GDM: Postpartum Care (2008)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To examine patterns of postpartum physical activity among women with recent gestational diabetes mellitus (GDM) and psychosocial factors related to this behavior that could be addressed in diabetes prevention interventions.
Inclusion Criteria:
  • Women diagnosed with GDM who attended the diabetes in pregnancy clinics at one of four public hospitals in Western Sydney for GDM management (Diagnosis based on 75-g glucose tolerance test, for which the fasting blood glucose level was > 5.5 mmol/l or a 2-h level > 8.0 mmol/l)
  • 6–24 months postpartum 
  • able to speak English
Exclusion Criteria:
  • Gave birth in past 6 months (rationale: limitations caused by the postpartum recovery, particularly for those undergoing cesarean deliveries, and early adjustment to parenting would have created additional temporary barriers to physical activity)
Description of Study Protocol:

Recruitment

Random sample from 4 GDM clinics in Sydney; women recruited by mailed invitation and up to 10 follow-up calls

Design

Cross-sectional phone survey completed in ~20 minutes

Blinding used (if applicable):  Not applicable

Intervention (if applicable):  Not applicable

Statistical Analysis

  • Physical Activity metric - duration of walking, moderate, and vigorous intensity activity was converted to MET minutes by multiplying the reported minutes by MET values representing energy expenditure relative to the resting state: 3.3 MET for walking, 4 MET for moderate-intensity activity, and 8 MET for vigorous-intensity activity.
  • Physical activity was classified into three levels:
    • sufficient,  > 600 MET min and > 5 sessions of activity or reporting the recommended minimum or five 30-min sessions of moderate-intensity activity or three 20-min sessions of vigorous-intensity activity
    • low, > 100 MET min but not meeting the criteria for sufficient activity
    • sedentary, <100 MET min of activity.
  • The proportions of women in each category were calculated with 95% CIs, applying a finite population correction factor to take into account the limited size of the study population.

To explore the relative amount of time spent in walking and moderate- and vigorous-intensity activity median MET minutes were calculated, because the physical activity data were not normally distributed. The median test was used to test the differences in medians between subgroups of respondents.

Multiple logistic regression modeling, using the enter method, was used to identify variables that were independently associated with sedentariness and sufficient activity. The independent variables in the models included age (<35 or >35 years), language spoken at home (English or other), educational attainment (university level or lower), number of children (>2 or 1), and BMI (<25 or > 25 kg/m2). The scales for self-efficacy and social support were dichotomized using a median split and included in the models, together with perceived barriers, categorized as >3 or <3 reported barriers.

Data Collection Summary:

Timing of Measurements

 6-24 months postpartum via 20-minute phone interview

Dependent Variables

  • Physical activity - Active Australia Questionnaire - # times walking for 10 min or more and moderate and vigorous activities in the past week time spent doing each activity; converted to METS 

Independent Variables

  • Self-efficacy for physical activity -  participants rated level of confidence (very confident to not at all confident) to undertake physical activity in five situations: feeling tired, being in a bad mood, having limited time, being on holidays, and feeling like it takes too much effort.
  • Social support for physical activity  -asked to report how often family or friends supported them by exercising with them, giving encouragement to keep exercising, looking after the children so they could exercise, and doing household chores so they could exercise.

  • Barriers to physical activity -  respondents rated their level of agreement (strongly agree to strongly disagree) with five statements concerning physical activity: regular exercise would take too much of my time; I would find it difficult to find an exercise activity that I enjoy; I would be too tired for my daily tasks if I exercised; I don’t exercise as much as I would like because of poor public facilities around where I live; and I don’t exercise as much as I would like because I can’t get enough help with child care. In addition to these, they were asked to rate their agreement with the statement: I do not know what type of exercise will reduce my risk of type 2 diabetes.  

Control Variables 

  • number of children
  • living arrangements (with spouse, parents, or others)
  • hours per week of paid work
  • educational attainment
  • language spoken at home
  • self-reported height and weight
  • completion of postpartum glucose testing

 

Description of Actual Data Sample:

Initial N: 392/625 (63%) of letters mailed resulted in a contact; 65 women ineligible

Attrition (final N):  244 of 327 eligible women completed survey

Age: mean (SD)= 33.4 (5.2)

Ethnicity: Australian; 38.5% spoke language other than English, most commonly reported was Arabic, Turkish, Hindi, Tamil, Chinese

Other relevant demographics: 22.2% overweight (BMI 25-29.9); 29.1% obese (BMI>=30)

Anthropometrics:

Location:  Australia

Summary of Results:

Table 1— Prevalence of sedentariness, low physical activity, and sufficient physical activity

  Sedentary Low activity Sufficient activity

All 26.1 (±2.4) 39.4 (±2.7) 33.2 (±2.6)
Age      
    <35 years 24.8 (±3.0) 40.4 (±3.4) 34.8 (±3.3)
    >35 years 28.8 (±4.2) 38.8 (±4.6) 32.5 (±4.3)
Language spoken      
    English 21.9 (±2.9) 40.1 (±3.5) 38.0 (±3.4)
    Other 33.7 (±4.2) 39.5 (±4.4) 26.7 (±4.0)
Children      
    1 child 26.6 (±3.8) 40.4 (±4.2) 33.0 (±4.0)
    >2 children 26.4 (±3.2) 39.5 (±3.6) 34.1 (±3.5)
Educational attainment      
    Senior high school or lower 29.4 (±3.2) 35.7 (±3.3) 35.0 (±3.3)
    University 21.3 (±3.8) 47.5 (±4.7) 31.3 (±4.3)
BMI      
    Healthy weight 27.9 (±3.6) 39.4 (±4.0) 32.7 (±3.8)
    Overweight/obese 24.8 (±3.4) 40.4 (±3.9) 34.9 (±3.8

Data are % (95% CI).

Other Findings

  •  Walking was most common type of physical activity reported; median 208 MET minutes reported (63 min/wk)
  • Situations in which women most often reported feeling "very confident" or "confident" to undertake physical activity, measuring self-efficacy, was:
    •  on holidays (67.8%)
    • in a bad mood (45.9%)
    • felt that it required a lot of effort (35.9%)
    • felt tired (22.6%)
    • lacked time (16.6%).
  • Social support
    • verbal encouragement (39.1%)
    • assistance with child care (32%)
    • help with household chores (21.3%)
    • being accompanied during physical activity (20.5%).
  • More than half of the women reported never receiving support through assistance with housework or others exercising with them.
  • Barriers to physical activity
    •  lack of child care (49.1%)
    • lack of time (37.6%)
    • unsuitable local neighborhood (25.4%)
    • lack of enjoyment of physical activity (25.3%)
    • feeling tired (24.9%) to be barriers.
  • (48.9%) of the women did not know the type of physical activity that would be beneficial for diabetes prevention.
  • Predictors of lack of sedentariness:
    • university education (.43 (95% CI 0.26-0.96))
    • high self-efficacy (.31 (0.21-0.71)
  • Sufficient physical activity was independently associated with high self-efficacy (2.09 [1.06–3.20]) and high social support (2.5 [1.21–3.79]).
Author Conclusion:
The findings demonstrate a need to promote physical activity in the postpartum period among women who have had recent GDM. Just over one-fourth of the women reported the equivalent of <30 min of walking per week, whereas more than two-thirds did not attain the recommended amount of total activity that would reduce their risk of developing type 2 diabetes.
Funding Source:
University/Hospital: University of Sydney, Westmead Hospital (Aus.)
Reviewer Comments:

-adapted measures from work of other researchers and reported reliability

-statistical methods a bit unclear (i.e.'enter' method is for logistic regression)

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? 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? ???
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.) 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? 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? 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.) N/A
  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? Yes
  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? N/A
  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? Yes
  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? N/A
  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? 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)? 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? 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