- Email: [email protected]
Original research: Postpartum testing rates among women with a history of gestational diabetes—Systematic review
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
Contents lists available at ScienceDirect
Primary Care Diabetes journal homepage: http://www.elsevier.com/locate/pcd
Review
Original research: Postpartum testing rates among women with a history of gestational diabetes—Systematic review Michael P. Carson a,∗ , Matthew I. Frank a,b,1 , Erin Keely c,2 a
UMDNJ-Robert Wood Johnson Medical School, Jersey Shore University Medical Center, Department of Medicine, Ackerman 3, 1945 Route 33, Neptune, NJ 07753, United States b 20 Harrison Street, Edison, NJ 08817, United States c Division of Endocrinology and Metabolism, Ottawa Hospital – Riverside Campus, Room 4-05, 1967 Riverside Drive, Ottawa, ON K1H 7W9, United States
a r t i c l e
i n f o
a b s t r a c t
Article history:
Aims: Gestational diabetes mellitus (GDM) is increasing and 30% have persistent postpartum
Received 21 November 2012
dysglycemia. Reported compliance with recommended postpartum testing ranges 9–95%
Received in revised form
without a clear explanation for this wide variation. Small and conflicting differences in
13 April 2013
testing rates are associated with some demographics (race, use of insulin), but system factors
Accepted 16 April 2013
likely play a larger role. A systematic literature review was performed to identify system
Available online 15 May 2013
based factors that could explain the broad variation in postpartum GDM testing rates. Methods: Original articles reporting postpartum testing rates among women with GDM were
Keywords:
identified within PubMed, OVID, EMBASE, and the Cochrane Database of systematic reviews.
Gestational diabetes mellitus
Articles that did not report rates for the entire GDM cohort were excluded.
Glucose intolerance
Results: 54/307 citations met inclusion criteria. The use of proactive patient contact programs
Postpartum testing
increased postpartum testing rates from an average of 33% (range 9–71%) up to 60% (range
Pregnancy
14–95%). Conclusions: Proactively contacting patients via phone calls, education programs, or postal reminders was associated with higher postpartum testing rates. Rather than working to identifying individual demographic factors, systems based approaches were associated with a larger potential impact, and appear easily generalizable. Clinicians should think beyond individual habits and consider systematic approaches to improving testing rates. © 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.
Contents 1. 2.
∗
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corresponding author. Tel.: +1 732 776 4826; fax: +1 732 776 3795. E-mail addresses: [email protected] (M.P. Carson), [email protected] (M.I. Frank), [email protected] (E. Keely). 1 Tel.: +1 732 776 4826. 2 Tel.: +1 613 738 8400x81941; fax: +1 613 738 8327. 1751-9918/$ – see front matter © 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pcd.2013.04.007
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2.1. Search strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Study selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Data abstraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Characteristics of the studies reviewed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Primary findings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Timeframe of testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Incidence table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conflict of interest statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.
Introduction
Women who develop gestational diabetes mellitus (GDM) during their pregnancy have a higher risk of developing overt diabetes mellitus and dysglycemia (impaired fasting glucose, impaired glucose tolerance, or prediabetes) later in life, compared to women without GDM. The prevalence of GDM increased from 2 to 4% in the United States, from 2.9% to 8.8% in Australia, and the number of pregnancies complicated by preexisting diabetes mellitus doubled from 10 to 21% [1–3]. Obesity, an obvious risk factor for diabetes mellitus and GDM, is also increasing [4]. Because the at-risk population is growing, and postpartum testing of women with GDM will identify the 20–30% with persistent dysglycemia, it is important that an efficient system be in place to identify women with early diabetes mellitus or pre-diabetes for whom evidence based interventions exist [5]. Reported rates of women who follow through with the recommended postpartum testing range from 9 to 95% [6–50]. A recent review summarized studies between 2008 and 2010 and, like similar reports, lists conflicting findings regarding the association between specific patient demographics and testing rates, such as Hispanic women being tested 2% more or 10% less than White women [22,27,51]. However, because the differences associated with individual demographics are modest, it seems possible that the large variation in screening rates is due to differences in health care delivery that affected the entire population within individual study cohorts. Understanding these differences can help providers design quality improvement initiatives. This systematic review regarding postpartum testing for women with GDM was designed to determine if factors such as the use of systematic protocols within care systems could explain the variation reported between studies. The specific aim was to identify approaches associated with higher testing rates that could be incorporated into practice models and caresystems.
2.
Methods
2.1.
Search strategy
We referenced the AMSTAR framework and the PRISMA Statement (www.prisma-statement.org) to construct the search and develop the Flowchart (Fig. 1) [52,53]. We searched major
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electronic databases: PUBMED (1902 through 2012 Week 29), OVID (1950–2012 Week 29), EMBASE (1947–2012 Week 29), and the Cochrane Database of systematic reviews to identify literature reporting rates of postpartum testing among women with GDM. The search included MeSH terms related to GDM and postpartum screening or testing, and was limited to English language studies conducted on female humans published with an abstract. The PubMed, OVID, and Embase search terms/strategies and results are described in Fig. 2 available in the appendix.
2.2.
Study selection
Two investigators conducted independent abstract reviews (MC, MF). The complete versions of 93 articles identified by their abstracts as potentially addressing the research question were then individually reviewed. The goal was to identify articles that listed the postpartum follow-up rates for the entire GDM cohort within that system; to avoid inappropriate exclusion, the complete articles where reviewed when the abstract reported any postpartum testing. Articles were excluded if one or more of the following criteria were met: (1) full version was not in English, (2) postpartum testing was not included, (3) it did not list the number of women with GDM who did not return for testing, (4) did not address the key question. Disagreements in any phase of the review were discussed and resolved by consensus. The Flow Chart (Fig. 1) summarizes this process. Many articles in the initial search were excluded as “not addressing the key question” because they remotely discussed gestational diabetes or HbA1C testing, but did not focus on testing in the postpartum GDM population.
2.3.
Data abstraction
A sequential review process was used. A primary reviewer abstracted the data, while a second reviewer checked the primary reviewer’s findings for completion and accuracy. The data abstraction table divided the studies into two main categories: (1) “Usual Care” (data obtained via retrospective chart or database review) or (2) “Active Care” (reporting results of a proactive plan enacted to improve testing rates; such as a nurse or case manager who contacted patients, process changes, physician reminders, letters to patients/providers). Some articles reported the historical rates of testing in their practices using Usual Care, then the rates after implementing
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Electronic Databases: Pubmed (n=268) Ovid (n=121) Embase (n=130) Duplicates (n=212) Abstract Review (n=307) Excluded (n=214)
Article Review (n=93)
Excluded (n=39)
Reasons For Exclusion Review Article (n=47) Case Study or Case Report (n=11) Survey or Interview n=18) Did not address the key question (n=83) Did not contain GDM patient population (n=23) Did not include postpartum testing (n=32)
Reasons For Exclusion Article not in English (n=8) Did not include postpartum testing (n=2) Only discussed patients who returned for testing, but did not list the number of women at risk who did not return (n=28) Did not address key question (n=1)
54 Studies Included (Table 1) Studies with ONLY Usual Care Data (n=25): Studies with ONLY Active Care Data (n=22): Studies Reporting Both Usual and Active Care Data (n=7)
Fig. 1 – Gestational diabetes postpartum testing literature search flowchart.
an Active Care plan. Intervention strategies to increase testing compliance were identified. The following was recorded: the type(s) of postpartum test performed, the time(s) since delivery at which it was administered, the criteria used for diagnosis of abnormal glucose tolerance, and the prevalence of abnormal glucose tolerance (postpartum development of type 2 diabetes, impaired fasting glucose and impaired glucose tolerance). The primary table (Table 1) was organized according to timeframe in which the testing was obtained (within 3 months of delivery, within 6 months, or after 6 months) because the standard American Diabetes Association (ADA)/American College of Obstetrics and Gynecology (ACOG) recommendations are to obtain testing between 6 and 12 weeks postpartum, and
these rates could be compared to studies that included those tested later. No funding was received.
3.
Results
3.1.
Characteristics of the studies reviewed
Of 307 abstracts reviewed 54 articles met the inclusion criteria and were organized into three groups: 25 reported Usual Care follow-up rates based on retrospective cohort/database reviews, or prospective data collected without (a) allocation of additional staff/resources or (b) systematic changes to the way caregivers practiced. When a proactive system or process was
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PUMBED Search 1) ((((postpartum) AND gestational diabetes) AND ((testing) OR (screening)) (hasabstract[text] AND Humans[Mesh] AND Female[MeSH Terms])) NOT Fructosamine. a. 268 citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 40 , Left with 228 citations. 3) Excluded studies not related to GDM a. Dropped 21, Left with 207 citations 4) Excluded studies that did not have postpartum testing a. Dropped 29, Left with 178 citations 5) Excluded Case Studies a. Dropped 11 Left with 167 citations 6) Excluded Surveys a. Dropped 17 Left with 150 citations 7) Excluded Studies not related to key question a. Dropped 70 Left with 80 citations Article review phase 8) Excluded studies that did not list the number of women in that practice who had GDM but only listed those that returned for testing a. Dropped 23 Left with 57 citations 9) Excluded studies not written in English a. Dropped 5 Left with 52 citations 10) Excluded studies that did not have postpartum testing a. Dropped 2 Left with 50 citations 11) Excluded Studies not related to key question a. Dropped 1 Left with 49 citations Final 12) 48 studies included OVID search 1) Identified 9 new citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 3 , Left with 6 citations. 3) Excluded studies not related to GDM a. Dropped 1, Left with 5 citations 4) Excluded studies that did not have postpartum testing a. Dropped 1, Left with 4 citations 5) Excluded Studies not related to key question a. Dropped 3 Left with 1 citations Article Review phase 6) No exclusions Final 7) 1 study included EMBASE search 1) Identified 30 new citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 4 , Left with 26 citations. 3) Excluded studies not related to GDM a. Dropped 1, Left with 25 citations 4) Excluded studies that did not have postpartum testing a. Dropped 2, Left with 23 citations 5) Excluded Surveys a. Dropped 1 Left with 22 citations 6) Excluded Studies not related to key question a. Dropped 10 Left with 12 citations Article review phase 7) Excluded studies that did not list the number of women in that practice who had GDM but only listed those that returned for testing a. Dropped 3 Left with 9 citations 8) Excluded studies not written in English a. Dropped 3 Left with 6 citations Final 9) 5 studies included
Fig. 2 – Pubmed search terms and results.
developed to improve follow-up rates, we classified them as Active Care, and 22 articles reported such data. The final group was 7 articles that reported both the historical rates of testing and the rates after implementing Active Care changes to their practices (Table 1) [6–9,12–14,16,18–20,22–28,30–50,54–67]. Table 2 lists data regarding the rates of diabetes/impaired fasting glucose/impaired glucose tolerance reported within identified studies. Some studies followed a clinic/practice over
a number of years, and specific detail regarding how many patients were seen within a particular year was not always provided [6,40,62].
3.2.
Primary findings
The average follow-up rate in Active Care studies (60.3%) was 27% higher than those reporting Usual Care (33.5%) [Table 1].
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Table 1 – Articles reporting rates of postpartum testing. Postpartum testing up to 3 months Usual Care Reference
Year
[19] [13] [9]a [8] [34]
2004 1999 2008 1995 2012 2012 2011 2009 2006 2003 2011 2002 2005
[56] [37] [12] [20] [7]a [60] [22]
Test
Active Care N (Total)
OGTT OGTT
1641 1017 1127 OGTT 238 OGTT 6239 OGTT 536 OGTT 882 OGTT 855 FPG or OGTT 344 OGTT 344 OGTT 560 OGTT 105 OGTT 70 Raw Average
% Returned
Reference
Year
Test
N (Total)
33.5% 17.6% 9.0% 39.0% 3.4% 51.7% 43.2% 37.0% 45.3% 64.2% 33.4% 62.9% 14.3% 35.0%
[32] [33] [9]a [54] [56] [34] [35] [36] [58] [59] [7]a [38]
2003 1994 2008 2010 2008 2003 2008 1990 2010 1990 2011 2009
OGTT OGTT FPG OGTT FPG or OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT
982 230 1127 188 707 392 738 525 1189 270 245 887
Raw Average
% Returned 70.9% 63.0% 57.8% 92.6% 56.6% 79.3% 55.0% 52.2% 82.8% 63.0% 52.7% 66.1% 64.8%
Postpartum testing up to 6 months Usual Care a
[31] [23] [18] [24] [25] [26] [27] [63]* [64]
1997 2011 2009 2010 2005 2006 2010 2011 2011
OGTT Any Test FPG or OGTT FPG or OGTT OGTT FPG or OGTT FPG or OGTT OGTT OGTT Raw Average
Active Care 799 23,299 909 11,825 159 1350 745 46, 812 117
a
9.4% 19.3% 48.2% 50.2% 47.0% 20.7% 33.7% 16.5% 13.7% 36.5%
[31] [39] [40] [62] [41] [42] [43] [64] [64]
1997 1998 1995 2011 1993 1999 2002 2011 2011
OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT Raw Average
4243 223 3318 314 274 1425 4041 90 55
69.7% 54.7% 50.0% 48.0% 72.3% 55.3% 46.1% 23.3% 36.4% 56.6%
Postpartum testing > 6 months Usual Care
Active Care
[46] [28] [66] [6]a [15] [68]a [69] [50] [16]
2009 2003 2003 2009 2006 2012 2012 2009 2005
OGTT Any Test Any Test FPG or OGTT FPG or OGTT OGTT OGTT OGTT FPG or OGTT
35 254 158
[30]
1997
OGTT Raw Average
79
a
570 102 733 1184 197
14.3% 47.6% 22.0% 20.3% 23.0% 14.7% 31.5% 51.1% 37.0%
71.0% 33.3%
[44] [45] [65] [46] [46] [46]
2002 2011 2011 2009 2009 2009
OGTT OGTT OGTT OGTT OGTT OGTT
315 252 160 76 31 81
73.0% 77.4% 47.0% 55.3% 51.6% 60.5%
[47] [48] [49] [6]a [68]a [68]a
2004 1992 1999 2009 2012 2012
OGTT OGTT OGTT FPG or OGTT OGTT OGTT Raw Average
297 298 481 14,448 110 54
49.8% 80.9% 69.0% 55.9% 30.9% 85.2% 61.4%
Indicates study presented both retrospective and prospective data. “Any test” = OGTT, FPG, HbA1C, Random glucose.
The Clark study (Table 1: Testing > 6 months section) was a randomized controlled trial of Usual Care vs. sending reminders to patients, their primary care providers, or both. The testing rate for Usual Care was 14%, it increased to 50% when reminders were sent to the patient or the provider, and 60% when sent to both [46].
3.3.
Timeframe of testing
Table 1 was also organized into the time frames in which the testing was done, relative to the most recent delivery date. The reporting of the test’s timing varied from specific
(“6–12 weeks”), to less specific (“within 12 weeks” – no lower limit mentioned), to descriptive statistics for the entire cohort. However, follow-up intervals varied from 7 days postpartum out to 2 years [24,64]. The studies by Dietz and Ferrara and their respective colleagues, rather than listing the number of women at risk each year, reported cumulative rates of postpartum testing over 7 and 11 years, respectively [6,9]. Lawrence et al. focused on the importance of timing and postpartum testing: of the 50.2% of women who returned, 41.4% did so between 1 and 6 weeks after delivery, 46.3% between 6 and 12 weeks, and the remaining 12.3% between 12 weeks and 6 months [24]. This observation could be due to
182
Table 2 – Rates of prediabetes/diabetes reported within articles. Year
Test
Criteria
[19]
2004
FPG OGTT
ADA-1997 Criteria WHO-1985 WHO-1999 NDDG-79 Criteriaa ADA-1997 Criteria NDDG-79 Criteria NDDG-79 Criteria WHO-1999 WHO-1999 ADA-1997 Criteria ADA-1997 Criteria NDDG-79 Criteria WHO-1999 WHO-1985 WHO-1999 ADA-1997 Criteria Not Stated ADA-1997/WHO-1999 WHO
[13]a
1999
OGTT
[33] [8] [56] [25] [56] [57] [36] [58] [59] [37] [12] [20] [60] [22]
1994 1995 2008 2005 2012 2011 1990 2010 1990 2009 2006 2003 2002 2005
OGTT OGTT OGTT or FPG OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT or FPG OGTT OGTT OGTT
N [returned) % Returned TESTED UP TO 12 WEEKS POSTPARTUM 549
IGT%
33.5%
179
17.6%
145 94 400 74 277 381 274 985 170 318 156 221 66 10
63.0% 39.0% 56.6% 47.0% 51.7% 43.2% 52.2% 82.8% 63.0% 37.0% 45.3% 64.0% 62.9% 14.3%
15.5% 15.3% 5.0% 14.0% 5.0% 18.0% 12.8% 16.2% 28.0% 10.0% 11.6% 9.0% 7.5% 17.6% 18.2%
DM%
IFG%
6.6% 8.2% 9.1% 5.6% 7.8% 10.0% 16.0% 4.5% 10.8% 9.0% 7.1% 9.0% 11.1% 1.0% 1.3% 7.7%
9.3%
IGT or IFG %
5.5% 6.1%
18.8% 4.1% 32.0% 42.3% 5.0% 2.5%
2.2% 28.2%
7.6% 8.8%
TESTED UP TO 6 MONTHS POSTPARTUM [23] [18] [24] [41] [25] [42]
2011 2009 2010 1993 2005 1999
OGTT or HbA1C > 6.5% OGTT or FPG OGTT or FPG OGTT OGTT OGTT
[26]
2006
FPG OGTT OGTT OGTT or FPG
[60] [27]b
2002 2010
ADA CDA/WHO-1999 ADA-1997 NDDG-79 Criteria WHO-1999 ADA-1997 WHO-1985 CDA/WHO-1999
4486 438 5857 198 74 788 788 275
NDDG-79 Criteria See Belowb
19.3% 48.2% 18.2% 72.3% 47.0% 55.3% 55.3% 20.7%
1636 251
33.7%
13.0% 17.2% 16.0% 10.4% 14.8% 32.0% 21.8% 28.3%
1.4% 3.2% 1.1% 25.3% 11.0% 5.4% 4.7% 4.4% 9.5% 14.1% 2.0%
3.4% 16.3%
5.8%
3.7%
2.5% 2.5%
TESTED 1 OR MORE YEARS POSTPARTUM [44] [45] [32] [31] c [47] [48] [64] [57] [69] [50] [30]
2002 2011 2003 1997 2004 1992 2010 2006 2012 2009 1997
OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT or FPG OGTT OGTT OGTT
WHO-1999 ADA-1997 WHO-1999 WHO-1985 WHO-1999 WHO-1985 WHO-1999 WHO-1999 ADA-1997 ADA-1997 WHO-1985
229 195 696 2433 148 241 112 217 231 605 56
73.0% 77.4% 70.9% 69.7% 49.8% 80.9% 38.0% 31.5% 51.1% 71.0%
22.0% 22.6%
9.0% 13.8%
24.3% 18.9% 17.0% 24.0%
10.5% 4.7% 13.7% 12.5% 2.0% 6.1% 5.5% 14.0%
6.9% 13.6% 15.0%
29.3%
3.6% 25.1% 2.8%
3.0% 7.8%
ADA = American Diabetes Association; CDA = Canadian Diabetes Association; DM = diabetes mellitus; FPG = fasting plasma glucose; IFG = impaired fasting glucose; IGT = imparied glucose tolerance; NDDG = National Diabetes Data Group; OGTT = Oral Glucose Tolerance Test; WHO = World Health Organization Criteria 1985 vs.1999. a 30 had “nondiagnostic result”. b Oral Glucose Tolerance Test result > 140 mg/dL defined as “abnormal”, result > 177 mg/dL was “Impaired Glucose Tolerance”. c Only reported test results for the entire cohort at 5 years.
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
Reference
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
timing and/or intensity of the efforts to promote testing being focused on the 6–12 week timeframe. Nineteen of the 21 studies used either the FPG or OGTT. Two studies included women who had HbA1Cs ordered as having “appropriate” testing but did not provide specific data [23,28]. Including women who had a postpartum HbA1C as compliant increased the testing rates by 13–15%, however only two studies were conducted after the HbA1C was approved as a screening test by the ADA [15,16,23,27]. In summary, among Active Care studies, six increased the rate of follow-up by developing quality improvement and care management programs; three of those specifically list their historical follow-up rates, indicating that the care management was improved in response to their respective programs [6,9,31]. Whether Usual or Active Care, it was interesting that the average testing rates did not increase as the timeframe within which testing could be obtained was extended. That is, the average testing rate for Usual Care was 34% when the monitoring interval was within 3 months of delivery, 37.8% up to 6 months after delivery, and 34.5% for studies collecting data after 6 months. The respective rates for Active Care studies were 66%, 56%, and 62%.
3.4.
Incidence table
The primary objective of this search was to determine postpartum testing rates, but many articles published the results of the various tests that were performed, and these are summarized in Table 2. Results from Sinha et al. are not included in the table because the diagnostic criteria were not specified [20]. The two largest retrospective database studies utilizing information from commercial laboratories found 6 month testing rates of 18–19%, but low rates of overt diabetes mellitus (1.1–1.4%), suggesting that higher diabetes mellitus rates in smaller studies could be confounded by patient or practice characteristics [23,24].
4.
Discussion
Organizing this review in terms of Usual vs. Active Care, and the timeframes of the testing, permits the following conclusions: The primary factor associated with higher rates was implementation of an active system-based program designed to improve the postpartum testing rate after the authors observed low rates in a retrospective review, typically allocation of a nurse manager to contact patients. While this might appear to be self evident, to our knowledge this is the first review to systematically address this hypothesis. Neither the ADA nor ACOG guidelines make suggestions beyond the responsibility of individual practitioners, but there is evidence that practitioners are not ordering testing for 61–85% of those with a recent diagnosis of GDM [62,68]. A focus group identified women with GDM who consciously ignored the recommendation for postpartum testing to avoid being diagnosed with “diabetes”, presumably due to a fear of the disease, but these same women may present to their primary care physician/provider for other issues [69]. Another observation, likely confounded by the care system and patient habits, is that except for the Clark study, the rates
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of postpartum testing, whether Usual or Active Care, did not increase when the follow-up interval was extended beyond three months [46]. This could be explained by the intensity of interventions being greatest during the puerperium. Perhaps all of the providers who are good at screening only think to order it at the postpartum visit, but not at other visits. Similarly, the Lawrence study provides evidence that women who agree to get the test done are those likely to do it right away, but not later that year [24]. If a patient did not go for the recommended test and never returned to the obstetrician’s office after the 6–12 week postpartum timeframe, then the provider will not have an opportunity to reorder the test and the post 12-week testing rates will look “low”. If primary care providers do not inquire about the obstetric history, then they will did not identify the need to order the test. This theory is supported by the Clark Study that dramatically increased the rate of follow-up testing by contacting patients as late as 6 months postpartum [46]. These data support the assertion that a systematic approach to identify women who did not go for follow-up testing, or did not have it ordered, could improve the testing rates regardless of the timeframe in which it is implemented. In the United States, women with insurance coverage provided by the government to promote appropriate antenatal care (Medicaid) lose benefits 6 weeks after delivery, but if these patients show up for the postpartum visit, the cost of the test will be covered. Our institutions care for women with private and public insurance and we are not aware of differential contact efforts based on insurance status. While obesity can be associated with socio-economic status, those demographic factors were not presented consistently enough to allow an analysis. Prior studies regarding postpartum testing rates identified age, race, weight, and use of insulin during pregnancy as having modest and sometimes conflicting findings of +2 or −10% absolute rate differences [22,27,51]. Rather than reviewing single centers and focusing on specific patient demographics, we sought to identify system based factors that could be generalized to many other practices while explaining the wide variation in reported rates (9–95%). One author concluded that “the dedication of the follow-up team administrators, rather than the clinical variables of the patients, was probably the main determinant of compliance with the follow-up program” [31]. Reasons to improve the rates of postpartum glucose tolerance testing among women with GDM include the high prevalence of postpartum dysglycemia (28%), the current obesity epidemic that will increase the incidence of GDM and overt DM, and evidence that lifestyle modification and/or metformin will decrease the incidence of overt diabetes mellitus by 58%, particularly in those with a history of GDM [5,70–73]. Finally, uncontrolled diabetes at the time of conception is a major teratogen, so controlling diabetes could decrease the risk of future pregnancy complications [74]. In summary, this systematic review, we contend, firmly establishes that implementation of proactive programs was associated with higher rates of postpartum testing, and this information could be used to justify up-front resource allocation to decrease the maternal risk of hyperglycemia and the associated obstetric complications. Systems to track and follow through with women were effective, as were postal
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reminders sent to the patient and primary care physician as late as 6 months postpartum. Medical issues may be present in up to 36% of pregnancies, in part due to the increased average maternal age, so practitioners should identify women in the pre-, post- and inter-conception periods who may benefit from risk-factor identification and screening [75–78]. The recommended timeframe to screen GDM women 6 weeks after delivery may be a carryover from the past, but because interaction between postpartum women and their caregivers is common, it is a reasonable timeframe upon which we can focus efforts to improve screening rates.
Conflict of interest statement The authors have no financial or personal relationships with organizations that could bias this work. No funding was provided.
Acknowledgement MP and MF had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
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Contents lists available at ScienceDirect
Primary Care Diabetes journal homepage: http://www.elsevier.com/locate/pcd
Review
Original research: Postpartum testing rates among women with a history of gestational diabetes—Systematic review Michael P. Carson a,∗ , Matthew I. Frank a,b,1 , Erin Keely c,2 a
UMDNJ-Robert Wood Johnson Medical School, Jersey Shore University Medical Center, Department of Medicine, Ackerman 3, 1945 Route 33, Neptune, NJ 07753, United States b 20 Harrison Street, Edison, NJ 08817, United States c Division of Endocrinology and Metabolism, Ottawa Hospital – Riverside Campus, Room 4-05, 1967 Riverside Drive, Ottawa, ON K1H 7W9, United States
a r t i c l e
i n f o
a b s t r a c t
Article history:
Aims: Gestational diabetes mellitus (GDM) is increasing and 30% have persistent postpartum
Received 21 November 2012
dysglycemia. Reported compliance with recommended postpartum testing ranges 9–95%
Received in revised form
without a clear explanation for this wide variation. Small and conflicting differences in
13 April 2013
testing rates are associated with some demographics (race, use of insulin), but system factors
Accepted 16 April 2013
likely play a larger role. A systematic literature review was performed to identify system
Available online 15 May 2013
based factors that could explain the broad variation in postpartum GDM testing rates. Methods: Original articles reporting postpartum testing rates among women with GDM were
Keywords:
identified within PubMed, OVID, EMBASE, and the Cochrane Database of systematic reviews.
Gestational diabetes mellitus
Articles that did not report rates for the entire GDM cohort were excluded.
Glucose intolerance
Results: 54/307 citations met inclusion criteria. The use of proactive patient contact programs
Postpartum testing
increased postpartum testing rates from an average of 33% (range 9–71%) up to 60% (range
Pregnancy
14–95%). Conclusions: Proactively contacting patients via phone calls, education programs, or postal reminders was associated with higher postpartum testing rates. Rather than working to identifying individual demographic factors, systems based approaches were associated with a larger potential impact, and appear easily generalizable. Clinicians should think beyond individual habits and consider systematic approaches to improving testing rates. © 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.
Contents 1. 2.
∗
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Corresponding author. Tel.: +1 732 776 4826; fax: +1 732 776 3795. E-mail addresses: [email protected] (M.P. Carson), [email protected] (M.I. Frank), [email protected] (E. Keely). 1 Tel.: +1 732 776 4826. 2 Tel.: +1 613 738 8400x81941; fax: +1 613 738 8327. 1751-9918/$ – see front matter © 2013 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pcd.2013.04.007
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2.1. Search strategy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Study selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Data abstraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Characteristics of the studies reviewed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Primary findings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3. Timeframe of testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4. Incidence table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conflict of interest statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.
Introduction
Women who develop gestational diabetes mellitus (GDM) during their pregnancy have a higher risk of developing overt diabetes mellitus and dysglycemia (impaired fasting glucose, impaired glucose tolerance, or prediabetes) later in life, compared to women without GDM. The prevalence of GDM increased from 2 to 4% in the United States, from 2.9% to 8.8% in Australia, and the number of pregnancies complicated by preexisting diabetes mellitus doubled from 10 to 21% [1–3]. Obesity, an obvious risk factor for diabetes mellitus and GDM, is also increasing [4]. Because the at-risk population is growing, and postpartum testing of women with GDM will identify the 20–30% with persistent dysglycemia, it is important that an efficient system be in place to identify women with early diabetes mellitus or pre-diabetes for whom evidence based interventions exist [5]. Reported rates of women who follow through with the recommended postpartum testing range from 9 to 95% [6–50]. A recent review summarized studies between 2008 and 2010 and, like similar reports, lists conflicting findings regarding the association between specific patient demographics and testing rates, such as Hispanic women being tested 2% more or 10% less than White women [22,27,51]. However, because the differences associated with individual demographics are modest, it seems possible that the large variation in screening rates is due to differences in health care delivery that affected the entire population within individual study cohorts. Understanding these differences can help providers design quality improvement initiatives. This systematic review regarding postpartum testing for women with GDM was designed to determine if factors such as the use of systematic protocols within care systems could explain the variation reported between studies. The specific aim was to identify approaches associated with higher testing rates that could be incorporated into practice models and caresystems.
2.
Methods
2.1.
Search strategy
We referenced the AMSTAR framework and the PRISMA Statement (www.prisma-statement.org) to construct the search and develop the Flowchart (Fig. 1) [52,53]. We searched major
178 178 178 179 179 180 181 183 183 184 184 184
electronic databases: PUBMED (1902 through 2012 Week 29), OVID (1950–2012 Week 29), EMBASE (1947–2012 Week 29), and the Cochrane Database of systematic reviews to identify literature reporting rates of postpartum testing among women with GDM. The search included MeSH terms related to GDM and postpartum screening or testing, and was limited to English language studies conducted on female humans published with an abstract. The PubMed, OVID, and Embase search terms/strategies and results are described in Fig. 2 available in the appendix.
2.2.
Study selection
Two investigators conducted independent abstract reviews (MC, MF). The complete versions of 93 articles identified by their abstracts as potentially addressing the research question were then individually reviewed. The goal was to identify articles that listed the postpartum follow-up rates for the entire GDM cohort within that system; to avoid inappropriate exclusion, the complete articles where reviewed when the abstract reported any postpartum testing. Articles were excluded if one or more of the following criteria were met: (1) full version was not in English, (2) postpartum testing was not included, (3) it did not list the number of women with GDM who did not return for testing, (4) did not address the key question. Disagreements in any phase of the review were discussed and resolved by consensus. The Flow Chart (Fig. 1) summarizes this process. Many articles in the initial search were excluded as “not addressing the key question” because they remotely discussed gestational diabetes or HbA1C testing, but did not focus on testing in the postpartum GDM population.
2.3.
Data abstraction
A sequential review process was used. A primary reviewer abstracted the data, while a second reviewer checked the primary reviewer’s findings for completion and accuracy. The data abstraction table divided the studies into two main categories: (1) “Usual Care” (data obtained via retrospective chart or database review) or (2) “Active Care” (reporting results of a proactive plan enacted to improve testing rates; such as a nurse or case manager who contacted patients, process changes, physician reminders, letters to patients/providers). Some articles reported the historical rates of testing in their practices using Usual Care, then the rates after implementing
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
179
Electronic Databases: Pubmed (n=268) Ovid (n=121) Embase (n=130) Duplicates (n=212) Abstract Review (n=307) Excluded (n=214)
Article Review (n=93)
Excluded (n=39)
Reasons For Exclusion Review Article (n=47) Case Study or Case Report (n=11) Survey or Interview n=18) Did not address the key question (n=83) Did not contain GDM patient population (n=23) Did not include postpartum testing (n=32)
Reasons For Exclusion Article not in English (n=8) Did not include postpartum testing (n=2) Only discussed patients who returned for testing, but did not list the number of women at risk who did not return (n=28) Did not address key question (n=1)
54 Studies Included (Table 1) Studies with ONLY Usual Care Data (n=25): Studies with ONLY Active Care Data (n=22): Studies Reporting Both Usual and Active Care Data (n=7)
Fig. 1 – Gestational diabetes postpartum testing literature search flowchart.
an Active Care plan. Intervention strategies to increase testing compliance were identified. The following was recorded: the type(s) of postpartum test performed, the time(s) since delivery at which it was administered, the criteria used for diagnosis of abnormal glucose tolerance, and the prevalence of abnormal glucose tolerance (postpartum development of type 2 diabetes, impaired fasting glucose and impaired glucose tolerance). The primary table (Table 1) was organized according to timeframe in which the testing was obtained (within 3 months of delivery, within 6 months, or after 6 months) because the standard American Diabetes Association (ADA)/American College of Obstetrics and Gynecology (ACOG) recommendations are to obtain testing between 6 and 12 weeks postpartum, and
these rates could be compared to studies that included those tested later. No funding was received.
3.
Results
3.1.
Characteristics of the studies reviewed
Of 307 abstracts reviewed 54 articles met the inclusion criteria and were organized into three groups: 25 reported Usual Care follow-up rates based on retrospective cohort/database reviews, or prospective data collected without (a) allocation of additional staff/resources or (b) systematic changes to the way caregivers practiced. When a proactive system or process was
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PUMBED Search 1) ((((postpartum) AND gestational diabetes) AND ((testing) OR (screening)) (hasabstract[text] AND Humans[Mesh] AND Female[MeSH Terms])) NOT Fructosamine. a. 268 citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 40 , Left with 228 citations. 3) Excluded studies not related to GDM a. Dropped 21, Left with 207 citations 4) Excluded studies that did not have postpartum testing a. Dropped 29, Left with 178 citations 5) Excluded Case Studies a. Dropped 11 Left with 167 citations 6) Excluded Surveys a. Dropped 17 Left with 150 citations 7) Excluded Studies not related to key question a. Dropped 70 Left with 80 citations Article review phase 8) Excluded studies that did not list the number of women in that practice who had GDM but only listed those that returned for testing a. Dropped 23 Left with 57 citations 9) Excluded studies not written in English a. Dropped 5 Left with 52 citations 10) Excluded studies that did not have postpartum testing a. Dropped 2 Left with 50 citations 11) Excluded Studies not related to key question a. Dropped 1 Left with 49 citations Final 12) 48 studies included OVID search 1) Identified 9 new citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 3 , Left with 6 citations. 3) Excluded studies not related to GDM a. Dropped 1, Left with 5 citations 4) Excluded studies that did not have postpartum testing a. Dropped 1, Left with 4 citations 5) Excluded Studies not related to key question a. Dropped 3 Left with 1 citations Article Review phase 6) No exclusions Final 7) 1 study included EMBASE search 1) Identified 30 new citations Abstract review phase 2) Excluded “reviews” and consensus statements a. Dropped 4 , Left with 26 citations. 3) Excluded studies not related to GDM a. Dropped 1, Left with 25 citations 4) Excluded studies that did not have postpartum testing a. Dropped 2, Left with 23 citations 5) Excluded Surveys a. Dropped 1 Left with 22 citations 6) Excluded Studies not related to key question a. Dropped 10 Left with 12 citations Article review phase 7) Excluded studies that did not list the number of women in that practice who had GDM but only listed those that returned for testing a. Dropped 3 Left with 9 citations 8) Excluded studies not written in English a. Dropped 3 Left with 6 citations Final 9) 5 studies included
Fig. 2 – Pubmed search terms and results.
developed to improve follow-up rates, we classified them as Active Care, and 22 articles reported such data. The final group was 7 articles that reported both the historical rates of testing and the rates after implementing Active Care changes to their practices (Table 1) [6–9,12–14,16,18–20,22–28,30–50,54–67]. Table 2 lists data regarding the rates of diabetes/impaired fasting glucose/impaired glucose tolerance reported within identified studies. Some studies followed a clinic/practice over
a number of years, and specific detail regarding how many patients were seen within a particular year was not always provided [6,40,62].
3.2.
Primary findings
The average follow-up rate in Active Care studies (60.3%) was 27% higher than those reporting Usual Care (33.5%) [Table 1].
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Table 1 – Articles reporting rates of postpartum testing. Postpartum testing up to 3 months Usual Care Reference
Year
[19] [13] [9]a [8] [34]
2004 1999 2008 1995 2012 2012 2011 2009 2006 2003 2011 2002 2005
[56] [37] [12] [20] [7]a [60] [22]
Test
Active Care N (Total)
OGTT OGTT
1641 1017 1127 OGTT 238 OGTT 6239 OGTT 536 OGTT 882 OGTT 855 FPG or OGTT 344 OGTT 344 OGTT 560 OGTT 105 OGTT 70 Raw Average
% Returned
Reference
Year
Test
N (Total)
33.5% 17.6% 9.0% 39.0% 3.4% 51.7% 43.2% 37.0% 45.3% 64.2% 33.4% 62.9% 14.3% 35.0%
[32] [33] [9]a [54] [56] [34] [35] [36] [58] [59] [7]a [38]
2003 1994 2008 2010 2008 2003 2008 1990 2010 1990 2011 2009
OGTT OGTT FPG OGTT FPG or OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT
982 230 1127 188 707 392 738 525 1189 270 245 887
Raw Average
% Returned 70.9% 63.0% 57.8% 92.6% 56.6% 79.3% 55.0% 52.2% 82.8% 63.0% 52.7% 66.1% 64.8%
Postpartum testing up to 6 months Usual Care a
[31] [23] [18] [24] [25] [26] [27] [63]* [64]
1997 2011 2009 2010 2005 2006 2010 2011 2011
OGTT Any Test FPG or OGTT FPG or OGTT OGTT FPG or OGTT FPG or OGTT OGTT OGTT Raw Average
Active Care 799 23,299 909 11,825 159 1350 745 46, 812 117
a
9.4% 19.3% 48.2% 50.2% 47.0% 20.7% 33.7% 16.5% 13.7% 36.5%
[31] [39] [40] [62] [41] [42] [43] [64] [64]
1997 1998 1995 2011 1993 1999 2002 2011 2011
OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT Raw Average
4243 223 3318 314 274 1425 4041 90 55
69.7% 54.7% 50.0% 48.0% 72.3% 55.3% 46.1% 23.3% 36.4% 56.6%
Postpartum testing > 6 months Usual Care
Active Care
[46] [28] [66] [6]a [15] [68]a [69] [50] [16]
2009 2003 2003 2009 2006 2012 2012 2009 2005
OGTT Any Test Any Test FPG or OGTT FPG or OGTT OGTT OGTT OGTT FPG or OGTT
35 254 158
[30]
1997
OGTT Raw Average
79
a
570 102 733 1184 197
14.3% 47.6% 22.0% 20.3% 23.0% 14.7% 31.5% 51.1% 37.0%
71.0% 33.3%
[44] [45] [65] [46] [46] [46]
2002 2011 2011 2009 2009 2009
OGTT OGTT OGTT OGTT OGTT OGTT
315 252 160 76 31 81
73.0% 77.4% 47.0% 55.3% 51.6% 60.5%
[47] [48] [49] [6]a [68]a [68]a
2004 1992 1999 2009 2012 2012
OGTT OGTT OGTT FPG or OGTT OGTT OGTT Raw Average
297 298 481 14,448 110 54
49.8% 80.9% 69.0% 55.9% 30.9% 85.2% 61.4%
Indicates study presented both retrospective and prospective data. “Any test” = OGTT, FPG, HbA1C, Random glucose.
The Clark study (Table 1: Testing > 6 months section) was a randomized controlled trial of Usual Care vs. sending reminders to patients, their primary care providers, or both. The testing rate for Usual Care was 14%, it increased to 50% when reminders were sent to the patient or the provider, and 60% when sent to both [46].
3.3.
Timeframe of testing
Table 1 was also organized into the time frames in which the testing was done, relative to the most recent delivery date. The reporting of the test’s timing varied from specific
(“6–12 weeks”), to less specific (“within 12 weeks” – no lower limit mentioned), to descriptive statistics for the entire cohort. However, follow-up intervals varied from 7 days postpartum out to 2 years [24,64]. The studies by Dietz and Ferrara and their respective colleagues, rather than listing the number of women at risk each year, reported cumulative rates of postpartum testing over 7 and 11 years, respectively [6,9]. Lawrence et al. focused on the importance of timing and postpartum testing: of the 50.2% of women who returned, 41.4% did so between 1 and 6 weeks after delivery, 46.3% between 6 and 12 weeks, and the remaining 12.3% between 12 weeks and 6 months [24]. This observation could be due to
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Table 2 – Rates of prediabetes/diabetes reported within articles. Year
Test
Criteria
[19]
2004
FPG OGTT
ADA-1997 Criteria WHO-1985 WHO-1999 NDDG-79 Criteriaa ADA-1997 Criteria NDDG-79 Criteria NDDG-79 Criteria WHO-1999 WHO-1999 ADA-1997 Criteria ADA-1997 Criteria NDDG-79 Criteria WHO-1999 WHO-1985 WHO-1999 ADA-1997 Criteria Not Stated ADA-1997/WHO-1999 WHO
[13]a
1999
OGTT
[33] [8] [56] [25] [56] [57] [36] [58] [59] [37] [12] [20] [60] [22]
1994 1995 2008 2005 2012 2011 1990 2010 1990 2009 2006 2003 2002 2005
OGTT OGTT OGTT or FPG OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT or FPG OGTT OGTT OGTT
N [returned) % Returned TESTED UP TO 12 WEEKS POSTPARTUM 549
IGT%
33.5%
179
17.6%
145 94 400 74 277 381 274 985 170 318 156 221 66 10
63.0% 39.0% 56.6% 47.0% 51.7% 43.2% 52.2% 82.8% 63.0% 37.0% 45.3% 64.0% 62.9% 14.3%
15.5% 15.3% 5.0% 14.0% 5.0% 18.0% 12.8% 16.2% 28.0% 10.0% 11.6% 9.0% 7.5% 17.6% 18.2%
DM%
IFG%
6.6% 8.2% 9.1% 5.6% 7.8% 10.0% 16.0% 4.5% 10.8% 9.0% 7.1% 9.0% 11.1% 1.0% 1.3% 7.7%
9.3%
IGT or IFG %
5.5% 6.1%
18.8% 4.1% 32.0% 42.3% 5.0% 2.5%
2.2% 28.2%
7.6% 8.8%
TESTED UP TO 6 MONTHS POSTPARTUM [23] [18] [24] [41] [25] [42]
2011 2009 2010 1993 2005 1999
OGTT or HbA1C > 6.5% OGTT or FPG OGTT or FPG OGTT OGTT OGTT
[26]
2006
FPG OGTT OGTT OGTT or FPG
[60] [27]b
2002 2010
ADA CDA/WHO-1999 ADA-1997 NDDG-79 Criteria WHO-1999 ADA-1997 WHO-1985 CDA/WHO-1999
4486 438 5857 198 74 788 788 275
NDDG-79 Criteria See Belowb
19.3% 48.2% 18.2% 72.3% 47.0% 55.3% 55.3% 20.7%
1636 251
33.7%
13.0% 17.2% 16.0% 10.4% 14.8% 32.0% 21.8% 28.3%
1.4% 3.2% 1.1% 25.3% 11.0% 5.4% 4.7% 4.4% 9.5% 14.1% 2.0%
3.4% 16.3%
5.8%
3.7%
2.5% 2.5%
TESTED 1 OR MORE YEARS POSTPARTUM [44] [45] [32] [31] c [47] [48] [64] [57] [69] [50] [30]
2002 2011 2003 1997 2004 1992 2010 2006 2012 2009 1997
OGTT OGTT OGTT OGTT OGTT OGTT OGTT OGTT or FPG OGTT OGTT OGTT
WHO-1999 ADA-1997 WHO-1999 WHO-1985 WHO-1999 WHO-1985 WHO-1999 WHO-1999 ADA-1997 ADA-1997 WHO-1985
229 195 696 2433 148 241 112 217 231 605 56
73.0% 77.4% 70.9% 69.7% 49.8% 80.9% 38.0% 31.5% 51.1% 71.0%
22.0% 22.6%
9.0% 13.8%
24.3% 18.9% 17.0% 24.0%
10.5% 4.7% 13.7% 12.5% 2.0% 6.1% 5.5% 14.0%
6.9% 13.6% 15.0%
29.3%
3.6% 25.1% 2.8%
3.0% 7.8%
ADA = American Diabetes Association; CDA = Canadian Diabetes Association; DM = diabetes mellitus; FPG = fasting plasma glucose; IFG = impaired fasting glucose; IGT = imparied glucose tolerance; NDDG = National Diabetes Data Group; OGTT = Oral Glucose Tolerance Test; WHO = World Health Organization Criteria 1985 vs.1999. a 30 had “nondiagnostic result”. b Oral Glucose Tolerance Test result > 140 mg/dL defined as “abnormal”, result > 177 mg/dL was “Impaired Glucose Tolerance”. c Only reported test results for the entire cohort at 5 years.
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
Reference
p r i m a r y c a r e d i a b e t e s 7 ( 2 0 1 3 ) 177–186
timing and/or intensity of the efforts to promote testing being focused on the 6–12 week timeframe. Nineteen of the 21 studies used either the FPG or OGTT. Two studies included women who had HbA1Cs ordered as having “appropriate” testing but did not provide specific data [23,28]. Including women who had a postpartum HbA1C as compliant increased the testing rates by 13–15%, however only two studies were conducted after the HbA1C was approved as a screening test by the ADA [15,16,23,27]. In summary, among Active Care studies, six increased the rate of follow-up by developing quality improvement and care management programs; three of those specifically list their historical follow-up rates, indicating that the care management was improved in response to their respective programs [6,9,31]. Whether Usual or Active Care, it was interesting that the average testing rates did not increase as the timeframe within which testing could be obtained was extended. That is, the average testing rate for Usual Care was 34% when the monitoring interval was within 3 months of delivery, 37.8% up to 6 months after delivery, and 34.5% for studies collecting data after 6 months. The respective rates for Active Care studies were 66%, 56%, and 62%.
3.4.
Incidence table
The primary objective of this search was to determine postpartum testing rates, but many articles published the results of the various tests that were performed, and these are summarized in Table 2. Results from Sinha et al. are not included in the table because the diagnostic criteria were not specified [20]. The two largest retrospective database studies utilizing information from commercial laboratories found 6 month testing rates of 18–19%, but low rates of overt diabetes mellitus (1.1–1.4%), suggesting that higher diabetes mellitus rates in smaller studies could be confounded by patient or practice characteristics [23,24].
4.
Discussion
Organizing this review in terms of Usual vs. Active Care, and the timeframes of the testing, permits the following conclusions: The primary factor associated with higher rates was implementation of an active system-based program designed to improve the postpartum testing rate after the authors observed low rates in a retrospective review, typically allocation of a nurse manager to contact patients. While this might appear to be self evident, to our knowledge this is the first review to systematically address this hypothesis. Neither the ADA nor ACOG guidelines make suggestions beyond the responsibility of individual practitioners, but there is evidence that practitioners are not ordering testing for 61–85% of those with a recent diagnosis of GDM [62,68]. A focus group identified women with GDM who consciously ignored the recommendation for postpartum testing to avoid being diagnosed with “diabetes”, presumably due to a fear of the disease, but these same women may present to their primary care physician/provider for other issues [69]. Another observation, likely confounded by the care system and patient habits, is that except for the Clark study, the rates
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of postpartum testing, whether Usual or Active Care, did not increase when the follow-up interval was extended beyond three months [46]. This could be explained by the intensity of interventions being greatest during the puerperium. Perhaps all of the providers who are good at screening only think to order it at the postpartum visit, but not at other visits. Similarly, the Lawrence study provides evidence that women who agree to get the test done are those likely to do it right away, but not later that year [24]. If a patient did not go for the recommended test and never returned to the obstetrician’s office after the 6–12 week postpartum timeframe, then the provider will not have an opportunity to reorder the test and the post 12-week testing rates will look “low”. If primary care providers do not inquire about the obstetric history, then they will did not identify the need to order the test. This theory is supported by the Clark Study that dramatically increased the rate of follow-up testing by contacting patients as late as 6 months postpartum [46]. These data support the assertion that a systematic approach to identify women who did not go for follow-up testing, or did not have it ordered, could improve the testing rates regardless of the timeframe in which it is implemented. In the United States, women with insurance coverage provided by the government to promote appropriate antenatal care (Medicaid) lose benefits 6 weeks after delivery, but if these patients show up for the postpartum visit, the cost of the test will be covered. Our institutions care for women with private and public insurance and we are not aware of differential contact efforts based on insurance status. While obesity can be associated with socio-economic status, those demographic factors were not presented consistently enough to allow an analysis. Prior studies regarding postpartum testing rates identified age, race, weight, and use of insulin during pregnancy as having modest and sometimes conflicting findings of +2 or −10% absolute rate differences [22,27,51]. Rather than reviewing single centers and focusing on specific patient demographics, we sought to identify system based factors that could be generalized to many other practices while explaining the wide variation in reported rates (9–95%). One author concluded that “the dedication of the follow-up team administrators, rather than the clinical variables of the patients, was probably the main determinant of compliance with the follow-up program” [31]. Reasons to improve the rates of postpartum glucose tolerance testing among women with GDM include the high prevalence of postpartum dysglycemia (28%), the current obesity epidemic that will increase the incidence of GDM and overt DM, and evidence that lifestyle modification and/or metformin will decrease the incidence of overt diabetes mellitus by 58%, particularly in those with a history of GDM [5,70–73]. Finally, uncontrolled diabetes at the time of conception is a major teratogen, so controlling diabetes could decrease the risk of future pregnancy complications [74]. In summary, this systematic review, we contend, firmly establishes that implementation of proactive programs was associated with higher rates of postpartum testing, and this information could be used to justify up-front resource allocation to decrease the maternal risk of hyperglycemia and the associated obstetric complications. Systems to track and follow through with women were effective, as were postal
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reminders sent to the patient and primary care physician as late as 6 months postpartum. Medical issues may be present in up to 36% of pregnancies, in part due to the increased average maternal age, so practitioners should identify women in the pre-, post- and inter-conception periods who may benefit from risk-factor identification and screening [75–78]. The recommended timeframe to screen GDM women 6 weeks after delivery may be a carryover from the past, but because interaction between postpartum women and their caregivers is common, it is a reasonable timeframe upon which we can focus efforts to improve screening rates.
Conflict of interest statement The authors have no financial or personal relationships with organizations that could bias this work. No funding was provided.
Acknowledgement MP and MF had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
references
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