DOI: 10.2337/dc06-1887 © 2007 by the American Diabetes Association
Maternal Glycemic Control and Hypoglycemia in Type 1 Diabetic PregnancyA randomized trial of insulin aspart versus human insulin in 322 pregnant women
1 Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark Address correspondence and reprint requests to Elisabeth R. Mathiesen, Copenhagen Centre for Pregnant Women With Diabetes, Department of Endocrinology 2132, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. E-mail: em{at}rh.dk
OBJECTIVETo assess the safety and efficacy of insulin aspart (IAsp) versus regular human insulin (HI) in basal-bolus therapy with NPH insulin in pregnant women with type 1 diabetes.
RESEARCH DESIGN AND METHODSSubjects (n = 322) who were pregnant or planning pregnancy were randomized to IAsp or HI as meal-time insulin in an open-label, parallel-group, multicenter study. Subjects had A1C
RESULTSMajor hypoglycemia occurred at a rate of 1.4 vs. 2.1 episodes/year exposure with IAsp and HI, respectively (relative risk 0.720 [95% CI 0.361.46]). Risk of major/major nocturnal hypoglycemia was 52% (RR 0.48 [0.201.143]; P = NS) lower with IAsp compared with HI. A1C was comparable with human insulin in second (IAsp-HI 0.04 [0.18 to 0.11]) and third (0.08 [0.23 to 0.06]) trimesters. A total of 80% of subjects achieved an A1C CONCLUSIONSIAsp is at least as safe and effective as HI when used in basal-bolus therapy with NPH insulin in pregnant women with type 1 diabetes and may potentially offer some benefits in terms of postprandial glucose control and preventing severe hypoglycemia.
Abbreviations: HI, human insulin IAsp, insulin aspart ITT, intention-to-treat
Recent surveys show that the risk of perinatal complications remains increased in women with diabetes (15). Many maternal and fetal complications are associated with poor maternal glycemic control during pregnancy (69), and avoiding hyperglycemia improves pregnancy outcome (1012). However, tightening glycemic control may increase the risk of major hypoglycemia (1317), with potential adverse maternal outcomes including coma, seizures, and maternal death (16,18). We hypothesized that use of the rapid-acting insulin analog, insulin aspart (IAsp), for meal-related insulin replacement may be of benefit during pregnancy complicated by diabetes by providing better control of postprandial hyperglycemia with less hypoglycemia, compared with regular human insulin (HI). IAsp has onset of action within 1020 min of injection, peak action within 4050 min, and duration of action of 35 h (19). In clinical studies, compared with HI, IAsp provides superior postprandial glycemic control with less risk of major and nocturnal hypoglycemic episodes and small improvement in A1C (2024). Safety and efficacy of the use of insulin analogs during pregnancy has yet to be confirmed in randomized controlled trials, although observational studies have not identified cause for concern (2529). The aim of this study was to evaluate the risk of major maternal hypoglycemia, metabolic control, and safety, including perinatal outcomes in pregnant women with type 1 diabetes on IAsp. This study presents data on maternal hypoglycemia, glycemic control, and safety. Data on perinatal outcomes are reported separately.
A total of 417 women with type 1 diabetes participated in this open-label, randomized, parallel-group study conducted at 63 sites in 18 countries, mainly within Europe. The study was performed in accordance with the Declaration of Helsinki and was approved by respective ethics committees and health authorities according to local regulations. Written informed consent was obtained from subjects before study start.
Eligible subjects were aged
Treatments IAsp was injected immediately before meals and HI within 30 min before the meal. All insulins were injected subcutaneously using the NovoPen 3.0 (Novo Nordisk). Because study insulin injection timing varied, an open-label approach was used. The starting dose for both study insulins was 100% of dose at study entry. Insulin doses were titrated to optimal levels throughout the study based on self-monitored plasma glucose levels and the targets for blood glucose control: preprandial 4.16.1 mmol/l, 1 h postprandial <8.6 mmol/l, 2 h postprandial <7.5 mmol/l (according to American Diabetes Association guidelines), and A1C <6.5%.
Assessments Primary study end point was major (requiring third-party assistance with plasma glucose <3.1 mmol/l or reversal of symptoms after food, glucagon, or intravenous glucose) hypoglycemia during pregnancy. Minor (plasma glucose <3.1 mmol/l with or without symptoms) and symptoms-only (no plasma glucose measurement or plasma glucose >3.0 mmol/l) hypoglycemia were also recorded by subjects in their diaries. Nocturnal hypoglycemia was taken as episodes between midnight and 0600 h. Efficacy end points were A1C and self-measured 8-point plasma glucose profile. Subjects were asked to perform an 8-point plasma glucose profile during the week before randomization and clinic visits P1P4 using a Medisense (Maidenhead, U.K.) blood glucose meter. Other safety assessments included maternal adverse events, obstetric complications, diabetes complications, pregnancy outcomes, and delivery details. Treatment satisfaction was assessed using the Diabetes Treatment Satisfaction Questionnaire (30) at randomization and at follow-up visits for subjects pregnant at screening, visit P1, and at follow-up for subjects pregnant after screening. Subjects ranked eight items on a 7-point Likert scale to measure overall treatment satisfaction (satisfaction with treatment, flexibility, diabetes understanding, convenience, and willingness to continue treatment and recommend treatment) and perception of hyper- and hypoglycemia. Items were scored on a 06 scale then transformed to a 0100 scale (higher scale = greater treatment satisfaction). Laboratory analyses (A1C, hematology, biochemistry, and urinalysis) were performed by MDS Pharma Services Central Lab (Hamburg, Germany). A1C was analyzed using a National Glycohemoglobin Standardization Programcertified method (Diabetes Control and Complications Trial standard).
Statistical analysis Results presented are based on the intention-to-treat (ITT) analysis set (all treated/exposed subjects confirmed pregnant during the study even if they did not complete all study visits, ITTpregnant n = 322, with 264 completers).
Risk of major maternal hypoglycemia was assessed from its incidence during pregnancy. Episodes were analyzed as recurrent events using a As supportive analyses to the primary safety end point, a noninferiority criterion (<0.4% difference in A1C) was tested at visits P3 and P4 using a linear mixed model, with treatment and pregnancy status at screening as fixed effects and country as a random effect using a one-sided t test with a 2.5% significance level. Average plasma glucose increments (average postprandial values minus preprandial values), average 24-h plasma glucose, and each of the 8-point plasma glucose values at visits P2P4 were analyzed based on the model described above. Treatment differences in quality-of-life assessments at the follow-up visit were analyzed using the Wilcoxon rank-sum test. A significance level of 5% was used for statistical analyses, which were generated using SAS version 8.2 (SAS Institute, Cary, NC) on a UNIX platform or S-PLUS version 6.0 Professional for Windows (Microsoft, Seattle, WA).
Subjects were recruited between September 2002 and August 2004; the last follow-up visit was in April 2005. In total, 412 subjects were randomized and treated. Of these, 322 (IAsp, 157; HI, 165) were pregnant during the study (ITTpregnant cohort). In total, 223 (IAsp, 113; HI, 110) were pregnant at screening, and 99 (IAsp, 44; HI, 55) became pregnant after screening. Withdrawal patterns in pregnant women were similar between treatments. Overall, 190 (IAsp, 102; HI, 88) of those pregnant and 74 (IAsp, 31; HI, 43) of those not pregnant at screening completed pregnancy and the trial intervention. Of 58 noncompleters (IAsp, 24; HI, 34), 31 were withdrawn due to adverse events (IAsp, 14; HI, 17) and 27 for other reasons (IAsp, 10; HI, 17). Age, A1C, BMI, duration of diabetes, and mean daily insulin requirements at baseline were similar between treatment groups (Table 1).
Hypoglycemic episodes Observed rates of major maternal hypoglycemia were lower with IAsp than HI (Table 2). A 28% lower risk for major hypoglycemia (IAsp/HI; relative risk [RR] 0.720 [95% CI 0.361.46]) and a 52% lower risk for major nocturnal hypoglycemia (0.48 [0.201.14]) was estimated for the IAsp versus HI groups, respectively, although this did not reach statistical significance. Risks for major daytime (0.85 [0.401.78]), all (0.97 [0.661.44]), and minor (0.97 [0.661.43]) hypoglycemia were similar between treatments (Table 2). The estimated risk of any nocturnal hypoglycemia was 24% lower on IAsp (0.76 [0.571.03]). Risk of all daytime hypoglycemia was similar between treatments (1.08 [0.711.63]).
Efficacy Glycemic control Treatment with IAsp was noninferior to treatment with HI as assessed by A1C at the end of the second and third trimesters (mean difference [95% CI]) (IAsp minus HI: 0.04% [0.18 to 0.11], P = NS; 0.08% [0.23 to 0.06], P = NS). In both treatment groups, A1C decreased during the first two trimesters then increased toward delivery and follow-up (Fig. 1A). A1C was 6.5% for most subjects in both treatment groups during the second and third trimesters (P3: IAsp, 83%; HI, 79%; P4: IAsp, 78%; HI, 73%).
Mean 8-point plasma glucose profile at P2 is shown in Fig. 1B. Overall profiles were similar at P3 and P4 (data not shown), although estimated mean values of 24-h plasma glucose increased from visit P2 to P3, then decreased at visit P4 (IAsp: 6.82, 6.96, and 6.23; HI: 6.82, 7.10, and 6.48 mmol/l, respectively). Postprandial plasma glucose levels were consistently lower with IAsp after breakfast (B90), with statistically significant between-treatment differences at P2 (P = 0.044) and P4 (P = 0.0007) but not at P3 (P = 0.153). Preprandial (prebreakfast, prelunch, and predinner) plasma glucose levels were comparable between treatments at all visits. Mean prandial plasma glucose increments (mean of difference in pre- and postprandial plasma glucose at breakfast, lunch, and dinner) during pregnancy were lower with IAsp than HI. Between-treatment differences were statistically significant at visits P2 and P4 (IAsp minus HI [in mmol/l] P2: 0.75 [95% CI 1.25 to 0.25], P = 0.003; P4: 0.40 [0.80 to 0.01], P = 0.044).
Insulin dose
Adverse events The frequency and profile of obstetric complications were similar between treatments. The most frequent complications were preeclampsia (IAsp, 13; HI, 11), threatened preterm labor (IAsp, 6; HI, 7), prolonged labor (IAsp, 5; HI, 7), and unplanned cesarean section (IAsp, 20; HI, 19). Thirty-one subjects left the study because of adverse events (IAsp, 14; HI, 17). These were due to fetal loss (induced/spontaneous abortion or stillbirth) in 13 IAsp-treated and 14 HI-treated subjects. Most (IAsp, 79%; HI, 60%) fetal losses were spontaneous, occurring in the first 12 gestational weeks. Other withdrawals were due to hypoglycemia (IAsp, 1) and congenital malformation (HI, 3).
Diabetes complications and physical examination
Pregnancy outcome
Quality-of-life assessments
This is the largest, randomized, controlled study to date of a rapid-acting insulin analog in pregnant women with type 1 diabetes. Although glycemic control, assessed by A1C, was similar with IAsp and HI, postprandial hyperglycemic excursions were lower with IAsp than with HI, especially after breakfast, with no difference in preprandial glucose control and no increase in major hypoglycemia. Indeed, the observed rate of major episodes was lower for IAsp-treated than HI-treated subjects. Hypoglycemia, especially nocturnal episodes, is more frequent during pregnancy (1618), especially during intensified insulin treatment (16,32). In the present study, rates of major hypoglycemia (all and nocturnal episodes) tended to be lower with IAsp than with HI treatment. Similarly, Garg et al. (28) reported relatively few major hypoglycemic episodes in 62 insulin lispro-treated pregnant women with type 1 diabetes. The lack of statistical significance in the risk estimates may be because rates of major hypoglycemia in the present study were lower than expected, reducing its statistical power. Furthermore, the mean duration of exposure during pregnancy was slightly less than the planned 7 months (IAsp, 6.5 months; HI, 6.2 months), and fewer pregnant subjects than planned (264 vs. 305) completed the study. Postprandial glucose excursions were generally lower with IAsp than with HI treatment, particularly during the first and third trimesters, with significantly lower glycemic excursions after breakfast. Preprandial plasma glucose values were similar between treatment groups. The improvement in postprandial glycemic control with IAsp in this study was similar to that reported in nonpregnant subjects (22,3336). Lower postprandial glucose levels during pregnancy have been linked to decreased neonatal risks and perinatal complications (37). Mean A1C levels during pregnancy were not different between treatments, and similar proportions of subjects achieved A1C <6.5% with a trend toward a lower incidence of major hypoglycemia in IAsp-treated subjects. Although recent data suggest that this target should be reevaluated as A1C levels are as low as 4.45.6% in the healthy pregnancy (36,38), this has to be balanced against the risk of hypoglycemia. In the current study a minor deterioration in glycemic control with trend toward increasing A1C in the last trimester occurred in both treatment groups. Total daily insulin doses during this trimester were similar between IAsp-treated subjects achieving and not achieving target A1C <6.5% levels, but HI-treated subjects not meeting target had lower bolus insulin doses, suggesting that they could have benefited from further dose increments. Throughout pregnancy, total daily insulin doses were similar between treatment groups, although bolus insulin doses were consistently lower for patients receiving IAsp than HI. Despite increases in bolus insulin doses toward the end of pregnancy, dose titration may have been insufficient to maintain or optimize postprandial glycemic control during pregnancy due to changes in insulin sensitivity, body weight, food consumption, and reduced exercise. By the end of the third trimester, doses of IAsp and HI were at their highest, and it was at this point that IAsp was again superior to HI with regard to control of postprandial hyperglycemia. The apparently lower incidence of major hypoglycemia with IAsp may allow more aggressive dose titration late in pregnancy to optimize glycemic control. The greater treatment satisfaction score seen with IAsp compared with HI has been described previously in trials of rapid-acting analogs and may reflect the differences in the timing of injection relative to eating (34,39). Safety profiles of IAsp and HI were comparable. No maternal deaths were reported and pregnancy outcome was comparable between treatments.
In conclusion, treatment with IAsp resulted in superior postprandial glycemic control to HI with a nonsignificantly lower incidence of major hypoglycemia at comparable levels of A1C, which were mostly
This trial was sponsored by Novo Nordisk. We thank the Insulin Aspart Pregnancy Study Group: M.H., Peter Damm, Risto Kaaja, Gerard H.A. Visser, Fidelma Dunne, Irina Demidova, Anne-Sofie Pade-Hansen, Henriette Mersebach, E.R.M., B.K., S.A.A., S.H., D.M., S.D., S.B., A.R., Linda Elise Jensen, Julie Marie Fiona Clyde, Mark White, Anne Romstad, Karin Kanc Hanzel, Julius Anthony Vaz, and Benedikte Jade Lertoft. We also thank all investigators who participated in this trial (online appendix 1 [available at http://dx.doi.org/10.2337/dc06-1887]).
Clinical trial reg. no. NCT00365170, clinicaltrials.gov. E.R.M. is a member of the scientific advisory panel for this study and has received monetary compensation for this consulting work. S.A.A. has served on advisory panels for Pfizer, Sanofi-Aventis, Novartis, MSD, Eli Lilly U.K., and Amylin. S.H. has served on advisory boards for, has received research funds from, and has given lectures sponsored by Novo Nordisk. Additional information for this article can be found in an online appendix at http://dx.doi.org/10.2337/dc06-1887. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C Section 1734 solely to indicate this fact. Received for publication September 8, 2006. Accepted for publication December 28, 2006.
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