EAL

DM: Blood Glucose Self-Monitoring (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine, in children and adolescents with type 1 diabetes

if the continuous glucose monitoring system (CGMS) could be used to make clinical decisions
if CGMS has an inpact on glycemia (especially asymptomatic hypoglycemia)

Inclusion Criteria:

HbA_1c > 8.0% associated with one of the following:

elevated fasting blood glucose or suspected dawn phenomenon
glycemic excursion with exercise
insulin dosage > 1-1.5 units/kg/day for prepubertal and pubertal children respectively
widely fluctuating blood glucose levels
erratic response to blood glucose correction

HbA_1c < or = to 8.0% and recurrent hypoglycemia, hypoglycemia awareness, or suspected nocturnal hypoglycemia

Exclusion Criteria:

none given

Description of Study Protocol:

Recruitment

Recruitment during routine clinical visits to the Comprehensive Diabetes Center at Childrens Hospital Los Angeles during a 6-month period from the end of 1999 to the beginning of 2000

Design

Comparisons of numbers of high and low glucose patterns determined by CGMS and logbook in 47 adolescents with type 1 diabetes. Comparison of HbA_1c 4 times over 9 months.

Blinding used (if applicable): no

Intervention (if applicable)

Subjects were given recommended changes based on the CGMS, which included

change in one or more bolus or rapid-acting insulin dosage
change in one or more basal or intermediate/long-acting insulin dosage
change in the correction algorithm
alteration in the approach to exercise to include change in carbohydrate management
reinforcing treatment algorithm for hypoglycemia (rechecking, adding extra carbohydrate, and protein)
change in early morning basal rate (pump patients) or bedtime insulin dosage and/or timing (insulin patients or adding square-wave bolus (pump patients) for high-fat meals
increase in meal insulin dosage for high glycemic foods
referral for counseling to improve adherence with diabetes regimen.

Statistical Analysis

Descriptive statistical analysis for frequency of sensor findings, differences between information obtained from the CGMS and logbooks, and treatment recommendations
ANOVA was used to evaluate change in HbA_1c
Paired student's t test used to determine differences in HbA_1c before and after sensor placement

Data Collection Summary:

Timing of Measurements

Three days of CGMS plus logbook measures
HbA_1c at three months pre-baseline, baseline, three months and 6 months

Dependent Variables

CGMS using MiniMed (Sylmar, CA)
logbook (at least four SMBG measures as well as recorded meals, insulin doses, exercise periods, and symptomatic hypoglycemia)
HbA_1c by DCA 2000 (Bayer, Tarrytown, NY)

Independent Variables

duration of type 1 diabetes

Control Variables

insulin treatment (injections vs CSII)

Description of Actual Data Sample:

Initial N: 47 pediatric patients with type 1 diabetes (18 males, 29 females) agreed to participate

Attrition (final N): none reported

Age: 11.8±4.6 yrs (range 2.7-29.1)

Ethnicity: not reported

Other relevant demographics: duration of diabetes was 5.5±3.5 yrs (range 0.8-20)

Anthropometrics: not reported

Location: Comprehensive Diabetes Center at Childrens Hospital, Los Angeles

Summary of Results:

Variables	Subjects on CSII n = 23 means±SE	Subjects on 3-4 injections/day n= 24 means±SE	Statistical Significance of Group Difference*
HbA_1c, -3 mo (%)	8.5±1.6	8.9±1.6
HbA_1c, baseline (%)	8.4±1.7	8.8±1.4
HbA_1c, +3 mo (%)	8.2±1.3	8.5±1.3
HbA_1c, + 6 mo (%)	8.1±1.3	8.5±1.4

*For the whole group, at +three months, a significant difference was found in HbA1c vs baseline (P=0.03) and from -three months to +six months, the significance was P=0.04

Other Findings

In patients on injection therapy, 30 high/low glucose patterns were discerned with logbook records and 120 patterns with the CGMS; for patients on insulin pump therapy, 12 patterns with logbooks and 71 with CGMS.
Of the nine recommendations, the most common (70-85% of patients) was to make a change in one or more of the subject's basal insulin dosages for those on CSII and in one or more of the long- or intermediate-acting insulin doses for those taking injections. Non-insulin changes were made by 10-20 percent of subjects.
With CGMS, a mean of 1.17±1.3 asymptomatic nocturnal hypoglycemic events were noted per patient.

Author Conclusion:

The CGMS can be used by pediatric patients to detect abnormal patterns of glycemia, and this information can be used to alter the diabetes regimen and impact glycemic outcome

Funding Source:

Reviewer Comments:

Authors provided both insulin adjustment suggestions as well as non-insulin (food, exercise) adjustments, and attempted to determine adherence to the recommendations.
Because of confounding factors, improvement in HbA_1c can't be directly linked to instituting the recommendations that came from the CGMS

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		???
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	???
	2.2.	Were criteria applied equally to all study groups?	???
	2.3.	Were health, demographics, and other characteristics of subjects described?	???
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		???
	4.1.	Were follow-up methods described and the same for all groups?	N/A
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	N/A
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	???
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	Yes
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	N/A
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	???
	7.7.	Were the measurements conducted consistently across groups?	N/A
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	???
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	???
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes