Matern Child Health J DOI 10.1007/s10995-014-1614-9
METHODOLOGICAL NOTES
Preventive Letter: Doubling the Return Rate After Gestational Diabetes Mellitus Pablo R. Olmos • Gisella R. Borzone • Loni Berkowitz • Nicola´s Mertens • Dolores Busso • Jose´ L. Santos • Jose´ A. Poblete • Claudio Vera • Cristia´n Belmar Denisse Goldenberg • Ba´rbara Samith • Ana M. Acosta • Manuel Escalona
•
Ó Springer Science+Business Media New York 2014
Abstract To measure the impact of a ‘‘Preventive Letter’’ designed to encourage the return of gestational diabetes mellitus (GDM) mothers to follow up visit after delivery, in the context of a worldwide concern about low return rates after delivery of these patients. Mothers with GDM require medical evaluation and an oral glucose tolerance test (OGTT) 6 weeks after delivery, in order to: [a] confirm remission of GDM and [b] provide advice on the prevention of type 2 diabetes. In the year 2003 we developed a ‘‘Preventive Letter’’, containing three aspects: [a] current treatment, [b] suggested management during labor, and [c] a stapled laboratory order for OGTT to be
Project Identification: FONDECYT No. 1120682. P. R. Olmos L. Berkowitz N. Mertens D. Busso J. L. Santos D. Goldenberg B. Samith A. M. Acosta M. Escalona Department of Nutrition, Pontificia Universidad Cato´lica de Chile, Santiago, Chile P. R. Olmos J. A. Poblete C. Vera C. Belmar B. Samith Department of Obstetrics and Gynecology, Pontificia Universidad Cato´lica de Chile, Santiago, Chile P. R. Olmos (&) College of Medicine, Pontificia Universidad Cato´lica de Chile, Alameda 340, Santiago, Chile e-mail: [email protected] G. R. Borzone Respiratory Diseases, College of Medicine, Pontificia Universidad Cato´lica de Chile, Santiago, Chile L. Berkowitz D. Busso Department of Gastroenterology, Pontificia Universidad Cato´lica de Chile, Santiago, Chile
performed 6 weeks after delivery. The return rate after delivery was assessed in two groups of GDM mothers: [a] ‘‘Without Preventive Letter’’ (n = 253), and ‘‘With Preventive Letter’’ (n = 215). Both groups, similar with respect to age (33.0 ± 5.4 and 32.3 ± 4.9 years respectively, p = 0.166) and education time (14.9 ± 1.8 and 15.0 ± 1.8 years respectively, p = 0.494), showed a significant difference in the 1-year return rate after delivery, as assessed by the Kaplan–Meier test: 32.0 % for the group ‘‘Without Preventive Letter’’, and 76.0 % for the group ‘‘With Preventive Letter’’ (p \ 0.001). The 1-year return rate after delivery of GDM mothers was 2.4 times higher in the group ‘‘With Preventive Letter’’ than in the group without it. We believe that this low-cost approach could be useful in other institutions caring for pregnant women with diabetes. Keywords
Diabetes Gestational Postpartum
Introduction Gestational diabetes mellitus (GDM) is defined as a glucose intolerance of variable severity occurring or diagnosed for the first time during pregnancy [1]. It is known that 6–12 weeks after delivery, up to onethird of women with GDM have either impaired glucose tolerance (IGT) or type-2 diabetes (DM2) [2]. A study in Danish mothers with GDM showed that the 11-year cumulative risk of DM2 plus IGT was 30.7 % (13.7 % DM2 and 17 % IGT), in comparison with mothers without GDM (0.0 and 5.3 % respectively) [3]. Other studies have shown that the risk of developing DM2 is up to 7 times higher in women with GDM compared to women without GDM [1].
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The World Health Organization (WHO) currently recommends postpartum glucose screening following GDM [2] in order to detect IGT and DM2. The outpatient visit needed for reviewing the screening tests provides a unique opportunity not only for detecting IGT and DM2, but also to discuss lifestyle changes in mothers who are still not diabetic, thus providing useful advice on the prevention of type 2 diabetes. Despite these recommendations, worldwide the majority of women with GDM fail to return for postpartum glucose testing. In 2010, Hunt et al. [2] stressed the need for the development of clinical procedures that encourage women with GDM to return for postpartum glucose screening. In this context, postal reminders have shown to be a useful approach to increase postpartum attendance for oral glucose tolerance testing [4]. Recently, Heatley et al. [4] in Australia, published their plan for a controlled clinical trial using a technically sophisticated and expensive cellular phone text message reminder system, aimed at increasing the attendance of GDM mothers for oral glucose tolerance test (OGTT) after delivery. The publication in 2013 of the planned study of Heatley et al., prompted us to share our experience, since our institution has significantly increased the return rate of GDM mothers for OGTT without escalating money expenditure. We aimed to measure the impact of what we called ‘‘Preventive Letter’’ on postpartum return rate of GDM mothers. This letter is a written document given directly (not by mail) to GDM patients on the last outpatient visit before delivery. Results show that since the introduction of this approach in 2003, our institution has more than doubled the rate of postpartum glucose screening among GDMs.
Patients and Methods This observational-prospective study included 468 singleton pregnancies, referred by Obstetricians to our diabetes and pregnancy team. The Health care network of our College of Medicine includes six Obstetrics and Gynecology outpatient clinics in the city of Santiago, in which faculty and staff carry out the evaluation and follow up of pregnant mothers, who in due course are admitted for delivery in our teaching hospital. Recruitment of patients and informed consent were approved by the College of Medicine Ethics Committee, and fulfilled the principles of the Declaration of Helsinki as revised in the year 2000. In Chile, 68.3 % of the population is covered by the Public National Health Fund (FONASA), whereas 31.7 % is covered by several types of private health insurance
123
Fig. 1 A model of the ‘‘Preventive Letter’’. The letter is divided into c three parts (from top to bottom): [A] current treatment of the patient´s GDM, [B] a summarized reminder of in-patient management of hyperglycemia, for the benefit of the in-duty Resident of the Obstetrics and Gynecology Department on the day of admission for delivery, and [C] a short paragraph prompting the patient to carry out OGTT, fasting insulin levels and serum lipid profile 6 weeks after delivery. (Laboratory orders are stapled to the back of the letter)
plans [5]. The healthcare network of our College of Medicine provides medical care to patients with both public and private insurance health plans. In 2009 we reported that, in addition to glucose, other nutrients were responsible for macrosomia in glucosecontrolled GDMs with overweight or obesity [6]. Thus, we applied for and obtained a 3-year research project whose objectives included the measurement of: [a] newborn C-Peptide levels in cord blood, and [b] maternal lipid profile and fasting insulin 6 weeks post partum. Thus, a sample tube for C-Peptide and laboratory orders for maternal lipids and fasting insulin (plus OGTT and HbA1c) were stapled to each preventive letter (see below, and Figs. 1, 2). In this context, usual postpartum laboratory tests (OGTT and HbA1c) were covered by the patient´s health insurance plan, and other tests, such as C-Peptide level in the cord blood (intrapartum) and maternal lipid profile and fasting insulin (6 weeks postpartum) were covered by our research project. Therefore, the patients had no extra payment for intra or postpartum laboratory tests. In 2003 we realized that only one-in-three of our patients with GDM returned for postpartum glucose screening. In order to improve this figure, we developed what we called a ‘‘Preventive Letter’’ (Fig. 1), i.e. a singlepage letter, written by the Endocrinologist, and given to the GDM patient on the last outpatient visit prior to delivery. As seen in Fig. 1, this document includes three parts: [A] current treatment of GDM, [B] a summarized reminder of inpatient management of hyperglycemia, intended for the benefit of Residents and Staff of the Obstetrics and Gynecology Department, and [C] a paragraph prompting the patient to carry out OGTT and other tests 6 weeks after delivery. As seen in Fig. 2, the whole set given to each patient included: the Preventive Letter itself, orders for postpartum laboratory tests (dated 6 weeks after expected date of birth), and a transparent plastic bag containing a tube with instructions for a sample of cord blood to be taken at delivery. We recorded anonymous patient data in PASW Statistics No. 18 (version 18.0.0, July 30th, 2009; Ó 2003–2007 Polar Engineering Consulting). Continuous variables were expressed as the mean plus/minus one standard deviation. Comparisons of means were carried out with Student t test.
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Categorical variables were analyzed by Chi square test. Kaplan–Meier analysis was performed for the actuarial probability of returning for OGTT within 1-year (52 weeks) after delivery. Comparison of two Kaplan– Meier curves was carried out by Log Rank Test. Variables influencing actuarial probabilities were analyzed by Cox
Table 2 Cox Regression of variables potentially capable of influencing the return rate after GDM in the two groups of singleton pregnancies with gestational diabetes mellitus treated and followed between 1998 and 2013 Variable
Without Preventive Letter (n = 215)
With Preventive Letter (n = 253)
B
p value*
B
Maternal age (years)
-0.084
0.024
0.031
0.209
Maternal education (years) Maternal BMI (kg/m2)
-0.165 0.088
0.161 0.124
0.015 0.029
0.833 0.339
p value*
Insulin therapy
0.166
0.737
-0.556
0.055
Out-of-town
0.987
0.987
11.3
0.971
* Bonferroni adjustment for 5 tests: p \ 0.01
Fig. 2 From left to right hand side, we show a summary of the whole set given to the GDM patient on the last visit prior to delivery: The ‘‘Preventive Letter’’ itself, with parts A, B and C (as described in Fig. 1); the post partum laboratory order (dated 6 weeks after expected date of birth), and a transparent plastic bag containing a tube plus instructions for taking a sample of cord blood at delivery
Table 1 Clinical characteristics of the two groups of singleton pregnancies with gestational diabetes mellitus treated and followed between 1998 and 2013
Regression. A value of p \ 0.05 was considered significant for all tests.
Variable
Without Preventive Letter (n = 215)
With Preventive Letter (n = 253)
Maternal age (years)
33.0 ± 5.4
32.4 ± 4.8
0.199
Results
Maternal education (years)
14.9 ± 1.8
15.0 ± 1.8
0.516
Maternal BMI C25 (kg/m2)
132 (61.3 %)
134 (53.0 %)
0.052
OGTT 2-h glucose (mg/ dL)
165.9 ± 25.8
161.9 ± 21.3
0.068
Insulin therapy
68 (31.6 %)
121 (47.7 %)
\0.001*
Large for gestational age newborn
32 (14.9 %)
35 (14.0 %)
0.891
Out-of-town
5 (2.3 %)
2 (0.8 %)
0.705
In longitudinal-observational fashion, we evaluated two groups of GDM pregnancies: ‘‘Without Preventive Letter’’ (n = 253, years 1998–2002), and ‘‘With Preventive Letter’’ (n = 215, years 2003–1013). Table 1 shows the clinical characteristics of the two groups of singleton pregnancies with GDM treated and followed between 1998 and 2013. The single variable that was significantly different between the groups was the frequency of insulin therapy, which was higher in the group ‘‘With Preventive Letter’’ than in the group without it. However, Cox Regression in both groups (Table 2) shows that neither insulin therapy nor any other variable influenced the return rate after GDM.
* Bonferroni adjustment for 7 tests: p \ 0.0073
123
p value
Fig. 3 Two Kaplan–Meier curves for the probability of GDM patients to return for a postpartum visit with OGTT results. Comparing both curves at 52 weeks (1 year): With Preventive Letter (n = 215; probability = 76.0 %), and Without Preventive Letter (n = 253, probability = 32.0 %). Log Rank v2 = 113.5; p \ 0.001
Matern Child Health J
Fig. 4 Three Kaplan–Meier curves for the probability of GDM patients to return for a postpartum visit with OGTT. These are the results observed in GDM patients with ‘‘Preventive Letter’’ belonging to three different periods, as determined by the date of last menstrual period: 2003–2005 (n = 13), 2006–2008 (n = 46), and 2009–2011 (n = 81). When we compared the three curves at 52 weeks (1 year), the return probabilities were, respectively, 51.0, 79.0, and 84.0 % (Log Rank v2 = 14.1; p = 0.003). The 2012–2014 period (n = 75) was not included as some patients [a] have not had their delivery by the time this manuscript was written, or [b] did not have enough postpartum follow up time for the return visit to take place
Figure 3 shows the probability of GDM patients to return for a postpartum visit with OGTT results. The 1-year probabilities were 32 % (‘‘Without Preventive Letter’’) and 76 % (‘‘With Preventive Letter’’), with p \ 0.001. When we compared our data with the return rate 428 days (61.1 weeks) after delivery published by Smirnakis et al. [7], our return figures became 33 and 78 % respectively. Further analysis of the data showed that the return rate increased over time, as shown in Fig. 4, where we divided the group of patients ‘‘With Preventive Letter’’ into three periods, as determined by the date of last menstrual period: 2003–2005 (n = 13), 2006–2008 (n = 46), and 2009–2011 (n = 81). The probability of GDM patients to return for a postpartum visit with OGTT, were, respectively, 51, 79, and 84 % (p = 0.003). The 2012–2014 period (n = 75) was not included since [a] some patients have not had their delivery yet, or [b] their post-partum follow up time was too short.
Discussion We studied the impact of a ‘‘Preventive Letter’’ in the return rate after delivery of 468 singleton GDM pregnancies treated at our institution between 1998 and 2013. We found that after the introduction of the ‘‘Preventive Letter’’ in 2003, the 1-year postpartum return rate with OGTT increased 2.4 times, from 32 to 76 %.
We also observed a stepwise increase in the return rates between 2003 and 2013, to 51, 79, and 84 %. We interpret this phenomenon as the result of a ‘‘learning effect’’ in the faculty and staff of the Obstetrics and Gynecology department, who gradually have became skilled at reinforcing in their patients the educative contents of the ‘‘Preventive Letter’’. In 2005, in Boston, MA, USA, Smirnakis et al. [7] found that only 37 % of women having a history of GDM were screened for postpartum DM, following the guidelines published by the American Diabetes Association. These authors reported a median time from delivery to the first such testing of 428 days (61 weeks). By using the same cutoff point, our postpartum return rates for the groups with and without ‘‘Preventive Letter’’ would be 33–78 %, respectively. In other words, our 61-week return rate with the ‘‘Preventive Letter’’ was 2.1 times higher than the figures reported by Smirnakis et al. In 2013, Carson et al. [8] reviewed the literature and found that reported GDM postpartum testing ranged from 9 to 95 % without a clear explanation for this wide variation. They concluded that the use of proactive patient contact programs (phone calls, education programs, or postal reminders) significantly increased postpartum testing rates from a mean of 33 % up to 60 %. In the year 2013, in Australia, Heatley et al. [4] published their plans for a controlled clinical trial using a cellular phone text message reminder system. Their method was intended to increase the attendance to OGTT within 6 months after delivery of GDM mothers from 37 to 55 % in the intervention group. What does our study add to the current knowledge on GDM? Between 1996—when our diabetes and pregnancy interdisciplinary team started- and 2003, the return rate for OGTT after GDM was only 32 %. At that time we implemented the ‘‘Preventive Letter’’ as described above, and in the subsequent years, as we continued to care for GDM pregnancies, we observed a significant increase in the return rate of our patients. In other words, the ‘‘Preventive Letter’’ method was not designed as a ‘‘trial’’. Instead, it was a simple approach that was successfully implemented to solve a well-known clinical problem. It was not until September 2013, that we realized that our successful experience could be of utility to other institutions worldwide. The paper that prompted our decision to publish the results of the use of the ‘‘Preventive Letter’’ was the one by Heatley et al. [4], explaining their DIAMIND protocol using short message service (SMS) for cellular phones in order to remind women who had GDM to return for OGTT testing. This well-designed trial, to be carried out in Australia and New Zealand, has the potential to be highly successful, but it is quite expensive. As healthcare institutions in other countries could not be in the
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position to spend the sums needed to implement such a sophisticated SMS system, we decided to share our experience with the ‘‘Preventive Letter’’ method, which is much less expensive. We conclude that the ‘‘Preventive Letter’’, given to the patient in person on the last antepartum visit, can increase the postpartum return rate with OGTT from 32 to 76 %. Apart from this 2.4-fold increase in return rates, the ‘‘Preventive Letter’’ has in our view, three additional advantages, particularly when attendance of the delivery by staff unfamiliar with the patient is a possibility: (a) It gives information about both current and intrapartum treatment; (b) the letter is accompanied by the laboratory orders needed for postpartum testing, and (c) the letter can be accompanied by other materials in case other laboratory evaluations are necessary.
References 1. Kaiser, B., Razurel, C., & Jeannot, E. (2013). Impact of health beliefs, social support and self-efficacy on physical activity and dietary habits during the post-partum period after gestational diabetes mellitus: Study protocol. BMC Pregnancy and Childbirth, 13, 133–141. doi:10.1186/1471-2393-13-133.
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2. Hunt, K. J., Logan, S. L., Conway, D. L., & Korte, J. E. (2010). Postpartum screening following GDM: How well are we doing? Current Diabetes Reports, 10(3), 235–241. doi:10.1007/s11892010-0110-x. 3. Damm, P. (1998). Gestational diabetes mellitus and subsequent development of overt diabetes mellitus. Danish Medical Bulletin, 45(5), 495–509. 4. Heatley, E., Middleton, P., Hague, W., & Crowther, C. (2013). The DIAMIND study: Postpartum SMS reminders to women who have had gestational diabetes mellitus to test for type 2 diabetes: a randomised controlled trial—study protocol. BMC Pregnancy Childbirth, 12(13), 92. doi:10.1186/1471-2393-13-92. 5. Missoni, E., Solimano, G. (2014). Towards universal health coverage: the chilean experience. World Health Report (2010) Background paper, no. 4. http://www.who.int/healthsystems/ topics/financing/healthreport/4Chile.pdf. Accessed 6 May 2014. 6. Olmos, P. R., Borzone, G. R., Olmos, R. I., Valencia, C., Bravo, F. A., Hodgson, M. I., et al. (2012). Gestational diabetes and prepregnancy overweight: Possible factors involved in newborn macrosomia. Journal of Obstetrics and Gynaecology Research, 38, 208–214. doi:10.1111/j.1447-0756.2011.01681.x. 7. Smirnakis, K. V., Chasan-Taber, L., Wolf, M., Markenson, G., Ecker, J. L., & Thadhani, R. (2005). Postpartum diabetes screening in women with a history of gestational diabetes. Obstetrics and Gynecology, 106(6), 1297–1303. 8. Carson, M. P., Frank, M. I., & Keely, E. (2013). Original research: Postpartum testing rates among women with a history of gestational diabetes-Systematic review. Primary Care Diabetes, 7(3), 177–186. doi:10.1016/j.pcd.2013.04.007.
METHODOLOGICAL NOTES
Preventive Letter: Doubling the Return Rate After Gestational Diabetes Mellitus Pablo R. Olmos • Gisella R. Borzone • Loni Berkowitz • Nicola´s Mertens • Dolores Busso • Jose´ L. Santos • Jose´ A. Poblete • Claudio Vera • Cristia´n Belmar Denisse Goldenberg • Ba´rbara Samith • Ana M. Acosta • Manuel Escalona
•
Ó Springer Science+Business Media New York 2014
Abstract To measure the impact of a ‘‘Preventive Letter’’ designed to encourage the return of gestational diabetes mellitus (GDM) mothers to follow up visit after delivery, in the context of a worldwide concern about low return rates after delivery of these patients. Mothers with GDM require medical evaluation and an oral glucose tolerance test (OGTT) 6 weeks after delivery, in order to: [a] confirm remission of GDM and [b] provide advice on the prevention of type 2 diabetes. In the year 2003 we developed a ‘‘Preventive Letter’’, containing three aspects: [a] current treatment, [b] suggested management during labor, and [c] a stapled laboratory order for OGTT to be
Project Identification: FONDECYT No. 1120682. P. R. Olmos L. Berkowitz N. Mertens D. Busso J. L. Santos D. Goldenberg B. Samith A. M. Acosta M. Escalona Department of Nutrition, Pontificia Universidad Cato´lica de Chile, Santiago, Chile P. R. Olmos J. A. Poblete C. Vera C. Belmar B. Samith Department of Obstetrics and Gynecology, Pontificia Universidad Cato´lica de Chile, Santiago, Chile P. R. Olmos (&) College of Medicine, Pontificia Universidad Cato´lica de Chile, Alameda 340, Santiago, Chile e-mail: [email protected] G. R. Borzone Respiratory Diseases, College of Medicine, Pontificia Universidad Cato´lica de Chile, Santiago, Chile L. Berkowitz D. Busso Department of Gastroenterology, Pontificia Universidad Cato´lica de Chile, Santiago, Chile
performed 6 weeks after delivery. The return rate after delivery was assessed in two groups of GDM mothers: [a] ‘‘Without Preventive Letter’’ (n = 253), and ‘‘With Preventive Letter’’ (n = 215). Both groups, similar with respect to age (33.0 ± 5.4 and 32.3 ± 4.9 years respectively, p = 0.166) and education time (14.9 ± 1.8 and 15.0 ± 1.8 years respectively, p = 0.494), showed a significant difference in the 1-year return rate after delivery, as assessed by the Kaplan–Meier test: 32.0 % for the group ‘‘Without Preventive Letter’’, and 76.0 % for the group ‘‘With Preventive Letter’’ (p \ 0.001). The 1-year return rate after delivery of GDM mothers was 2.4 times higher in the group ‘‘With Preventive Letter’’ than in the group without it. We believe that this low-cost approach could be useful in other institutions caring for pregnant women with diabetes. Keywords
Diabetes Gestational Postpartum
Introduction Gestational diabetes mellitus (GDM) is defined as a glucose intolerance of variable severity occurring or diagnosed for the first time during pregnancy [1]. It is known that 6–12 weeks after delivery, up to onethird of women with GDM have either impaired glucose tolerance (IGT) or type-2 diabetes (DM2) [2]. A study in Danish mothers with GDM showed that the 11-year cumulative risk of DM2 plus IGT was 30.7 % (13.7 % DM2 and 17 % IGT), in comparison with mothers without GDM (0.0 and 5.3 % respectively) [3]. Other studies have shown that the risk of developing DM2 is up to 7 times higher in women with GDM compared to women without GDM [1].
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The World Health Organization (WHO) currently recommends postpartum glucose screening following GDM [2] in order to detect IGT and DM2. The outpatient visit needed for reviewing the screening tests provides a unique opportunity not only for detecting IGT and DM2, but also to discuss lifestyle changes in mothers who are still not diabetic, thus providing useful advice on the prevention of type 2 diabetes. Despite these recommendations, worldwide the majority of women with GDM fail to return for postpartum glucose testing. In 2010, Hunt et al. [2] stressed the need for the development of clinical procedures that encourage women with GDM to return for postpartum glucose screening. In this context, postal reminders have shown to be a useful approach to increase postpartum attendance for oral glucose tolerance testing [4]. Recently, Heatley et al. [4] in Australia, published their plan for a controlled clinical trial using a technically sophisticated and expensive cellular phone text message reminder system, aimed at increasing the attendance of GDM mothers for oral glucose tolerance test (OGTT) after delivery. The publication in 2013 of the planned study of Heatley et al., prompted us to share our experience, since our institution has significantly increased the return rate of GDM mothers for OGTT without escalating money expenditure. We aimed to measure the impact of what we called ‘‘Preventive Letter’’ on postpartum return rate of GDM mothers. This letter is a written document given directly (not by mail) to GDM patients on the last outpatient visit before delivery. Results show that since the introduction of this approach in 2003, our institution has more than doubled the rate of postpartum glucose screening among GDMs.
Patients and Methods This observational-prospective study included 468 singleton pregnancies, referred by Obstetricians to our diabetes and pregnancy team. The Health care network of our College of Medicine includes six Obstetrics and Gynecology outpatient clinics in the city of Santiago, in which faculty and staff carry out the evaluation and follow up of pregnant mothers, who in due course are admitted for delivery in our teaching hospital. Recruitment of patients and informed consent were approved by the College of Medicine Ethics Committee, and fulfilled the principles of the Declaration of Helsinki as revised in the year 2000. In Chile, 68.3 % of the population is covered by the Public National Health Fund (FONASA), whereas 31.7 % is covered by several types of private health insurance
123
Fig. 1 A model of the ‘‘Preventive Letter’’. The letter is divided into c three parts (from top to bottom): [A] current treatment of the patient´s GDM, [B] a summarized reminder of in-patient management of hyperglycemia, for the benefit of the in-duty Resident of the Obstetrics and Gynecology Department on the day of admission for delivery, and [C] a short paragraph prompting the patient to carry out OGTT, fasting insulin levels and serum lipid profile 6 weeks after delivery. (Laboratory orders are stapled to the back of the letter)
plans [5]. The healthcare network of our College of Medicine provides medical care to patients with both public and private insurance health plans. In 2009 we reported that, in addition to glucose, other nutrients were responsible for macrosomia in glucosecontrolled GDMs with overweight or obesity [6]. Thus, we applied for and obtained a 3-year research project whose objectives included the measurement of: [a] newborn C-Peptide levels in cord blood, and [b] maternal lipid profile and fasting insulin 6 weeks post partum. Thus, a sample tube for C-Peptide and laboratory orders for maternal lipids and fasting insulin (plus OGTT and HbA1c) were stapled to each preventive letter (see below, and Figs. 1, 2). In this context, usual postpartum laboratory tests (OGTT and HbA1c) were covered by the patient´s health insurance plan, and other tests, such as C-Peptide level in the cord blood (intrapartum) and maternal lipid profile and fasting insulin (6 weeks postpartum) were covered by our research project. Therefore, the patients had no extra payment for intra or postpartum laboratory tests. In 2003 we realized that only one-in-three of our patients with GDM returned for postpartum glucose screening. In order to improve this figure, we developed what we called a ‘‘Preventive Letter’’ (Fig. 1), i.e. a singlepage letter, written by the Endocrinologist, and given to the GDM patient on the last outpatient visit prior to delivery. As seen in Fig. 1, this document includes three parts: [A] current treatment of GDM, [B] a summarized reminder of inpatient management of hyperglycemia, intended for the benefit of Residents and Staff of the Obstetrics and Gynecology Department, and [C] a paragraph prompting the patient to carry out OGTT and other tests 6 weeks after delivery. As seen in Fig. 2, the whole set given to each patient included: the Preventive Letter itself, orders for postpartum laboratory tests (dated 6 weeks after expected date of birth), and a transparent plastic bag containing a tube with instructions for a sample of cord blood to be taken at delivery. We recorded anonymous patient data in PASW Statistics No. 18 (version 18.0.0, July 30th, 2009; Ó 2003–2007 Polar Engineering Consulting). Continuous variables were expressed as the mean plus/minus one standard deviation. Comparisons of means were carried out with Student t test.
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Categorical variables were analyzed by Chi square test. Kaplan–Meier analysis was performed for the actuarial probability of returning for OGTT within 1-year (52 weeks) after delivery. Comparison of two Kaplan– Meier curves was carried out by Log Rank Test. Variables influencing actuarial probabilities were analyzed by Cox
Table 2 Cox Regression of variables potentially capable of influencing the return rate after GDM in the two groups of singleton pregnancies with gestational diabetes mellitus treated and followed between 1998 and 2013 Variable
Without Preventive Letter (n = 215)
With Preventive Letter (n = 253)
B
p value*
B
Maternal age (years)
-0.084
0.024
0.031
0.209
Maternal education (years) Maternal BMI (kg/m2)
-0.165 0.088
0.161 0.124
0.015 0.029
0.833 0.339
p value*
Insulin therapy
0.166
0.737
-0.556
0.055
Out-of-town
0.987
0.987
11.3
0.971
* Bonferroni adjustment for 5 tests: p \ 0.01
Fig. 2 From left to right hand side, we show a summary of the whole set given to the GDM patient on the last visit prior to delivery: The ‘‘Preventive Letter’’ itself, with parts A, B and C (as described in Fig. 1); the post partum laboratory order (dated 6 weeks after expected date of birth), and a transparent plastic bag containing a tube plus instructions for taking a sample of cord blood at delivery
Table 1 Clinical characteristics of the two groups of singleton pregnancies with gestational diabetes mellitus treated and followed between 1998 and 2013
Regression. A value of p \ 0.05 was considered significant for all tests.
Variable
Without Preventive Letter (n = 215)
With Preventive Letter (n = 253)
Maternal age (years)
33.0 ± 5.4
32.4 ± 4.8
0.199
Results
Maternal education (years)
14.9 ± 1.8
15.0 ± 1.8
0.516
Maternal BMI C25 (kg/m2)
132 (61.3 %)
134 (53.0 %)
0.052
OGTT 2-h glucose (mg/ dL)
165.9 ± 25.8
161.9 ± 21.3
0.068
Insulin therapy
68 (31.6 %)
121 (47.7 %)
\0.001*
Large for gestational age newborn
32 (14.9 %)
35 (14.0 %)
0.891
Out-of-town
5 (2.3 %)
2 (0.8 %)
0.705
In longitudinal-observational fashion, we evaluated two groups of GDM pregnancies: ‘‘Without Preventive Letter’’ (n = 253, years 1998–2002), and ‘‘With Preventive Letter’’ (n = 215, years 2003–1013). Table 1 shows the clinical characteristics of the two groups of singleton pregnancies with GDM treated and followed between 1998 and 2013. The single variable that was significantly different between the groups was the frequency of insulin therapy, which was higher in the group ‘‘With Preventive Letter’’ than in the group without it. However, Cox Regression in both groups (Table 2) shows that neither insulin therapy nor any other variable influenced the return rate after GDM.
* Bonferroni adjustment for 7 tests: p \ 0.0073
123
p value
Fig. 3 Two Kaplan–Meier curves for the probability of GDM patients to return for a postpartum visit with OGTT results. Comparing both curves at 52 weeks (1 year): With Preventive Letter (n = 215; probability = 76.0 %), and Without Preventive Letter (n = 253, probability = 32.0 %). Log Rank v2 = 113.5; p \ 0.001
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Fig. 4 Three Kaplan–Meier curves for the probability of GDM patients to return for a postpartum visit with OGTT. These are the results observed in GDM patients with ‘‘Preventive Letter’’ belonging to three different periods, as determined by the date of last menstrual period: 2003–2005 (n = 13), 2006–2008 (n = 46), and 2009–2011 (n = 81). When we compared the three curves at 52 weeks (1 year), the return probabilities were, respectively, 51.0, 79.0, and 84.0 % (Log Rank v2 = 14.1; p = 0.003). The 2012–2014 period (n = 75) was not included as some patients [a] have not had their delivery by the time this manuscript was written, or [b] did not have enough postpartum follow up time for the return visit to take place
Figure 3 shows the probability of GDM patients to return for a postpartum visit with OGTT results. The 1-year probabilities were 32 % (‘‘Without Preventive Letter’’) and 76 % (‘‘With Preventive Letter’’), with p \ 0.001. When we compared our data with the return rate 428 days (61.1 weeks) after delivery published by Smirnakis et al. [7], our return figures became 33 and 78 % respectively. Further analysis of the data showed that the return rate increased over time, as shown in Fig. 4, where we divided the group of patients ‘‘With Preventive Letter’’ into three periods, as determined by the date of last menstrual period: 2003–2005 (n = 13), 2006–2008 (n = 46), and 2009–2011 (n = 81). The probability of GDM patients to return for a postpartum visit with OGTT, were, respectively, 51, 79, and 84 % (p = 0.003). The 2012–2014 period (n = 75) was not included since [a] some patients have not had their delivery yet, or [b] their post-partum follow up time was too short.
Discussion We studied the impact of a ‘‘Preventive Letter’’ in the return rate after delivery of 468 singleton GDM pregnancies treated at our institution between 1998 and 2013. We found that after the introduction of the ‘‘Preventive Letter’’ in 2003, the 1-year postpartum return rate with OGTT increased 2.4 times, from 32 to 76 %.
We also observed a stepwise increase in the return rates between 2003 and 2013, to 51, 79, and 84 %. We interpret this phenomenon as the result of a ‘‘learning effect’’ in the faculty and staff of the Obstetrics and Gynecology department, who gradually have became skilled at reinforcing in their patients the educative contents of the ‘‘Preventive Letter’’. In 2005, in Boston, MA, USA, Smirnakis et al. [7] found that only 37 % of women having a history of GDM were screened for postpartum DM, following the guidelines published by the American Diabetes Association. These authors reported a median time from delivery to the first such testing of 428 days (61 weeks). By using the same cutoff point, our postpartum return rates for the groups with and without ‘‘Preventive Letter’’ would be 33–78 %, respectively. In other words, our 61-week return rate with the ‘‘Preventive Letter’’ was 2.1 times higher than the figures reported by Smirnakis et al. In 2013, Carson et al. [8] reviewed the literature and found that reported GDM postpartum testing ranged from 9 to 95 % without a clear explanation for this wide variation. They concluded that the use of proactive patient contact programs (phone calls, education programs, or postal reminders) significantly increased postpartum testing rates from a mean of 33 % up to 60 %. In the year 2013, in Australia, Heatley et al. [4] published their plans for a controlled clinical trial using a cellular phone text message reminder system. Their method was intended to increase the attendance to OGTT within 6 months after delivery of GDM mothers from 37 to 55 % in the intervention group. What does our study add to the current knowledge on GDM? Between 1996—when our diabetes and pregnancy interdisciplinary team started- and 2003, the return rate for OGTT after GDM was only 32 %. At that time we implemented the ‘‘Preventive Letter’’ as described above, and in the subsequent years, as we continued to care for GDM pregnancies, we observed a significant increase in the return rate of our patients. In other words, the ‘‘Preventive Letter’’ method was not designed as a ‘‘trial’’. Instead, it was a simple approach that was successfully implemented to solve a well-known clinical problem. It was not until September 2013, that we realized that our successful experience could be of utility to other institutions worldwide. The paper that prompted our decision to publish the results of the use of the ‘‘Preventive Letter’’ was the one by Heatley et al. [4], explaining their DIAMIND protocol using short message service (SMS) for cellular phones in order to remind women who had GDM to return for OGTT testing. This well-designed trial, to be carried out in Australia and New Zealand, has the potential to be highly successful, but it is quite expensive. As healthcare institutions in other countries could not be in the
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position to spend the sums needed to implement such a sophisticated SMS system, we decided to share our experience with the ‘‘Preventive Letter’’ method, which is much less expensive. We conclude that the ‘‘Preventive Letter’’, given to the patient in person on the last antepartum visit, can increase the postpartum return rate with OGTT from 32 to 76 %. Apart from this 2.4-fold increase in return rates, the ‘‘Preventive Letter’’ has in our view, three additional advantages, particularly when attendance of the delivery by staff unfamiliar with the patient is a possibility: (a) It gives information about both current and intrapartum treatment; (b) the letter is accompanied by the laboratory orders needed for postpartum testing, and (c) the letter can be accompanied by other materials in case other laboratory evaluations are necessary.
References 1. Kaiser, B., Razurel, C., & Jeannot, E. (2013). Impact of health beliefs, social support and self-efficacy on physical activity and dietary habits during the post-partum period after gestational diabetes mellitus: Study protocol. BMC Pregnancy and Childbirth, 13, 133–141. doi:10.1186/1471-2393-13-133.
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2. Hunt, K. J., Logan, S. L., Conway, D. L., & Korte, J. E. (2010). Postpartum screening following GDM: How well are we doing? Current Diabetes Reports, 10(3), 235–241. doi:10.1007/s11892010-0110-x. 3. Damm, P. (1998). Gestational diabetes mellitus and subsequent development of overt diabetes mellitus. Danish Medical Bulletin, 45(5), 495–509. 4. Heatley, E., Middleton, P., Hague, W., & Crowther, C. (2013). The DIAMIND study: Postpartum SMS reminders to women who have had gestational diabetes mellitus to test for type 2 diabetes: a randomised controlled trial—study protocol. BMC Pregnancy Childbirth, 12(13), 92. doi:10.1186/1471-2393-13-92. 5. Missoni, E., Solimano, G. (2014). Towards universal health coverage: the chilean experience. World Health Report (2010) Background paper, no. 4. http://www.who.int/healthsystems/ topics/financing/healthreport/4Chile.pdf. Accessed 6 May 2014. 6. Olmos, P. R., Borzone, G. R., Olmos, R. I., Valencia, C., Bravo, F. A., Hodgson, M. I., et al. (2012). Gestational diabetes and prepregnancy overweight: Possible factors involved in newborn macrosomia. Journal of Obstetrics and Gynaecology Research, 38, 208–214. doi:10.1111/j.1447-0756.2011.01681.x. 7. Smirnakis, K. V., Chasan-Taber, L., Wolf, M., Markenson, G., Ecker, J. L., & Thadhani, R. (2005). Postpartum diabetes screening in women with a history of gestational diabetes. Obstetrics and Gynecology, 106(6), 1297–1303. 8. Carson, M. P., Frank, M. I., & Keely, E. (2013). Original research: Postpartum testing rates among women with a history of gestational diabetes-Systematic review. Primary Care Diabetes, 7(3), 177–186. doi:10.1016/j.pcd.2013.04.007.
