THE MYSTERY BOLUS

As with every year, we've been looking for the dreaded 'mystery bolus' and we've found plenty to go around at diabetes camp yet again.

So... what exactly is a "mystery bolus", you ask?

A mystery bolus is a dose of insulin delivered by an insulin pump at a time when insulin normally isn't given. I broaden the definition to include boluses of insulin taken for some reason which might be unique to the camper, but never shared with the medical staff (or parent) responsible for that child.

An insulin pump is largely controlled by its user. There are pumps where the user can be blocked from taking unplanned doses either using a button lock (not too hard to deactivate by the child) or using a tubeless pump with a PDM which can be kept in a secure location between scheduled or intentional doses (ie OmniPod).

The reality is that parents almost universally trust their older kids to use their pumps properly. I find this to be a potential barrier to better control at camp for some insulin pumping kids.

At camp we routinely review the insulin bolus delivery histories of each pump. This includes the time before camp starts and certainly during camp. This week we have 60% of all campers using an insulin pump of some kind. That's a lot of data to review but it's necessary.

What we find used to shock us, but now it's almost a certainty that we will discover several campers who either bolus more often than we know or less often than they should. Since most are behind the parental "firewall" at home, rarely is suspicion aroused.

The poor control which results from reckless pumping is usually blamed on diabetes in general, bad pump settings, hormones, poor carb counting, etc... Ignoring the possibility that the pump user could be the source is a flawed assumption.

As a pediatric endocrinologist, I see patterns of reckless insulin dosing in my practice. For example, kids not bolusing for meals. This could be due to a variety of reasons. It's so common that endos often simply grow numb to it and just assume it's part of wearing an insulin pump and being a child or teen. It's not uncommon that meaningful discussion never happens aside from mild threats and lectures.

Perhaps more insulin pump settings are offered as a solution to reckless pumping. But as stated in the first of my '12 Commandments of Insulin Pumping', a pump is no better (or worse) than the human being attached to it. Most of my patients do better with fewer, not more, insulin pump settings.

Missed insulin boluses raise A1C levels over time. Research shows that 2 missed boluses per week equals a 0.5 point higher A1C. We only 'see' the missed boluses from meals based on some pump histories showing no boluses at all during an entire day. Only the basal insulin is being delivered. This is called 'riding the basal'. Missed doses are sometimes an assumption. It's hard to prove a negative. But when a pump user has an A1C over 10-11% it's almost a certainty that there have been many missed or ignored opportunities to dose insulin based on blood sugar and meals/snacks eaten.

We had one camper dosing insulin through the pump as staff was trying to treat a low BG. The camper was not new to diabetes or pumping. It created more low BG issues as a result. It has now been addressed. But it was not apparent at first until the bolus history was reviewed. The reasons behind this behavior are still being explored but it's not because the camper doesn't know their way around a pump. In fact this shows a rather keen ability, albeit misdirected IMO.

Diabetes care is overrun with behavioral psychology. Thanks to the ability to track bolus history, nowhere is this more apparent than with insulin pumpers. With data tracking coming to insulin pens, this issue may finally be exposed for non-pumpers.

My recommendation? It hasn't changed over my 35 years of managing type 1 diabetes and wearing a pump myself for 30 years: