The Math Behind Basal Insulin
Companion for episode 820, ‘The Math Behind Setting Basal Insulin’.
Total Daily Insulin (TDD), for those not honeymooning, starts with this BASIC calculation. Weight (in pounds) divided by 4. You can also use weight (in pounds) multiplied by 0.25. For those who measure weight in kilograms use weight (in kilograms) multiplied by 0.55. To find your weight in kilogram divide your weight (in pounds) by 2.2 or multiply weight (in pounds) by 0.454.
This calculation provides an estimated total daily dose (TDD) of insulin.
Expect the Basal dose to be about 40-60% of TDD. IN this example a 120 pound adult needs about 30u per day of total insulin. This makes the daily target between 12 units of basal (40% of TDD) up to 18 units basal (60% of TDD). This is for adults and is a general starting place if someone is really just wanting to improve management. Someone who is more active will need less basal insulin - 0.15u/kg up to 0.70u/kg covers the range of inactive to very active. Assessing where you are starting along with activity level will help you get an idea of where to start tweaking up or down from your current dose. Those on low carb diets tend to have higher overall basal needs.
For kids prior to puberty, the starting evaluation for TDD is less than adults so weight (in pounds) multiplied by 0.2 (0.44 x weight in kg) and then adjusted for activity level.
Adolescent doses for basal alone could be 0.25 -1.0u/kg of body weight, again depending on very active to sedentary.
Older adults have a decrease in basal need with a range of 0.1 - 0.5u/kg body weight.
Basal doses for kids out of the TDD could be 0.15 to 0.60u/kg from active to sedentary.
For all age groups, the TDD as well as basal needs will typically go down the more active the person is and initial assessment and establishment of insulin need is usually done considering a moderate level of activity.
For a simple math calculation to optimize pump settings, there is a great tool that does the math for you atwww.opensourcediabetes.org - http://www.opensourcediabetes.org/tools.php and is free for all to use. This is the work of John Walsh PA/Ruth Roberts MA who co-wrote the Pumping Insulin book. This takes into consideration your current weight as well as current insulin doses, current BG and where you'd like your target BG to be and gives the calculations to make adjustments with a note to contact your provider prior to adjusting settings based on the suggestion.
Books that include dosing strategy charts, tables and the math referenced. ‘Think Like a Pancreas’, Gary Scheiner, MS, CDCES - ‘Pumping Insulin’, John Walsh/Ruth Roberts - ‘Type 1 Diabetes in Children, Adolescents and Young Adults’, Dr. Ragnar Hanas.
Also suggested. The math for this dosing plan from the research of Dr. Paul Davidson and Dr. Bruce Bode. Results: With use of the AIM system, the TDD for continuous subcutaneous insulin infusion = 0.24 * BWlb; basal insulin = 0.47 * TDD; CF = 1,700/TDD; and CIR = 2.8 * BWlb/TDD. -https://pubmed.ncbi.nlm.nih.gov/19158048/
