Chief Medical Advisor and pediatric endocrinologist Dr. Saleh Adi discusses guidelines for basal testing and optimization for insulin pump users. Drawing from his decades of expertise, he highlights example use cases and basal optimization techniques, which you can also find in our webinars library.
Benefits of basal optimization
Optimizing your patients’ basal rate settings on their insulin pumps can be complex and time-consuming, but having an accurate basal rate dialed in is critical to improving patient outcomes. A basal rate approximates the background insulin per hour that the body needs to cover basic metabolic processes and prevent severe hypoglycemia (lows) or hyperglycemia (highs). With Tidepool’s software, you have a proactive way for patients to get the most out of any technology they are using and a way they can work with you to set rates that work for their bodies, habits, and lifestyles.
For your patients using closed loop systems, optimizing basal rates provides your patients with a safe “fall back” option if their automation stops, and they’re required to manually take over. Tidepool’s software allows you to see the actual delivery of basal insulin feature over several days in a row to fine-tune your patient’s settings — taking some of the guesswork out of the equation. More importantly, those scheduled basal rates may be the base rate from which automation is adjusting. If their scheduled basal rate is suboptimally set, your closed loop patient may be getting larger percentages of basal change than intended.
Guidelines for basal rates
Basal rates are highly individual and can vary from day-to-day, especially throughout childhood and adolescence. That being said, data generated through the Tidepool Big Data Donation Project can help give you and your patients a place to start as you review settings. This data originates from 803 Tidepool users who opted in to donate their data, totaling more than 479 person-years of insulin pump use. You can check out the full data analysis here: “Let’s talk about your insulin pump data”.
In this graph, you can see the typical distribution of hourly basal rates by age, with a noticeable increase during adolescence as insulin resistance increases due to hormones.
This data visualization shows the median basal rate for each age cohort.
As you can see from these graphs, median basal rates for our data donors increase until a peak at 15–17 years old, and then come back down between the range of 0.75 to 0.9 units of insulin per hour for most adults. We have also found most people in our dataset run their scheduled basals for 4–6 hours at a time and most adults in our dataset maintain an average basal to bolus ratio of the often recommended 50:50 (though there is updated thinking on whether that goal makes sense for all people with diabetes).
You can refer to these charts as additional guidance as you optimize your patients’ basal rates based on your usual clinical algorithms.
Looking for patterns
To optimize and personalize a patient’s basal rates, Dr. Saleh Adi explains that you’ll need to consider a few factors, including: age; time since diagnosis; current insulin doses; pubertal status (if applicable); and your patient’s bedtime and wake time. These can all have an impact on overall insulin needs and overall glucose management. Our webinar with Dr. Adi discusses particular insulin requirements related to pre-puberty and dawn phenomenon, as well.
You and your patients can get a big picture view of how basal insulin compares to bolus insulin using Tidepool. Dr. Adi recommends reviewing basal to bolus ratios in the Daily View of Tidepool Web to see an information-rich compilation of data. (Overall current basal to bolus ratio lives in the summary widget on the right side of the screen.)
To explore glucose trends, you’ll want to select a 3–5 day period and review similar periods of each day. Tidepool Web’s Trends view separates the day into three-hour segments for easier review.
Look first at the glucose overnight period (the first two segments of the graph) from midnight to 6 am. Getting the nighttime basals right allows you to fine-tune basal rates without the added variables of food and insulin-to-carb ratios. And that’s a quarter of your patient’s day!
“Start with the nighttime data — that’s what I always do. When I see somebody’s data, I first look at this midnight to 6 am chunk that is pure and clean with no food, no snacking, no exercise, and no stress. Assuming the [person with diabetes] is sleeping, looking at that clean data is going to give us a good idea of basal rate function.”
Next, look at similar periods of the day where the patient may already be skipping meals or snacks, such as the window from 2 pm–6 pm. Are there opportunities to find other areas like this where there are fewer variables? If you find patterns of rises and falls during these segments, you’ll see opportunities for tweaks to the basal rate to keep those glucose lines flatter.
Tidepool also helps you see, at a glance, whether or not meal boluses are happening since insulin usage is superimposed right there with the glucose trends. It may be that your patient needs a single correction bolus before bed rather than an increase in evening basal rates.
When your patients use a CGM (continuous glucose monitor), you will hopefully find you have plenty of data to take advantage of, eliminating the need for more traditional basal testing. If your patient is not utilizing CGM, basal testing will require the person with diabetes to fast breakfast or dinner for three days in a row and take frequent fingerstick glucose measurements to see what their glucose is doing.
Glycemic patterns are discoverable in Tidepool in part because insulin and glucose data from so many patient devices are integrated in one location. When your patients’ basal rates are optimized, you can feel more confident that their day-to-day diabetes management has been made a little easier, empowering both you and your patients to focus more on what matters.