Selection of controls in case-control studies on maternal medication use and risk of birth defects

Incidence of venous thromboembolism following head and neck surgery

PURPOSE

Venous thromboembolism (VTE) is associated with significant morbidity and mortality in patients undergoing surgery, but conflicting data exist on VTE risk in patients undergoing head and neck surgery for malignant and non-malignant conditions. Our aim was to examine the risk of VTE among patients with and without cancer undergoing head and neck surgery.

METHODS

We conducted a nationwide cohort study to examine the risk of VTE among patients with an otolaryngological diagnosis using data from the Danish National Patient Register between 2010 and 2018. Analyses were stratified by cancer and anatomical areas of the surgical procedure.

RESULTS

In total, 116,953 patients were included of whom 10% (n = 12,083) had active cancer. After 3 months, 1.2% of the patients with cancer and 0.3% of the patients without cancer experienced VTE, respectively. For patients undergoing mouth/throat surgery, 0.8% with cancer and 0.2% without cancer had VTE, respectively. After nose/sinuses surgery 0.7% and 0.2%, respectively. No patients experienced VTE after ear surgery; and after endoscopies the numbers were 1.3% and 0.6% respectively.

CONCLUSIONS

While the minority of patients undergoing head and neck surgery develop VTE postoperatively, the risk increases among those with cancer. To support clinical decision making on anticoagulation, risk stratification tools could be further developed to recognize this hazard in patients with cancer undergoing head and neck surgery.

Re-Accessing Mental Health Care After Age 18: A Longitudinal Cohort Study of Youth Involved with Community-based Child and Youth Mental Health Agencies in Ontario

OBJECTIVE

About 20-26% of children and youth with a mental health disorder (depending on age and respondent) report receiving services from a community-based Child and Youth Mental Health (CYMH) agency. However, because agencies have an upper age limit of 18-years old, youth requiring ongoing mental health services must "transition" to adult-oriented care. General healthcare providers (e.g., family physicians) likely provide this care. The objective of this study was to compare the likelihood of receiving physician-based mental health services after age 18 between youth who had received community-based mental health services and a matched population sample.

METHOD

A longitudinal matched cohort study was conducted in Ontario, Canada. A CYMH cohort that received mental health care at one of five CYMH agencies, aged 7-14 years at their first visit (N=2,822), was compared to age, sex, region-matched controls (N=8,466).

RESULTS

CYMH youth were twice as likely as the comparison sample to have a physician-based mental health visit (i.e., by a family physician, pediatrician, psychiatrists) after age 18; median time to first visit was 3.3 years. Having a physician mental health visit before age 18 was associated with a greater likelihood of experiencing the outcome than community-based CYMH services alone.

CONCLUSION

Most youth involved in community-based CYMH agencies will re-access services from physicians as adults. Youth receiving mental health services only within community agencies, and not from physicians, may be less likely to receive physician-based mental health services as adults. Collaboration between CYMH agencies and family physicians may be important for youth who require ongoing care into adulthood.

Maternal risk factors for the VACTERL association: A EUROCAT case-control study

BACKGROUND

The VACTERL association (VACTERL) is the nonrandom occurrence of at least three of these congenital anomalies: vertebral, anal, cardiac, tracheoesophageal, renal, and limb anomalies. Despite suggestions for involvement of several genes and nongenetic risk factors from small studies, the etiology of VACTERL remains largely unknown.

OBJECTIVE

To identify maternal risk factors for VACTERL in offspring in a large European study.

METHODS

A case-control study was performed using data from 28 EUROCAT registries over the period 1997-2015 with case and control ascertainment through hospital records, birth and death certificates, questionnaires, and/or postmortem examinations. Cases were diagnosed with VACTERL, while controls had a genetic syndrome and/or chromosomal abnormality. Data collected included type of birth defect and maternal characteristics, such as age, use of assisted reproductive techniques (ART), and chronic illnesses. Multivariable logistic regression analyses were performed to estimate confounder adjusted odds ratios (aOR) with 95% confidence intervals (95% CI).

RESULTS

The study population consisted of 329 VACTERL cases and 49,724 controls with recognized syndromes or chromosomal abnormality. For couples who conceived through ART, we found an increased risk of VACTERL (aOR 2.3 [95% CI 1.3, 3.9]) in offspring. Pregestational diabetes (aOR 3.1 [95% CI 1.1, 8.6]) and chronic lower obstructive pulmonary diseases (aOR 3.9 [95% CI 2.2, 6.7]) also increased the risk of having a child with VACTERL. Twin pregnancies were not associated with VACTERL (aOR 0.6 [95% CI 0.3, 1.4]).

CONCLUSION

We identified several maternal risk factors for VACTERL in offspring befitting a multifactorial etiology.

Use of systemic glucocorticoids and the risk of major osteoporotic fractures in patients with sarcoidosis

This study revealed the risk of major osteoporotic fracture in patients with sarcoidosis exposed to glucocorticoids. Current use of glucocorticoids was associated with a risk of fracture, with no difference between patients with and without sarcoidosis. Sarcoidosis per se was not associated with an increased fracture risk.

INTRODUCTION

Sarcoidosis is a multi-organ, chronic inflammatory, granulomatous disorder that most frequently affects the lungs, lymph nodes, skin, eyes, and liver, but may occur in any organ, including the bones. While oral glucocorticoids (GCs) are commonly used as initial treatment, little is known about the risk of major osteoporotic fractures in patients with sarcoidosis exposed to GCs.

METHODS

A case-control study was conducted using the Danish National Hospital Discharge Registry (NHDR) between January 1995 and December 2011. Conditional logistics regression models were used to derive adjusted odds ratios (OR) of major osteoporotic fractures in subjects with and without sarcoidosis stratified by average daily and cumulative dose exposures.

RESULTS

A total of 376,858 subjects with a major osteoporotic fracture and the same number of subjects without this event were identified (mean age 64.2 ± 19.5 years, 69% female). In patients with sarcoidosis (n = 124), current use of GC was associated with an increased risk of major osteoporotic fracture (adjusted (adj.) OR 1.74; 95% CI 1.17-2.58), which dropped to baseline levels after discontinuation. In subjects without sarcoidosis, this risk was comparable (adj. OR 1.36; 95% CI 1.32-1.40). In sarcoidosis patients, cumulative dose 1.0-4.9 g and >10 g prednisolone equivalents were associated with increased risk of major osteoporotic fracture (adj. OR 2.75; 95% CI 1.06-7.14 and 2.22; 95% CI 1.17-4.22, respectively), whereas a cumulative dose of <1.0 g and 5.0-9.9 g was not associated with major osteoporotic fracture risk.

CONCLUSION

Both in subjects with and without sarcoidosis, current expose to GC is associated with increased risk of major osteoporotic fractures, with no between-group difference. Sarcoidosis per se was not associated with increased fracture risk. Having sarcoidosis per se, i.e., if not treated with GC, is not a risk factor for fracture, and such patients may only need risk assessment when they commence GC therapy.

Prenatal exposure to acid-suppressive drugs and the risk of allergic diseases in the offspring: a cohort study

BACKGROUND

Recent studies reported increased risks for the development of asthma in children after prenatal exposure to acid-suppressive drugs. As a result of common pathogenesis, associations could also be present for other allergic diseases.

METHODS

Using the prescription database IADB.nl, we conducted a cohort study amongst 33 536 children in the Netherlands, with a maximum follow-up of 8 years. Maternal exposure was defined as ≥1 dispensed prescription for proton pump inhibitors (PPIs) and/or Histamine 2-antagonists (H2As) during pregnancy. Children were considered to have a drug-treated allergic disease if they received either ≥2 prescriptions for dermal (atopic dermatitis), inhaled (asthma) or nasal (allergic rhinitis) steroids within a 12-month period. Clustered Cox proportional hazard regression was used to estimate crude and adjusted hazard ratios (aHR) with 95% confidence intervals (95% CI).

RESULTS

The aHR for the development of any allergic disease was 1.37 (95% CI: 1.14-1.66) for children exposed to PPIs or H2As. Prenatal exposure to PPIs and/or H2As was associated with atopic dermatitis, asthma and allergic rhinitis with aHRs of 1.32 (95% CI 1.06-1.64), 1.57 (95% CI 1.20-2.05) and 2.40 (95% CI 1.42-4.04), respectively. The aHR for the development of two or more (aHR 2.13 95% CI: 1.43-3.19) and three allergic diseases (aHR 5.18 95% CI: 2.16-12.42) were even more elevated after prenatal exposure to PPIs or H2As.

CONCLUSION

Prenatal exposure to PPIs and H2As appeared associated with an increased risk for the development of atopic dermatitis, asthma and allergic rhinitis in the offspring, especially with the development of multiple allergic diseases. Because our study has limitations inherent to observational studies, prospective studies are now warranted to confirm our findings.

Maternal high-dose folic acid during pregnancy and asthma medication in the offspring

PURPOSE

Low-dose folic acid supplementation (0.5 mg) taken during pregnancy has been associated with an increased risk for childhood asthma. The effect of high-dose folic acid (5 mg) advised to women at risk for having a child with neural tube defect has not been assessed so far. Our aim was to investigate the effect of dispensed high-dose folic acid during pregnancy and asthma medication in the offspring.

METHODS

We used data from the pregnancy database IADB.nl, which contains pharmacy-dispensing data of mothers and children from community pharmacies in the Netherlands from 1994 until 2011. The dispension of asthma medication in children exposed in utero to high-dose folic acid was compared with children who were not exposed to this high dose. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

In 2.9% (N = 913) of the 39,602 pregnancies in the database, the mother was dispensed high-dose folic acid. Maternal high-dose folic acid was associated with an increased rate of asthma medication among children: recurrent asthma medication IRR = 1.14 (95%CI: 1.04-1.30) and recurrent inhaled corticosteroids IRR = 1.26 (95%CI: 1.07-1.47). Associations were clustered on the mother and adjusted for maternal age, maternal asthma medication, and dispension of benzodiazepines during pregnancy.

CONCLUSION

Almost 3% of the children were prenatally exposed to high-dose folic acid. This study suggests that supplementation of high-dose folic acid during pregnancy might increase the risk of childhood asthma.

Identifying associations between maternal medication use and birth defects using a case-population approach: an exploratory study on signal detection

BACKGROUND

The effects of many drugs on the unborn child are unknown. In a case-population design, drug exposure of cases is compared with that of a source population; this kind of study can be useful for generating signals.

OBJECTIVE

To see whether a comparison of drug use rates from the birth defect registry EUROCAT NNL (cases) with prescription rates from a population-based prescription database, the IADB (population), could be used to detect signals of teratogenic risk of drugs.

METHODS

We defined 3,212 cases from the EUROCAT NNL database, a population-based birth defect registry in the Northern Netherlands and 29,223 population controls from the IADB, a prescription database with data from community pharmacies in the same geographical area, born between 1998 and 2008. We classified the malformations of the 3,212 cases into several malformation groups according to organ system (based on the International Classification of Diseases codes and the EUROCAT guidelines). If a child had multiple malformations in several organ systems (n = 253, 7.9 %), he/she was counted in all the categories represented. For several groups of malformations we calculated rate ratios (RR) and 95 % confidence intervals for drugs acting on the central nervous system and for drugs considered to be safe for use in pregnancy. The RRs were based on first-trimester drug use rates from the cases in the EUROCAT NNL database and prescription rates from the population controls in the IADB.

RESULTS

For drugs acting on the central nervous system we found significantly increased RRs for the anti-epileptic drug valproic acid and for some selective serotonin reuptake inhibitors. For drugs considered to be safe only the anti-hypertensive methyldopa showed significantly increased RRs.

CONCLUSION

We show that a case-population study is a suitable method for detecting signals of possible teratogenicity, provided that the teratogenic effects and the drugs under study are as specific as possible and the drugs are widely used.

Anorectal malformations and pregnancy-related disorders: a registry-based case-control study in 17 European regions

OBJECTIVE

To identify pregnancy-related risk factors for different manifestations of congenital anorectal malformations (ARMs).

DESIGN

A population-based case-control study.

SETTING

Seventeen EUROCAT (European Surveillance of Congenital Anomalies) registries, 1980-2008.

POPULATION

The study population consisted of 1417 cases with ARM, including 648 cases of isolated ARM, 601 cases of ARM with additional congenital anomalies, and 168 cases of ARM-VACTERL (vertebral, anal, cardiac, tracheo-esophageal, renal, and limb defects), along with 13 371 controls with recognised syndromes or chromosomal abnormalities.

METHODS

Multiple logistic regression analyses were used to calculate adjusted odds ratios (ORs) for potential risk factors for ARM, such as fertility treatment, multiple pregnancy, primiparity, maternal illnesses during pregnancy, and pregnancy-related complications.

MAIN OUTCOME MEASURES

Adjusted ORs for pregnancy-related risk factors for ARM.

RESULTS

The ARM cases were more likely to be firstborn than the controls (OR 1.6, 95% CI 1.4-1.8). Fertility treatment and being one of twins or triplets seemed to increase the risk of ARM in cases with additional congenital anomalies or VACTERL (ORs ranging from 1.6 to 2.5). Maternal fever during pregnancy and pre-eclampsia were only associated with ARM when additional congenital anomalies were present (OR 3.9, 95% CI 1.3-11.6; OR 3.4, 95% CI 1.6-7.1, respectively), whereas maternal epilepsy during pregnancy resulted in a five-fold elevated risk of all manifestations of ARM (OR 5.1, 95% CI 1.7-15.6).

CONCLUSIONS

This large European study identified maternal epilepsy, fertility treatment, multiple pregnancy, primiparity, pre-eclampsia, and maternal fever during pregnancy as potential risk factors primarily for complex manifestations of ARM with additional congenital anomalies and VACTERL.

Disturbed development of the enteric nervous system after in utero exposure of selective serotonin re-uptake inhibitors and tricyclic antidepressants. Part 2: Testing the hypotheses

AIMS

Antidepressant use has increased in the last decade. Several studies have suggested a possible association between maternal antidepressant use and teratogenic effects.

METHODS

The pharmacy prescription database IADB.nl was used for a cohort study in which laxative and antidiarrhoeal medication use in children after in utero exposure to antidepressants (TCA, SSRI, fluoxetine or paroxetine exposed) was compared with no antidepressant exposure. Laxatives and antidiarrhoeal medication use were applied as a proxy for constipation and diarrhoea respectively, which may be associated with disturbed enteric nervous system (ENS) development.

RESULTS

Children exposed in utero to SSRIs (mainly fluoxetine and paroxetine) in the second and third trimester or to TCAs in the first trimester, more often received laxatives. Combined exposure to TCAs and SSRIs in pregnancy was associated with a 10-fold increase in laxative use. In utero exposure to SSRIs is not associated with antidiarrhoeal medication use compared with non-exposed children. In contrast, antidiarrhoeal medication use was significantly higher in children exposed to TCAs anytime in pregnancy.

CONCLUSIONS

The increased laxative use after second and third trimester exposure to SSRIs might be explained through the inhibitory effect of the serotonin re-uptake transporter (SERT) and because of selectivity for the 5-HT(2B) receptor which affects the ENS. TCA exposure during the first trimester leads to increased laxative use probably through inhibition of the norepinephrine transporter (NET). Exposure of TCAs anytime in pregnancy leads to increase diarrhoeal use possibly through down-regulation of α₂-adrenoceptors or up-regulation of the pore forming α(1c) subunit.

Evaluation of the representativeness of a Dutch non-malformed control group for the general pregnant population: are these controls useful for EUROCAT?

PURPOSE

A case-control study is the most powerful design to test the risk of specific congenital malformations associated with a specific drug. However, malformation registries often lack non-malformed controls. For the Dutch EUROCAT, we collected a non-malformed control group: the 'Healthy Pregnant'. The aim of this study was to evaluate the representativeness of this control group for the general pregnant population in the northern part of the Netherlands.

METHODS

The Healthy Pregnant data set includes data from two midwife practices. The baseline characteristics of mother and child including smoking status, drinking status, body mass index, maternal age, educational level, exposures to several drugs for chronic diseases and pregnancy related symptoms were evaluated.

RESULTS

Compared with the general population, mothers in Healthy Pregnant group (n = 556) were from either low or high education level, were more likely to have a body mass index > 25 kg/m² (26% versus 22%, p = 0.08) or to smoke (19% versus 10%, p < 0.01) but were less likely to consume alcohol (20% versus 29%, p < 0.01). The use of drugs for chronic conditions was lower in Healthy Pregnant group. Furthermore, drugs for occasional use were prescribed less frequently, and a significant underreporting of children with a low birth weight and a short duration of gestation was found.

CONCLUSION

The Healthy Pregnant data set was not representative of the general pregnant population in the northern part of the Netherlands. Specifically, the exposure to (chronic) drugs was underestimated, possibly a result of second-line care on the basis of medical indication. Thus, continuous investigation of options for improvement of the Healthy Pregnant database is required.

Fluoxetine and infantile hypertrophic pylorus stenosis: a signal from a birth defects-drug exposure surveillance study

PURPOSE

We report an association found in a surveillance study which systematically evaluated combinations of specific birth defects and drugs used in the first trimester of pregnancy.

METHOD

The database of a population-based birth defects registry (birth years 1997-2007) was systematically screened for combinations of drugs and malformations that were disproportionately present compared to the rest of the database. Combinations with at least three exposed cases and a p < 0.01 (Fisher Exact test) were studied to analyse details of the malformation, timing of exposure, and additional case-control analyses.

RESULTS

Among the significant associations found, an association between maternal use of fluoxetine and infantile hypertrophic pyloric stenosis (IHPS) was of particular interest. In total 3/178 (1.7%) of the children with a HPS were exposed to fluoxetine in the first trimester compared to 8/4077 (0.2%) fluoxetine exposures among the children with other malformations (p = 0.009, OR = 8.7, 95%CI = 2.3-33.2). The three exposed cases were all isolated and fluoxetine was used in gestational weeks 4-8, 2-8 and -10-19, respectively. In additional case-control analyses, using controls with a genetic disorder and after adjustment for maternal age and smoking in the first trimester of pregnancy, the adjusted odds ratio was 9.8 (95% confidence interval: 1.5-62.0).

CONCLUSIONS

Because we cannot rule out the possibility that the association between IHPS and fluoxetine is caused by chance, we encourage other investigators to study the association between IHPS and fluoxetine in their data.

First-trimester use of paroxetine and congenital heart defects: a population-based case-control study

BACKGROUND

There is a need for case-control studies of the effect of paroxetine on the occurrence of specific heart defects.

METHODS

We performed a case-control study with data from a population-based birth defects registry in the Netherlands. All the children born between 1997 and 2006 were selected. Cases were defined as fetuses and children with isolated heart defects, and the controls were fetuses and children with a genetic disorder with no heart defect. We excluded children for whom there was no information on maternal medication use and deceased children and fetuses who were not examined postmortem. First-trimester exposure to paroxetine was compared between cases and controls by calculating adjusted odds ratios (AOR).

RESULTS

We included 678 cases with isolated heart defects and 615 controls. The first trimester exposure rate was 1.5% for cases and 1.0% for controls. After excluding mothers who used paroxetine outside the first trimester, or who had used another SSRI, we found no significantly increased risk for heart defects overall (10 exposed cases; AOR, 1.5; 95% confidence interval [CI], 0.5-4.0), but we did find a significantly increased risk for atrium septum defects (three exposed cases; AOR, 5.7; 95% CI, 1.4-23.7).

CONCLUSIONS

Our results suggest that the use of paroxetine in early pregnancy is associated with an increased risk of atrium septum defects. The results stress the importance of studying possible teratogenic effects of a drug, preferably in regard to well-specified malformations.

Prevalence of severe congenital heart disease after folic acid fortification of grain products: time trend analysis in Quebec, Canada

OBJECTIVE

To investigate whether the 1998 government policy for mandatory fortification of flour and pasta products with folate was followed by a reduction in the prevalence of severe congenital heart defects.

DESIGN

Time trend analysis.

SETTING

Province of Quebec, Canada.

PARTICIPANTS

Infants born in 1990-2005 identified with severe congenital heart defects (tetralogy of Fallot, endocardial cushion defects, univentricular hearts, truncus arteriosus, or transposition complexes) in Quebec administrative databases.

METHODS

Data analysed in two time periods (before and after fortification). Birth prevalence measured annually as infants (live and stillbirths) with severe congenital heart defects per 1000 births in Quebec. Changes in the birth prevalence from the period before to the period after fortification were estimated with Poisson regression.

RESULTS

Among the 1, 324,440 births in Quebec in 1990-2005 there were 2083 infants born with severe congenital heart defects, corresponding to an average birth prevalence of 1.57/1000 births. Time trend analysis showed no change in the birth prevalence of severe birth defects in the nine years before fortification (rate ratio 1.01, 95% confidence interval 0.99 to 1.03), while in the seven years after fortification there was a significant 6% decrease per year (0.94, 0.90 to 0.97).

CONCLUSIONS

Public health measures to increase folic acid intake were followed by a decrease in the birth prevalence of severe congenital heart defects. These findings support the hypothesis that folic acid has a preventive effect on heart defects.