I gave a talk yesterday to a great crowd at the annual UCSF CME conference, Diabetes Update. The slides from my presentation, “The Future of Diabetes Management: Social Networking and New Technologies,” can be viewed on Slideshare.
Nearly every day in my practice, a patient with diabetes asks me whether he or she should switch from multiple daily insulin injections to an insulin pump. I often have a discussion with patients about whether or not they should be using a CGM (continuous glucose monitor) to help monitor blood glucose instead of just using SMBG (self-monitoring of blood glucose). As an endocrinologist, it is very important to be able to advise patients about specifically what these new technologies have to offer them. Do they decrease mortality? Do they decrease long-term diabetes complications? Do they improve glycemic control? Do they improve quality of life for patients? Do they lower costs? All new medical technologies need to undergo a rigorous evaluation and testing with these types of questions in mind. This is critical not just so that I can be honest and helpful to my patients, but also from the overall perspective of the healthcare system.
In that vein, Yeh et al recently published a meta-analysis in the Annals of Internal Medicine called “Comparative Effectiveness and Safety of Methods of Insulin Delivery and Glucose Monitoring for Diabetes Mellitus: A Systematic Review and Meta-analysis.”
This meta-analysis, funded by AHRQ, looked at the differences between:
- MDI vs CSII (multiple daily injections vs continuous subcutaneous insulin infusion)
- Type 1 vs type 2 diabetes
- SMBG (self-monitoring of blood glucose) vs rt-CGM (real-time continuous glucose monitoring)
What types of studies did they include in their meta-analysis?
- Studies of adults, adolescents, or children with type 1 or type 2 diabetes mellitus
- Studies from 1966-2012
- 19 studies comparing CSII with MDI (>3 injections per day of either basal/bolus insulin or NPH/regular)
- 10 studies comparing CGM with SMBG (>3 fingersticks per day)
- 4 studies comparing SAP (Sensor-augmented pump) use with MDI + SMBG
* Studies were excluded if regular insulin was used in the CSII (pump) group (they felt this to be a weakness of prior analyses)
Here is the key data table:
A few things pop out from this table:
- Overall, they assessed the strength of evidence as relatively weak.
- In children and adolescents, CSII showed no difference in clinical outcomes from MDI. CSII was better in terms of quality-of-life.
- In adults with type 1 diabetes, CSII led to more symptomatic hypoglycemia, but better hemoglobin A1c and quality-of-life.
- There were no differences between CSII and MDI in adults with type 2 diabetes.
- CGM, whether with an insulin pump or not, led to a benefit in glycemic control without any difference in hypoglycemia.
Some concerns and words of caution when interpreting these results:
- Meta analyses can always suffer from publication bias. That is, studies are much more likely to be published if they show positive results. So it is possible that studies have been done that generated results that would have shown no difference between the two methods being studied, but these may never have been published and thus cannot be included in the meta-analysis.
- These studies all had durations of 12-52 weeks. There were no studies reporting on long-term outcomes like micro or macrovascular disease.
- 24 of the articles (approximately 2/3) were supported by pharmaceutical companies
What does this mean?
According to this meta-analysis, CGMs did improve glycemic control. Insulin pumps did not appear to have a significant effect on clinical outcomes, but did positively effect quality of life. Remember that the studies included were all between 12 and 52 weeks, so one major limitation is that any longer-term effects would not be teased out.
While some may discount the quality of life improvements seen with the pump as being less important than clinical outcomes, I caution people from doing so. In a condition as omnipresent as diabetes, maintaining good quality of life for the patient is critical and a very important goal.
In the end, the decision about whether or not to use one of these devices comes down to a conversation with the patient and their family, based on their personal preferences and what each device might offer them in terms of benefits and harms. This meta-analysis adds some more information to that conversation.
Finally, this meta-analysis shows that we simply need more data to study so that more concrete conclusions can be drawn.
I had a chance this week to spend some hands-on time learning about the new V-Go insulin delivery device from Valeritas. Valeritas’ website states that “The V-Go is engineered to simplify basal–bolus insulin therapy for the millions of people suffering from Type 2 diabetes.”
– This is the first disposable insulin-delivery device that will give basal-bolus insulin.
– It is mechanical, containing no electronics.
– It is designed to be worn for 24 hours before it needs to be refilled with insulin.
– The needle is a 30 gauge needle that stays in the user while the V-Go is in use.
– The V-Go comes in 3 “sizes”: one that delivers 20 units of basal insulin over 24 hours, one that delivers 30 units, and one that delivers 40 units. Each device is also capable of giving bolus insulin in 2 unit increments up to 36 total units of bolus insulin per 24 hour period.
Three thoughts about the V-Go:
1) Convenient: This device appears well-built and relatively easy to use. It is about the size of an Omnipod, and because it is placed on the user for 24 hours straight, allows her to leave insulin at home when going out for the day. The device needs to be refilled every 24 hours with rapid-acting insulin. So, the user need only take fingerstick/testing supplies out with her when going to work, running errands, or going out to meals. It is also somewhat elegant that there are no electronics in the device.
2) Not enough insulin for some patients: Though this device promises convenience, the amount of insulin that can be delivered is too little for some people with type 2 diabetes. The most that can be delivered is 40 units of basal insulin and 12 units of bolus insulin per meal (totaling 36 units of bolus insulin a day).
3) Inability to titrate: The device comes in 3 sizes, each delivering a set basal amount of insulin over 24 hours. These are either 20, 30, or 40 units. While this may be useful for a patient who has already been on a steady dose of basal insulin, it does not give much flexibility to titrate doses. Once a patient has paid her co-pay at the pharmacy and picked up a month’s supply, she would have to pay again to switch to a different basal rate.
I think this device represents an interesting start towards a market that will likely increase rapidly in the next few years of devices intended to deliver insulin to people with type 2 diabetes. Given the above limitations, I think it’s overall usefulness will prove limited, but I look forward to seeing what future iterations and generations of devices will look like.
What do you think? Would you want to try this (either patients with type 2 diabetes or providers caring for patients with type 2 diabetes)?
Gizmodo, a well-known consumer electronics and technology blog, posted a story about progress towards the artificial pancreas. Is diabetes technology moving more into the popular consciousness?
On February 9th, Cellnovo, a company based in the UK, announced they were launching a new system comprised of an integrated insulin pump connecting wirelessly to a touch-screen handset which then connects wirelessly to their software, allowing remote monitoring of a patient’s diabetes. They also announced that they will be performing a clinical trial looking at their new system, as well as specifically focusing on the usability of insulin pumps and wireless diabetes technology
- Integrated pump with handheld and software: Everything looks to be well-designed and will work seamlessly together. In fact, the handheld will also serve as a glucose monitor.
- Wireless and automated: Anything that is going to succeed is going to have to be wireless. Patients already spend enough time managing their diabetes. Asking them to do more work and take extra steps is unfair and not going to work. This system will record your glucose values and your insulin doses without you doing any extra work. That is a big deal!
- Closed system: Though the products designed by Cellnovo should all work well together, they represent yet another closed ecosystem in diabetes. If you like one device from one company and one device from another, sorry. Your data won’t be shared between them.
Medtronic just published results from their ASPIRE study showing decreased time in hypoglycemia for patients using their new “low glucose suspend” feature. The new system will automatically and temporarily suspend insulin delivery if the patient’s glucose falls below a set threshold value. In this case, the threshold of <70 mg/dl was used.
Automatic prevention of hypoglycemia is a big step forward in assuring the safety of patients with type 1 diabetes. What will be an interesting next step will be to see if this data is reproducible in a “normal,” home environment, since this study was done by inducing hypoglycemia through exercise in a research setting. Though we may or may not see major improvements in long-term clinical outcomes with this new technology, it seems like it may start to reduce the need for waking up with hypoglycemia and having a snack at 4am, and it seems like a step closer to realizing a “closed loop.”
I know that there are a number of patients who use Medtronic pumps and Dexcom sensors because they find the Dexcom sensor more comfortable. This new feature requires use of both the Medtronic pump and Medtronic sensor in order to create the first step towards a closed-loop system. I wonder whether this new feature will convince at least a few patients to switch to using a Medtronic sensor.
I’d be curious to hear comments from any patients who are in this situation and what your thoughts are.
Graph below taken from the Diabetes Technology and Therapeutics publication showing glucose values from patients with and without the low glucose suspend feature.