Days of a Conscientious Diabetic
ADB Log - Diabetic Treatments
Days in the Life of a Conscientious Type 1 Diabetic
This log documents my treatments for diabetes, using two types of injected insulin, a glucose meter, a balanced diet, and counting the grams of carbohydrates that I consume. My “plan” is to maintain blood glucose readings within a “safe” range (80 – 200 milligrams/deciliter).
I inject insulin four or more times daily. My meter is a continuous glucose monitor (CGM). I constantly adjust my dose, based more on the anticipated insulin effectiveness than to changes in my diet. By the way, I’d advise Type 1 diabetics who eat a variety of foods to include carbohydrate counts in their insulin-dose plans.
My dose adjustments are based on some of the same principles used to automate insulin delivery by pumps in conjunction with CGMs. [1, 2] Pumps can operate continuously delivering both small ‘basal’ streams as well as occasional large boluses. When a pump is not used, all doses, small and large, are delivered with a syringe.
I have included narratives of several consecutive days. After the several days of narrative, I’ll switch to a tabular presentation.
Here are some terms and abbreviations for readers not familiar with them:
Novolog (insulin): injectable hormone solution for lowering blood glucose; it stimulates cells to take up and metabolize glucose; its effectiveness lasts for about 5 hours; its level of activity varies over that 5 hour period;
Lantus (insulin): injectable hormone solution for lowering blood glucose, active during 24 hours; its activity is fairly constant over the 24 hour period;
mg/dL: milligrams of glucose per deci-liter, a standard blood glucose concentration available on glucose meters;
Glucose: the source of energy for most tissues in the human body (brain, muscles, etc.); Note: insulin stimulates tissues to receive glucose; without insulin, glucose accumulates in the bloodstream and passes out in urine; a CGM reports the amount of glucose currently in the bloodstream;
CGM: continuous glucose monitor; this system comprises a transmitter+sensor which is attached to the skin; the user carries a miniature battery-powered radio receiver which has a screen graph readout that allows the user to observe their glucose reading at any time;
Carbohydrate: starch and similar foodstuff digested by the human body to produce glucose;
Carbohydrate Ratio (CR): the number of grams of carbohydrates that 1 unit of insulin can compensate for, so that blood glucose concentration remains unchanged.
Insulin sensitivity factor (ISF): the amount by which blood glucose readings in mg/dL will be decreased by use of 1 unit of insulin.
References
[1] https://openaps.readthedocs.io/en/latest/
[3] Scheiner, Gary, Think Like a Pancreas. Managing Diabetes with Insulin (Da Capo Press, 2011, www.dacapopress.com), pg. 110.
November 1, 2020
I stayed “on plan” this day, adjusting insulin doses to avoid big swings in my CGM readings.
Morning Lantus dose:
Overnight my (continuous glucose) meter (CGM) readings were 154 at 10 PM, then rose to 170 around 6 AM, and then to 230 at 7:15 AM. (These units are in mg/dL.) I’m happy with these results, so I will again take 12 units of Lantus (my 24-hour insulin) in the morning.
Morning Novolog Dose:
I plan to take a 5 mile hike this morning. Typically, my Carbohydrate Ratio (CR) is 8.5 – 9 grams of carbodydrates per unit of insulin while hiking. I plan to have a breakfast comprising 53 grams of carbohydrates (based on food package labels). Thus I should take 53/8.7 = 6.09 units of Novolog.
My CGM reading was 236, significantly higher than my target for hiking, which is 150 mg/dL, so I will take a small amount of additional Novolog with the aim of reducing that 236 to 150. My insulin sensitivity factor (ISF) has been around 90 lately, so I will add (236-150)/90 = 0.89 units of Novolog.
My total Novolog dose is 6.09 + 0.89 = 6.98 units. But my syringe can deliver only multiples of 0.5 units. So I will take 6.5 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units.)
I took this dose at 6:50 AM.
After the hike:
At 10:47 AM my CGM reading was 121. That is close to the target CGM reading but surprisingly lower already. I’ve only used about 5.8 units out of the 6.5. The remaining 0.7 units could drive my CGM readings still lower: 0.7 * ISF = 63.
I do not want the reading to be near 60, so I will have a snack: maybe half an energyt bar, or maybe some popcorn. I’ll limit it to about 6-8 grams of carbohydrate.
Perhaps my CR above was a little too low, or my ISF above was a little too low. (My Novolog did an even better job than I though it would.)
I’ll make a note that the CR and ISF values that I used were too low.
Noon Novolog Dose
Time: 12:45 PM. Typically, my Carbohydrate Ratio (CR) at this hour is 7.5 grams of carbodydrates per unit of insulin. I plan to have a lunch comprising 53 grams of carbohydrates (based on food package labels). Thus I should take 53/7.5 = 7.06 units of Novolog.
My CGM reading was 170 (milligram%/liter), significantly higher than my target for hiking, 120 mg/d, so I will take a small amount of additional Novolog with the aim of reducing that 170 to 120. My insulin sensitivity factor (ISF) has been around 90 lately, so I will add (170-120)/90 = 0.55 units of Novolog.
My total Novolog dose is 7.06 + 0.55 = 7.61 units. My syringe can deliver only multiples of 0.5 units, so I will take 7.5 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units.)
I took this dose at 12:50 PM.
Mid Afternoon:
CGM reading around 200
Dinnertime Novolog Dose
Time: 5:45 PM. Typically, my Carbohydrate Ratio (CR) at this hour is 7 grams of carbodydrates per unit of insulin. I plan to have a dinner comprising 68 grams of carbohydrates (based on food package labels). Thus I should take 68/7 = 9.71 units of Novolog.
My CGM reading was 170 (mg/dL), which is higher than my evening target of 150 mg/dL. I will therefore take a small amount of additional Novolog with the aim of reducing that 170 to 150. My insulin sensitivity factor (ISF) has been around 94 lately, so I will add (170-150) / 94 = 0.21 units of Novolog.
My total Novolog dose is 9.71 + 0.21 = 9.92 units. My syringe can deliver only multiples of 0.5 units, so I will take 9.5 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units, because I prefer to err on the side of a higher rather than lower blood glucose and CGM reading.)
I took this dose at 5:50 PM.
My sensor expired and so I replaced it around 8 PM. The new one requires a two hour warm up period. After those two hours, I used a finger-stick test and learned that my blood glucose was 215 MPC. Although the CGM read ‘162’ when it emerged from the warmup period, I used its calibration feature to set it the CGM reading to 215.
At 8:30 PM I felt hunger pangs that might indicate lower blood glucose, but I did not have use of my CGM. Nevertheless I consumed about 8 grams of carbohydrate in the form of a small helping of popcorn and an ounce of Bailey’s Irish Cream.
Bedtime Novolog Dose:
Time: 10:23 PM. I will use 7.6 and and 98 as the respective CR and ISF. Why? Because my previous estimates, CR=7 and ISF=84 were too low. My actual CGM reading (215) is lower than the predicted CGM reading (297) given the insulin dose (9.5) and the consumed grams of carbohydrate (68+8=76): 76/9.5 = 8. I have nudged both the CR and ISF upward a bit based on looking back at the effectiveness of the most recent insulin dose.
I will not consume any carbohydrates, so there is no insulin dose needed to compensate for carbohydrates.
My CGM reading is 215, which is higher than my overnight target level of 150. Therefore I will take a small dose of Novolog to attempt to bring my CGM reading down from 215 to 150. My ISF is about 90, so my calculated dose is (215 – 150) / 90 = 0.66 Units. My syringe can deliver only multiples of 0.5 units, so I will take 0.5 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units.)
November 2, 2020
I stayed “on plan” this day both by adjusting insulin doses and by consuming additional carbohydrates (i.e., snacking).
Morning Lantus dose:
Overnight my (continuous glucose) meter (CGM) readings ranged from 215 at 10 PM to 300 around 2 AM, and then back to 200 at 6:15 AM. Perhaps the wider range is characteristic of a newly installed sensor. The CGM readings were flat during the last 3-4 hours, so I will again take 12 units of Lantus (my 24-hour insulin).
Morning Novolog Dose:
Typically, my Carbohydrate Ratio (CR) in the morning housrs is 6.5 grams of carbodydrates per unit of insulin. I plan to have a breakfast comprising 45 grams of carbohydrates (based on food package labels). Thus I should take 45/6.5 = 6.92 units of Novolog.
My CGM reading was 200 mg/dL, significantly higher than my target of 120 mg/dL, so I will take a small amount of additional Novolog with the aim of reducing that 200 to 120. My insulin sensitivity factor (ISF) has been around 90 lately, so I will add (200-120)/90 = 0.89 units of Novolog.
My total Novolog dose is 6.92 + 0.89 = 7.81 units. My syringe can deliver only multiples of 0.5 units, so I will take 7.5 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units.)
I took this dose at 6:40 AM.
Apparently overnight my ISF was not 90, but something lower. Given the wanderings of the CGM I’ll postpone re-estimating ISF.
Mid-morning:
At 9:48 AM my CGM reading was 103. That is already lower than my target, plus I’ve only used about 5.15 units of the 7.5. (A dose is typically active over a course of 5 hours, but it has only been 3 hours.)
The remaining 2.35 units could drive my blood glucose down below 60, so I will consume another snack – a banana comprising 20 grams of carbohydrate.
My initial CR and ISF estimates were too low; the insulin was more effective than initially guessed, so I must again nudge those estimates upward. I’ll use CR=7.5 and ISF=95 for the next Novolog dose.
Noon Novolog Dose
Time: 12:15 PM. I’ll use the above CR and ISF. I plan to have a lunch comprising 53 grams of carbohydrates (based on food package labels). Thus I should take 53/7.5 = 7.06 units of Novolog.
My CGM reading was 188 (milligram%/liter), significantly higher than my target, which is 120 mg/dL. I will take a small amount of additional Novolog with the aim of reducing that 188 to 120. Using ISF = 95 I will add (188-120)/95 = 0.69 units of Novolog.
My total Novolog dose is 7.06 + 0.69 = 7.75 units. My syringe can deliver only multiples of 0.5 units. So I will take 7.5 units of Novolog.
I took this dose at 12:20 PM.
Mid Afternoon
CGM reading was 80 at 3 PM. Accordingly I had a snack of about 8 grams of carbohydrate (popcorn).
Dinnertime Novolog Dose
Time: 5:45 PM. Typically, my Carbohydrate Ratio (CR) at this hour is 7 grams of carbodydrates per unit of insulin. However, my 3 PM CGM reading of only 80 suggests that the CR=7 is too low, so I’ll use CR=7.5 and ISF = 95..I plan to have a dinner comprising 68 grams of carbohydrates (based on food package labels). Thus I should take 68/7.5 = 9.07 units of Novolog.
My 5:45 PM CGM reading was 220 mg/dL, higher than my evening target of 150 mg/dL. I will therefore take a small amount of additional Novolog with the aim of reducing that 220 to 150. I will add (220-150) / 95 = 0.74 units of Novolog.
My total Novolog dose is 9.07 + 0.74 = 9.81 units. My syringe can deliver only multiples of 0.5 units, so I will take 9.5 units of Novolog.
I took this dose at 5:50 PM.
Bedtime Novolog Dose:
Time: 10:12 PM. I will use 7.5 and and 95 as the respective CR and ISF. Why? Because my actual CGM reading (193) closely matches the predicted CGM reading (196) given the insulin dose (9.5) and the consumed grams of carbohydrate (68): I have consumed only 8.68 units of the 9.5 taken at 5:45. 68/8.68 = 7.8. The remaining units (0.82) will bring me perhaps to 120.
I will not consume any additional carbohydrates, so there is no insulin dose needed to compensate for carbohydrates.
My CGM reading is 193, which is higher than my overnight target level of 150. I expect it to go lower with the remaining 0.82 units of Novolog still in my body.
Therefore I will not take additional Novolog. Instead, I will set a bottle of Stonyfield Smoothie® by my beside, in case my CGM readings go still lower than 120.
Update 11:00 PM, CGM now at 246. Sorry, but it didn’t go down like I hoped. I will lower my CR and ISF estimates because I missed the 150 target. I did not ‘cheat’ with extra snacks, by the way. Instead of 7.5 and 95, I will use 6.95 and 91.4. (I will explain later the basis of these estimates.)
Therefore I will take a small dose of Novolog after all, to attempt to bring my CGM reading down from 246 to 150. My ISF is 91.4, so my calculated dose is (246 – 150) / 91.4 = 1.05 Units. Since my syringe can deliver only multiples of 0.5 units, I will take 1 unit of Novolog.
Although the Dexcom G6 system claims not to need finger-stick blood test calibrations twice per day, as did its predecessor G5 system, I try to do a calibration once per day. Tonight the meter reads 212, and the finger stick test reads 231. This is close, but it may drift further with additional time.
November 3, 2020
Today my initial CGM reading was surprisingly high. I treated this with higher Lantus and Novolog doses throughout the day in an effort to get back on the plan
Morning Novolog and Lantus Dose:
Overnight my CGM only decreased to 200 MPC, whereas I had hoped it would decrease to 150 MPC. This means that my ISF was effectively around 40, versus near 90. This also means that I should lower both my CR and ISF for dose calculations. I will try CR= 6 and ISF=75.
Overnight my CGM readings increased from 200 up to 304. This is a larger increase than I want, so I will increase my Lantus dose to 13 units.
I plan to consume 45 grams of carbohydrates for breakfast. Therefore, my Novolog dose will be 45/6 = 7.5 units.
My CGM reading of 304 mg/dL is significantly higher than my target of 120 mg/dL. I will take an additional amount of Novolog with the aim of reducing that 304 to 120. Based on my reduced insulin sensitivity factor (ISF) estimate, I will add (304-120)/75 = 2.45 units of Novolog.
My total Novolog dose is 7.5 + 2.45 = 9.95 units. Since my syringe can deliver only multiples of 0.5 units, I will take 9.5 units of Novolog and hope for better. (Perhaps I should round upwards, because 9.95 is so close to 10.)
I took this dose (9.5 units) at 7:08 AM.
Mid-morning:
At 10:15 AM my CGM reading was 367. Why? The insulin seems to have had no effect. Did I actually take it or not? I double-checked by syringe’s top end dial, which shows that I did take 9.5 units, alright. But it’s like I didn’t take any at all.
I will try to estimate my new CR and ISF, based on using 6.78 units out of that 9.5 unit dose. In the calculations, I see that the 367 reading is not far from the predicted reading.
The new estimates are CR=5.9 and ISF=74. (Yes, I will explain the calculation at some point.) This informs me that the rise is to be expected before things (hopefully) head back down. I will not inject any insulin and will wait until noon-time instead.
The remaining 2.72 units could drive my blood glucose down to 367 – (2.72 * 74) = 165.
Contrast this with my observation from yesterday – too-low CR and ISF estimates, to be nudged upward. The take-home lesson is that these ratios vary! It is my hope that “staying on top of them” is better than sticking to single CR and ISF values (for dose calculations) over time. By “staying on top of them”, I mean that I use hindsight to calculate them in order to calculate the next dose.
I observe that the CR and ISF effective values are lower when the CGM readings are higher. Perhaps with good data some non-linear function could be estimated, or, neural network could be trained, to take this non-linearity into account.
Noon Novolog Dose
Time: 12:00 PM. CGM reading is 278. Based on 9.5 units of insulin, 45 grams of carbohydrate, the predicted CGM reading was 157, close to the hoped-for above 165, but these did not happen. The calculated CR was 4.97 and the calculated ISF was 67.9. I’ll use 5.5 and 70, expecting that these may increase from the morning into the afternoon.
I plan to have a lunch comprising 53 grams of carbohydrates (based on food package labels). Thus I should take 53/5.5 = 9.64 units of Novolog.
My CGM reading was 278 (milligram%/liter), significantly higher than my target 120 mg/dL, so I will take an additional amount Novolog with the aim of reducing that 278 to 120. My insulin sensitivity factor (ISF) is 70, so I will add (278-120)/70 = 2.26 units of Novolog.
My total Novolog dose is 9.64 + 2.26 = 11.9 units. My syringe can deliver only multiples of 0.5 units, so I will take 11.5 units of Novolog.
I took this dose at 12:000 PM.
I will wait until about 12:25 PM to begin eating, in order to reduce the CGM reading further and hopefully enhance my ISF.
Mid Afternoon
CGM reading was 103 at 3 PM. Accordingly I had a snack of about 8 grams of carbohydrate (popcorn).
Dinnertime Novolog Dose
Time: 5:05 PM. My CGM reading is 170, after above-mentioned popcorn snack. New estimates for CR and ISF are 6.3 and 76. .I plan to have a dinner comprising 69 grams of carbohydrates (based on food package labels). Thus I should take 69/6.3 = 10.95 units of Novolog.
My CGM reading was 170 (milligram%/liter), higher than my evening target of 150 mg/dL, so I will take a small amount of additional Novolog with the aim of reducing that 170 to 150. mg/dL. I will add (170-150) / 76 = 0.26 units of Novolog.
My total Novolog dose is 10.95 + 0.26 = 11.21 units. My syringe can deliver only multiples of 0.5 units, so I will take 11 units of Novolog. (I almost always round downwards to the nearest multiple of 0.5 units.)
I took this dose at 5:15 PM.
Bedtime Novolog Dose:
Time: 9:50 PM. I will use 6.7 and and 78 as the respective CR and ISF. Why? Because my actual CGM reading (103) at 0 PM is lower than predicted based on consuming 9.84 units of Novolog. The remaining units (1.16) will bring me still lower.
I will consume additional grams of carbohydrate to avoid going too low.
Also, I will set a bottle of orange juice by my bedside in the case that my CGM readings go still lower than 120.
November 4
Today my initial CGM reading was satisfyingly low. However it rose quite unexpectedly during the morning. I used a lower carbohydrate ratio and insulin sensitivity factor during the rest of the day. This was a day of a surprising fall off of the plan and then getting back on with revised parameters.
Morning Novolog and Lantus Dose:
My CGM reading is 109. It stayed flat during the night, but did drift downward. Therefore I will decrease my Lantus dose to 12.5 units.
I will use CR=6 and ISF=75 based on yesterday’s calculations. I plan to consume 45 grams of carbohydrates at breakfast, so I will take 45/6 = 7.5 units of Novolog. I will add (109-120)/75 = -0.04 units. (Really, this is a subtraction.)
The total dose is 7.5 – 0.04 = 7.46. I round this down to 7, but wonder if it should be 7.5.
Mid-morning:
At 10 my CGM reading is 380. This is a surprise. It effectively means that my CR and ISF estimates were too high. They should have been something like 4.4 and 63.
Hopefully the insulin still on board will reduce this level.
Noon Novolog Dose
My CGM reading is still around 380. It did not decrease noticeably despite the unused insulin on board. It is as if my body did not respond much to the insulin dose. This does happen from time to time, and I have not been able to predict such occasions, except in times of high stress or illness.
I will hope that my CR can be 5.5 for the afternoon, up from the 4.4 of the morning. Likewise, I will hope for ISF=70.
I plan to have a lunch comprising 53 grams of carbohydrates (based on food package labels). Thus I should take 53/5.5 = 9.64 units of Novolog.
My CGM reading was 380 (milligram%/liter), significantly higher than my target of 120 mg/dL, so I will take an additional amount Novolog with the aim of reducing that 380 to 120. I hope that my insulin sensitivity factor (ISF) is 70, so I will add (380-120)/70 = 3.71 units of Novolog.
My total Novolog dose is 9.64 + 3.71 = 13.35 units. My syringe can deliver only multiples of 0.5 units, so I will take 13 units of Novolog.
I took this dose at 12:000 PM.
I will wait until about 12:25 to begin eating, in order to reduce the CGM reading further and hopefully enhance my ISF.
Mid Afternoon
CGM reading 220 at 2 PM. Hopefully will head lower
Dinnertime Novolog Dose
CGM reading 167 at 5 PM;
this is as expected per the CR=5.5 and ISF=70 values. I will use these for calculting the Novolog dose.
Novolog dose: I plan to consume 54 grams of carbohydrates, so I will take 54/5.5 = 9.8 units.
My CGM reading is 167, slightly above the evening target, 150. Therefore, I will add (167-150)/70 = 0.24 units.
The total Novolog dose is 9.8 + 0.24 = 10.04 units. I will take 10 units.
Bedtime Novolog Dose:
At 7 PM the CGM reading was 80, so I consumed 3 gm (popcorn) + 6 gm (orange juice) = 9 grams carbohydrate.
At 9:11 PM the CGM reading was 171, falling slightly. I re-estimate the CR and ISF as 6.8 and 78, based on the now-higher insulin effectiveness. At this time, 9.19 units of the Novolog has been consumed, based on a 5-hour activity period for Novolog [3].
At 10 PM, 5 hours after the last Novolog dose the CGM reading is 242. This is higher than the target value, 150. Accordingly, I will take (242-150)/78 = 1.17 units of Novolog to bring the CGM level to 150,.
November 5
Morning Lantus Dose
Overnight my (continuous glucose) meter (CGM) readings ranged from 240 at 10 PM, down to 90 at 3 AM. After 3 AM there was no change. I had taken 1 unit of Novolog, so the apparent insulin sensitivity factor (ISF) is (240-90)/1 = 150. I do not believe that I can apply this value during the day, however. Although the CGM reading was ‘flat’ after 3 AM, I will retain my Lantus at 12.5, hoping to avoid too-low readings overnight.
Morning Novolog Dose
I will use CR=6 and ISF=90. (Higher ISF based on discounted overnight apparent ISF=150.) I plan to consume 45 grams of carbohydrates at breakfast, so I will take 45/6 = 7.5 units of Novolog. I will add (169-120)/75 = 0.65 units.
The total dose is 7.5 + 0.65 = 8.15 I round this down to 8.
Noon Novolog Dose
Dinnertime Novolog Dose
Bedtime Novolog Dose