Medtronic Continuous Glucose Monitoring & MiniMed 530G: Two Months Later

Medtronic Continuous Glucose Monitoring & MiniMed 530G: Two Months Later

Back at the end of October I upgraded my insulin pump to the MiniMed 530G and started using the new Enlite Continuous Glucose Monitoring sensors and posted some of my initial thoughts on the new insulin pump and my experiences with CGM as a first-time user. I wanted to follow that blog up with a more in-depth description of what this pump has enabled me to do.

How about you? If you’re already a user of CGM, what things are you doing that I haven’t discovered? If you’re considering using a pump, what kinds of questions or ideas do you have that I didn’t touch on? Please feel free to use the comments to discuss, I’d love to know what you’re doing too!


One of the things I wanted to touch on was the cost for supplies, with and without insurance. One thing to keep in mind when reading this is that it takes many years of studying black magic to understand insurance discounts and pricing with regards to your out-of-pocket costs. I am fortunate to have what I consider to be pretty decent health insurance.

In looking at the pricing on the Medtronic store’s website and in deciphering my insurance explanation of benefits, I’ve tossed together the following costs.

Insulin Infusion Sets (changed every 3 days, roughly 10 per month):

  • Quick-set 9mm Cannula / 43” Tubing (10/box): $136.70 / $23.00 (after insurance)
  • Paradigm Reservoir 3.0ml (10/box): $38.00 / $8.00 (after insurance)

CGM Sensor (changed every 6 days, roughly 5 per month):

  • Enlite Sensor: (5 pack) $473.00/ $62.00 (after insurance)

Altogether, the maximum cost per month is around $647.70, and assuming I’ve decrypted my insurance’s explanation of benefits correctly, the cost to me is roughly $93.00 each month. The majority of that cost is the Enlite sensors, which I hope, as they get more widely used, we’ll see the prices come down a little bit.

Thoughts and Observations

Overall, I’m pretty happy with the pump. Initially, I had some pretty consistent issues overnight with hypoglycemia, which was unusual, because I didn’t make any changes at all to any of my basal or bolus rates, but for some reason with the new pump I was waking up each night feeling pretty miserable. However, I was able to tweak and fix that pretty simply by reducing my basal rate during the night.

I do have a bit of negative feedback, and I’m not even sure it should be considered negative, but at the very least it’s a complaint that I have about the new pump. The pump is very chatty and noisy when using the CGM. You can set up alerts for both high blood sugar and low blood sugar, both of which make the pump beep. The pump also nags you when you need to take a blood sugar reading and help calibrate the sensor. Add this on top of the other normal beeps you get and the pump can generate a ton of beeps throughout the day.

I’m not sure about you guys, but I feel pretty awful when my blood sugar is low, and I get really cranky. The entire time that your blood sugar is low, the pump is periodically beeping at you and spazzing out. You can acknowledge the alert, but it’ll come right back a few minutes later. On a few occasions I found it infuriating to be sitting there feeling poorly waiting for your snack to kick in only to have your pump beeping at you.

Please keep in mind, these alerts can be incredibly useful. If I’m sleeping and my blood sugar gets low, I appreciate that it beeps and wakes myself or my wife up. I’m sure if it ever happened, I’d be thankful if someone came upon me unconscious and my pump alerted to them to what might be going wrong. But this fact doesn’t really stop me from being annoyed when some sort of alert is going off about something that I’m already painfully aware of.

One of the more exciting features of using the 530G and CGM is the amount of data that’s being collected by the pump and can be uploaded to Carelink for some analysis. I’d still rather prefer that I didn’t have to upload this data somewhere and that it could remain private and I get to decide who uses it. Aside from a minor gripe with which browsers are supported by the Carelink website, I don’t have any other points of feedback.

This time, I wanted to upload some of my personal data to demonstrate some of the reports available on the Carelink website and the other kinds of things that I was excited about doing on my own. I’m a bit weirded out with publishing some of my information on the Internet, but because these are the questions that I had and wanted answered, I thought it was worth being a bit uncomfortable if it helps someone make up their mind. Please don’t misunderstand me posting this stuff as a request for advice or analysis on the management of my Diabetes.

Here are a few screenshots of the different reports available on the Carelink using my personal data:

Reports Main Screen Modal Day BG by Period Report Modal Day BG by Hour Report Daily Summary Report Quick View Summary Report Sensor Daily Overlay Report Sensor Overlay by Meal Report

I grabbed screenshots of the reports that I found the most helpful. However, I’d like to point out that I believe that both the modal reports (Modal Day Periods and Modal Day Hourly) appear not to be using the sensor values from the CGM, and only use the blood glucose values measured with your glucometer and stored in the pump. I think this diminishes the values of those reports a bit.

I wanted to point out a couple other things about the other reports. In the Daily Summary, you can see a couple events. Firstly, on the X-axis on the bottom, each time you see the little speaker icon that’s an alert that sounded. Earlier in the blog I mentioned that it could be a bit noisy and this displays it.

Aside from that, my two favorite reports on Carelink are the Sensor Daily Overlay and Sensor Overlay by Meal reports. I think these give you a great view of what your CGM is reading at a high enough level that you can start looking for trends. Each of these reports can only be run for a duration of one week, which I don’t personally think is long enough to make decisions on all by itself, but you can generate a few of these reports for over a longer period to try and look for those trends.

Lastly, I spoke about being excited to get access to an export of the data captured in Carelink. This is by far my favorite feature on Carelink. I opened that export (a comma-separated-values file) up in Excel and tinkered around with it. I used only the rows which had values in the field named Sensor Glucose (mg/dL) or BG Reading (mg/dL) and then used the Time column to make my own chart of what my average blood glucose was on across the average day. This is much like what the Sensor Overlay reports was giving me, but in my case I used both the blood sugar values from my glucometer as well as the values captured by the CGM. My point in this was to try and discover some trends during the day and respond by tinkering with my basal rate during those times of day to see if there was some improvement. Here’s what I was able to put together:


One of the things I find most exciting about CGM and the Carelink software is the ability to have this kind of data at your fingertips for exactly this kind of analysis.

My immediate plan is to bump the basal rate on my pump up a notch between 8:00 p.m. and 4:00 a.m. to see if I can bring those numbers down a bit. I’d like to do something for 9:00 a.m. to 11:00 a.m., but I think the best bet in that range is to be a bit more aggressive in my boluses to see if that helps.

I’d like to keep this going in a series of blogs somehow; the past two articles have been very pump-specific. But now I’m thinking I’d like to start grabbing some of this data, making adjustments to my pump and keeping track of it. Hopefully sharing it on my blog might demonstrate to other Diabetics the tremendous potential benefit there is in insulin pump therapy and continuous glucose monitoring.