Wellness iNPractice Diabetes

SMBG and Glucose Pattern Analysis

Glucose pattern analysis is a systematic approach to identifying patterns within self-monitoring of blood glucose (SMBG) data, determining their relationship to patient behaviors, and then taking appropriate action to help improve glycemic control.1 Structured glucose pattern analysis has been helpful for improving A1C over time compared to conventional SMBG testing.2

Any patient with diabetes has the potential to benefit from better blood glucose control based on the information revealed by glucose pattern analysis, but patients must be able and willing to participate in pattern analysis for it to be effective. They must:

  • Be capable of performing regular and frequent SMBG or be capable of using continuous glucose monitoring (CGM)
  • Have an understanding of how glucose patterns can be affected by specific behaviors or other factors (e.g., stress, sleep)
  • Be willing to work with their provider to discuss the results and determine how to alter behaviors or medications to correct abnormalities identified in their blood glucose pattern analysis1  

Five Steps to Glucose Pattern Analysis3

Step 1: Establish pre- and postprandial glucose target ranges

Current treatment guidelines for diabetes provide a range of target glucose levels, which means that you need to determine pre- and postprandial targets for each patient based on their specific needs and goals.

Blood Glucose Goals for Nonpregnant Adults with Diabetes4

Preprandial capillary blood glucose 80-130 mg/dL (4.4-7.2 mmol/L)a
Peak postprandial capillary blood glucoseb <180 mg/dL (<10.0 mmol/L)a

a More or less stringent glycemic goals may be appropriate for individual patients. Goals should be individualized based on duration of diabetes, age/life expectancy, comorbid conditions, known cardiovascular disease or advanced microvascular complications, hypoglycemia unawareness, and individual patient considerations.

b Postprandial glucose may be targeted if A1C goals are not met despite reaching preprandial glucose goals. Postprandial glucose measurements should be made 1-2 h after the beginning of the meal, when insulin levels generally peak in patients with diabetes.

Step 2: Patients collect data on glucose levels and self-care activities

SMBG data collected over at least 3 days for up to 7 days is used for blood glucose pattern analysis.3 Current American Diabetes Association (ADA) guidelines recommend that patients who are on multiple daily insulin injections or insulin pump therapy perform SMBG prior to meals and snacks, postprandially, at bedtime, prior to exercise, when they suspect low blood glucose, after treating low blood glucose until they are normoglycemic, and prior to critical tasks such as driving.4

For patients who do SMBG less frequently, such as patients with type 2 diabetes who are not taking an intensive regimen, or for whom cost is an issue, 7-point SMBG can be performed for 3-7 days or SMBG can be taken at different times of day for a period of 3 weeks.5 For example, pre- and post-breakfast SMBG could be performed on Sunday and Wednesday, pre- and post-lunch SMBG on Monday and Thursday, pre- and post-dinner SMBG on Tuesday and Friday, and so on.

Seven-point SMBG5

Pre-breakfast

Post-breakfast

Pre-lunch

Post-lunch

Pre-dinner

Post-dinner

Bedtime

For glucose pattern analysis, several other types of information need to be collected by the patient during the same time as SMBG data is collected3:

  • Food intake – type, amount, timing for all meals and snacks, including alcohol
  • Physical activity – intensity, duration, time of day
  • Medications – type, dose, and timing (including glucose-lowering and any other medications, both prescription and over-the-counter)
  • Stressors – illness, life events causing emotional stress, work stress, etc.

Data collection can be done manually, with the patient completing a paper-based or digital diary or log book that can be brought to each visit.6

Newer blood glucose meters have data storage functionality and can be linked to web-based or mobile apps to upload data for analysis in conjunction with patient-reported food intake, physical activity, medications, and other factors.1 Continuous blood glucose monitors also store data that can be uploaded and used for glucose pattern analysis.6

Step 3: Data analysis

Confirm the data are complete, sufficient, and accurate. Analyze data to identify any glycemic excursions and results that are above or below the patient’s pre- and postprandial glucose targets that were established in Step 1. Are there any inconsistencies in behaviors or in the patient’s daily schedule with regard to food intake, physical activity, medications, or stress that coincide with these abnormal results? Are there trends in the data or are glucose fluctuations isolated events? Engage the patient in the analysis of the data they have collected. Patients should be encouraged to identify patterns and outliers and consider what might have caused them. This approach can be used as a teaching tool with patients. There are several points where discussion can take place regarding the impact of diet and exercise on glucose levels and the role of medications in helping them reach their glycemic goals.

Example of a Patient Logbook for Glucose Pattern Analysis
(1 week of 7-point SMBG)

Breakfast Lunch Dinner Bedtime Activity Level Meals and Snacks Medicines Other Notes
Pre Post Pre Post Pre Post
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday

Factors That Can Affect Blood Glucose

Raise blood glucose Lower blood glucose
  • Insufficient dose of glucose-lowering medication
  • Increased carb intake
  • Decreased intensity or amount of physical activity
  • Stress
  • Medications (e.g., corticosteroids, estrogen, diuretics, nicotinic acid, thyroxine)
  • Excessive dose of glucose-lowering medication
  • Low carb intake
  • Increased intensity or amount of physical activity
  • Stress
  • Alcohol
  • Medications (e.g., MAOIs, NSAIDs, salicylates, verapamil)
MAOI=monoamine oxidase inhibitors; NSAID=nonsteroidal anti-inflammatory drug.

Step 4: Develop appropriate therapeutic, educational, or behavioral changes

This step should also be done in close collaboration with the patient. Discuss any changes that might need to be made to food intake (e.g., limiting carbs) or physical activity (e.g., timing exercise with insulin injection), medication regimen (e.g., matching insulin dose to carb intake), or other factors (e.g., correcting problems with blood glucose testing technique, implementing stress management) to meet glycemic goals. It is always helpful to start small and set goals that can be achieved. Don’t make the mistake of trying to fix everything all at once. If the glycemic patterns continue despite these changes, then an adjustment of the insulin regimen might be necessary.3

In contrast to the approach of immediately altering the insulin dose to compensate for an abnormal blood glucose test result, glucose pattern analysis informs changes to the insulin regimen by revealing problems with the efficacy of insulin taken in the past. For example, blood glucose readings taken before bedtime reflect the action of the short-acting insulin dose that was taken before dinner. If the glucose pattern analysis reveals that bedtime glucose levels are consistently higher than the target range, then an increase in the pre-dinner short-acting insulin dose might need to be considered.3 Similarly, if the pre-lunch blood glucose levels are consistently higher than normal, then the pre-breakfast short-acting insulin dose may need to be adjusted. Glucose pattern analysis requires an understanding of when each type of insulin—basal vs. rapid-acting insulin—taken at different times of day is having its effect.

Pattern analysis of the postprandial glucose reading, combined with patient-recorded information about meals, can be used to help better match the mealtime insulin dose to carbohydrate intake.3

Adjustment of insulin levels based on glucose pattern analysis should start with assessment of mealtime insulin (based on postprandial glucose patterns) and then basal insulin (based on preprandial glucose patterns).

Engaging patients in glucose pattern analysis can help them better understand the importance of monitoring glucose, that many factors can affect blood glucose control, and that many of these factors are modifiable and can be changed in a rational way in response to the data they have collected.1

Step 5: Perform ongoing SMBG to assess the impact of any therapeutic changes

After any change in therapy, patients should continue to collect SMBG data to determine whether the changes they have implemented are making a difference. Over time and multiple iterations, patients will be able to analyze their own blood glucose patterns, identify potential causal factors, and come up with appropriate ways to address abnormal glucose test results.

References

  1. Parkin CG, Davidson JA. Value of self-monitoring blood glucose pattern analysis in improving diabetes outcomes. J Diabetes Sci Technol. 2009;3:500-508.
  2. Polonsky WH, Fisher L, Schikman CH, et al. Structured self-monitoring of blood glucose significantly reduces A1C levels in poorly controlled, noninsulin-treated type 2 diabetes: results from the Structured Testing Program study. Diabetes Care. 2011;34:262-267.
  3. Pearson J, Bergenstal R. Fine-tuning control: pattern management versus supplementation: view 1: pattern management: an essential component of effective insulin management. Diabetes Spectrum. 2001;14:75–78.
  4. American Diabetes Association. Standards of Medical Care in Diabetes. Diabetes Care. 2017;40(Suppl 1):S1-S135.
  5. International Diabetes Federation Clinical Guidelines Taskforce, SMBG International Working Group. Self-Monitoring of Blood Glucose in Non-Insulin-Treated Type 2 Diabetes. 2009. https://www.idf.org/guidelines/self-monitoring. Accessed September 16, 2015.
  6. Klonoff DC. Improved outcomes from diabetes monitoring: the benefits of better adherence, therapy adjustments, patient education, and telemedicine support. J Diabetes Sci Technol. 2012;6:486-490.