Association of pregnancy outcomes in women with type 2 diabetes treated with metformin versus insulin when becoming pregnant

North American clinical practice guidelines for the medical management of hidradenitis suppurativa in special patient populations

BACKGROUND

Hidradenitis suppurativa (HS) affects different patient populations that require unique considerations in their management. However, no HS guidelines for these populations exist.

OBJECTIVE

To provide evidence-based consensus recommendations for patients with HS in 7 special patient populations: (i) pregnancy, (ii) breastfeeding, (iii) pediatrics, (iv) malignancy, (v) tuberculosis infection, (vi) hepatitis B or C infection, and (vii) HIV disease.

METHODS

Recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system to ascertain level of evidence and selected through a modified Delphi consensus process.

RESULTS

One hundred eighteen expert consensus statements are provided for the management of patients with HS across these 7 special patient populations.

The Methodological Quality of Observational Studies Examining the Risk of Pregnancy Drug Use on Congenital Malformations Needs Substantial Improvement: A Cross-Sectional Survey

BACKGROUND AND OBJECTIVE

An increasing number of observational studies have investigated the risk of using drugs during pregnancy on congenital malformations. However, the credibility of the causal relationships drawn from these studies remains uncertain. This study aims to evaluate the potential methodological issues in existing observational studies.

METHODS

We used a stepwise approach to investigate this issue. First, we identified observational studies published in 2020 that examined the risk of congenital malformations associated with medication use during pregnancy. We assessed the methodological characteristics for establishing causality, including study design, confounding control, and sensitivity analysis, and compared them between "core clinical journals" and "general journals." For studies reporting an increased risk of congenital malformations in core clinical journals, we searched for subsequent studies addressing the same research question published between January 2021 and May 2023 to assess the consistency of the literature.

RESULTS

A total of 40 eligible studies were published in 2020, primarily focused on the safety of vitamin B12 and folic acid (n = 4), antidepressants (n = 4), and others (n = 32). Our findings suggest that only two (5.00%) studies used causal models to guide the identification of confounding, and only eight (20.00%) studies assessed the potential dose-response relationship. In all, 15 (37.50%) studies used propensity score analysis strategy to achieve "mimic-randomization." In addition, 22 studies (55.00%) performed sensitivity analyses, while 10 (45.45%) showed inconsistency with the primary outcome. Furthermore, 5 studies reported positive outcomes, whereas only 1 out of 11 studies demonstrated a positive correlation between drug usage during pregnancy and major malformations in subsequent studies.

CONCLUSION

A significant portion of the studies has failed to sufficiently consider the essential methodological characteristics required to improve the credibility of causal inferences. The increased risk of congenital malformations documented in core clinical journal was not adequately replicated in subsequent studies.

Perinatal Outcomes Associated With Metformin Use During Pregnancy in Women With Pregestational Type 2 Diabetes Mellitus

OBJECTIVE

We emulated a modified randomized trial (Metformin in Women With Type 2 Diabetes in Pregnancy [MiTy]) to compare the perinatal outcomes in women continuing versus discontinuing metformin during pregnancy among those with type 2 diabetes treated with metformin plus insulin before pregnancy.

RESEARCH DESIGN AND METHODS

This study used two health care claims databases (U.S., 2000-2020). Pregnant women age 18-45 years with type 2 diabetes who were treated with metformin plus insulin at conception were eligible. The primary outcome was a composite of preterm birth, birth injury, neonatal respiratory distress, neonatal hypoglycemia, and neonatal intensive care unit admission. Secondary outcomes included the components of the primary composite outcome, gestational hypertension, preeclampsia, maternal hypoglycemia, cesarean delivery, infants large for gestational age, infants small for gestational age (SGA), sepsis, and hyperbilirubinemia. We adjusted for potential baseline confounders, including demographic characteristics, comorbidities, and proxies for diabetes progression.

RESULTS

Of 2,983 eligible patients, 72% discontinued use of metformin during pregnancy. The average age at conception was 32 years, and the prevalence of several comorbidities was higher among continuers. The risk of the composite outcome was 46% for continuers and 48% for discontinuers. The adjusted risk ratio was 0.92 (95% CI 0.81, 1.03). Risks were similar between treatments and consistent between databases for most secondary outcomes, except for SGA, which was elevated in continuers only in the commercially insured population.

CONCLUSIONS

Our findings were consistent with those reported in the MiTy randomized trial. Continuing metformin during pregnancy was not associated with increased risk of a neonatal composite adverse outcome. However, a possible metformin-associated risk of SGA warrants further consideration.

Metformin Use in the First Trimester of Pregnancy and Risk for Nonlive Birth and Congenital Malformations: Emulating a Target Trial Using Real-World Data

BACKGROUND

Metformin is a first-line pharmacotherapy for type 2 diabetes, but there is limited evidence about its safety in early pregnancy.

OBJECTIVE

To evaluate the teratogenicity of metformin use in the first trimester of pregnancy.

DESIGN

In an observational cohort of pregnant women with pregestational type 2 diabetes receiving metformin monotherapy before the last menstrual period (LMP), a target trial with 2 treatment strategies was emulated: insulin monotherapy (discontinue metformin treatment and initiate insulin within 90 days of LMP) or insulin plus metformin (continue metformin and initiate insulin within 90 days of LMP).

SETTING

U.S. Medicaid health care administration database (2000 to 2018).

PARTICIPANTS

12 489 pregnant women who met the eligibility criteria.

MEASUREMENTS

The risk and risk ratio of nonlive births, live births with congenital malformations, and congenital malformations among live births were estimated using standardization to adjust for covariates.

RESULTS

A total of 850 women were in the insulin monotherapy group and 1557 in the insulin plus metformin group. The estimated risk for nonlive birth was 32.7% under insulin monotherapy (reference) and 34.3% under insulin plus metformin (risk ratio, 1.02 [95% CI, 1.01 to 1.04]). The estimated risk for live birth with congenital malformations was 8.0% (CI, 5.7% to 10.2%) under insulin monotherapy and 5.7% (CI, 4.5% to 7.3%) under insulin plus metformin (risk ratio, 0.72 [CI, 0.51 to 1.09]).

LIMITATION

Possible residual confounding by glycemic control and body mass index.

CONCLUSION

Compared with switching to insulin monotherapy, continuing metformin and adding insulin in early pregnancy resulted in little to no increased risk for nonlive birth among women receiving metformin before pregnancy. Under conventional statistical criteria, anything between a 49% decrease and a 9% increase in risk for congenital malformations was highly compatible with our data.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Efficacy and safety of metformin during pregnancy: an update

During the last decades, gestational diabetes mellitus (GDM) prevalence has been on the rise. While insulin remains the gold standard treatment for GDM, metformin use during pregnancy is controversial. This review aimed to comprehensively assess the available data on the efficacy and safety of metformin during pregnancy, both for the mother and the offspring. Metformin has been validated for maternal efficacy and safety, achieving comparable glycemic control with insulin. Additionally, it reduces maternal weight gain and possibly the occurrence of hypertensive disorders. During the early neonatal period, metformin administration does not increase the risk of congenital anomalies or other major adverse effects, including lower APGAR score at 5 min, neonatal intensive care unit admissions, and respiratory distress syndrome. Several studies have demonstrated a reduction in neonatal hypoglycemia. Metformin has been associated with an increase in preterm births and lower birth weight, although this effect is controversial and depends on the indication for which it was administered. Evidence indicates possible altered fetal programming and predisposition to childhood obesity and metabolic syndrome during adulthood after use of metformin in pregnancy. With critical questions still requiring a final verdict, ongoing research on the field must be conducted.

Achieving comparability in glycemic control between antidiabetic treatment strategies in pregnancy when using real world data

PURPOSE

Healthcare utilization databases often lack information on glycemic control, a key confounder when studying the safety of antidiabetic treatments, since patients with worse control are channeled to second-line agents, in particular insulin, versus first-line agents such as metformin. We evaluated whether adjustment for measured characteristics attains balance in glycemic control when comparing antidiabetic treatment strategies in pregnant women with pregestational type 2 diabetes (T2DM).

METHODS

In a US insurance claims database, we identified 3360 women with T2DM pregnant between 2004 and 2015, of whom a subset of 996 had data on hemoglobin A1c (HbA1c ) levels. We selected insulin only as the comparator group and used propensity score (PS)-matching on comorbidities and proxies of diabetes severity, but not on HbA1c , to adjust for confounding. We used standardized differences (st.diff) to assess balance in claims-based covariates and mean HbA1c (% ± SD) in the subset.

RESULTS

There were imbalances in claims-based covariates before PS-matching, with smaller differences when both treatment strategies included insulin. After PS-matching, balance was achieved in most claims-based covariates (st.diff <0.1). Mean HbA1c was similar before and after PS-matching when both treatments included insulin (e.g., 7.1 ± 1.5 vs. 7.7 ± 1.8 and 7.1 ± 1.5 vs. 7.5 ± 1.7, respectively, for metformin + insulin vs. insulin only). Differences in mean HbA1c remained after PS-matching when non-insulin treatments were compared to treatments including insulin (e.g., 6.3 ± 1.1 vs. 7.6 ± 1.7 for metformin only vs. insulin only).

CONCLUSIONS

Balance in both claims-based characteristics and glycemic control was attained after restricting the population to women with T2DM and comparing treatment strategies indicated for patients with similar diabetes severity. When comparing treatment strategies with versus without insulin, differences in glycemic control persisted after PS-matching even when balance was attained for other measured characteristics.

Management of type 2 diabetes in pregnancy: a narrative review

The prevalence of type 2 diabetes (T2DM) at reproductive age is rising. Women with T2DM have a similarly high risk for pregnancy complications as pregnant women with type 1 diabetes. To reduce adverse pregnancy and neonatal outcomes, such as preeclampsia and preterm delivery, a multi-target approach is necessary. Tight glycemic control together with appropriate gestational weight gain, lifestyle measures, and if necessary, antihypertensive treatment and low-dose aspirin is advised. This narrative review discusses the latest evidence on preconception care, management of diabetes-related complications, lifestyle counselling, recommendations on gestational weight gain, pharmacologic treatment and early postpartum management of T2DM.

Major malformations risk following early pregnancy exposure to metformin: a systematic review and meta-analysis

Metformin is considered as first-line treatment for type 2 diabetes and an effective treatment for polycystic ovary syndrome (PCOS). However, evidence regarding its safety in pregnancy is limited. We conducted a systematic review and meta-analysis of major congenital malformations (MCMs) risk after first-trimester exposure to metformin in women with PCOS and pregestational diabetes mellitus (PGDM). Randomized controlled trials (RCTs) and observational cohort studies with a control group investigating risk of MCM after first-trimester pregnancy exposure to metformin were searched until December 2021. ORs and 95% CIs were calculated separately according to indications and study type using Mantel-Haenszel method; outcome data were combined using random-effects model. Eleven studies (two RCTs; nine observational cohorts) met the inclusion criteria: four included pregnant women with PCOS, four included those with PGDM and three evaluated both indications separately and were considered in both indication groups. In PCOS group, there were two RCTs (57 exposed, 52 control infants) and five observational studies (472 exposed, 1892 control infants); point estimates for MCM rates in RCTs and observational studies were OR 0.93 (95% CI 0.09 to 9.21) (I2=0%; Q test=0.31; p value=0.58) and OR 1.35 (95% CI 0.37 to 4.90) (I2=65%; Q test=9.43; p value=0.05), respectively. In PGDM group, all seven studies were observational (1122 exposed, 1851 control infants); the point estimate for MCM rates was OR 1.05 (95% CI 0.50 to 2.18) (I2=59%; Q test=16.34; p value=0.01). Metformin use in first-trimester pregnancy in women with PCOS or PGDM do not meaningfully increase the MCM risk overall. However, further studies are needed to characterize residual safety concerns.

Metformin in pregnancy and risk of adverse long-term outcomes: a register-based cohort study

This study aimed to investigate if maternal pregnancy exposure to metformin is associated with increased risk of long-term and short-term adverse outcomes in the child. RESEARCH DESIGN AND METHODS : This register-based cohort study from Finland included singleton children born 2004-2016 with maternal pregnancy exposure to metformin or insulin (excluding maternal type 1 diabetes): metformin only (n=3967), insulin only (n=5273) and combination treatment (metformin and insulin; n=889). The primary outcomes were long-term offspring obesity, hypoglycemia, hyperglycemia, diabetes, hypertension, polycystic ovary syndrome, and challenges in motor-social development. In a sensitivity analysis, the primary outcomes were investigated only among children with maternal gestational diabetes. Secondary outcomes were adverse outcomes at birth. Analyses were conducted using inverse- probability of treatment weighting (IPTW), with insulin as reference. RESULTS  : Exposure to metformin or combination treatment versus insulin was not associated with increased risk of long-term outcomes in the main or sensitivity analyses. Among the secondary outcomes, increased risk of small for gestational age (SGA) was observed for metformin (IPTW-weighted OR 1.65, 95% CI 1.16 to 2.34); increased risk of large for gestational age, preterm birth and hypoglycemia was observed for combination treatment. No increased risk was observed for neonatal mortality, hyperglycemia, or major congenital anomalies. CONCLUSIONS : This study found no increased long-term risk associated with pregnancy exposure to metformin (alone or in combination with insulin), compared with insulin. The increased risk of SGA associated with metformin versus insulin suggests caution in pregnancies with at-risk fetal undernutrition. The increased risks of adverse outcomes at birth associated with combination treatment may reflect confounding by indication or severity.

Current Therapeutic Use of Metformin During Pregnancy: Maternal Changes, Postnatal Effects and Safety

Metformin is one of the most easily available medications for diabetes and has a relatively low cost. It is not only used in diabetes but is also effective in polycystic ovarian syndrome (PCOS) and obesity. Although insulin is the first choice when it comes to treating pregnant women with gestational diabetes mellitus (GDM), metformin has also been debated as a good choice after modification of diet. As metformin passes through the placenta, it is essential to know its consequence of leading to insulin resistance in the fetus as well as the impact on postnatal development. The use of metformin during GDM has raised many trials demonstrating that outcomes from the use of metformin are similar to those achieved with insulin. Follow-up studies were also conducted that assessed the impact on children exposed to metformin in utero. This review highlights the experimental evidence relating to the use of metformin during pregnancy for different conditions, and its impact on the growth and development of offspring.