Can We Ensure the Safe Use of Known Human Teratogens?

Using Natural Language Processing to Examine the Uptake, Content, and Readability of Media Coverage of a Pan-Canadian Drug Safety Research Project: Cross-Sectional Observational Study

Background

Isotretinoin, for treating cystic acne, increases the risk of miscarriage and fetal abnormalities when taken during pregnancy. The Health Canada–approved product monograph for isotretinoin includes pregnancy prevention guidelines. A recent study by the Canadian Network for Observational Drug Effect Studies (CNODES) on the occurrence of pregnancy and pregnancy outcomes during isotretinoin therapy estimated poor adherence to these guidelines. Media uptake of this study was unknown; awareness of this uptake could help improve drug safety communication.

Objective

The aim of this study was to understand how the media present pharmacoepidemiological research using the CNODES isotretinoin study as a case study.

Methods

Google News was searched (April 25-May 6, 2016), using a predefined set of terms, for mention of the CNODES study. In total, 26 articles and 3 CNODES publications (original article, press release, and podcast) were identified. The article texts were cleaned (eg, advertisements and links removed), and the podcast was transcribed. A dictionary of 1295 unique words was created using natural language processing (NLP) techniques (term frequency-inverse document frequency, Porter stemming, and stop-word filtering) to identify common words and phrases. Similarity between the articles and reference publications was calculated using Euclidian distance; articles were grouped using hierarchical agglomerative clustering. Nine readability scales were applied to measure text readability based on factors such as number of words, difficult words, syllables, sentence counts, and other textual metrics.

Results

The top 5 dictionary words were pregnancy (250 appearances), isotretinoin (220), study (209), drug (201), and women (185). Three distinct clusters were identified: Clusters 2 (5 articles) and 3 (4 articles) were from health-related websites and media, respectively; Cluster 1 (18 articles) contained largely media sources; 2 articles fell outside these clusters. Use of the term isotretinoin versus Accutane (a brand name of isotretinoin), discussion of pregnancy complications, and assignment of responsibility for guideline adherence varied between clusters. For example, the term pregnanc appeared most often in Clusters 1 (14.6 average times per article) and 2 (11.4) and relatively infrequently in Cluster 3 (1.8). Average readability for all articles was high (eg, Flesch-Kincaid, 13; Gunning Fog, 15; SMOG Index, 10; Coleman Liau Index, 15; Linsear Write Index, 13; and Text Standard, 13). Readability increased from Cluster 2 (Gunning Fog of 16.9) to 3 (12.2). It varied between clusters (average 13th-15th grade) but exceeded the recommended health information reading level (grade 6th to 8th), overall.

Conclusions

Media interpretation of the CNODES study varied, with differences in synonym usage and areas of focus. All articles were written above the recommended health information reading level. Analyzing media using NLP techniques can help determine drug safety communication effectiveness. This project is important for understanding how drug safety studies are taken up and redistributed in the media.

Occurrence of pregnancy and pregnancy outcomes during isotretinoin therapy

BACKGROUND

Isotretinoin, a teratogen, is widely used to treat cystic acne. Although the risks of pregnancy during isotretinoin therapy are well recognized, there are doubts about the level of adherence with the pregnancy prevention program in Canada. Our objective was to evaluate the effectiveness of the Canadian pregnancy prevention program in 4 provinces: British Columbia, Saskatchewan, Manitoba and Ontario.

METHODS

Using administrative data, we identified 4 historical cohorts of female users of isotretinoin (aged 12-48 yr) for the period 1996 to 2011. We defined pregnancy using International Statistical Classification of Diseases and billing codes. One definition included only cases with documented pregnancy outcomes (high-specificity definition); the other definition also included individuals recorded as receiving prenatal care (high-sensitivity definition). We studied new courses of isotretinoin and detected pregnancies in 2 time windows: during isotretinoin treatment only and up to 42 weeks after treatment. Live births were followed for 1 year to identify congenital malformations.

RESULTS

A total of 59 271 female patients received 102 308 courses of isotretinoin. Between 24.3% and 32.9% of participants received prescriptions for oral contraceptives while they were taking isotretinoin, compared with 28.3% to 35.9% in the 12 months before isotretinoin was started. According to the high-specificity definition of pregnancy, there were 186 pregnancies during isotretinoin treatment (3.1/1000 isotretinoin users), compared with 367 (6.2/1000 users) according to the high-sensitivity definition. By 42 weeks after treatment, there were 1473 pregnancies (24.9/1000 users), according to the high-specificity definition. Of these, 1331 (90.4%) terminated spontaneously or were terminated by medical intervention. Among the 118 live births were 11 (9.3%) cases of congenital malformation. Pregnancy rates during isotretinoin treatment remained constant between 1996 and 2011.

INTERPRETATION

Adherence to the isotretinoin pregnancy prevention program in Canada was poor during the 15-year period of this study.

Prenatal-onset neurodevelopmental disorders secondary to toxins, nutritional deficiencies, and maternal illness

Neurodevelopmental disorders result from an inordinate number of genetic and environmental causes during the embryological and fetal periods of life. In the clinical setting, deciphering precise etiological diagnoses is often difficult. Newer screening technologies allow a gradual shift from traditional nature-versus-nurture debates toward the focused analysis of gene-by-environment interactions (G X E). Further understanding of developmental adaptation and plasticity requires consideration of epigenetic processes such as maternal nutritional status, environmental toxins, maternal illnesses, as well as genetic determinants, alone or in combination. Appreciation of specific G X E mechanisms of neurodevelopmental pathogenesis should lead to better risk-modifying or preventive strategies. We provide a brief overview of clinical and experimental observations that link prenatal-onset toxic exposures, metabolic disturbances, and maternal illnesses to certain neurodevelopmental disorders.

iPLEDGE allegiance to the pill: evaluation of year 1 of a birth defect prevention and monitoring system

The United States Food and Drug Administration (FDA), in collaboration with pharmaceutical manufacturers, have recently implemented a heavily revised risk-management program for patients on isotretinoin (Accutane), a drug with known and pronounced teratogenic effects. This revised risk management plan places significant burdens on both providers and patients in the hopes of achieving its goal of reducing fetal exposure to isotretinoin. The main focus of this paper is to discuss the burdens of various aspects of the program in relationship to potential corresponding benefits. In particular, we evaluate the pregnancy rates of women on isotretinoin therapy compared with that of the general population and the rate changes based on the risk management programs. Additionally, we investigate whether the benefits of the program for women have increased as the benefits have risen. We devote special attention to the ethical implications of the intent of the program and to an analysis of the ethical justification of the restrictions placed on women of childbearing potential (WCP) as it compares to the risk-benefit relationship of using isotretinoin.

Can we ensure the safe use of known human teratogens?: The iPLEDGE test case

Minimising the public health burden of isotretinoin-induced teratogenicity has been a challenge for 24 years, the duration of availability of isotretinoin in the US for the treatment of severe, recalcitrant nodular acne. Although the teratogenicity of this drug is well known and risk-management programmes had been implemented, preventable fetal exposures continued to occur, largely as a result of the lack of sufficient controls within the programmes themselves. The manufacturers of isotretinoin implemented a new risk-management programme, iPLEDGE, in March 2006. iPLEDGE is a comprehensive distribution system that includes mandatory registration of patients, healthcare providers, pharmacies, and wholesalers. It allows real-time linkage of pregnancy-test results for verification prior to the dispensing of isotretinoin. Although the challenges of implementing a closed distribution system for a very widely used medication have been extensive, the potential public health benefits from preventing fetal exposure to isotretinoin are substantial.

What is the best approach to reducing birth defects associated with isotretinoin?

Isotretinoin is an effective treatment for severe acne, a condition which can be physically, emotionally, and socially disabling. Because the drug is teratogenic, causing severe birth defects, women taking the drug are directed to avoid pregnancy. In the United States, a series of risk reduction programs have been implemented that aim to prevent pregnant women from taking the drug and to prevent women taking it from getting pregnant. The most recent, and most stringent, is an Internet-based, performance-linked system called iPLEDGE, which tries to ensure that the drug is dispensed only when there is documentary proof that the patient is not pregnant and is using two forms of birth control. Is iPLEDGE the best way to reduce isotretinoin birth defects, or is it an unproven and overly burdensome system?

A survey of pregnant women using isotretinoin

BACKGROUND

Isotretinoin is a known human teratogen, causing birth defects and/or subnormal cognitive performance in prenatally-exposed children.

METHODS

A survey was conducted among women who called teratology information services throughout North America. Using a structured questionnaire, women with an isotretinoin-exposed pregnancy were prospectively interviewed before the outcome of the pregnancy was known.

RESULTS

Almost 1/4 of the women surveyed (24%; 8/34) did not recall having contraception counseling before starting their medications. Once therapy was initiated, 62% (21/34) recalled using a birth control method, but only 29% (6/21) recalled using 2 forms of birth control, as specified by the voluntary pregnancy prevention programs. Monthly pregnancy tests were not always conducted during treatment, as recalled by the surveyed women (56%; 19/34). As many as 24% (8/34) of the women surveyed recalled that they were not screened using 2 pregnancy tests before receiving a prescription, another recommendation of the programs. Only a small number of the women (30%; 6/20) in the United States recalled being enrolled in any manufacturers' voluntary pregnancy prevention survey.

CONCLUSIONS

Results demonstrate that essential components of voluntary pregnancy prevention programs were not consistently followed, which resulted in fetal exposures.