DM: Blood Glucose Self-Monitoring (2007)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
- To evaluate the extent of plasma/blood glucose excursions after meals;
- To explore the relations among plasma/blood glucose levels at different times of the day; and
- To examine the relations between HbA1c (A1C) and plasma/blood glucose levels at different times of the day in a large sample of persons with non-insulin treated type 2 diabetes.
Inclusion Criteria:
Outpatients at the Diabetes Clinic and Outpatients at Home:
- Type 2 diabetes
- Non-insulin treated
- No changes made in diet, treatment, or lifestyle with the 3 months before the study
- No concomitant chronic diseases
- No recent acute illness
- Willingness to return to the clinic five times in 1 day to measure plasma glucose
Inpatients:
- Type 2 diabetes patients admitted to the Division of Endocrinology and Metabolic Diseases because of poor metabolic control, screening or staging of chronic diabetes complications between years of 1987-2000
- No diabetes within the previous 6 months
- Admission in the morning after an overnight fast
- No change in diabetes treatment their first hospital day
- No insulin treatment before admission or for the first day hospital day
- No changes in diet, treatment, or lifestyle within 3 months before admission
- No concomitant chronic diseases or recent acute illnesses
Exclusion Criteria:
Outpatients at the Diabetes Clinic and Outpatients at Home:
- Diabetes diagnosed within the previous 6 months
Description of Study Protocol:
Recruitment
- Patients screened from those regularly attending the hospital diabetes clinic of Montecchio Maggiore
Design: Cross-Sectional Study
- Simultaneous measurement of plasma/blood glucose and A1C
- Patients were asked to eat their usual diet (isocaloric for inpatients) the day/days of the study
Blinding used (if applicable)
- Not applicable
Intervention (if applicable)
- Not applicable
Statistical Analysis
- Calculations of means, standard deviation, SEM, and simple correlation coefficients
- Analysis of variance, X2 tests, and multiple linear regression
Data Collection Summary:
Timing of Measurements
- Outpatients at diabetes clinic: On one day patients had drawn fasting, ~2 hours post-breakfast, pre-lunch, ~2 hours post-lunch, and pre-dinner plasma/blood glucose. A1C was drawn with first blood draw of the day.
- Outpatients at home: On 5 non-consecutive days subjects were to perform home blood glucose monitoring fasting, ~2 hours post-breakfast, pre-lunch, ~2 hours post-lunch, and pre-dinner, and ~2 hours post-dinner. A1C was drawn in the middle of the month.
- Inpatients: On one day patients had drawn fasting, pre-lunch, ~3 hours post-lunch, pre-dinner, and ~2 hour post-dinner plasma/blood glucose.
Dependent Variables
- A1C
Independent Variables
- Plasma/blood glucose; measured either with laboratory method of glucooxidase, or Euroflash Lifescan home glucose meters.
- A1C; measured with high preformance liquid chromatography (reference range was 3.5-5.5%).
Control Variables
- None
Description of Actual Data Sample:
Initial N: see table
Attrition (final N): n/a
Age: see table
Ethnicity: not mentioned
Other relevant demographics: see table
Anthropometrics: see table
Location: Verona, Italy
Outpatients at diabetes clinic | Outpatients at home | Inpatients | |
N (men/women) | 371 (211/160) | 30 | 455 (229/226) |
Mean age (years) | 60.3 ± 9.7 | 60.3 ± 10.3 | 58.9 ± 11.5 |
Duration of diabetes (years) | 7.8 ± 5.8 | 8.3 ± 7.3 | 8.0 ± 6.8 |
Body Mass Index (kg/m2) | 28.5 ± 4.38 | 28.6 ± 5.9 | 32.2 ± 8.23 |
Diet only treatment (% of subjects) | 7.9 | 20.7 | 12.2 |
Metformin only treatment (% of subjects) | 6.2 | 10.3 | 5.3 |
Sulfonylurea only treatment (% of subjects) | 58.3 | 27.6 | 49.7 |
Metformin and Sulfonylrurea treatment (% of subjects) | 27.6 | 41.4 | 32.8 |
Summary of Results:
Outpatients at diabetes clinic |
Outpatients at home |
Inpatients | |
A1C vs prebreakfast | 0.483* | 0.580* | 0.646* |
A1C vs postbreakfast |
0.445* |
0.568 |
no data |
A1C vs prelunch | 0.496* | 0.673* | 0.630* |
A1C vs postlunch | 0.477* | 0.580* | 0.550* |
A1C vs predinner | 0.491* | 0.674* | 0.620* |
A1C vs postdinner | no data | 0.495 | 0.528* |
A1C vs daily mean | 0.574* | 0.685* | 0.694* |
* P<0.001
Other Findings
- Multiple regression analysis showed premeal, but not postmeal plasma glucose to be independent predictors of A1C in both inpatients and outpatients.
Author Conclusion:
- Majority of these study subjects had higher-than-recommended plasma/blood glucose levels and/or exaggerated glucose excursions after meals.
- High postmeal glucose excursions were often found when A1C was less than 7%. For this reason the authors suggest self-monitoring of blood glucose (SMBG) at various times during the day, in addition to A1C measurements.
- Plasma/blood glucose levels thoughout the day were less interrelated as expected (data not shown in this review). Consequently, fasting glucose is poor indicator of glucose throughout the day.
- A1C was more related to premeal plasma/blood glucose than postmeal plasma/blood glucose.
Funding Source:
Reviewer Comments:
Good theoretical rationale for need of SMBG.
Quality Criteria Checklist: Primary Research
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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? | Yes | |
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? | Yes | |
2.2. | Were criteria applied equally to all study groups? | Yes | |
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? | Yes | |
3. | Were study groups comparable? | ??? | |
3.1. | Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) | ??? | |
3.2. | Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? | No | |
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? | ??? | |
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.) | ??? | |
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? | N/A | |
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? | N/A | |
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? | No | |
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.) | No | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | No | |
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? | 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? | N/A | |
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? | No | |
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? | 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)? | 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? | ??? | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | ??? | |