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People with Type II Diabetes requiring long-acting insulin can inject themselves once a day with a syringe or insulin pen, but there is an alternative to that: insulin pumps. Insulin pumps provide a continuous supply of rapid-acting insulin throughout the day, which has the same effect on the body as one daily injection of long-acting insulin. (And if you require mealtime insulin, you can get the insulin pump to deliver a "bolus" or extra amount of insulin.)

Now insulin pumps come in two types: tube pumps and patch pumps. Tube pumps require you to inject a new injection set into your skin every 2-3 days. Concerning patch pumps, there are two patch pumps on the market, V-Go which is injected once every 24 hours, and Omnipod which is injected once every 3 days. There are also insulin ports like the I-Port, which is also injected once every three days.

But my question is, are there any insulin pumps (or ports) which you can keep attached to your skin for more than a few days? I just want to minimize the frequency of injections as much as possible. Something that you just inject once and then it stays attached for two weeks or a month would be great.

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Unfortunately no, I have not found in my research any pumps which can be attached for a longer amount of time, although I did find a study which you may find relates to your question. Link to Study

The following is the rationale behind site transfer and the suggested schedule.

The manufacturers of IISs and insulin formulations used in insulin pumps recommend changing IISs and infusion site every 2–3 days in order to avoid skin and infusion problems. However, in reality, these infusion site-related recommendations are based only on reports derived from anecdotal data sets about use of the IIS in daily practice. Thorough investigations providing a scientific rationale for depicting a safe interval for the changes are still lacking to date.

  • It's strange, you can keep a CGM system like the one discussed in my question here attached for a period of two weeks. So I don't know why a pump can only be attached for a few days. – Keshav Srinivasan May 11 '17 at 0:23
  • The linked study gets into much more detail than my answer so definitely check it out. The main issues are insulin reservoir and skin reactions. Most CGM units are much smaller than a pump and weigh much less. While it may seem ideal for your lifestyle to have a two weeks of use out of one site the toll it would take outweigh the convenience(per the manufacturers). – Parker McA May 12 '17 at 21:01
  • Well, consider something like the I-port: medtronicdiabetes.com/products/i-port-advance It has no insulin in it, and it's as small as a CGM. Yet it has to be replaced every three days. It seems counterintuitive. – Keshav Srinivasan May 12 '17 at 21:29
  • What's counter intuitive about that? I think it's counter intuitive to think having an open port, essentially a managed wound on the body, should be able to remain open for an arbitrarily longer amount of time due to your longing not to change a site. Have you read the linked study? – Parker McA May 15 '17 at 17:17
  • Well, isn't a CGM equally a "managed wound on the body"? So why would a CGM be able to be kept for two weeks when an I-Port can only be kept 3 days? That's what seems counterintuitive. – Keshav Srinivasan May 15 '17 at 17:19
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It would be great to be able to keep an infusion set for that long.

The reason why infusion sets cannot stay as long as CGM sensors is that the cannula used for injecting insulin in an infusion set is a lot more invasive and damaging than the very thin fiber that is used for measurement in a CGM sensor.

CGM users often make their sensors last much longer than the manufacturer's requirements: the Dexcom sensor is supposed to stay on 7 days, but many users use them for 14 days, sometimes much more. In fact, there are online competitions as to who can keep them longest...

On the other hand, I don't know of pump users who commonly use their infusion sites for longer -- I am sure they exist, but it is simply not a common thing. I do hear a lot of users complaining that they cannot keep their site going for three days -- and many users also report that their third-day site absorption is worse than the other two days (a commonly mentioned factor is 20% worse). Infusion sets are a costly part of the system for pump users, so I would expect to have heard about a lot of users reporting on forums how successful they are at making them last very long -- but that's not the case.

So, imho, existing cannula technology is unlikely to allow for an infusion site lasting beyond 3-4 days. It will take some radical innovation, I think, to make it possible.

[EDIT] Per the discussion in the comments section, to reply to the need for more precision in this answer by the OP, I actually asked some users in a diabetes forum to summarize their exposure to leaving infusion sets for a longer duration. The anecdotal results were that, while a small number of people are able to leave infusion sets longer than 3 days, a fairly significant number of posters reported problems on day 3 or later, as well as potential long-term damage to the site (lipodystrophy). When going user-per-user to compare their report to their pump brand using their previous posts, results appear similar across tubeless and tubed pumps.

  • Is the 20% worse thing only relevant to tube pumps, or is it also relevant to patch pumps and the I-port? – Keshav Srinivasan Jun 6 '17 at 17:17
  • I want to say it is common to both, but I will confirm that. Let me ask the question directly on a few user forums and see what I find out in terms of anecdotal evidence. It will probably take me a couple of days. – WestOfPecos Jun 6 '17 at 17:25
  • Ok. By the way, since you've posted answers to all my other diabetes-related questions, can you take a look at my question here: health.stackexchange.com/q/12192/9100 – Keshav Srinivasan Jun 6 '17 at 18:01
  • OK, I asked: unconnected to the pump. Those reporting problems are spread on Tandem, Medtronic, Omnipod if you look up what they are using (I am sure I-port would generate same results at best): forum.fudiabetes.org/t/infusion-sites-how-long-do-yours-last/… – WestOfPecos Jun 6 '17 at 23:22
  • I think it's possible that I-port might generate better results, because it could be that sending insulin constantly through a cannula does more damage to the cannula than just sending insulin through the cannula sporadically. – Keshav Srinivasan Jun 8 '17 at 21:45

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