Drug use in pregnancy: a comparative appraisal of data collecting methods

Medication use before and during pregnancy in Japan: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

PURPOSE

To elucidate the status of medication use among pregnant women in Japan, by means of a multigenerational genome and birth cohort study: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study (TMM BirThree Cohort Study).

METHODS

Questionnaires were distributed to pregnant women participating in the TMM BirThree Cohort Study (from July 2013 to March 2017) around 12 weeks (early pregnancy) and 26 weeks (middle pregnancy). We analysed medication use over three periods: (1) 12 months prior to pregnancy diagnosis, (2) the period between pregnancy diagnosis and around week 12 of pregnancy, and (3) post around week 12 of pregnancy.

RESULTS

In total, 19,297 women were included in the analysis. The proportion of pregnant women using medications was 49.0% prior to pregnancy diagnosis, 52.1% from diagnosis to week 12, and 58.4% post week 12 of pregnancy. The most frequently prescribed medications were loxoprofen sodium hydrate (5.5%) prior to pregnancy diagnosis, magnesium oxide (5.9%) from diagnosis to week 12, and ritodrine hydrochloride (10.5%) post week 12 of pregnancy. The number of women who used suspected teratogenic medications during early pregnancy was 96 prior to pregnancy diagnosis, 48 from diagnosis to week 12, and 54 post week 12 of pregnancy.

CONCLUSION

We found that ~ 50% of the pregnant women used medications before and during pregnancy and some took potential teratogenic medications during pregnancy. In birth genomic cohort study, it is expected that investigations into the safety and effectiveness of medications used during pregnancy will advance.

Assessing agreement between population-level administrative pharmaceutical databases and patient-reported medication dispensation in cardiac rehabilitation patients

BACKGROUND

Pharmacoepidemiology has emerged as a crucial field in evaluating the use and effects of medications in large populations to ensure their safe and effective use. This study aimed to assess the agreement of cardiac medication use between a provincial medication database, the Pharmaceutical Information Network (PIN), and reconciled medication data from confirmation through patient interviews for patients referred to cardiac rehabilitation.

METHODS

The study included data from patients referred to the TotalCardiology Rehabilitation CR program, and medication data was available in both TotalCardiology Rehabilitation charts and PIN. The accuracy of medication data obtained from patient interviews was compared to that obtained from PIN with proportions and kappa statistics to evaluate the reliability of PIN data in assessing medication use.

RESULTS

Patient-reported usage was higher for statins (41.6 %) vs. 38.4 %), ACE/ARB, beta-blockers (75.7 %) vs. 73.7 %), DOAC (3.5 %) vs. 2.6 %), and ADP-receptor antagonists (71.0 %) vs. 68.1 %) than if PIN was used. Patient-reported usage data was lower for Ezetimibe (4.7 vs. 4.8 %), Aldosterone antagonists (5.4 %) vs. 5.5 %), digoxin (0.9 %) vs. 1.0 %), calcium channel blockers (19.2 vs. 19.9 %) and warfarin (7.2 %) vs. 8.1 %). The results indicated that the differences between the two sources were very small, with an average agreement of 95.3 % and a kappa of 0.70.

CONCLUSION

The study's results, which show a high level of agreement between PIN and patient self-reporting, affirm the reliability of PIN data as a source for obtaining an accurate assessment of medication use. This finding is crucial in the context of pharmacoepidemiology research, where the accuracy of data is paramount. Further research to explore the complementary use of both data sources will be valuable.

Determining antenatal medicine exposures in South African women: a comparison of three methods of ascertainment

BACKGROUND

In the absence of clinical trials, data on the safety of medicine exposures in pregnancy are dependent on observational studies conducted after the agent has been licensed for use. This requires an accurate history of antenatal medicine use to determine potential risks. Medication use is commonly determined by self-report, clinician records, and electronic pharmacy data; different data sources may be more informative for different types of medication and resources may differ by setting. We compared three methods to determine antenatal medicine use (self-report, clinician records and electronic pharmacy dispensing records [EDR]) in women attending antenatal care at a primary care facility in Cape Town, South Africa in a setting with high HIV prevalence.

METHODS

Structured, interview-administered questionnaires recorded self-reported medicine use. Data were collected from clinician records and EDR on the same participants. We determined agreement between these data sources using Cohen's kappa and, lacking a gold standard, used Latent Class Analysis to estimate sensitivity, specificity and positive predictive value (PPV) for each data source.

RESULTS

Between 55% and 89% of 967 women had any medicine use documented depending on the data source (median number of medicines/participant = 5 [IQR 3-6]). Agreement between the datasets was poor regardless of class except for antiretroviral therapy (ART; kappa 0.6-0.71). Overall, agreement was better between the EDR and self-report than with either dataset and the clinician records. Sensitivity and PPV were higher for self-report and the EDR and were similar for the two. Self-report was the best source for over-the-counter, traditional and complementary medicines; clinician records for vaccines and supplements; and EDR for chronic medicines.

CONCLUSIONS

Medicine use in pregnancy was common and no single data source included all the medicines used. ART was the most consistently reported across all three datasets but otherwise agreement between them was poor and dependent on class. Using a single data collection method will under-estimate medicine use in pregnancy and the choice of data source should be guided by the class of the agents being investigated.

Assessment of medication use during pregnancy by Web-based questionnaires, pharmacy records and serum screening

OBJECTIVE

To compare assessment of early pregnancy medication exposure using three methods of data collection.

METHODS

Serum samples were obtained from 752 women participating in the PRegnancy and Infant DEvelopment (PRIDE) Study before gestational week 17. For 52 women using medication at the date of blood sampling according to Web-based questionnaires or pharmacy records, we analysed serum samples using untargeted liquid chromatography time-of-flight spectrometry.

RESULTS

Medication was detected in 18 serum samples (35%). Medications taken orally for chronic conditions reported in the questionnaire were detected in serum and vice versa. Pharmacy records did not identify additional exposed women, but missed exposure in 5 women mainly due to unavailability. We observed substantial discordance between the three methods for inhaled medication, dermatological preparations, and medications for short-term use, which went often undetected in serum.

CONCLUSIONS

It remains challenging to assess medication use in large-scale studies as no 'gold standard' is currently available.

Risk factors for discontinuation of thyroid hormone replacement therapy in early pregnancy: a study from the Norwegian Mother and Child Cohort Study and the Medical Birth Registry of Norway

INTRODUCTION

Approximately 3-5% of pregnant women have hypothyroidism. Despite the potential impact of untreated hypothyroidism on infant neurodevelopment, few studies have investigated the risk factors associated with discontinuation of thyroid hormone replacement therapy (THRT) in pregnancy. We aimed to identify such factors in a population of women using THRT prior to pregnancy.

MATERIAL AND METHODS

Data from the Norwegian Mother and Child Cohort Study were linked to records in the Medical Birth Registry of Norway. Pregnant women with hypothyroidism prior to pregnancy were categorized as discontinuers or continuers of THRT in pregnancy. The main analysis used generalized estimating equations based on multiply imputed data.

RESULTS

Of 86 848 enrolled pregnant women, 2720 (3.2%) had a medically confirmed thyroid disorder and/or reported use of thyroid therapy. More than half (n = 1587; 57.8%) used THRT prior to pregnancy; of these, 207 (13.0%) discontinued and 1380 (86.9%) continued THRT during early pregnancy. Having a non-medicated mental disorder [odds ratio (OR) 1.64, 95% CI 1.03-2.63] and non-compliance with recommended nutritional supplementation (OR 2.51, 95% CI 1.82-3.47) increased the odds of discontinuing THRT. Women medicated for somatic comorbidities (OR 0.56, 95% CI 0.33-0.98) had a 44% decreased odds of discontinuing THRT.

CONCLUSIONS

In Norway, around 13% of women with hypothyroidism discontinue THRT in early pregnancy. For discontinuers, non-medicated mental comorbidity and non-compliance with nutritional supplements presented increased risk, whereas having a medicated somatic disorder was protective. Health professionals advising women with hypothyroidism should be aware of risk factors associated with THRT discontinuation.

Using Web-Based Questionnaires to Assess Medication Use During Pregnancy: A Validation Study in 2 Prospectively Enrolled Cohorts

Medication use is often underreported in paper-based questionnaires or interviews. Web-based questionnaires may improve recall of medication use, but data on their validity are currently lacking. Participants in the Pregnancy and Infant Development (PRIDE) Study (2014-2016; n = 557) and the Pregnancy Drug Registry (pREGnant) (2015-2016; n = 169) completed a 6-week paper-based medication diary during gestational weeks 19-24 or 26-31. In week 34, they completed a Web-based questionnaire with questions on medication names, time period and frequency of use, and quantity taken. To assess the degree of underreporting, we calculated the questionnaire's sensitivity using the medication diary as the reference standard. Sensitivity was high for many medication groups, including antiepileptic medication (sensitivity (Sn) = 0.96, 95% confidence interval (CI): 0.89, 1.00), antacids (Sn = 0.89, 95% CI: 0.86, 0.93), and iron preparations (Sn = 0.81, 95% CI: 0.64, 0.98). However, medications for short-term use were underreported more frequently, with sensitivities of 0.54 (95% CI: 0.35, 0.72) for antihistamines, 0.63 (95% CI: 0.57, 0.69) for analgesic and antipyretic agents, and 0.57 (95% CI: 0.51, 0.64) for acetaminophen. Shortening the period of time between exposure and questionnaire administration increased sensitivity substantially. In conclusion, underreporting in Web-based questionnaires is limited for many medication groups. In prospective studies, underreporting of medications for short-term use may be reduced by decreasing the interval between consecutive questionnaires.

Agreement Between Maternal Report and Medical Records During Pregnancy: Medications for Rheumatoid Arthritis and Asthma

BACKGROUND

There are limited data regarding the comparability of medication exposure information during pregnancy from maternal report and medical records, including for rheumatoid arthritis and asthma-related medications.

METHODS

This study included pregnant women with rheumatoid arthritis (n = 216) and asthma (n = 172) enrolled in the MothertoBaby Pregnancy Studies (2009-2014). Women reported types and dates of medications used through semi-structured telephone interviews up to three times during pregnancy and once after delivery, and medical records were obtained. We calculated Cohen's kappa coefficients and 95% confidence intervals (CIs) and per cent agreement for agreement between report and records.

RESULTS

For rheumatoid arthritis, prednisone was reported most frequently (53%). During pregnancy, kappa coefficients for rheumatoid arthritis medications ranged from 0.32 (95% CI 0.15, 0.50) for ibuprofen, with 84.3% agreement, to 0.90 (95% CI 0.84, 0.96) for etanercept with 95.4% agreement, and was 0.44 (95% CI 0.33, 0.55) for prednisone, with 71.3% agreement. For asthma, albuterol was reported most frequently (77.9%). During pregnancy, kappa coefficients for asthma medications ranged from 0.21 (95% CI 0.08, 0.35), with 64.5% agreement for albuterol to 0.84 (95% CI 0.71, 0.96) for budesonide/formoterol, with 96.5% agreement. Where kappas for any use during pregnancy were less than excellent (i.e. ≤0.80), medication use was more frequently captured by report than record.

CONCLUSIONS

Agreement was higher for medications typically used continuously than sporadically. Information on medication use from medical records alone may not be adequate when studying the impact of intermittently used medications during pregnancy on perinatal outcomes.

Administrative Claims Data Versus Augmented Pregnancy Data for the Study of Pharmaceutical Treatments in Pregnancy

Purpose of Review

Administrative claims databases, which collect reimbursement-related information generated from healthcare encounters, are increasingly used to evaluate medication safety in pregnancy. We reviewed the strengths and limitations of claims-only databases and how other data sources may be used to improve the accuracy and completeness of information critical for studying medication safety in pregnancy.

Recent Findings

Research on medication safety in pregnancy requires information on pregnancy episodes, mother-infant linkage, medication exposure, gestational age, maternal and birth outcomes, confounding factors, and (in some studies) long-term follow-up data. Claims data reliably identifies live births and possibly other pregnancies. It allows mother-infant linkage and has prospectively collected prescription medication information. Its diagnosis and procedure information allows estimation of gestational age. It captures maternal medical conditions but generally has incomplete data on reproductive and lifestyle factors. It has information on certain, typically short-term maternal and infant outcomes that may require chart review confirmation. Other data sources including electronic health records and birth registries can augment claims data or be analyzed alone. Interviews, surveys, or biological samples provide additional information. Nationwide and regional birth and pregnancy registries, such as those in several European and North American countries, generally contain more complete information essential for pregnancy research compared to claims-only databases.

Summary

Claims data offers several advantages in medication safety in pregnancy research. Its limitations can be partially addressed by linking it with other data sources or supplementing with primary data collection. Rigorous assessment of data quality and completeness is recommended regardless of data sources.

Can We Rely on Pharmacy Claims Databases to Ascertain Maternal Use of Medications during Pregnancy?

BACKGROUND

Administrative databases are increasingly used to measure drug exposure in perinatal pharmacoepidemiology. We aimed to estimate the concordance between records of prescriptions filled in pharmacies and self-reported drug use during pregnancy.

METHODS

Data on self-reported medication use were collected at each trimester of pregnancy among a sub-sample from the Organization of Teratology Information Specialists Antidepressants in Pregnancy Cohort. Women were eligible if they were Quebec resident and provided their pharmacist's contact information. Maternal self-reports were compared with prescriptions filled in pharmacies, which are transferred to pharmaceutical services files of Quebec provincial health plan database (Régie de l'asssurance maladie du Québec). Positive and negative predictive values (PPV and NPV) for medications taken chronically (antidepressants, thyroid hormones), acutely (antibiotics), and as needed (antiemetics, asthma medications) were calculated.

RESULTS

Among the 93 participants (mean age = 30.2 ± 3.8 years), 41.9% (n = 39) took at least one antidepressant during pregnancy according to self-reports, and 39.8% (n = 37) according to pharmacy records. Other commonly used drugs were antiemetics (self-reported 22.6%, pharmacy record 24.7%), antibiotics (20.4%, 16.1%), asthma medications (15.1%, 15.1%), and thyroid hormones (10.8%, 8.6%). PPVs and NPVs were: (1) chronic medication: antidepressants PPV = 100% (95% confidence interval [CI], 100-100%), NPV = 96% (95% CI, 92-100%); thyroid hormones PPV = 100% (95% CI, 100-100%), NPV = 98% (95% CI, 95-100%); (2) Acute medication: antibiotics PPV = 87% (95% CI, 70-100%), NPV = 92% (95% CI, 86-98%); (3) as needed medications: antiemetics: PPV = 78% (95% CI, 62-95%), NPV = 96% (95% CI, 91-100%); asthma: PPV = 33% (95% CI, 3-64%), NPV = 99% (95% CI, 97-100%).

CONCLUSION

The high PPV and NPV validate the use of filled prescription data in large databases as a measure of medication exposure. Birth Defects Research 109:423-431, 2017. © 2017 Wiley Periodicals, Inc.

Validation of maternal recall of early pregnancy medication exposure using prospective diary data

PURPOSE

Data about maternal recall accuracy for classifying early pregnancy medication exposure are meager. Nonetheless, studies often rely on recall to evaluate potential impact of pharmaceuticals on the developing fetus.

METHODS

Right from the Start is a community-based pregnancy cohort that enrolled women from North Carolina, Tennessee, and Texas. A subset of 318 women participated in daily medication diaries initiated before conception (2006-2012). We examined nonsteroidal anti-inflammatory drugs (NSAIDs) as an example of a drug type that is difficult to study due to its intermittent and primarily over-the-counter use as well as its incomplete documentation in medical and pharmaceutical records. Selective serotonin reuptake inhibitors (SSRI) were assessed as a prescription medication comparator. Maternal recall of NSAID and SSRI use in early pregnancy was examined by comparing diary data (gold standard) to first-trimester interview.

RESULTS

Sensitivity and specificity for recall of NSAID exposure were 78.6% and 62.3%, respectively (kappa statistic: 0.41), with 72.3% agreement for exposure classification. Sensitivity and specificity for recall of SSRI exposure were 77.8% and 99.0%, respectively (kappa statistic: 0.79), with 97.8% agreement.

CONCLUSIONS

Our findings suggest the validity of maternal recall varies with medication type and prospective data collection should be prioritized when studying early pregnancy drug exposures.

Antenatal drug consumption: the burden of self-medication in a developing world setting

This institutional-based cross-sectional study examines the burden of self-medication during pregnancy in a middle-income country setting and the impact on fetal wellbeing. Using a blend of open-ended and indication-oriented questionnaires, 346 pregnant women at term were interviewed about their pregnancy complaints and drug intake. Inferential statistical data analysis was employed with level of significance (α) set at 0.05. Excluding routine supplements and vaccinations, 251 (72.5%) women used medicines, of whom 79 (31.5%) had self-medicated. Consuming drugs without prescription was associated with increased US Food & Drug Administration (FDA) risk category (χ2 = 8.375; P = 0.015). There is therefore a need to scale up efforts towards educating women about the dangers of self-medication, while also introducing effective restrictive policies on over-the-counter drug sales.

Actual Use of Medications Prescribed During Pregnancy: A Cross-Sectional Study Using Data from a Population-Based Congenital Anomaly Registry

Introduction and Aim

Data from prescription databases are increasingly being used to study associations between maternal medications used in pregnancy and congenital anomalies. We therefore investigated the extent to which prescriptions reflect the actual use of medication during pregnancy, and whether medicines used during pregnancy are taken according to the prescribed dosage and duration.

Methods

We performed a cross-sectional study in a population-based congenital anomaly register (EUROCAT Northern Netherlands). We included 202 women who had at least one prescription during their pregnancy and who gave birth between 2009 and 2011. Compliance with the prescribed medication was verified by telephone interview. We calculated the compliance rates for several medication groups by dividing the number of mothers who confirmed they had taken the medication by the total number to whom it had been prescribed. Compliance was positive if the mother confirmed she took the medication, even if she only took one of several prescriptions from the same medication group. For each prescription taken, we also determined whether her use conformed to the prescribed dosage and duration.

Results

During the first trimester, the compliance rates ranged from 0.84 (for chronic diseases) to 0.92 (for pregnancy-related symptoms). Most of the medications actually taken were used at the prescribed dosage or lower. More than half of the medications actually taken were used for the duration prescribed or shorter.

Conclusion

Prescription records are generally a relatively reliable source of data for research into associations between medication use in pregnancy and congenital anomalies compared with other data sources. Pharmacy records of medication use in pregnancy might represent an overestimation, which should be taken into account. However, our results show that, except for ‘corticosteroids, dermatological preparations’; ‘ear, eye, nose and throat preparations’; and ‘anxiolytics, hypnotics and sedatives’, this overestimation generally seems minimal.

Electronic supplementary material

The online version of this article (doi:10.1007/s40264-015-0302-z) contains supplementary material, which is available to authorized users.

Medication use during pregnancy, gestational age and date of delivery: agreement between maternal self-reports and health database information in a cohort

Background

Health databases are a promising resource for epidemiological studies on medications safety during pregnancy. The reliability of information on medications exposure and pregnancy timing is a key methodological issue. This study (a) compared maternal self-reports and database information on medication use, gestational age, date of delivery; (b) quantified the degree of agreement between sources; (c) assessed predictors of agreement.

Methods

Pregnant women recruited in a prenatal clinic in Friuli Venezia Giulia (FVG) region, Italy, from 2007 to 2009, completed a questionnaire inquiring on medication use during pregnancy, gestational age and date of delivery. Redeemed prescriptions and birth certificate records were extracted from regional databases through record linkage. Percent agreement, Kappa coefficient, prevalence and bias-adjusted Kappa (PABAK) were calculated. Odds Ratio (OR), with 95 % confidence interval (95 % CI), of ≥1 agreement was calculated through unconditional logistic regression.

Results

The cohort included 767 women, 39.8 % reported medication use, and 70.5 % were dispensed at least one medication. Kappa and PABAK indicated almost perfect to substantial agreement for antihypertensive medications (Kappa 0.86, PABAK 0.99), thyroid hormones (0.88, 0.98), antiepileptic medications (1.00, 1.00), antithrombotic agents (0.70, 0.96). PABAK value was greater than Kappa for medications such as insulin (Kappa 0.50, PABAK 0.99), antihistamines for systemic use (0.50, 0.99), progestogens (0.28, 0.79), and antibiotics (0.12, 0.63). Adjusted OR was 0.48 (95 % CI 0.26; 0.90) in ex- vs. never smokers, 0.64 (0.38; 1.08) in < high school vs. university, 1.55 (1.01; 2.37) in women with comorbidities, 2.25 (1.19; 4.26) in those aged 40+ vs. 30–34 years.

Gestational age matched exactly in 85.2 % and date of delivery in 99.5 %.

Conclusions

For selected medications used for chronic conditions, the agreement between self-reports and dispensing data was high. For medications with low to very low prevalence of use, PABAK provides a more reliable measure of agreement. Maternal reports and dispensing data are complementary to each other to increase the reliability of information on the use of medications during pregnancy. Birth certificates provide reliable data on the timing of pregnancy. FVG health databases are a valuable source of data for pregnancy research.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-015-0745-3) contains supplementary material, which is available to authorized users.

Risks of miscarriage and inadvertent exposure to artemisinin derivatives in the first trimester of pregnancy: a prospective cohort study in western Kenya

BACKGROUND

The artemisinin anti-malarials are widely deployed as artemisinin-based combination therapy (ACT). However, they are not recommended for uncomplicated malaria during the first trimester because safety data from humans are scarce.

METHODS

This was a prospective cohort study of women of child-bearing age carried out in 2011-2013, evaluating the relationship between inadvertent ACT exposure during first trimester and miscarriage. Community-based surveillance was used to identify 1134 early pregnancies. Cox proportional hazard models with left truncation were used.

RESULTS

The risk of miscarriage among pregnancies exposed to ACT (confirmed + unconfirmed) in the first trimester, or during the embryo-sensitive period (≥6 to <13 weeks gestation) was higher than among pregnancies unexposed to anti-malarials in the first trimester: hazard ratio (HR) = 1.70, 95 % CI (1.08-2.68) and HR = 1.61 (0.96-2.70). For confirmed ACT-exposures (primary analysis) the corresponding values were: HR = 1.24 (0.56-2.74) and HR = 0.73 (0.19-2.82) relative to unexposed women, and HR = 0.99 (0.12-8.33) and HR = 0.32 (0.03-3.61) relative to quinine exposure, but the numbers of quinine exposures were very small.

CONCLUSION

ACT exposure in early pregnancy was more common than quinine exposure. Confirmed inadvertent artemisinin exposure during the potential embryo-sensitive period was not associated with increased risk of miscarriage. Confirmatory studies are needed to rule out a smaller than three-fold increase in risk.

Changes in the pattern of paracetamol use in the periconception period in a Danish cohort

Paracetamol is the most commonly used over-the-counter drug in pregnancy. It is generally considered to be safe, but prolonged antenatal exposure has been associated with offspring short- and long-term morbidity. Our aim was to describe the pattern of paracetamol use with a focus on frequent ingestion (more than once a week), 3 months before and in early pregnancy. In this cohort, 8650 pregnant women responded to a web-based clinical questionnaire that included questions about drug use. Paracetamol was the most used drug before and in early pregnancy (35.2% and 6.5% of respondents, respectively). The proportion of frequent users decreased from 3.9% before to 0.9% in early pregnancy. Frequent paracetamol use was associated with smoking, co-morbidities, body mass index ≥ 25 kg/m(2), unplanned pregnancy, no education and inability to understand Danish. A significant decrease in the proportion of women with any paracetamol use in early pregnancy was noted after access to large packs was restricted by legislation.

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.

Use of medicines with unknown fetal risk among parturient women from the 2004 Pelotas Birth Cohort (Brazil)

Background. To estimate the exposure to medicines with unknown fetal risk during pregnancy and to analyze the maternal characteristics associated with it. Methods. A questionnaire was administered to 4,189 mothers of children belonging to the 2004 Pelotas (Brazil) birth cohort study about use of any medicine during gestation. We evaluated the associations between use of medicines with unknown fetal risk and the independent variables through logistic regression models. Unknown fetal risk was defined as medicines in which studies in animals have revealed adverse effects on the fetus, and no controlled studies in women, or studies in women and animals, are available. Results. Out of the 4,189 women, 52.5% used at least one medicine from unknown fetal risk. Use of these medicines was associated with white skin color, high schooling, high income, six or more antenatal care consultations, hospital admission during pregnancy, and morbidity during gestation. Conclusion. The use of unknown fetal risk medicines is high, suggesting that their use must be addressed with caution with the aim of restricting their use to cases in which the benefits are greater than the potential risks.

Drug use during pregnancy in Sweden - assessed by the Prescribed Drug Register and the Medical Birth Register

Purpose:

The purpose of this research is to study drug use during pregnancy in Sweden and agreement between use according to antenatal medical records and dispensed drugs from a pharmacy database.

Patients and methods:

From the Swedish Medical Birth Register (MBR), we established a population-based cohort of 102,995 women who gave birth in 2007. Using the unique personal registration number, information on dispensed drugs from the Prescribed Drug Register (PDR) was obtained prior to, during, and after the pregnancies and compared with MBR information on drug use from standardized antenatal medical records.

Results:

According to the PDR, 57.6% of the 102,995 women filled a prescription with at least one drug during pregnancy and 50.9% during the lactating period (until 3 months after delivery). The most dispensed drugs during pregnancy were B-lactam antibacterials and penicillins. Agreement between drugs recorded in antenatal medical records and dispensed drugs was highest for drugs used for chronic conditions. The agreement was particularly high for thyroid therapy (85.3%), anti-intestinal inflammatory drugs (80.3%), antiepileptics (69.2%), immunosuppressants (67.4%), and insulin (63.8%). Agreement for drugs used for occasional use was generally lower, ranging between 42.5% for antihistamines and 0.8% for gynecological anti-infectives.

Conclusions:

A large proportion of women filled a prescription during pregnancy or the lactating period. Agreement between drug use in medical antenatal records and register information from a national pharmacy database was high for drugs used for chronic conditions but low for occasional use. For occasionally used drugs, medical record and register-based data may provide incomplete exposure information because of nonreporting or noncompliance.

Effect of questionnaire structure on recall of drug utilization in a population of university students

BACKGROUND

Self-reported data are a common source of information about drug exposure. Modes of data collection differ considerably and the questionnaire's structure may affect prevalence estimates. We compared the recall of medication use evaluated by means of two questionnaires differing in structure and length.

METHODS

Drug utilization was assessed by two alternative versions of a questionnaire (A - 4 pages, including specific questions for 12 indications/pharmacological groups and one question for "other medicines"; B - 1 page, including 1 open-ended question to cover overall drug consumption). Each of 32 classes in a private University in Maputo, Mozambique, was randomly assigned questionnaire A (233 participants) or B (276 participants). Logistic regression (allowing for clustering by classroom) was used to compare the two groups in terms of socio-demographic characteristics and medication used during the previous month.

RESULTS

Overall, 67.4% of the subjects had used at least one drug during the previous month. The following prevalences were greater among participants completing questionnaire A: use of drugs from two or more pharmacological groups (60.5% vs. 34.4%, p < 0.001), use of two or more drugs (66.2% vs. 43.0%, p < 0.001), and use of antibiotics (14.6% vs. 6.9%, p = 0.001), antifungals (9.4% vs. 4.0%, p = 0.013), antiparasitics (5.6% vs. 1.8%, p = 0.031) and antacids (8.6% vs. 3.6%, p = 0.024). Information about duration of treatment and medical advice was more complete with version A.

CONCLUSION

The indication/drug-specific questions (questionnaire A) revealed a significantly higher prevalence of use of medicines - antibiotics, antifungals, antiparasitics and antacids - without compromising the completeness of the information.

A comparison of three questionnaire-based measures of analgesic use over 11 years in adult males: a retrospective analysis of data from a prospective, population-based cohort study

BACKGROUND

Few data are available on whether 3 commonly used, yet slightly different, questionnaire-based measures assessing the use of analgesics provide congruent and comparable results.

OBJECTIVE

The objective of this study was to compare 3 different measures of analgesic use in 1 study population over an 11-year period.

METHODS

Data for this study were gathered from a prospective, population-based cohort study in which 3 different measures were applied simultaneously for measuring use of analgesics at baseline, 4 years, and 11 years. The first measure was "weekly analgesic use in general," the second measure "analgesic use for pain symptoms within the past week," and the third measure "giving the name of any analgesic used within the past week." The subjects were Finnish men who completed 11 years of follow-up in the Kuopio Ischemic Heart Disease Risk Factor (KIHD) Study, conducted at the Research Institute of Public Health, University of Kuopio, Kuopio, Finland. Agreement between the 3 different measures was determined by Kappa statistics.

RESULTS

A total of 829 men completed 11 years of follow-up (mean [SD] age, 51.4 [6.7] years at baseline; 62.4 [6.5] at study end). At baseline, the prevalence of weekly analgesic use varied from 12.3% to 17.4% and at 11 years from 16.5% to 25.9%, depending on which measure was being used. The third measure yielded the highest prevalence at all 3 points of time and the lowest was obtained using the first measure. The Kappa agreement between the 3 measures at the 3 time points varied from moderate (0.37) to good (0.71).

CONCLUSIONS

The results of this study suggest that the measure being used influences the obtained prevalence of analgesic use. All 3 measures tested consistently throughout the course of the study. The best results, with regard to determining prevalence, were obtained by asking the respondents to name the medicines they had been using during the previous week.

Use of Over-the-Counter Medications and Natural Products in Patients With Moderate and Severe Chronic Renal Insufficiency

BACKGROUND

Use of over-the-counter medications and natural products may be associated with drug-related problems among patients with chronic renal insufficiency. The aim of this study is to describe the use of nonprescription medications in patients attending a predialysis clinic and identify drug-related problems associated with the use of these products.

METHODS

In a 6-month cluster randomized controlled trial, patients with moderate (n = 46) and severe (n = 41) chronic renal insufficiency were interviewed over the telephone at baseline by a community pharmacist to document their use of over-the-counter medications and natural products. The safety of each product was assessed, and drug-related problems were identified independently by 2 pharmacists.

RESULTS

Overall, 83% (95% confidence interval [CI], 72 to 94) of patients with moderate chronic renal insufficiency and 68% (95% CI, 54 to 83) with severe chronic renal insufficiency reported using at least 1 over-the-counter medication. Contraindicated over-the-counter medications were reported by 9% of patients. Natural products were used by 22% (95% CI, 10 to 34) and 29% (95% CI, 15 to 43) of patients with moderate and severe chronic renal insufficiency, respectively. Similarly, 3% of patients reported using at least 1 contraindicated natural product. Patients had consulted a health professional for 49% of over-the-counter medications and 19% of natural products. Overall, 65 drug-related problems were identified.

CONCLUSION

The use of over-the-counter medications and natural products is highly prevalent in patients with chronic renal insufficiency and often is associated with a drug-related problem. These results emphasize the importance for community pharmacists to closely monitor the use of these products in patients with chronic renal insufficiency.

O uso de medicamentos na gravidez

O uso de medicamentos na gravidez é cada vez mais intenso, enquanto a prática médica volta-se para a incorporação do conceito de risco. Embora a tragédia da talidomida tenha marcado o início da reflexão sobre a ocorrência de efeitos adversos de medicamentos usados durante a gestação, as percepções dos prescritores, no âmbito da terapêutica medicamentosa na gravidez, ainda oscilam entre a certeza de que tudo é nocivo e a relativa crença de que tudo é seguro até que se prove o contrário. Faz-se necessária a produção de evidências que substanciem as condutas clínicas. O ensaio clínico randomizado é considerado a pedra angular do paradigma da medicina baseada em evidências. Sugerem-se os contextos nos quais a aplicação dos diversos tipos de pesquisa clínica seriam apropriados na gestação e ainda o emprego ampliado da farmacoepidemiologia para a construção de evidências nessa população, por meio de estudos analíticos, em especial a coorte. Entende-se que estes estudos, desde que executados com rigor metodológico, possam oferecer informação balizada, geradora de hipóteses, essenciais para a prática clínica.

Drug prescription in pregnancy: analysis of a large statutory sickness fund population

OBJECTIVE

To examine the prescription of drugs in Germany prior to, during and after pregnancy.

METHODS

For the first time, prescription data of a large cohort of pregnant women, from a German statutory sickness fund, were available for scientific analysis. For each woman who gave birth between June 2000 and May 2001 reimbursed prescriptions for two periods (90 days each) before pregnancy, three during and two after delivery were considered. The drugs were classified according to the ATC code.

RESULTS

Of the 41,293 women, 96.4% received at least one drug during pregnancy. A median of 7 drugs per women was prescribed. Excluding vitamins, minerals, iodide and iron, 85.2% received at least one drug and the median was 3. Magnesium, which was seldom prescribed outside of pregnancy, was by far the most frequently prescribed substance (20% of all prescriptions, 61% of the women). Iron (54% of the women) and iodide (31%) were also prescribed often. The prescription rates of gynaecological antiinfectives (maximum in third trimester: 23% of the women), antacids (max. in third trim.: 11%), as well as antiemetics and antinauseants (max. in first trim.: 8%) during pregnancy considerably increased. A decrease was seen for analgesics, antiinflammatory and antirheumatic drugs, muscle relaxants, ophtalmologicals and anti-acne preparations, for example. Potential teratogenic drugs were prescribed to 1.3% of the women.

CONCLUSION

This analysis of a large nation-wide cohort of pregnant women showed that during pregnancy drugs were prescribed to most women, even when vitamins, minerals, iodide and iron were omitted. Magnesium and iron seemed to have been over-prescribed. On the other hand, the official recommendation for iodide substitution, to prevent thyroid diseases in mother and child, was insufficiently implemented. In our opinion, regular analysis of prescription data can identify potential harmful therapies and focal points where guidelines are needed and can check their implementation.

Medication use during pregnancy: data from the Avon Longitudinal Study of Parents and Children

OBJECTIVE

To present data on the self-reported use of all types of medicinal products collected during pregnancy in a large cohort in southwest England.

METHODS

Pregnant women with a delivery date during 1991-1992 and forming part of the prospective, population-based Avon Longitudinal Study of Parents and Children (ALSPAC) were sent up to four self-completion postal questionnaires during pregnancy. Text data collected from the questions on drug usage were coded using an ALSPAC drug dictionary based on the World Health Organization Drug Dictionary.

RESULTS

At least one antenatal self-completion questionnaire was completed for 14,119 pregnancies, and 11,545 women completed all four. The data included prescription, over-the-counter, herbal and homeopathic products as well as iron, vitamins and other supplements. Only 7.6% did not report use of any medicinal product throughout their entire pregnancy. The remaining 92.4% used at least one product at some stage. After exclusion of iron, folate, vitamins, supplements, herbal and homeopathic products and skin emollients, 83% of those completing all questionnaires had used conventional therapeutic drugs. Analgesics were reported by approximately one-third of women at each stage during pregnancy, and paracetamol was the most frequently reported substance. Iron preparations were reported by 33% of the full cohort, at some stage, and folate by 21.9%. Use of anti-anaemic products increased during pregnancy with the greatest incidence at 32 weeks. Other vitamins and supplements were taken by 17.4% at some stage. Use of vitamins decreased throughout pregnancy from 9.6% in early pregnancy to 5% at 32 weeks. Antacids were reported by 23% at 32 weeks. The reported incidence of antibiotic use decreased slightly during pregnancy from 8% early on to 5.8% at 32 weeks; amoxicillin was the most frequently reported antibacterial.

CONCLUSION

Use of medicinal products was high during pregnancy in the ALSPAC cohort. This finding is consistent with data from recent publications.

[Prescribed and reported drug use during pregnancy]

Few studies describe drug utilization in pregnancy focusing on prescribing practices. This study is part of a larger survey on perinatal care in the City of Rio de Janeiro, Brazil. The type of hospital (public, contracted out by the Unified National Health System, or private) determined the stratification of 10,072 hospitalized post-partum women, who were asked about medication used during pregnancy. Hospital records supplied information on drugs prescribed during labor. Drugs were classified according to the Anatomical Therapeutic Chemical (ATC) system. Another system was used for specific cases of referred use. A mean of 2.08 drugs was prescribed during labor, and a mean of 2.3 was reported during pregnancy. Anesthetics, antibiotics, oxytocin, and analgesics were the most frequently prescribed during labor, with significant differences between strata. Ferrous sulfate, vitamins, scopolamine, and acetaminophen were the main drugs reported during pregnancy. Women who had attempted abortion referred use of various kinds of tea (49.7%) and misoprostol (9.2%). The drug utilization pattern was consistent with the literature. This study offers knowledge on prescribing patterns during labor and self-reported use during pregnancy in both the public and private sectors.

Drug use during breastfeeding. A survey from the Netherlands

OBJECTIVE

To survey drug use by breastfeeding women, and to compare this with nonbreastfeeding women. In addition, we were interested whether drug use was of influence on the decision to give breastfeeding, and the other way around.

DESIGN AND SETTING

During a 6-week period in 2002, a questionnaire was handed out to all women with a child not older than 6 months, who visited a Well-Baby Clinic in the province of Friesland, the Netherlands, eventually resulting in 549 returned questionnaires (response 43%).

RESULTS

In all, 82.1% of the participants breastfed their baby at least at any time during the first 6 months after birth. More than half (65.9%) of all breastfeeding women had used drugs; however, they used drugs less frequently than nonbreastfeeding women (79.6%). The pattern of drug use differed: oral contraceptives, iron preparations, drugs for peptic ulcer, and several psychotropic drugs were more frequently used by nonbreastfeeding women, while vitamins were more frequently used by breastfeeding women. Drugs play an important role in women's decision to start or continue breastfeeding: women frequently hesitated to use drugs during breastfeeding, stopped either breastfeeding or drug use to avoid combining the two, took a measure to minimise exposure to the child, did not use any drug because of breastfeeding, or did not breastfeed because of drug use.

CONCLUSIONS

Drugs are frequently though reluctantly used during breastfeeding, and play an important role in the decision to start and stop breastfeeding. Information how to deal with drugs seems therefore indispensable in efforts to promote breastfeeding.

Validity of performance indicators for assessing prescribing quality: the case of asthma

OBJECTIVES

The aim of this study was to assess the concurrent validity between the identification of sub-optimal treatment based on clinical information and computer generated indicators. Indicators that are associated with sub-optimal treatment in one of the four steps of asthma management were assessed.

DESIGN

The ability of each indicator to identify patients with sub-optimal asthma treatment from computerised general practitioner (GP) prescription records was assessed by comparing them with the results of an individual patient assessment using clinical data.

SETTING

Chronic asthma patients ( n=146) registered with 16 Dutch GPs.

MAIN MEASURES

The sensitivity and positive predictive value (PPV) of each performance indicator was determined.

RESULTS

The step-1 indicator, focusing on patients not prescribed a short-acting beta-agonist, had an acceptable sensitivity (0.86), but a low PPV (0.52). The two step-2 indicators, targeting under-prescription of inhaled corticosteroids, had sensitivities of 0.74 and 0.37 and PPVs of 0.46 and 0.71, respectively. The step-3 indicator, which targeted under-dosing of inhaled corticosteroids, had a sensitivity of 0.07 and a PPV of 0.2. The fourth indicator, focusing on under-prescription of long-acting beta-agonists, could not be validated due to inadequate numbers of patients with severe asthma in our study sample.

DISCUSSION

None of the indicators investigated was considered valid for assessing prescriber performance, despite having good face and content validity. Performance indicators that have not been validated can only provide a broad-brush approach for assessing prescribing quality and should be used with extreme caution.

Pharmacy data in epidemiological studies: an easy to obtain and reliable tool

PURPOSE

The agreement between drug use measured in computerized pharmacy records and patient interviews or questionnaires is generally good. However, most investigations on this subject studied selected populations or subsets. We studied the coverage of Dutch pharmacy data for our study cohort, and the agreement between the different sources.

METHODS

We used the data from 8592 subjects of an on-going population-based study, focused on the impact of microalbuminuria (PREVEND). Data on drug use was collected in a questionnaire and at community pharmacies. Drug use was measured in the year preceding the questionnaire. Agreement between the sources was measured using kappa-values, sensitivity and positive predictive value.

RESULTS

Pharmacy data could be collected for 7568 (88%) of the study cohort. Pharmacy data and questionnaires showed good agreement for antihypertensives, lipid lowering drugs, oral antidiabetics and oral contraceptives, but poor agreement for nitrates, hormone replacement therapy and painkillers.

CONCLUSIONS

Pharmacy data could be collected for a large proportion of our cohort. For chronically used drugs pharmacy data generally agrees well with questionnaires. However, for drugs used for shorter periods, as needed, or also available over-the-counter, the agreement is not so good. Pharmacy data can be a valuable source of drug information in epidemiological studies.

How do we best detect toxic effects of drugs taken during pregnancy? A EuroMap paper

It is a major clinical and public health problem that there is no clear strategy as to how we best make use of information obtained when pregnant women take drugs. For this reason, some pregnant women are not treated as they should be and some are given drugs they should not use. We suggest a monitoring system that combines some of the available datasets in Europe. Using these sources as a starting point, one can develop a system that has sufficient power to detect even rare diseases like congenital malformations and sufficient diversity to detect several possible outcomes from spontaneous abortions to childhood disorders. We also suggest that case-crossover designs should be used in case-control monitoring systems that carry a high risk of recall bias. These considerations are based upon our results from a European Union-funded concerted action called EuroMaP (Medicine and Pregnancy).

Case-population studies in pharmacoepidemiology

The case-population approach aims at providing a risk estimate by comparing the incidence of the disease of interest among those exposed to the drug under study with the incidence among the non-exposed. For that purpose, the cases with the disease of interest have to be ascertained independently of the exposure status. Their rate and pattern of exposure have to be ascertained by interview with a structured questionnaire. Information on the patterns and the prevalence of drug consumption is needed in order to estimate the rate of exposure, and drug consumption statistics can be used to this end. In this paper, we review the main characteristics of studies using this approach or a similar one, and studies where series of cases exposed to the drug of interest were compared with drug consumption statistics. We looked at selected basic methodological requirements. Most of the studies reviewed suffer from incomplete case ascertainment, inaccurate definition of the disease of interest, incomplete information on exposures and other risk factors, and/or limited control of potential confounding, among other limitations. All the reviewed studies had several limitations regarding the estimation of the population at risk. The methods used in case-population studies should be clearly described, particularly with respect to the identification of the cases (numerator) and the estimation of the consumption prevalence (denominator). Case-population studies can give approximate risk estimates, but the method should be validated by comparing its results with those of case-control studies.

Do pregnant women report use of dispensed medications?

Surveillance of drug safety in pregnancy often draws on administrative prescription registries. Noncompliance in the use of prescribed medication may be frequent among pregnant women owing to their fear of fetotoxic side effects. To estimate compliance in the use of prescription drugs dispensed during pregnancy, we compared prescription data from the North Jutland Prescription Database with information on drug use provided by pregnant women to the Danish National Birth Cohort (DNBC), which is a health interview survey. We used the North Jutland Prescription Database to identify all prescription drugs dispensed during pregnancy for the 2,041 women who were enrolled in the DNBC in the County of North Jutland, Denmark. Compliance was defined as the probability of reporting drug use in DNBC after purchasing a dispensed prescription drug. The overall compliance to drugs purchased within 120 days before the interview was 43% (95% confidence interval = 40-46). Drugs used for treating chronic diseases, for example, beta-blockers, insulin, thyroid hormones, and diuretic and antiepileptic drugs, were always reported to be used, but compliance was low for drugs used for local or short-term treatment such as antihistamines, antibiotics, antacids, nonsteroid anti-inflammatory drugs, and gynecologic drugs. Thus, for the latter drug groups the prescription database may provide an incomplete identification of exposure. Neither data source is unbiased regarding actual drug intake. Nevertheless, our results indicate that for some drug groups risk assessment studies based on prescription data may produce false negative results as a result of noncompliance.

Improvement of drug exposure data in a registration of congenital anomalies. Pilot-study: pharmacist and mother as sources for drug exposure data during pregnancy. EuroMAP Group. Europen Medicine and Pregnancy Group

We examined the possibilities of improving the retrospective collection of data on drug use during pregnancy. The European Registration of Congenital Anomalies (EUROCAT) has registered information on maternal drug exposure in the northern Netherlands through a question on the notification form for the registration of birth defects, filled out by physicians or midwives since 1981. Furthermore, hospital records are used and general practitioners are asked to add information on drug use. The present pilot study used pharmacy records and maternal questionnaires as well as maternal interview data to complete the data on drug exposure in the EUROCAT registration. Combined information from pharmacies, questionnaires, and interviews with the mother were used as the reference standard. Pharmacy records provided detailed data on 57% of drugs used (prescription drugs, mainly). Mothers were able to report 76% of drug groups used, but when only data on the exact name of the drug were studied, this figure was 52%. Of the drugs dispensed by the pharmacy, 6% were not used (false positives). We conclude that pharmacy records and maternal interviews are both indispensable sources of information on maternal drug exposure that provide much added value.

Vulvo-vaginal candidiasis associated with acitretin

The aim of this study was to estimate the risk of vulvo-vaginal candidiasis among the users of acitretin. The incidence rate ratio of vulvo-vaginal candidiasis was estimated in a cohort of acitretin users by using prescription sequence analysis. Study subjects were 196 women between 15 and 45 years of age, exposed to acitretin in 1990. Prescriptions of drugs for treatment of vulvo-vaginal candidiasis were used as proxy for the occurrence of vulvo-vaginal candidiasis. Validation of the proxy drug was performed by record linkage of pharmacy and medical records. In addition to the risk estimation by incidence rate ratios a case-crossover study with patient-stratified logistic regression analysis was performed to control for distortion due to individual differences in contribution of exposure time. The positive predictive value of the proxy drug for vulvo-vaginal candidiasis ranged between 57 and 100%, the sensitivity was 87% and the specificity estimated 99%. The crude incidence rate ratio for vulvo-vaginal candidiasis following acitretin exposure was 2.8 (CI95%: 1.1-7.1). The pooled Mantel-Haenszel incidence rate ratio was 3.3 (CI95%: 1.1-9.6) after stratification for accumulated level of exposure. Patient-stratified analysis on the subgroup of cases (n = 15) revealed an odds ratio of 6.5 (CI95%: 2.3-18.2). This study strongly suggests that the higher occurrence of vulvo-vaginal candidiasis during acitretin exposure is attributable to the drug.

Information on drug use in the elderly: a comparison of pharmacy, general-practitioner and patient data

Management of pharmacotherapy by the pharmacist and the general practitioner can be a difficult task in elderly patients in whom there is a high concomitant, long-term drug use. Adequate information on drug use is essential in managing pharmacotherapy as well as in an accurate assessment of drug exposure in pharmacoepidemiologic studies. In this study data from computerized pharmacy records, general-practitioner registries and home interviews with 100 elderly patients were compared. Pharmacy records contained 80% of all the prescriptions found at the home interviews, while in general-practitioner data 40% could be traced. Use of drugs dispensed long ago reduced the validity of pharmacy and general-practitioner data. Data on analgesics (70% was found) and respiratory drugs (68%) were less traceable compared to cardiovascular (83%) and psychotropic drugs (81%). Automated pharmacy records are an important source of longitudinal data on drug use and will improve the assessment of drug exposure in pharmacoepidemiologic studies and optimize pharmaceutical care.