to all this extra education."

European Association for the Study of Diabetes 2014 Meeting; September 18, 2014; Vienna, Austria. Abstract 196

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