DM: Blood Glucose Self-Monitoring (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
The purpose of this study was to evaluate the impact of self-monitoring of blood glucose (SMBG) on the metabolic control in people with non-insulin-treated type 2 diabetes over a 3 year period.
Inclusion Criteria:
  • Type 2 diabetes
  • Exclusion Criteria:
  • None described
  • 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 family support for SMBG practices.
    • Medical history and diabetes-specific data was collected from the subject's physician.

    Blinding used

    • Not applicable

     Intervention

    • None

     Statistical Analysis

    • Multi-level models (three-level random intercept models) were used to investigate whether SMBG frequency was an independent predictor of A1C during the 3 years of the study.
    • Patient subgroups were identified using the recursive partitioning and amalgamation (RECPAM) method.
    • Multi-level logistic regression model was used to determine if SMBG was an independent predictor of a reduction in the frequency of hypoglycemic reactions.
    Data Collection Summary:

    Timing of Measurements

    •  Questionaire completed at entry into study and every 6 months

    Dependent Variables

    • A1C; the normal ranges varied among the different clinics so percentage of change was analysed using a mathematical formula.
    • Hypoglycemia events.

    Independent Variables

    •  SMBG frequency through self-administered questionnaire with demonstrated reliability

    Control Variables

    • Gender
    • Age
    • Living alone
    • Years of school education
    • Household income
    • 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)
    • Diabetes treatment at baseline
    • Frequency of SMBG
    • Regular access to physicians
    • Setting of care

     

     

     

    Description of Actual Data Sample:

    Initial N: 2661 subjects recruited

    Attrition (final N):  1896 provided info regarding SMBG frequency (57% male)

    Age: 62.4 ± 10.0 years

    Ethnicity: not mentioned

    Other relevant demographics:

    Mean Duration of Diabetes:  9.1 ± 7.6 years

    Diabetes Treatments:  22% were diet treated only, 78% treated with oral agents

    Anthropometrics:  Respondents and non-respondents differed in terms of gender, age, mean diabetes duration, and setting of care.  They did not differ in terms of years of school education, BMI, HbA1c levels, treatment and TIBI score.

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

     

     

    Summary of Results:

     

    Baseline Data
     

    SMBG =/> 1 per day

    n = 195

    SMBG =/> 1 per week

    n = 578

    SMBG < 1 per week/never

    n = 1123

     

    P*

    A1C 7.3 ± 1.6 7.2 ± 1.6 7.0 ± 1.5 0.001

    Frequency of hypoglycemic symptoms (%)

    • =/> 1 per week
    • =/> 1 per month
    • < 1 per month/never

     

     

    6.5

    26.5

    67.0

     

     

     

    4.6

    18.0

    77.4

     

    4.1

    11.3

    84.6

     

    <0.0001

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

     Findings

    • Frequency of SMBG failed to show any significant change in A1C over the duration of the study (3 years).
    • Changes in SMBG frequency during the course of the study were not related to any significant changes in A1C.
    • No specific subgroup was identified for whom SMBG practice was associated with lower A1C.
    • SMBG was associated with decrease of frequency of hypoglycemic episodes during the study, although this decrease was not significant.

     

     

    Author Conclusion:

    Our data failed to document a clear, long-term benefit of SMBG on metabolic control in type 2 diabetes patients not treated with insulin.  SMBG should be prescribd only as a part of a comprehensive educational programme, aimed at the promotion of patient empowerment and self-management of diabetes.

    Funding Source:
    Reviewer Comments:
    Not all subjects who tested their blood glucose used a "glucometer."  Other methods of testing blood glucose were not described.   Final study data was not included in the paper, only the statistical results and narrative conclusions.
    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? 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? No
    3. Were study groups comparable? No
      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? No
      3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
      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? ???
      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? ???
      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? N/A
      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.) N/A
      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? ???
      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? Yes
      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? No
      6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? No
      6.6. Were extra or unplanned treatments described? No
      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? N/A
      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? 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? ???
      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? ???
      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)? No
      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? 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? 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