EAL

DM: Blood Glucose Self-Monitoring (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To investigate the frequency of self-monitoring of blood glucose (SMBG) and its association with metabolic control and quality of life in subjects with type 2 diabetes.

Inclusion Criteria:

Type 2 diabetes

Exclusion Criteria:

None discussed

Description of Study Protocol:

Recruitment

Subjects were selected from those attending routine clinic visits using random lists, statified by patient age (<65 years and =/> 65 years). 101 outpatient clinics participated in this study and 103 general practitioners.

Design

Study subjects completed questionaires which asked about SMBG practices, diabetes complications, co-morbidities, and quality of life.
Medical history and diabetes-specific data were collected from the subject's physician.

Blinding used

Not applicable

Intervention

Not applicable

Statistical Analysis

Analysis performed based on a series of univariate comparisons.
X² test was used to detect association between patient characteristics and SMBG frequency.
X² Mantel-Haenszel test used for linear associations.
Kruskall-Wallis one way analysis of variance used for continuous variables.
Multilevel logistic regression was used.
Multilevel linear regression models were used.

Data Collection Summary:

Timing of Measurements

All data discussed in this paper refers to data collected at study entry.
Questionaires were completed at study entry.
Clinical variables were retrieved from medical records, no earlier than 12 months prior to study entry.

Dependent Variables

A1C; the normal ranges varied among the different clinics so percentage of change was analyzed using a mathematical formula.
Quality of Life

Independent Variables

SMBG frequency

Control Variables

Gender
Age
Living alone
Education
Body Mass Index
Duration of diabetes
Presence and severity of diabetes complications and co-morbidities as measured by use of the Total Illness Burden Index (TIBI)
Frequency of SMBG
Setting of care
A1C
Treatment of diabetes
Additional variables tested in insulin-treated patients: frequency of hypoglycemia, ability to adjust insulin doses, number of insulin injections per day.

Description of Actual Data Sample:

Initial N: 3,567 recruited

Attrition (final N): 2,968 completed the questionaire of which 2,855 had information about SMBG available. 49.8% males (>1/day), 56.5% male (>1/week), 53.4% male (<1/week), 57.2% male (never)

Age: 61.1 +/- 11.2 years (>1/day), 62.0 +/- 10.2 years (>1/week), 63.0 +/- 10.4 years (<1/week), 63.7 +/- 9.6 years (never)

Ethnicity: not mentioned

Other relevant demographics:

Anthropometrics:

Location: 101 outpatient diabetes clinics and 103 general practictioners from Italy

Summary of Results:

Frequency of SMBG according to patient characteristics (n=2,855)
	SMBG =/> 1 per day n = 471	SMBG =/> 1 per week n = 899	SMBG < 1 per week n = 414	SMBG never n = 1,071	P*
A1C	7.5 ± 1.8	7.4 ± 1.7	7.3 ± 1.6	7.0 ± 1.6	0.0001
Male (%)	49.8	56.5	53.4	57.2	0.04
Age in years	61.1 ± 11.2	62.0 ± 10.2	63.0 ± 10.4	63.7 ± 9.6	0.001
Education =/< 5 years (%)	57.1	52.0	49.3	45.3	0.001
Duration of diabetes (years)	12.7 ± 9.0	11.5 ± 8.7	10.7 ± 8.7	8.7 ± 7.6	0.001
Setting of care : diabetes clinic (%)	84.5	82.1	75.1	70.6	0.001
Frequency of hypoglycemic symptoms (%) =/> 1 per week =/> 1 per month < 1 per month-never	15.9 31.8 52.3	6.7 22.4 70.9	3.2 20.4 74.4	5.8 11.1 83.1	0.001
Treated with insulin	n=212	n=209	n=80	n=65	0.001

*P-values refer to X² for categorical variables and Kruskal-Wallis one-way analysis of variance for continuous ones.

Other Findings

A higher frequency of SMBG was associated with better metabolic control for subjects on insulin and who can adjust their own insulin doses; no association between frequency of SMBG and metabolic control was found in all other subjects.
Multivariate analyses showed that SMBG frequency =/> 1 time per day was significantly related to higher levels of distress, worries, and depressive symptoms in non-insulin treated subjects.

Author Conclusion:

In conclusion, our results suggest it seems prudent to recommend SMBG practice to people with type 2 diabetes who are able to use the information for their daily glycemic control to adjust insulin doses. We do not have evidence to support the extension in the use of this practice to the majority of type 2 diabetic patients.

Funding Source:

Reviewer Comments:

Not all subjects who tested their blood glucose used a "glucometer." Other methods of testing blood glucose were not described. Questionnaire was shown to be reliable and valid. Authors note that patients were classified on the basis of the reported average number of blood glucose measurements per day with no possibility of assessing the true frequency and scheduling of tests. Authors note that the diabetes clinics and GPs were selected based on their willingness to participate.

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)	N/A
	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)	N/A

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?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		Yes
	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?	Yes
	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.)	Yes
	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?		Yes
	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%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	Yes
	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?	Yes
	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?		N/A
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	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?	N/A
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	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?		???
	7.1.	Were primary and secondary endpoints described and relevant to the question?	???
	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?	N/A
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	???
	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?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
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?	???
	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?	???
	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)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	No
	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?	Yes
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