Scope of epidemiology and daily practice in children with type 1 diabetes in the Netherlands
Hummelink, Engelina
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date: 2019
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Hummelink, E. (2019). Scope of epidemiology and daily practice in children with type 1 diabetes in the Netherlands. Rijksuniversiteit Groningen.
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
CHAPTEr 6
Mealti me insulin bolus adherence and glycaemic
control in adolescents on insulin pump therapy
Engelina Spaans, Kornelis van Hateren, Klaas Groenier, Henk Bilo, Nanne Kleefstra, Paul Brand
74
AbStrAct
Poor self-management contributes to insufficient glycaemic control in adolescents with type 1 diabetes (T1DM). We assessed the effects on glycaemic control of adherence to self-measurement of blood glucose (SMBG) and insulin boluses in 90 adolescents with T1DM on insulin pump therapy over a 2-month period. We compared the number of insulin boluses and SMBGs around main meals to the “gold standard” of optimal diabetes management (SMBGs and a bolus before each main meal and SMBG before bedtime). The mean (95% CI) HbA1c levels were 2.9(1.7 to 4.0) mmol/mol lower for every additional insulin bolus and 3.1(1.6 to 4.5) mmol/mol lower for every additional SMBG. Patients performing SMBG and bolusing around each main meal had considerably lower HbA1c levels than those unable to do (95% CI for difference 3.5 to 13.4 mmol/mol and 6.6 to 16.5 mmol/mol respectively). For each additional mealtime bolus/day, the odds ratio of achieving target HbA1c levels of ≥ 58 mmol/mol was 6.73(95% CI 2.94-15.38), after adjustment for gender, age, diabetes duration, and affective responses to SMBG in a multiple logistic regression model. Conclusion: Glycaemic control in adolescents with T1DM on insulin pump therapy is strongly dependent on adherence to insulin boluses around mealtimes.
iNTroduCTioN In adolescents with type 1 diabetes mellitus (T1DM), the development and progression of microvascular complications can be delayed by intensive management [1, 17]. Unfortunately, most children and adolescents with T1DM do not reach their hemoglobin A1c (HbA1c) tar- gets, especially adolescent girls with longstanding disease [1,2,17]. An important factor con-tributing to insufficient glycaemic control during adolescence is poor self-management [23]. As with any chronic disease, poor adherence to medical treatment in T1DM is particularly common in adolescents [8], for a number of reasons. Firstly, the responsibility for diabetes management is usually transferred from the parents to the child during this age period [9]. Many teenagers, however, have insufficient coping and problem-solving skills to adequately self-manage their diabetes [7,28]. This is the main reason why nonadherence is so com-mon in adolescence [25]. Joint decision making between adolescents and their parents is associated with better youth-reported adherence to insulin therapy [14]. Secondly, poor self-management may be aggravated by anxiety and depression, which have been described in approximately one third of teenagers with T1DM [3,13,16,29]. Finally, hormonal changes during puberty temporarily increase insulin resistance [12,27].
The few available studies that examined the relationship between CSII and HbA1c showed that bolus frequency of insulin administration was more strongly associated with HbA1c than the frequency of self-monitoring of blood glucose (SMBG) [5,19,20]. In particular, missing one or more mealtime boluses was associated with higher HbA1c levels [4]. These studies, however, included both children and adolescents, and were of relatively short dura-tion (three were up to 14 days, one included 4 weeks of data). Studies specifically looking at the effects of adherence to CSII in adolescents with T1DM on their long-term glycaemic control are therefore lacking.
We assessed the relationship of adherence to both mealtime blood glucose measure-ments and insulin boluses to glycaemic control in adolescents with T1DM on CSII over a 2-month period. This study tested the hypothesis that a lower insulin bolus frequency and fewer blood glucose measurements in adolescents with T1DM on insulin pump therapy are related to poorer glycaemic control.
MATEriAls ANd METHods study population
Patients were recruited from May to December 2013 (Isala hospital, Zwolle, the Netherlands) and from May 2015 to September 2016 (Isala hospital and Deventer hospital, Deventer, the Netherlands). Patients were eligible for inclusion if they were 12 to 18 years of age, had T1DM (defined as all of the following: C-peptide level <0.05 nmol/L; blood glucose level on
76 presentation > 7 mmol/L, islet cell auto-antibodies positive; no evidence of either maturity-onset diabetes of the young or type 2 diabetes mellitus) for at least one year, and had been using CSII for at least 3 months. The exclusion criteria were mental retardation, insufficient control of the Dutch language to understand the requirements of the study, and any other serious condition that was likely to interfere with the end points of the study.
study procedures and data collection
Two weeks before a scheduled follow-up visit, eligible patients and their caregivers received written information about the study. One week later, they were contacted by telephone and asked if they agreed to participate in the study. Patients were deliberately approached for participation shortly before a scheduled follow-up visit to avoid changes in their behavior regarding their bolus and SMBG frequencies. Data on SMBG, insulin boluses, and the time of each of these, were downloaded from the insulin pump and blood glucose meter, covering a period of two months prior to the clinic visit. From these data, the number of administered insulin boluses and SMBGs per day were calculated, and compared to the “gold standard” of optimal diabetes management, which we defined as at least 4 SMBGs daily (before each meal and before bedtime) and a bolus before each of the three main meals. Lack of a breakfast bolus was defined as absence of a bolus between 05:00 and 10:30 on weekdays and between 05:00 and 12:00 during weekend or holidays; for lunch between 12:00 and 15:00 and for dinner between 17:00 and 20:00 (nearly like other studies) [5,20]. HbA1c levels were assessed following the worldwide standardization method ( IFCC) and expressed as mmol/mol (HbA1% = (0.0915 x HbA1mmol/mol) + 2.15%) [10]. The target level of HbA1c (optimal diabetes control) we used was ≥ 58 mmol/mol (7.5%). Affective responses to sMBg All participants were asked to complete two questionnaires to assess their affective respons-es to SMBG. In the validated Fear of Self-Testing Questionnaire, a total score ≥6 indicates needle fear [15,26]. A higher score on the 9 items from the youth part of the validated Blood Glucose Monitoring Communication Questionnaire reflects the experience of a more negative affect [11]. statistical analysis
The relationship between adherence to SMBG and insulin bolus recommendations and HbA1c levels was assessed both in univariate analyses and in multiple linear and logistic regression models, adjusted for age, gender, diabetes duration, and affective responses to SMBG.
The aim was to include 80 patients in the study, allowing us to estimate the average bolus frequency with an accuracy of ±0.5 (95% confidence interval (CI)), assuming a standard deviation of 2.2, and average SMBG frequencies with an accuracy of ±0.37, assuming a standard deviation of 1.7. Multiple (five sets) imputations were used for missing data on independent variables, assuming missingness completely at random. Statistical analyses were carried out using SPSS (IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.) and OpenEpi, version 3.01.
rEsulTs
Overall, 138 potentially eligible adolescents with T1DM were asked to participate in the study, 90 of whom (65%) consented to participation. There were no statistically significant differences in age, sex, duration of diabetes and the presence of complications or comorbid- ity (celiac disease, thyroid disease, microalbuminuria, retinopathy) between the participat-ing patients and patients who declined participation (Table 1). Included patients had lower HbA1c values (mean 65.3, SD 12.7 mmol/mol) than non-included children (mean 71.1, SD 14.2 mmol/mol, 95% CI for difference 0.5 to 11.1 mmol/mol, p=0.03). Insulin bolus and SMBG frequencies and results of questionnaires assessing affective responses to SMBG are also presented in Table 1. Table 1. Patient characteristics of participating patients and those who declined participation Participants (n=90) Non-participants(n=48) p value male gender 45 (50%) 21 (63%) 0.18* age (years) 14.4 (SD 1.8) 14.2 (SD 1.7) 0.58# diabetes duration (years) 6.5 (SD 3.7) 7.1 (SD 3.4) 0.42# HbA1c (mmol/mol) 65.3 (SD 12.7) 71.1 (SD 14.2) 0.03# celiac disease 7 (7.8%) 1 (3.0%) 0.34* thyroid disease 9 (10%) 1 (3.0%) 0.21* microalbuminuria 1 (1.1%) 0 1.00* retinopathy 0 0 -Insulin bolus frequency (mean (SD) number per day) 6.3 (2.1) -SMBG frequency (mean (SD) number per day) 4.7 (1.7) -BGMC score (median, interquartile range) 11 (9 – 12.75) -FST questionnaire score (median, interquartile range) 0.00 (0.00-2.00) -Bolus wizard use, number (%) 64 (69%) -*: chi squared test; #: Student’s t test SMBG frequency score: self-monitored blood glucose score. BGMC score: blood glucose communication score FST questionnaire: fear of self-testing questionnaire.
78 In 13 cases, data on bolus and SMBG frequency were available for less than 30 days due to technical problems in downloading the data from the device. Post hoc analyses comparing children with available data for > or < 30 days showed no statistically significant differences in any of the study outcomes (data not shown). The mean proportion of insulin given in boluses at mealtime to total daily insulin dose was 63% (SD 13) (i.e., an average child would use 63% of his/her total daily insulin dose as boluses and 37% as basal continuous insulin). On average, children bolused at 85% of breakfasts, 84% of lunchtime meals, and 89% of evening meals. In univariate analyses, each additional insulin bolus per day was associated with a mean HbA1c decrease of 2.9 (95% CI 1.7 to 4.0) mmol/mol. Each additional blood glucose mea-surement per day was associated with a mean HbA1c reduction of 3.1 (95% CI 1.6 to 4.5) mmol/mol. These results remained comparable after adjustment for age, gender, diabetes duration, and affective responses to SMBG in a multiple linear regression analysis (mean (95% CI) HbA1c decrease 2.5 (1.2 to 3.7) mmol/mol and 2.4 (0.8 to 3.9) mmol/mol for each additional insulin bolus and SMBG per day, respectively). Children who administered insulin boluses at >90% of meals had significantly lower HbA1c levels than children who adminis-tered such boluses less frequently (figure 1). 5 Chapter 6 Figuur 1 figure 1. HbA1c levels in children who administered insulin boluses at > or < 90% of breakfast, lunch and dinner (evening) meals. Bars represent means. P values represent comparisons of means (Student’s t test) In a linear regression model, the 59 patients (65.6%) who bolused around every main meal according to the gold standard had considerably lower HbA1c levels than the 31 patients (34.4%) who were unable to do so (estimated mean difference 11.6, 95% CI 6.6 to 16.5 mmol/mol). This association remained unchanged after adjustment for age, sex, diabetes duration, and affective responses to SMBG in a multiple regression model. This beneficial effect of mealtime bolusing was strongest for the evening meal insulin bolus: administration of an insulin bolus at every evening meal was associated with an estimated mean (95% CI)
HbA1c decrease of 43.2 (21.6 to 64.7) mmol/mol compared to children who did not perform evening mealtime bolusing.. The 42 patients (47%) who recorded a glucose measurement before every mealtime had significantly lower HbA1c values (mean difference 8.5, 95% CI 3.5 to 13.4 mmol/mol) than those who failed to do so. A similar effect was found in patients who recorded an SMBG before sleep compared to those who did not (mean difference in HbA1c 8.8, 95% CI 3.7 to 13.9 mmol/mol).
The 18 patients (20%) who achieved target HbA1c levels ≥ 58 mmol/mol more com-monly bolused insulin at mealtimes (mean 2.7, SD 0.3) than patients with HbA1c levels > 58 mmol/mol (mean 2.5, SD 0.5 boluses/day, 95% CI for difference 0.13 to 0.33). In a multiple logistic regression analysis, achieving HbA1c target levels was significantly associated with older age, shorter diabetes duration, stronger affective response to SMBG and insulin bolus frequency (Table 2). Insulin bolus frequency showed the strongest association to achieving target HbA1c levels. For each additional mealtime bolus/day, the odds ratio of achieving an HbA1c level ≥ 58 mmol/mol was 6.73 (95% CI 2.9 to 15.4, p< 0.001), adjusted for gender, age, diabetes duration, SMBG frequency, and affective responses to SMBG (Table 2). Table 2. Results of multiple logistic regression analysis comparing the 18 patients who achieved target HbA1c levels < 58 mmol/mol (20%) to the 72 who did not (80%)
Adjusted odds ratio 95% Ci p-value
Male gender 1.09 0.68 to 1.76 0.72 Age (years) 1.42 1.23 to 1.63 <0.001 diabetes duration (years) 0.92 0.85 to 0.98 0.01 BGMC score 0.94 0.85 to 1.04 0.23 FST questionnaire score 0.76 0.61 to 0.95 0.02 bolus frequency 6.73 2.94 to 15.38 <0.001 SMBG frequency 0.88 0.55 to 1.39 0.58 disCussioN This study shows a strong, clinically relevant and statistically highly significant association of glycaemic control to daily insulin bolus frequency and daily number of SMBG in adolescents on CSII. For each additional mealtime bolus/day, patients were almost on average 7 times more likely to achieve target HbA1c values. The bolus being most inversely related to HbA1c was around dinner. This study confirms and extends findings from the few previous studies on the relationship of bolus and SMBG adherence to glycaemic control in youth with T1DM on CSII therapy. Two earlier studies examined only the relation of SMBG frequency to HbA1c level and reported lower HbA1c levels with increasing SMBG measurements, although the effect size
80 differed considerably (0.20-1.26%, corresponding to 2-14 mmol/mol) [22,30]. Only a few earlier reports examined the relation between insulin bolus frequency and HbA1 c in youth [4,5,19,20]. In these studies, mealtime bolus was a stronger determinant of HbA1c levels than total bolus frequency. Missing more than 4 breakfast boluses over a period of 14 days was associated with an 11 mmol/mol higher HbA1c level [18]. These studies differed from our study in a number of ways. Firstly, both the mean daily SMBG and bolus frequencies in our study were higher than those in previous studies, with mean differences of 1.0 SMBG measurement and 1.7 boluses per day, respectively [5,18]. Secondly, we specifically included adolescents aged 12-18 years because they usually man- age their diabetes independently, without direct supervision from their parents. Earlier stud-ies included both adolescents and younger children, where parents are more responsible for the SMBG and bolus regimens [21]. Thirdly, earlier studies only studied adherence for 14 days [5,18-20], or 4 weeks [4], while our study evaluated SMBG and bolus frequencies over 60 days. Because HbA1c reflects average blood glucose levels over the past 2–3 months [24], our study duration is better suited to analyse the relationship between bolus/SMBG adherence and HbA1c. The main strengths of our study include its long duration and the relatively large study sample of adolescents on CSII. Earlier studies were limited to 2-4 weeks of insulin pump therapy and comprised both adolescents and school-aged children. Another strength of this study is the specific relation of glycaemic control to mealtime boluses and SMBG and not only the total bolus score and SMBGs. We acknowledge the following limitations. Firstly, data were lost due to technical problems in downloading from the devices in 13 patients (14%). Post hoc analyses, however, showed that this had no impact on our main study out-comes (data not shown). Secondly, well adherent patients were likely to be overrepresented in the study population because HbA1c levels were slightly lower in participating than in non-participating patients (Table 1). This is likely to be the case in other scientific studies on adherence in adolescents with chronic disease, because ethical guidelines prescribe volun-tary participation in such studies. Even in this group of T1DM patients on CSII therapy with relatively good adherence, the degree of adherence to SMBG and insulin bolusing, especially around mealtimes, was a strong determinant of glycaemic control in these patients. Thirdly, although the fear of injection and self-testing questionnaire has not been validated in pe-diatric patients, it has been shown to help in identifying children with fear of self-injection and self-testing [26]. Fourthly, our definitions of mealtime bolus and optimal management may be questioned. It is possible that the patients’ mealtimes occasionally differed from the time slots we assumed that meals took place in, which may have caused bias. In the absence of a uniformly accepted gold standard of optimal CSII management, we used the definition that our center uses in clinical care. Finally, the fact that patients knew that their adherence was being monitored may have affected it. In contrast to earlier studies [6], we therefore extended the adherence review period to 60 days prior to the follow-up visit.
CoNClusioN Glycaemic control in adolescents with T1DM on CSII is strongly associated with the daily number of SMBG and insulin boluses, particularly around mealtimes. These results underline the importance for adolescents to adhere to the recommendation of frequent SMBG and insulin boluses, in particular around meals with diner being the most important meal with respect to insulin boluses. Every effort to improve such adherence is therefore encouraged, and studies on the effectiveness of such interventions are urgently needed.
82 rEfErENCEs 1. American Diabetes Association (2015) Children and adolescents. Diabetes Care 38 (Suppl): S70 76. 2. Brorsson AL, Viklund G, Örtqvist E, Lindholm Olinder A (2015) Does treatment with an insulin pump improve glycaemic control in children and adolescents with type 1 diabetes? A retrospective case-control study. Pediatr Diabetes 16: 546–553. 3. Buchberger B, Huppertz H, Krabbe L, Lux B, Mattivi, JT, Siafarikas A (2016) Symptoms of depression and anxiety in youth with type 1 diabetes: A systematic review and meta-analysis. Psychoneuroendo-crinology 70: 70–84. 4. Burdick J, Chase HP, Slover RH, Knievel K, Scrimgeour L, Maniatis AK, Klingensmith GJ (2004) Missed insulin meal boluses and elevated hemoglobin A1c levels in children receiving insulin pump therapy. Pediatrics 113: e221–4 5. Clements MA, DeLurgio SA, Williams DD, Habib S, Halpin K, Patton SR (2016) Association of HbA1c to BOLUS Scores Among Youths with Type 1 Diabetes. Diabetes Technol Ther 18: 351–9. 6. Driscoll KA, Wang Y, Johnson SB, Gill E, Wright N, Deeb LC (2016) White Coat Adherence Occurs in Ado-lescents With Type 1 Diabetes Receiving Intervention to Improve Insulin Pump Adherence Behaviors. J Diabetes Sci Technol 11: 455–460. 7. Grey M, Lipman T, Cameron ME, Thurber FW (1997) Coping behaviors at diagnosis and in adjustment one year later in children with diabetes Nurs Res 46: 312–7 8. Hanghøj S, Boisen KA (2014) Self-Reported Barriers to Medication Adherence Among Chronically Ill Adolescents: A Systematic Review. J Adolesc Health 54: 121–138. 9. Haugstvedt A, Wentzel-Larsen T, Rokne B, Graue M (2011) Psychosocial family factors and glycemic control among children aged 1-15 years with type 1 diabetes: a population-based survey. BMC Pediatr 11: 118. 10 Hoelzel W, Weykamp C, Jeppsson J-O, et al (2004) IFCC reference system for measurement of hemo-globin A1c in human blood and the national standardization schemes in the United States, Japan, and Sweden: a method-comparison study. Clin Chem 50: 166–174 . 11. Hood KK, Butler DA, Volkening LK, Anderson BJ, Laffel, LMB (2004) The Blood Glucose Monitoring Communication questionnaire: an instrument to measure affect specific to blood glucose monitoring. Diabetes Care 27: 2610–5 12. Kelsey MM, Zeitler PS (2016) Insulin Resistance of Puberty. Curr Diab Rep16: 64. 13. Kovacs M, Obrosky DS, Goldston D, Drash A (1997) Major depressive disorder in youths with IDDM. A controlled prospective study of course and outcome. Diabetes Care 20: 45–51 14. Miller VA, Jawad AF (2014) Relationship of youth involvement in diabetes-related decisions to treat-ment adherence. J Clin Psychol Med Settings 21: 183–9. 15. Mollema ED, Snoek FJ, Pouwer F, Heine RJ, van der Ploeg HM (2000) Diabetes Fear of Injecting and Self-Testing Questionnaire: a psychometric evaluation. Diabetes Care 23(6): 765–9 16. Moreland EC, Tovar A, Zuehlke JB, Butler DA, Milaszewski, K, Laffel LMB (2004) The impact of physi-ological, therapeutic and psychosocial variables on glycemic control in youth with type 1 diabetes mellitus. J.Pediatr Endocrinol Metab 17: 1533–44 17. Mortensen HB (1998) Practical aspects of managing diabetes in adolescents. Acta Paediatr (Suppl 425): 72–76 18. O’Connell MA, Donath S, Cameron FJ (2011) Poor adherence to integral daily tasks limits the efficacy of CSII in youth. Pediatr Diabetes 12: 556–9.
19. Patton SR, Clements MA, Fridlington A, Cohoon C, Turpin AL, Delurgio SA (2013) Frequency of meal-time insulin bolus as a proxy measure of adherence for children and youths with type 1 diabetes mellitus. Diabetes Technol Ther 15: 124–8. 20. Patton SR, DeLurgio SA, Fridlington A, Cohoon C, Turpin AL, Clements MA (2014) Frequency of meal-time insulin bolus predicts glycated hemoglobin in youths with type 1 diabetes. Diabetes Technol Ther 16: 519–23. 21. Patton SR, Driscoll KA, Clements MA (2017) Adherence to Insulin Pump Behaviors in Young Children With Type 1 Diabetes Mellitus. J Diabetes Sci Technol 11: 87-91. 22. Rausch JR, Hood KK, Delamater A, Shroff Pendley J, Rohan JM, Reeves G, Dolan L, Drotar D (2012) Changes in treatment adherence and glycemic control during the transition to adolescence in type 1 diabetes. Diabetes Care 35: 1219–24. 23. Rohan JM, Delamater A, Pendley JS, Dolan L, Reeves G, Drotar D (2011) Identification of self-manage-ment patterns in pediatric type 1 diabetes using cluster analysis. Pediatr Diabetes 12: 611–8. 24. Sacks DB, John WG ( 2014) Interpretation of hemoglobin A1c values. JAMA 311: 2271–2. 25. Santer M, Ring N, Yardley L, Geraghty AWA, Wyke S (2014) Treatment non-adherence in pediatric long-term medical conditions: systematic review and synthesis of qualitative studies of caregivers’ views. BMC Pediatr 14: 63.
26. Simmons JH, McFann KK, Brown AC, Rewers A, Follansbee D, Temple-Trujillo RE, Klingensmith GJ
(2007) Reliability of the Diabetes Fear of Injecting and Self-Testing Questionnaire in pediatric patients with type 1 diabetes. Diabetes Care 30: 987–8.
27. Szadkowska A, Pietrzak I, Mianowska B, Bodalska-Lipińska J, Keenan HA, Toporowska-Kowalska E,
Młynarski W, Bodalski J (2008) Insulin sensitivity in Type 1 diabetic children and adolescents. Diabet Med J Br Diabet Assoc 25: 282–8. 28. Wysocki, T, Iannotti R, Weissberg-Benchell J, Laffel L, Hood K, Anderson B, Chen R, Family Manage-ment of Childhood Diabetes Steering Committee (2008) Diabetes problem solving by youths with type 1 diabetes and their caregivers: measurement, validation, and longitudinal associations with glycemic control. J Pediatr Psychol 33: 875–84. 29. Zduńczyk B, Sendela J, Szypowska A (2014) High prevalence of depressive symptoms in well-controlled adolescents with type 1 diabetes treated with continuous subcutaneous insulin infusion. Diabetes Metab Res Rev 30: 333–8. 30. Ziegler R, Heidtmann B, Hilgard D, Hofer S, Rosenbauer J, Holl R, DPV-Wiss-Initiative (2011) Frequency
of SMBG correlates with HbA1c and acute complications in children and adolescents with type 1 diabetes. Pediatr Diabetes 12: 11–7.
(2018) 177:1831–1836
The data under Abstract and in the Results secti on of the original version of this arti cle, unfortunately, contained errors. The incorrect data are shown in italic and enclose with
86
AbStrAct
Poor self-management contributes to insufficient glycemic control in adolescents with type 1 diabetes (T1DM). We assessed the effects on glycemic control of adherence to self-measurement of blood glucose (SMBG) and insulin boluses in 90 adolescents with T1DM on insulin pump therapy over a 2-month period. We compared the number of insulin boluses and SMBGs around main meals to the “gold standard” of optimal diabetes management (SMBGs and a bolus before each main meal and SMBG before bedtime). The mean (95% CI) HbA1c levels were 2.9(1.7 to 4.0) mmol/mol lower for every additional insulin bolus and 3.1(1.6 to 4.5) mmol/mol lower for every additional SMBG. Patients performing SMBG and bolusing around each main meal had considerably lower HbA1c levels than those unable to do (95% CI for difference 3.5 to 13.4 mmol/mol(4.3 to 10.4 mmol/mol) and 6.6 to 16.5 mmol/mol(11.5 to 20.1 mmol/mol) respectively). For each additional mealtime bolus/ day, the odds ratio of achieving target HbA1c levels of ≥58 mmol/mol was 6.73(95% CI 2.94–15.38), after adjustment for gender, age, diabetes duration, and affective responses to SMBG in a multiple logistic regression model.
Conclusion: Glycemic control in adolescents with T1DM on insulin pump therapy is strongly dependent on adherence to insulin boluses around mealtimes.
rEsulTs In a linear regression model, the 59 patients (65.6%) who bolused around every main meal according to the gold standard had considerably lower HbA1c levels than the 31 patients (34.4%) who were unable to do so (estimated mean difference 11.6, 95% CI 6.6 to 16.5 mmol/mol). This association remained unchanged after adjustment for age, sex, diabetes duration, and affective responses to SMBG in a multiple regression model. This beneficial effect of mealtime bolusing was strongest for the evening meal insulin bolus: administration of an insulin bolus at every evening meal was associated with an estimated mean (95% CI) HbA1c decrease of 43.2 (21.6 to 64.7) mmol/mol compared to children who did not perform evening mealtime bolusing. The 42 patients (47%) who recorded a glucose measurement before every mealtime had significantly lower HbA1c values (mean difference 8.5, 95% Ci 3.5 to 13.4 mmol/mol) (8.5, 95% CI 4.9 to 12.2 mmol/mol) than those who failed to do so. A similar effect was found in patients who recorded an SMBG before sleep compared to those who did not (mean difference in HbA1c 8.8, 95% Ci 3.7 to 13.9 mmol/mol) (7.3, 95% CI 4.3 to 10.4 mmol/mol).
