Persistence of Benefits of Continuous Subcutaneous Insulin Infusion in Very Young Children With Type 1 Diabetes: A Follow-up Report
Objective. Use of continuous subcutaneous insulin infusion (CSII) has increased dramatically in recent years, and pump therapy has been shown to be a safe and effective alternative to multiple daily injections in adults and older pediatric patients with type 1 diabetes. Its use in very young children, however, has been limited, although this group might be expected to benefit the most from CSII. The objective of this study was to analyze the CSII efficacy and safety data in very young children with type 1 diabetes from our Diabetes Clinic database.
Methods. Glycosylated hemoglobin (HbA1c), severe hypoglycemia (SH), and ketoacidosis (DKA) in the year before CSII were compared with corresponding values during pump treatment in all children who started CSII before age 7.
Results. Sixty-five children (mean age: 4.5 y at CSII initiation; range: 1.4–6.9 years; 28 girls; 3 black, 1 Hispanic) were analyzed for >162 patient-years of follow-up. Mean HbA1c (7.4 ± 1.0 prepump) decreased to 7.0 ± 0.9 after 12 months of CSII and continued to improve even after 4 years on CSII. The rate of SH was reduced by 53% (from 78 to 37/100 patient-years). Children who received daytime care from paid caregivers (n = 26) experienced significant reductions in HbA1c and hypoglycemia frequency. There were no episodes of DKA requiring emergency treatment in the year before CSII and 4 episodes (4 per 100 patient-years) after transition to pump.
Conclusions. CSII is a durable and effective means of optimizing glycemic control in very young patients with type 1 diabetes and may be superior to multiple daily injections in minimizing the risk of severe hypoglycemia in this age group. Employment of paid caregivers does not preclude safe and effective use of CSII.
Although continuous subcutaneous insulin infusion (CSII), or insulin pump therapy, was introduced almost 25 years ago,1 its use in routine care of type 1 diabetes in children has increased dramatically only recently. Meta-analyses of trials of CSII versus intensive injection therapy in adults have demonstrated significant improvements in glycemic control and hypoglycemia with use of insulin pumps.2,3 We4,5 and others6–8 have previously demonstrated the effectiveness of insulin pump therapy to lower glycosylated hemoglobin (HbA1c) and to reduce the incidence of hypoglycemia in older children and adolescents. Adolescents have also reported improved ability to cope with diabetes when using insulin pump therapy as compared with standard multiple daily injection therapy.4
The incidence of type 1 diabetes also seems to be increasing at an alarming rate in toddlers and preschool-aged children. Epidemiologic studies from Sweden,9 the United Kingdom,10 France,11 Switzerland,12 and Eastern Europe13 all report significant increases in diabetes incidence rates in children younger than 5 years (by as much as 2-to 4-fold) and/or a shift of the mean age at presentation to younger children. Pediatric diabetes clinicians are well aware of the difficulties in achieving glycemic targets in this age group. This challenging population is particularly susceptible to both hyperglycemia and hypoglycemia as a result of wide fluctuations in physical activity from day to day, unpredictable eating habits, frequent intercurrent infections, and difficulties in measuring and administering very small doses of rapid- and intermediate-acting insulins. There are also heightened concerns that severe hypoglycemic events may cause neurologic sequelae in infants and toddlers that are not seen in adolescents and adults with type 1 diabetes. Insulin pump therapy seems to be an appropriate therapeutic option to overcome many of these obstacles and allay some of these concerns. The confounding issue of child care, however, may pose a potentially formidable barrier to using insulin pump therapy in this age group.
Published reports of insulin pump use in toddlers and preschool-aged children seem to indicate a beneficial effect on glycemic control, but these series are limited to small sample sizes with short periods of follow-up,14,15 including our own previous study that reported outcomes in 26 children who were younger than 7 years.5 The issue of daytime paid caregivers for young children has never been addressed in the context of insulin pump use. With the imperative to achieve tight glycemic control in these youngest of children while minimizing hypoglycemic exposure, we have made extensive use of insulin pump therapy for our toddlers and preschoolers. Our present report describes long-term benefits of CSII on HbA1c and hypoglycemia in very young children with diabetes, including those who receive care either inside or outside the home by paid daytime care providers.
The study population consisted of all children who were initiated on insulin pump therapy at the Yale Pediatric Diabetes Center before their seventh birthday and for whom at least 3 months of prepump and 3 months of postpump data were available. Preliminary data on 26 of these children were reported previously.5 Children were generally initiated on insulin pump therapy at the request of their parents and only with the approval of the health care team. Preinitiation requirements for pump therapy included frequent monitoring of glucose levels with transcription into a written or computer log, adequate adult supervision of diabetes care, and ability to comprehend and implement pump treatment. All families underwent two 60- to 90-minute pump education sessions, once at pump initiation and again 2 to 3 days later, by 1 of the diabetes advanced practice nurses (J.H.A., E.A.D., or M.R.V.), who have extensive experience with insulin pump therapy and pump initiation training. Frequent telephone contact was maintained in the week between visits. Thereafter, the children were seen in routine 3-month intervals, as during standard injection therapy. No child was taken off insulin pump therapy by the health care team during the period of study.
Since 1995, a standard case report form has been completed on all patients in our program during each outpatient visit to prospectively track treatment variables and outcomes. Collection of clinical data was approved by the Yale University School of Medicine Human Investigation Committee with waiver of the requirement for written or oral consent. Height, weight, body mass index (BMI), insulin dose per kilogram, and HbA1c at pump initiation, as well as episodes of severe hypoglycemia (SH) and diabetic ketoacidosis (DKA) in the year before pump initiation, were compared with the same variables postpump. For the purposes of this analysis, SH was defined as an episode that required treatment with parenteral glucagon or dextrose, either by the family or emergency medical personnel, or was associated with seizure and/or loss of consciousness. DKA was defined as the presence of hyperglycemia and/or ketosis that required emergency medical treatment or inpatient hospitalization. For analysis of maternal work status, “maternal work” was defined as full-time employment outside the home of the affected child. Capillary HbA1c levels were obtained every 3 months and determined by DCA 2000 (Bayer Diagnostics, Tarrytown, NY) with a nondiabetic range of 4.2% to 6.3%.
HbA1c data are reported as mean ± SD. A mean “prepump” HbA1c was determined for each child on the basis of the mean of all available capillary HbA1c measurements for that child for up to 1 year before the date of the insulin pump initiation visit. HbA1c levels that were obtained within 3 months of diabetes diagnosis, which would reflect prediagnosis hyperglycemia, were not included in this calculation. HbA1c levels prepump versus postpump at each 6-month increment were compared using a repeated measures covariance pattern model with a first-order autoregressive correlation structure and linear contrasts to compare pre- with postpump HbA1c levels. The number of children in the analysis decreased as the duration of follow-up increased; therefore, although some children have been treated with CSII for >5 years, the period of follow-up was truncated to 4 years, a period for which 6 children were still assessable. For comparisons of HbA1c levels in the 2 caregiver groups, mean pre- and postpump HbA1c levels were analyzed by t test. To account for varying duration of prepump and postpump therapy among patients, all SH rate data are normalized per year and compared using log-linear models with generalized estimating equations to account for correlated data.16
The study population was composed of 65 children (28 girls), with mean age at pump initiation of 4.5 ± 1.4 years (range: 1.7–6.9; Table 1). Mean duration of diabetes at initiation of CSII was 1.8 ± 1.2 years (range: 0.3–5.2). Sixty-one children were identified by their parents as non-Hispanic white, 3 as black, and 1 as Hispanic white. Thirty-eight (59%) children received daytime care from their mothers, and 26 (41%) children received care from paid caregivers, either in the home (nanny) or in an outside group setting (child care center). None of the children received their daytime care by the father or other adult relative. The care status of 1 child was not available and thus was not included in the analysis.
Changes in HbA1c levels over time are illustrated in Fig 1. Mean HbA1c fell from 7.4 ± 1.0% in the year before pump initiation to 7.0 ± 0.9% at 12 months after pump initiation (P < .001). Even more important, this improvement in glycemic control was sustained throughout the period of follow-up, with mean HbA1c of 6.8 ± 0.6% at 3 years of follow-up (P = .003 from prepump values) and 6.5 ± 0.9% in the 6 children who amassed 4 years of follow-up. The mean HbA1c for all postpump visits was 7.1 ± 0.8%, and the mean for each subject's most recent visit at the time of data closeout (at a mean duration of follow-up of 30 months) was 7.0 ± 0.9% (P < .02 from prepump values).
As shown in Table 2, the decrement in HbA1c levels was most notable in children who were younger than 3 years, who improved from a prepump value of 7.9 ± 1.1% to a mean postpump value of 6.9 ± 0.9% (P = .01). “Older” children experienced a more modest improvement, from 7.4 ± 0.9% to 7.2 ± 0.6% in the 3 to <5 years group, and from 7.2 ± 0.9 to 7.1 ± 0.9% in the 5 to < 7 years group, neither of which reached statistical significance.
Besides lowering HbA1c levels, insulin pump treatment lowered the frequency of SH (Table 2). SH rates decreased in the group as a whole by 53%, from 78 events per 100 patient-years to 37 per 100 patient-years (P = .02). The greatest improvement in SH occurred in the children 3 to < 5 years of age, whose rates decreased by 79%, from 141 to 29 events per 100 patient-years (P < .001). There were no episodes of DKA in the 12 months preceding initiation of pump therapy. The rate of DKA in the postpump period was 4 episodes per 100 patient-years. No patients returned to injection therapy after pump initiation, because of either family choice or practitioner discretion.
Excessive weight gain was not a consequence of insulin pump therapy in our subjects. BMI z score actually decreased from a prepump mean of 0.9 ± 1.1 at pump initiation to 0.7 ± 1.1 after 12 months of pump use (P = .002). Mean BMI z score at subjects' most recent visit was 0.7 ± 0.9, consistent with prepump values.
One of the lingering concerns about insulin pump use in very young children is that the technology is too complex for alternative or paid caregivers to use. Our database tracks caregiver status and therefore provided the opportunity to examine this question. The transition to insulin pump resulted in an improvement in HbA1c levels in children who received daytime care predominantly from their mothers, from 7.3 ± 1.0% prepump to 7.1 ± 0.9% postpump (P = .02). Children who received daytime care from paid caregivers either in the home or in an outside group setting had an even greater improvement in HbA1c levels, from 7.5 ± 0.9% prepump to 7.1 ± 0.8% postpump (P = .002; Table 2). SH rates in the mother-care group improved slightly but nonsignificantly with insulin pump treatment, from 64 to 43 per 100 patient-years, but improved substantially in the paid caregiver group with pump treatment, from 95 to 28 events per 100 patient-years (P = .02).
The usefulness of CSII in adults with type 1 diabetes is well established, and the ability of pump therapy to lower HbA1c levels and the risk for SH in school-aged and adolescent patients has been reported in several recent studies. However, clinical outcome data regarding the safety and efficacy of CSII in very young patients with type 1 diabetes is scarce. Bougneres et al,14 in a series of 6 patients who were younger than 5 years, reported a 21% reduction in HbA1c and improvement in SH after 6 months of CSII. More recently, Litton et al15 demonstrated a reduction in HbA1c from 9.5% to 7.9% in 9 young children, aged 2.5 to 5 years. Tubiana-Rufi et al17 did not find an improvement in HbA1c but did note a significant decrease in SH in 10 children who were younger than 6 years and treated with insulin pump therapy for up to 2 years, compared with 17 age-matched injection-treated children. Even in older children and adolescents, results vary with respect to the ability of pump therapy to sustain improvements in HbA1c levels after the first 6 to 12 months of treatment, with some centers demonstrating durable improvements in glycemic control5 and others showing deterioration over time.8
In this article, we report clinical outcomes in a relatively large cohort of preschool children who have type 1 diabetes and received pump treatment for up to 4 years. As previously reported in our first 26 patients, HbA1c levels fell significantly during the first 12 months of pump treatment. We now show that the lowering of HbA1c persisted throughout the period of observation, including the 26 patients who composed our original cohort and who remained on pump therapy for 3 to 5 years. Our study group was composed of children with a mean duration of diabetes of 1.8 ± 1.2 years at the time of pump initiation, so for some subjects, the prepump period of observation overlapped with their “honeymoon” period. Thus, improvements in HbA1c and hypoglycemia with pump therapy, particularly over time, are perhaps even greater than indicated in this study. The absence of DKA in the prepump observation period may reflect, in part, some residual β-cell function in this group. Our postpump DKA rate of 4 episodes per 100 patient-years is consistent with previously reported rates of 4 to 8 per 100 patient-years in children with established diabetes.18,19
Improvement in diabetes control should not be construed solely as a reduction of HbA1c. The ability of CSII to achieve lower mean blood glucose while simultaneously reducing the rate of SH is the most significant feature of insulin pump therapy. As seen in our data, the benefits of CSII may be somewhat different depending on the age group studied. The very youngest of the cohort, those younger than 3 years, had the greatest reduction in HbA1c, possibly reflecting the improved ability to achieve target blood glucose levels without the risk of unpredictable peaks of long-acting insulin depots. In the “older” children, aged 3 to 7, in whom physical activity and caloric intake are frequently variable and unpredictable, insulin pump therapy was associated with smaller reductions in HbA1c but more significant reductions in hypoglycemia rates.
Population-based studies have demonstrated that preschool children with type 1 diabetes are at greater risk for SH than school-aged children or adolescents.20,21 Young patients are in “double jeopardy,” because the risk for neurologic sequelae of hypoglycemia-induced seizures and coma is also thought to be greater in children who are younger than 7 years.22–24 Consequently, the observation that CSII markedly lowered the rate of SH may be even more important than the ability of this therapy to lower HbA1c levels.
Treatment of young children with type 1 diabetes is especially challenging for mothers, who usually bear most of the burden of managing their children's diabetes. In a previous study involving young children who received injection therapy, mothers described day-to-day management of diabetes as a full-time job that required constant vigilance.25 In contrast, many mothers of CSII-treated infants and toddlers report “getting their life back” after starting their children on pump therapy and returning to work outside the home.26
This report is the first to show that insulin pump use may be implemented successfully in very young children whose daytime care is provided by paid caregivers, such as nannies or child care center workers. When necessary, these personnel may be taught the basics of insulin pump use, such as insuring proper function of the pump, attending to alarms, and providing meal-related or hyperglycemia-related bolus doses of insulin. The use of preprinted bolus dose cards, which can be stored in the insulin pump case, aids the caregiver in the choosing of the correct dose. Furthermore, more recent models of pumps are equipped with “bolus calculators,” which allow the paid caregiver simply to enter the amount of carbohydrates to be consumed along with the current blood glucose level, and the pump will calculate the correct dose. Determination and/or confirmation of the bolus dose with a parent through the use of cell phone or e-mail communication before insulin delivery is another popular management tactic in our population. We have, on occasion, included a paid caregiver in a routine diabetes clinic visit with the parent(s) and health care team, not only to assure the parent and the clinician that the caregiver is competent to perform the necessary tasks but also to provide a forum to answer questions and decrease caregiver anxiety.
The present study may be considered to be limited by its nonrandomized, uncontrolled design. Children were selected for insulin pump therapy on the basis of the family's documented adherence to the diabetes care regimen, including multiple glucose monitoring tests daily, recording blood glucose values and other important variables in a written or computer log, and clear commitment to insulin pump treatment. It is clearly admitted that not all young children will be good candidates for CSII, and some nannies or child care centers will not be comfortable or competent to participate in the diabetes care regimen. It remains the task of the health care team to select good candidates for insulin pump treatment. It is shown with this report, however, that very young age and the reliance of the family on paid daytime caregivers should not automatically preclude the use of insulin pumps for optimizing diabetes care.
This work was supported by grants from the National Institutes of Health (RR06022), the Juvenile Diabetes Research Foundation, and the Stephen J. Morse Pediatric Diabetes Research Fund.
- Accepted June 21, 2004.
- Reprint requests to (S.A.W.) Department of Pediatrics, Yale University School of Medicine, PO Box 208064, 333 Cedar St, New Haven, CT 06520. E-mail:
No conflict of interest declared.
- ↵Pickup J, Mattock M, Kerry S. Glycaemic control with continuous subcutaneous insulin infusion compared with intensive insulin injections in patients with type 1 diabetes: meta-analysis of randomised controlled trials. BMJ.2002;324 :1– 6
- ↵Weissberg-Benchell J, Antisdel-Lomaglio J, Seshadri R. Insulin pump therapy: a meta-analysis. Diabetes Care.2003;26 :1079– 1087
- ↵Boland EA, Grey M, Oesterle A, Fredrickson L, Tamborlane WV. Continuous subcutaneous insulin infusion: a “new” way to achieve strict metabolic control, decrease severe hypoglycemia, and enhance coping in adolescents with type 1 diabetes. Diabetes Care.1999;22 :1779– 1784
- Maniatis AK, Klingensmith GJ, Slover RH, Mowry CJ, Chase HP. Continuous subcutaneous insulin infusion therapy for children and adolescents: an option for routine diabetes care. Pediatrics.2001;107 :351– 356
- ↵Plotnick LP, Clark LM, Brancati RL, Erlinger T. Safety and effectiveness of insulin pump therapy in children and adolescents with type 1 diabetes. Diabetes Care.2003;26 :1142– 1146
- ↵Gardner SG, Bingley PJ, Satwell PA, Weeks S, Gale AM, the Bart's-Oxford Study Group. Rising incidence of insulin dependent diabetes in children aged under 5 years in the Oxford region: time trend analysis. BMJ.1997;315 :713– 717
- ↵Schoenle EJ, Lang-Muritano M, Gschwend S, et al. Epidemiology of type 1 diabetes mellitus in Switzerland: steep rise in incidence in under 5 year old children in the past decade. Diabetologia.2000;44 :286– 289
- ↵Davis EA, Keating B, Byrne GC, Russell M, Jones TW. Hypoglycaemia: incidence and clinical predictors in a large population based sample of children and adolescents with IDDM. Diabetes Care.1997;20 :22– 25
- ↵Mortensen HB, Hohngaard P, for the Hvidore Study Group on Childhood diabetes. Persistent differences among centers over 3 years in glycaemic control and hypoglycemia in a study of 3805 children and adolescents with type 1 diabetes from the Hvidore Study Group. Diabetes Care.2001;24 :1340– 1347
- ↵Ryan C, Vega A, Drash A. Cognitive deficits in adolescents who developed diabetes early in life. Pediatrics.1985;75 :921– 927
- Rovet JF, Ehrlich RM, Hoppe M. Specific intellectual deficits in children with early onset diabetes mellitus. Child Dev.1988;53 :226– 234
- ↵Northam E, Anderson P, Werther GA, Warne GL, Adler RG, Andrews D. Neuropsychological complications of IDDM in children 2 years after disease onset. Diabetes Care.1998;21 :379– 384
- ↵Sullivan-Bolyai S, Knafl K, Tamborlane W, Grey M. Parents' reflections on managing their children's diabetes with the insulin pump. Diabetes Educator.2004; in press
- Copyright © 2004 by the American Academy of Pediatrics