Use of leflunomide among girls and women of childbearing age and occurrence of leflunomide-exposed pregnancies in Germany

Leflunomide is contraindicated during pregnancy and treatment cessation is recommended two years before pregnancy. We aimed to describe leflunomide use in women of childbearing age in Germany, the occurrence of pregnancies in women using leflunomide and malformations among children possibly exposed in utero. Using the GePaRD database (claims data, ∼20% of the German population), we determined annual age-standardized prevalences of leflunomide use between 2004 and 2019 among females aged 13-49 years. Further, we estimated the number of exposed pregnancies by assessing whether the exposure window assigned to the last dispensation before pregnancy (days covered by the dispensation plus two years) overlapped the onset of pregnancy or whether there was a dispensation in the first eight weeks of pregnancy. For exposed live births, a mother-baby linkage was performed and the presence of congenital malformation was assessed. The age-standardized prevalence of leflunomide use ranged between 0.34 and 0.46 per 1000 females during the study period. About one third of the users were ≤40 years. We identified 205 leflunomide-exposed pregnancies ending during the study period. 71% of these pregnancies ended in a live birth (26% preterm) and 10% in an induced abortion. In 86% of the live births (n=125) the mother-baby linkage was successful. Among these 125 children, 13 children (10%) had congenital malformations. In conclusion, we observed a considerable number of pregnancies in women using leflunomide in the two years before or during early pregnancy. This highlights the importance of monitoring the implementation of existing risk minimization measures for leflunomide in Germany.

Characterizing Fit-for-Purpose Real-World Data: An Assessment of a Mother-Infant Linkage in the Japan Medical Data Center Claims Database

Purpose

Observational postapproval safety studies are needed to inform medication safety during pregnancy. Real-world databases can be valuable for supporting such research, but fitness for regulatory purpose must first be vetted. Here, we demonstrate a fit-for-purpose assessment of the Japan Medical Data Center (JMDC) claims database for pregnancy safety regulatory decision-making.

Patients and Methods

The Duke-Margolis framework considers a database's fitness for regulatory purpose based on relevancy (capacity to answer the research question based on variable availability and a sufficiently sized, representative population) and quality (ability to validly answer the research question based on data completeness and accuracy). To assess these considerations, we examined descriptive characteristics of infants and pregnancies among females ages 12-55 years in the JMDC between January 2005 and March 2022.

Results

For relevancy, we determined that critical data fields (maternal medications, infant major congenital malformations, covariates) are available. Family identification codes permitted linkage of 385,295 total mother-infant pairs, 57% of which were continuously enrolled during pregnancy. The prevalence of specific congenital malformation subcategories and maternal medical conditions were representative of the general population, but preterm births were below expectations (3.6% versus 5.6%) in this population. For quality, our methods are expected to accurately identify the complete set of mothers and infants with a shared health insurance plan. However, validity of gestational age information was limited given the high proportion (60%) of missing live birth delivery codes coupled with suppression of infant birth dates and inaccessibility of disease codes with gestational week information.

Conclusion

The JMDC may be well suited for descriptive studies of pregnant people in Japan (eg, comorbidities, medication usage). More work is needed to identify a method to assign pregnancy onset and delivery dates so that in utero medication exposure windows can be defined more precisely as needed for many regulatory postapproval pregnancy safety studies.

Use of isotretinoin among girls and women of childbearing age and occurrence of isotretinoin-exposed pregnancies in Germany: A population-based study

BACKGROUND

Exposure to isotretinoin during pregnancy must be avoided due to its teratogenicity, but real-world data on its use are scarce. We aimed to describe (i) isotretinoin use in women of childbearing age in Germany; (ii) the occurrence of isotretinoin-exposed pregnancies; and (iii) malformations among children exposed in utero.

METHODS AND FINDINGS

Using observational data from the German Pharmacoepidemiological Research Database (GePaRD, claims data from approximately 20% of the German population), we conducted annual cross-sectional analyses to determine age-standardized prevalence of isotretinoin use between 2004 and 2019 among girls and women aged 13 to 49 years. In cohort analyses, we estimated the number of exposed pregnancies by assessing whether there was prescription supply overlapping the beginning of pregnancy (estimated supply was varied in sensitivity analyses) or a dispensation within the first 8 weeks of pregnancy. Data of live-born children classified as exposed in a critical period according to these criteria were reviewed to assess the presence of congenital malformations. The age-standardized prevalence of isotretinoin use per 1,000 girls and women increased from 1.20 (95% confidence interval [CI]: 1.16, 1.24) in 2004 to 1.96 (95% CI: 1.92, 2.01) in 2019. In the base case analysis, we identified 178 pregnancies exposed to isotretinoin, with the number per year doubling during the study period, and at least 45% of exposed pregnancies ended in an induced abortion. In sensitivity analyses, the number of exposed pregnancies ranged between 172 and 375. Among live-born children, 6 had major congenital malformations. The main limitation of this study was the lack of information on the prescribed dose, i.e., the supply had to be estimated based on the dispensed amount of isotretinoin.

CONCLUSIONS

Isotretinoin use among girls and women of childbearing age increased in Germany between 2004 and 2019, and there was a considerable number of pregnancies likely exposed to isotretinoin in a critical period. This highlights the importance of monitoring compliance with the existing risk minimization measures for isotretinoin in Germany.

Use of Acitretin Among Girls and Women of Childbearing Age and Occurrence of Acitretin-Exposed Pregnancies in Germany

BACKGROUND AND OBJECTIVE

Acitretin has long-lasting teratogenic properties. Therefore, pregnancies must be avoided during and within 3 years after acitretin treatment. We aimed to describe (i) acitretin use in women of childbearing age in Germany, (ii) the occurrence of acitretin-exposed pregnancies, and (iii) malformations among children exposed in utero.

METHODS

Using 2004-2019 data from the German Pharmacoepidemiological Research Database (GePaRD-claims data from ~ 20% of the German population), we determined annual age-standardized prevalence of acitretin use among girls and women aged 13-49 years. In longitudinal analyses, we estimated the number of exposed pregnancies by assessing whether the exposure window assigned to the last dispensation before pregnancy (days covered by dispensation plus 3 years) overlapped the onset of pregnancy or whether there was a dispensation in the first eight weeks of pregnancy. Data of live-born children with in utero exposure to acitretin were reviewed to assess the presence of congenital malformations.

RESULTS

The age-standardized prevalence of acitretin use per 1000 girls and women was 0.04 in 2019. We identified 35 acitretin-exposed pregnancies; 94.3% of these pregnancies were classified as exposed because they occurred within 3 years after stopping acitretin treatment. Among 18 live-born children linked to their mother, four children (22.2%) had congenital malformations (three children with a major malformation).

CONCLUSIONS

We observed 35 acitretin-exposed pregnancies mainly because treatment ended too late before pregnancy. Approximately one in five children born from these pregnancies had malformations, highlighting the importance of drawing more attention to the long-lasting teratogenicity of this drug.

Development and evaluation of an algorithm to link mothers and infants in two US commercial healthcare claims databases for pharmacoepidemiology research

BACKGROUND

Administrative healthcare claims databases are used in drug safety research but are limited for investigating the impacts of prenatal exposures on neonatal and pediatric outcomes without mother-infant pair identification. Further, existing algorithms are not transportable across data sources. We developed a transportable mother-infant linkage algorithm and evaluated it in two, large US commercially insured populations.

METHODS

We used two US commercial health insurance claims databases during the years 2000 to 2021. Mother-infant links were constructed where persons of female sex 12-55 years of age with a pregnancy episode ending in live birth were associated with a person who was 0 years of age at database entry, who shared a common insurance plan ID, had overlapping insurance coverage time, and whose date of birth was within ± 60-days of the mother's pregnancy episode live birth date. We compared the characteristics of linked vs. non-linked mothers and infants to assess similarity.

RESULTS

The algorithm linked 3,477,960 mothers to 4,160,284 infants in the two databases. Linked mothers and linked infants comprised 73.6% of all mothers and 49.1% of all infants, respectively. 94.9% of linked infants' dates of birth were within ± 30-days of the associated mother's pregnancy episode end dates. Characteristics were largely similar in linked vs. non-linked mothers and infants. Differences included that linked mothers were older, had longer pregnancy episodes, and had greater post-pregnancy observation time than mothers with live births who were not linked. Linked infants had less observation time and greater healthcare utilization than non-linked infants.

CONCLUSIONS

We developed a mother-infant linkage algorithm and applied it to two US commercial healthcare claims databases that achieved a high linkage proportion and demonstrated that linked and non-linked mother and infant cohorts were similar. Transparent, reusable algorithms applied to large databases enable large-scale research on exposures during pregnancy and pediatric outcomes with relevance to drug safety. These features suggest studies using this algorithm can produce valid and generalizable evidence to inform clinical, policy, and regulatory decisions.

Prescribing of endothelin receptor antagonists and riociguat in women of childbearing age in a large German claims database study

Use of endothelin receptor antagonists (ERAs) and riociguat, approved for treatment of pulmonary hypertension (PH), is contraindicated during pregnancy due to reported teratogenicity in animals. We aimed to investigate prescribing of these drugs in girls/women of childbearing age and to explore - as a secondary aim - the occurrence of pregnancies exposed to these drugs. Using the German Pharmacoepidemiological Research Database (GePaRD, claims data from 20% of the German population) we conducted cross-sectional analyses to determine prescribing prevalence of ERAs and riociguat between 2004 and 2019 and to characterize users and prescribing patterns. In a cohort analysis, we assessed the occurrence of pregnancies exposed to these drugs in the critical time window. Overall, we identified 407 women with ≥ 1 dispensation of bosentan between 2004 and 2019; the respective number was 73 for ambrisentan, 182 for macitentan, 31 for sitaxentan, and 63 for riociguat. In nearly all years, more than 50% of the girls/women were ≤ 40 years. Age-standardized prevalence was highest for bosentan (0.04/1000) in 2012 and 2013, followed by macitentan (0.03/1000) in 2018 and 2019. We observed 10 exposed pregnancies: 5 to bosentan, 3 to ambrisentan, and 2 to macitentan. The increased prevalence of macitentan and riociguat from 2014 onwards might reflect changes in PH treatment. Even though PH is a rare disease and pregnancy should be avoided in women with PH, particularly if they use ERAs, we identified pregnancies exposed to ERAs. Multi-database studies will be needed to assess the risk of these drugs on the unborn child.

Investigating drug safety in pregnancy based on the German Pharmacoepidemiological Research Database (GePaRD): A proof-of-concept analysis on the association between valproate and spina bifida

PURPOSE

Large health-care databases are increasingly used for research on drug utilization and safety in pregnancy. For the German Pharmacoepidemiological Research Database (GePaRD), covering ~20% of the German population, algorithms have been developed to identify pregnancies, to estimate their date of onset and to link mothers to their babies. Using this methodology, we aimed to conduct a proof-of-concept analysis on the known association between valproate (VPA) exposure in early pregnancy and spina bifida in the exposed child.

METHODS

We identified all pregnancies in GePaRD between 2006 and 2016 in women aged 12 to 50 years. To each VPA dispensation of these women, an exposure period was assigned, based on the dispensation date and the number of defined daily doses in the dispensed package. A pregnancy was classified as exposed to VPA in the critical time window if this exposure period overlapped with the first 55 days of pregnancy. Risk ratios were calculated for spina bifida in live births and induced abortions comparing VPA-exposed ones to all pregnancies.

RESULTS

Overall, we identified 1 271 384 pregnancies fulfilling the inclusion criteria. Of these, 668 pregnancies (0.053%) were classified as exposed to VPA in the critical time window regarding spina bifida. An induced abortion accompanied by a diagnosis of spina bifida was observed in one of the VPA-exposed pregnancies (0.15%) and in 154 of all pregnancies (0.012%), yielding a risk ratio of 12.4 (95% confidence interval [CI]: 1.7-88.2). Out of 775 875 pregnancies ending in a live birth, 366 (0.047%) were classified as VPA exposed. A diagnosis of spina bifida was coded in 3 of 366 VPA-exposed live births (0.82%) and in 260 of all live births (0.03%), yielding a relative risk of 24.5 (95% CI: 7.9-76.0).

CONCLUSIONS

Our proof-of-concept analysis based on GePaRD showed a strong association between intrauterine exposure to VPA and occurrence of spina bifida. The results are plausible and consistent with the literature, supporting the suitability of GePaRD and the developed algorithms to conduct studies on drug safety in pregnancy.

Use of Methotrexate in Girls and Women of Childbearing Age, Occurrence of Methotrexate-Exposed Pregnancies and Their Outcomes in Germany: A Claims Data Analysis

BACKGROUND AND OBJECTIVE

Methotrexate should be withdrawn before pregnancy because of its teratogenic potential. We aimed to describe the use of methotrexate in women of childbearing age in Germany and the occurrence and outcomes of pregnancies exposed to methotrexate.

METHODS

Using the German Pharmacoepidemiological Research Database (GePaRD, covering ~ 20% of the German population), we determined the age-specific and age-standardized prevalence of methotrexate use for each year between 2004 and 2019 among women aged 13-49 years (cross-sectional analyses). In a cohort analysis, we assessed the number and outcomes of pregnancies exposed to methotrexate in the critical time window. Exposure was defined as a dispensation overlapping with the onset of pregnancy or a dispensation in the first 8 weeks of pregnancy. For children born from exposed pregnancies, the mother's and children's data were linked and the occurrence of malformations was assessed by reviewing all available data of these children.

RESULTS

The age-standardized prevalence of methotrexate use per 1000 females increased from 1.5 in 2004 to 2.3 in 2019, i.e., by 52%. Overall, we identified 184 pregnancies exposed to methotrexate. Of these, 53% ended in a live birth (21% preterm) and 11% in an induced abortion. Among 81 live-born children linked to their mothers, five children (6%) had relevant malformations including congenital heart defects and musculoskeletal malformations.

CONCLUSIONS

In Germany, the use of methotrexate in women of childbearing age has substantially increased since 2004. Despite the known teratogenic effect, there was a considerable number of exposed pregnancies.  Also, malformations likely associated with methotrexate and thus avoidable were observed.

Fingolimod, teriflunomide and cladribine for the treatment of multiple sclerosis in women of childbearing age: description of drug utilization and exposed pregnancies in Germany

BACKGROUND

Authorizations of fingolimod, teriflunomide and cladribine were accompanied by risk minimization measures concerning their teratogenic potential. Real-world data on their use are scarce. We aimed to assess trends in the use of fingolimod, teriflunomide and cladribine among women of childbearing age, estimate the number of pregnancies occurring under treatment and explore the occurrence of malformations in newborns exposed during early pregnancy in Germany.

METHODS

Using the German Pharmacoepidemiological Research Database (GePaRD, claims data from ∼20% of the German population), we determined annual age-standardized prevalences of fingolimod, teriflunomide and cladribine use from their authorization until 2019 among women aged 13-49 years (cross-sectional analyses). In longitudinal analyses, we estimated the number of exposed pregnancies by assessing whether there was an overlap between the exposure windows assigned to dispensations and the onset of pregnancy or a dispensation in the first eight weeks of pregnancy. For live births, a mother-baby linkage was performed. All available data of children with in-utero exposure and malformation codes in the first year of life were reviewed to verify the occurrence of congenital malformations.

RESULTS

For fingolimod, the age-standardized prevalence of use per 1,000 females increased from 0.14 in 2011 to 0.46 in 2019; for teriflunomide, from 0.06 in 2013 to 0.28 in 2019; for cladribine, from 0.01 in 2017 to 0.07 in 2019. The proportion of users aged ≤40 years was 60% for fingolimod, 45% for teriflunomide and 65% for cladribine. We identified 136 pregnancies exposed to fingolimod, 50 to teriflunomide and one to cladribine. For fingolimod and teriflunomide, respectively, 72% and 62% of exposed pregnancies ended in a live birth. Mother-newborn linkage was successful in 64 (fingolimod) and 20 (teriflunomide) live-born children. Among these, there were six with relevant malformations (mainly heart defects) for fingolimod and two for teriflunomide.

CONCLUSION

Use of fingolimod, teriflunomide and cladribine among women of childbearing age has substantially increased in Germany. A high proportion of users was in age groups in which pregnancies typically occur. Despite risk minimization measures, early pregnancy exposure to these drugs was observed.

Maternal and infant outcomes in pregnancies of women with axial spondyloarthritis compared with matched controls: results from nationwide health insurance data

Objectives

To investigate pregnancy outcomes in women with axial spondyloarthritis (axSpA) under different pharmacological treatments in comparison with matched controls.

Methods

Using health insurance data from 2006 to 2019, pregnancy outcomes of women with axSpA were compared with those of age-matched and calendar year-matched controls without axSpA. Women with axSpA were further stratified by treatment prior to delivery and pregnancy outcomes compared. Adjusted ORs (aORs) with 95% CIs were calculated using generalised estimating equation analyses.

Results

A total of 1021 pregnancy outcomes in patients with axSpA were identified (928 deliveries, 80 abortions, 13 ectopic pregnancies) and compared with 10 210 pregnancy outcomes in controls (9488 deliveries, 615 abortions, 147 ectopic pregnancies). Compared with controls, women with axSpA showed higher odds of elective caesarean section (aOR 1.52; 1.25 to 1.85).

Among women with axSpA, the risk of preterm birth was higher under non-steroidal anti-inflammatory drugs (NSAIDs) treatment (aOR 2.22; 1.09 to 4.52) than without any anti-inflammatory treatment. The risks of preterm birth (aOR 4.01; 1.93 to 8.34) and small-for-gestational-age (aOR 3.22; 1.34 to 7.73) were increased under NSAIDs treatment in combination with conventional synthetic disease-modifying anti-rheumatic drugs (DMARDs), steroids or analgesics. Non-significant increased risks of small-for-gestational-age (aOR 1.68; 0.43 to 6.57) and preterm birth (aOR 1.56; 0.51 to 4.83) were found under biological DMARDs.

Conclusions

Women with axSpA have significantly increased odds of caesarean section compared with matched controls. Risks of preterm birth and small-for-gestational-age vary by type of anti-inflammatory treatment.

Characterization of pregnancies among women with epilepsy using valproate before or during pregnancy - A longitudinal claims data analysis from Germany

PURPOSE

To characterize pregnancies among women with epilepsy who have filled a prescription for valproate at any time before or during pregnancy and to assess other antiepileptic drug (AED) prescriptions.

METHODS

Based on health claims data (German Pharmacoepidemiological Research Database - GePaRD; covering ~20% of the population), we selected pregnancies beginning between 2014 and 2016 in women with at least three years of observation period before pregnancy and with at least one epilepsy diagnosis code in the year before pregnancy. Among those, we selected pregnancies with at least one valproate dispensation any time before or during pregnancy. We further described these pregnancies regarding patterns in the dispensation of valproate and other AED among the women from their first day in the database until the end of the pregnancy.

RESULTS

Among 2068 pregnancies fulfilling the inclusion criteria, we identified 454 pregnancies (89% ending in live births and 8% in induced abortions) in 430 women with at least one valproate dispensation before or during pregnancy. In 357 of these pregnancies (79%), valproate was only dispensed before pregnancy, while 97 pregnancies (21%) had a valproate dispensation during pregnancy and of these, 77% (N = 75) during the first trimester. The proportion with a valproate dispensation during pregnancy declined from 2014 (25%) to 2016 (19%), also concerning exposure during the first trimester (2014: 20%, 2015: 17%, 2016: 12%), while the proportion ending in an induced abortion was increasing (2014: 5%, 2015: 8%, 2016: 13%). In 48% of exposed pregnancies (N = 36), there was no other AED dispensed during the entire observation time before pregnancy. This proportion was lower for pregnancies beginning in 2016 (33%) than for those beginning in 2014 and 2015 (53% and 50%, respectively).

CONCLUSION

In most women with epilepsy using valproate before or during pregnancy, valproate was dispensed only well before pregnancy beginning. The proportion exposed to valproate during the first trimester declined between 2014 and 2016, but the low proportion treated with alternative AED before valproate treatment suggests there is still room for improvement.

Characterization of pregnancies exposed to St. John's wort and their outcomes: A claims data analysis

Little is known about the utilization of St. John's wort (Hypericum perforatum L.) during pregnancy. In Germany, certain preparations of St. John's wort can be reimbursed by statutory health insurances, facilitating to investigate exposure to St. John's wort based on claims data. We therefore aimed to characterize pregnancies exposed to St. John's wort and to explore potential malformations in the babies. Using claims data from the German Pharmacoepidemiological Research Database (GePaRD), pregnancies exposed to St. John's wort during at least one trimester between 2006 and 2016 and the corresponding babies were identified. Exposure was identified via outpatient dispensations. Pregnancies were characterized regarding timing of exposure, use of other antidepressants, pregnancy outcomes and the occurrence of major malformations in the babies (not considering codes for musculoskeletal and other malformations due to low data quality in this regard). Out of 496 pregnancies with a dispensation of St. John's wort during pregnancy, 420 (85 %) had a dispensation during the first trimester. There was a dispensation of other antidepressants before pregnancy in 21 % (during pregnancy: 12 %). Eleven percent of pregnancies ended in non-live births. In 312 babies linked to 305 pregnancies, major malformations were coded in 18 babies (5.8 %), of which 17 were exposed in the first trimester. The crude relative risk of major malformations for babies exposed during the first vs. the second or third trimester only was 3.56 (0.48-26.17). Our results suggest that only in a minority of pregnancies, St. John's wort is used as an alternative to other antidepressants. Even though the relatively high rates of non-live births and major malformations after exposure to St. John's wort during the first trimester need to be interpreted with caution, the findings are striking and generate hypotheses that merit further investigation.

Real-world evaluation of adverse pregnancy outcomes in women with gestational diabetes mellitus in the German health care system

AIMS

This study aims to estimate the incidence of adverse pregnancy outcomes in women with gestational diabetes mellitus (GDM) in Germany.

METHODS

Pregnant women were identified from a health claims database for the year of 2016. Three groups were defined: general population without GDM, women with GDM without treatment and women with GDM and insulin treatment. Operationalisation of outcomes was aligned with the hyperglycaemia and adverse pregnancy outcomes (HAPO) study.

RESULTS

The cohort consisted of 58,297 mother-child pairs. Of those, 7245 had a GDM diagnosis and 1407 had a GDM diagnosis with a prescription of insulin. Adverse pregnancy outcomes were higher in both GDM groups compared to the control group. Birthweight (OR 2.08 [95% CI 1.50-2.90]), primary caesarean section (OR 1.70 [95% CI 1.48-1.95]), intensive neonatal care (OR 1.25 [95% CI 1.04-1.50]), preeclampsia (OR 1.51 [95% CI 1.23-1.85]), and clinical neonatal hypoglycaemia (OR 5.32 [95% CI 4.27-6.62]) were higher in the GDM+insulin group in comparison to a control group after adjustment for potential confounders.

CONCLUSION

Most of the adverse pregnancy outcomes were moderately higher in both identified GDM groups in comparison to women without GDM. Women receiving insulin treatment are at an increased risk of most of the defined adverse pregnancy outcomes.

Estimating the Beginning of Pregnancy in German Claims Data: Development of an Algorithm With a Focus on the Expected Delivery Date

Background: Estimating the beginning of pregnancy is crucial when studying drug safety in pregnancy, but important information in this regard, such as the last menstrual period (LMP), is generally not recorded in claims databases. The beginning of pregnancy is therefore usually estimated by subtracting a median length of pregnancy from the date of birth. Due to the variability in pregnancy lengths, this might result in non-negligible errors. German claims data may offer the possibility to estimate the beginning of pregnancy more precisely based on the expected delivery date (EDD) which can be coded once or more often during a pregnancy.

Purpose: To estimate the beginning of pregnancy in German claims data focusing on the potential of the expected delivery date (EDD).

Methods: We included data of all pregnancies in women aged 12–50 years ending in a live birth between 2006 and 2015 identified in the German Pharmacoepidemiological Research Database (GePaRD). We assessed the number of coded EDDs per pregnancy and the concordance if ≥ 2 EDDs were coded. We estimated the beginning of pregnancy by subtracting 280 days from the EDD or the most frequent EDD (in case of discordant EDDs). To examine plausibility, we determined the distribution of pregnancy lengths and assessed whether the gestational age at which prenatal examinations were coded was plausible. For pregnancies without EDD, the beginning was estimated by subtracting the respective observed median lengths of pregnancy for preterm births, term births, and births after due date from the actual dates of birth.

Results: In 82.4% of pregnancies, at least one EDD was available (thereof 6.1% with only one EDD and 80.9% with ≥ 2 EDDs that were all concordant). The maximal difference between discordant EDDs was in median 5 days (interquartile range: 3–7 days). Based on the EDD, the median length of pregnancy was 276 days for term births and in 84.7% of pregnancies the second antibody screening test was performed in the recommended interval ± 2 weeks. In pregnancies without EDD the respective proportion was 84.9%.

Conclusions: By using the EDD, the beginning of pregnancy can plausibly be estimated in German claims data.

Validating linkage of multiple population-based administrative databases in Brazil

Background

Linking routinely-collected data provides an opportunity to measure the effects of exposures that occur before birth on maternal, fetal and infant outcomes. High quality linkage is a prerequisite for producing reliable results, and there are specific challenges in mother-baby linkage. Using population-based administrative databases from Brazil, this study aimed to estimate the accuracy of linkage between maternal deaths and birth outcomes and dengue notifications, and to identify potential sources of bias when assessing the risk of maternal death due to dengue in pregnancy.

Methods

We identified women with dengue during pregnancy in a previously linked dataset of dengue notifications in women who had experienced a live birth or stillbirth during 2007–2012. We then linked this dataset with maternal death records probabilistically using maternal name, age and municipality. We estimated the accuracy of the linkage, and examined the characteristics of false-matches and missed-matches to identify any sources of bias.

Results

Of the 10,259 maternal deaths recorded in 2007–2012, 6717 were linked: 5444 to a live birth record, 1306 to a stillbirth record, and 33 to both a live and stillbirth record. After identifying 2620 missed-matches and 124 false-matches, our estimated sensitivity was 72%, specificity was 88%, and positive predictive value was 98%. Linkage errors were associated with maternal education and self-identified race; women with more than 7 years of education or who self-declared as Caucasian were more likely to link. Dengue status was not associated with linkage error.

Conclusion

Despite not having unique identifiers to link mothers and birth outcomes, we demonstrated a high standard of linkage, with sensitivity and specificity values comparable to previous literature. Although there were no differences in the characteristics of dengue cases missed or included in our linked dataset, linkage error occurred disproportionally by some social-demographic characteristics, which should be taken into account in future analyses.

Drug-use patterns and severe adverse events with disease-modifying drugs in patients with multiple sclerosis: a cohort study based on German claims data

Purpose: To describe drug-use patterns in patients with multiple sclerosis (MS) using disease-modifying drugs (DMDs) and to estimate the incidence of severe adverse events (SAEs) of treatment. Methods: We conducted a cohort study within the German Pharmacoepidemiological Research Database between January 1, 2006 and December 31, 2013. MS patients on DMDs were described in terms of clinical characteristics and drug-use patterns. Next, we assessed the incidence of AEs in new users of fingolimod, natalizumab, glatiramer acetate, and IFNβ_1a. Results: Among approximately 11 million insured members of German Statutory Health Insurance, the DMD-user cohort comprised 15,377 patients with MS, with a mean age of 39.6 years and 68% females. Nearly half of all DMD users had a diagnosis of depression, with prevalence ranging from 40.1% for IFNβ_1a to 62.3% for immunoglobulins. The overall rate of MS relapses per patient and year was 0.34 (95% CI 0.33-0.34). During an average follow-up of 1,650 days, the majority (42.4%) of MS patients were adherent to DMD treatment ("continuous single users"), followed by patients interrupting treatment (39.5%, "interrupters"). Switch of DMD treatment (11.9%) was less frequent, and only 5.6% discontinued treatment. Treatment discontinuation was most common in users of natalizumab (7.5%) and IFNβ_1b (7.0%). The most frequent SAE was hospitalization for depression, followed by any infectious disease and any malignancy. The incidence rate of all adverse events did not significantly differ across different DMDs. Conclusion: Treatment discontinuation with DMDs and treatment switch were rare. Causes of rather frequent DMD-treatment interruption have to be evaluated in further studies based on primary data collection. Active safety monitoring of new DMDs based on claims data requires large data sets to detect rare AEs and availability of up-to-date data.

Evaluation of vaccination herd immunity effects for anogenital warts in a low coverage setting with human papillomavirus vaccine-an interrupted time series analysis from 2005 to 2010 using health insurance data

Background

Shortly after the human papillomavirus (HPV) vaccine recommendation and hence the reimbursement of vaccination costs for the respective age groups in Germany in 2007, changes in the incidence of anogenital warts (AGWs) were observed, but it was not clear at what level the incidence would stabilize and to what extent herd immunity would be present. Given the relatively low HPV vaccination coverage in Germany, we aimed to assess potential vaccination herd immunity effects in the German setting.

Methods

A retrospective open cohort study with data from more than nine million statutory health insurance members from 2005 to 2010 was conducted. AGW cases were identified using ICD-10-codes. The incidence of AGWs was estimated by age, sex, and calendar quarter. Age and sex specific incidence rate ratios were estimated comparing the years 2009–2010 (post-vaccination period) with 2005–2007 (pre-vaccination period).

Results

Incidence rate ratio of AGWs for the post-vaccination period compared to the pre-vaccination period showed a u-shaped decrease among the 14- to 24-year-old females and males which corresponds well with the reported HPV vaccination uptake in 2008. A maximum reduction of up to 60% was observed for the 16- to 20-year-old females and slightly less pronounced (up to 50%) for the 16- and 18-year-old males. Age groups outside of the range 14–24 years demonstrated no decrease. The decrease of incidence occurred in both sexes early after the vaccine recommendation and stabilized at lower levels in 2009–2010.

Conclusions

A relative reduction of up to 50% among males of approximately similar age groups as that of females receiving the HPV vaccination suggests herd protection resulting from assortative mixing by age. The early decrease among males can be reduced over time due to partner change.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2663-7) contains supplementary material, which is available to authorized users.

Non-Steroidal Anti-Inflammatory Drug Use and the Risk of Acute Myocardial Infarction in the General German Population: A Nested Case-Control Study

Introduction

Use of non-steroidal anti-inflammatory drugs (NSAIDs) has been associated with an increased relative risk of acute myocardial infarction (AMI), but the label warnings refer particularly to patients with cardiovascular risk factors. The magnitude of relative AMI risk for patients with and without cardiovascular risk factors varies between studies depending on the drugs and doses studied.

Objectives

The aim of our study was to estimate population-based relative AMI risks for individual and widely used NSAIDs, for a cumulative amount of NSAID use, and for patients with and without a prior history of cardiovascular risk factors.

Methods

Based on data from the German Pharmacoepidemiological Research Database (GePaRD) of about 17 million insurance members from four statutory health insurance providers, for the years 2004–2009, a nested case–control study was conducted within a cohort of 3,476,931 new NSAID users classified into current, recent, or past users. Up to 100 controls were matched to each case by age, sex, and length of follow-up using risk set sampling. Multivariable conditional logistic regression was applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Duration of NSAID use was calculated by the cumulative amount of dispensed defined daily doses (DDDs), and stratified analyses were conducted for potential effect modifiers.

Results

Overall, 17,236 AMI cases were matched to 1,714,006 controls. Elevated relative AMI risks were seen for current users of fixed combinations of diclofenac with misoprostol (OR 1.76, 95% CI 1.26–2.45), indometacin (1.69, 1.22–2.35), ibuprofen (1.54, 1.43–1.65), etoricoxib (1.52, 1.24–1.87), and diclofenac (1.43, 1.34–1.52) compared with past use. A low cumulative NSAID amount was associated with a higher relative AMI risk for ibuprofen, diclofenac, and indometacin. The relative risk associated with current use of diclofenac, fixed combinations of diclofenac with misoprostol, etoricoxib, and ibuprofen was highest in the younger age group (<60 years) and similar for patients with or without major cardiovascular risk factors.

Conclusion

Relative AMI risk estimates differed among the 15 investigated individual NSAIDs. Diclofenac and ibuprofen, the most frequently used NSAIDs, were associated with a 40–50% increased relative risk of AMI, even for low cumulative NSAID amounts. The relative AMI risk in patients with and without cardiovascular risk factors was similarly elevated.

Electronic supplementary material

The online version of this article (doi:10.1007/s40801-017-0113-x) contains supplementary material, which is available to authorized users.

Initiation and duration of dual antiplatelet therapy after inpatient percutaneous coronary intervention with stent implantation in Germany: An electronic healthcare database cohort study

BACKGROUND

Studies assessing the routine outpatient dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) in Germany are scarce. The aim of this study was (i) to investigate the initiation and duration of DAPT after inpatient PCI with stent implantation in Germany, and (ii) to identify factors associated with DAPT discontinuation during the recommended treatment period.

METHODS

This retrospective cohort study was based on data from a large German electronic healthcare database of the years 2004 to 2009. The study population comprised four groups of patients with acute coronary syndrome (ACS) or stable angina pectoris undergoing inpatient PCI with either bare metal stent (BMS) or drug eluting stent (DES) implantation between 2005 and 2008. Initiation of outpatient DAPT within a period from 100 days before the PCI to 60 days after the PCI was ascertained. Time until end of treatment was analysed using the Kaplan-Meier method. Factors potentially associated with DAPT discontinuation, like sex, age, cardiovascular comorbidity, contraindications, and other antithrombotic drugs were analysed in a Cox proportional hazard model.

RESULTS

The cohort comprised 37,001 patients. Depending on the type of stent and the indication for the PCI, DAPT was initiated in 85 % (ACS/BMS) and 95 % (AP/DES) of all patients. Of those, 12 % (AP/DES) and 64 % (ACS/BMS) discontinued DAPT during the recommended treatment duration. An age of over 80 years (OR 1.2-1.5 compared to patients aged 0-49 years) and the use of phenprocoumon (OR 2.7-5.0 compared to no phenprocoumon) were associated with an increased risk of DAPT discontinuation.

CONCLUSIONS

A high proportion of patients with coronary artery disease undergoing inpatient PCI with stent implantation received DAPT. However, DAPT discontinuation during the recommended time span was frequent, particularly in patients suffering from ACS. On the other hand, especially patients with AP and DES were often treated longer than recommended.

Risk of Stroke after Herpes Zoster - Evidence from a German Self-Controlled Case-Series Study

Background

Herpes zoster (HZ) is caused by reactivation of the latent varicella-zoster virus (VZV). A severe complication of HZ is VZV vasculopathy which can result in ischemic or hemorrhagic stroke. The aims of our study were to assess the risk of stroke after the onset of HZ and to investigate the roles of stroke subtype, HZ location and the time interval between HZ onset and stroke.

Methods

A self-controlled case-series study was performed on a cohort of patients with incident stroke recorded in the German Pharmacoepidemiological Research Database (GePaRD), which covers about 20 million persons throughout Germany. We estimated adjusted incidence rate ratios (IRR) by comparing the rate of stroke in risk periods (i.e., periods following HZ) with the rate of stroke in control periods (i.e., periods without HZ) in the same individuals, controlling for both time-invariant and major potentially time-variant confounders.

Results

The cohort included 124,462 stroke patients, of whom 6,035 (5%) had at least one HZ diagnosis identified in GePaRD either as main hospital discharge diagnosis or as HZ treated with antivirals. The risk of stroke was about 1.3 times higher in the risk periods 3 months after HZ onset, than in the control periods (IRR: 1.29; 95% confidence interval: 1.16–1.44). An elevated risk of similar magnitude was observed for ischemic and unspecified stroke, but a 1.5-fold higher risk was observed for hemorrhagic stroke. A slightly stronger effect on the risk of stroke was also observed during the 3 months after HZ ophthalmicus (HZO) onset (1.59; 1.10–2.32). The risk was highest 3 and 4 weeks after HZ onset and decreased thereafter.

Conclusions

Our study corroborates an increased risk of stroke after HZ, which is highest 3 to 4 weeks after HZ onset. The results suggest that the risk is more pronounced after HZO and is numerically higher for hemorrhagic than for ischemic stroke.

Frequency and trends of disease-modifying antirheumatic drug (DMARD) use in Germany

The aim of this study was to analyze the population‐based frequency of classic (c‐) and biologic (b‐) disease‐modifying antirheumatic drug (DMARD) use over time, selected underlying indications and the specialty of the prescribing physicians in Germany. Based on the claims data of the German Pharmacoepidemiological Research Database (GePaRD), yearly cross‐sectional studies were conducted from 2004 to 2011. The prevalence of DMARD use was calculated as the number of persons with at least one dispensation per 1000 persons stratified by sex and age. In 2011, we also obtained the proportion of c‐ and b‐DMARDs users with diagnoses of selected indications and the proportion of dispensations by specialty of the physician. Between 2004 and 2011, the annual prevalence of b‐DMARD and c‐DMARD use increased from 0.35‰ to 1.54‰ and from 6.53‰ to 8.93‰, respectively. In 2011, the study population comprised 12.8 million insurants with a mean age of 44.0 years. During this year, among c‐DMARDs, methotrexate was prescribed most frequently (4.76‰), followed by azathioprine (1.72‰) and sulfasalazine (1.20‰). For b‐DMARDs, adalimumab (0.57‰), etanercept (0.46‰), and rituximab (0.23‰) were most frequently used. Notably, b‐DMARD users more often had a diagnosis of ankylosing spondylitis and psoriasis compared to c‐DMARD‐users (20.7% vs. 2.9% and 20.0% vs. 11.4%, respectively) and b‐DMARDs were more frequently prescribed by rheumatologists and other specialists. Our population‐based study highlights the increasing use of c‐ and b‐DMARDs in Germany. Compared to c‐DMARDs, b‐DMARDs were commonly used for indications besides rheumatoid arthritis. Future research should therefore also focus on their prescription patterns and safety aspects in indications other than RA.

Comparative risk of death in older adults treated with antipsychotics: A population-based cohort study

Although the use of antipsychotics has been associated with an increased risk of death, data on the safety of individual substances is scarce. We thus aimed to compare the risk of death in new users of individual antipsychotics aged =>65 years and conducted a cohort study in the German Pharmacoepidemiological Research Database between 2005 and 2011. Patients were followed from initiation of treatment until death, 90 days after cohort entry, end of insurance or the end of the study period. Multivariable cox regression was used to estimate confounder adjusted hazard ratios (aHR) of death for 14 individual antipsychotics compared to risperidone. In sensitivity analyses, we also applied high-dimensional propensity score (HDPS) methods to explore possible unmeasured confounding. In a cohort of 137,713 new users of antipsychotics, a higher risk of death was found for haloperidol (aHR: 1.45; 95% confidence interval: 1.35-1.55), levomepromazine (aHR: 1.34; 1.16-1.54), zuclopenthixol (aHR: 1.32; 1.02-1.72) and to a lesser extent for melperone (aHR: 1.13; 1.07-1.19) compared to risperidone. Lower risks were observed for quetiapine, prothipendyl, olanzapine, tiapride, clozapine, perazine and flupentixol. In subgroup analyses, levomepromazine and chlorprothixene were only associated with a higher risk of death in patients aged =>80 years and with dementia. The application of HDPS methods did not substantially change the results. In conclusion, our study suggests that initiation of haloperidol, levomepromazine, zuclopenthixol and chlorprothixene treatment is associated with an increased risk of death compared to risperidone and should be avoided in older patients except in palliative care when treatment alternatives are available.

[Benefits of large healthcare databases for drug risk research]

Large electronic healthcare databases have become an important worldwide data resource for drug safety research after approval. Signal generation methods and drug safety studies based on these data facilitate the prospective monitoring of drug safety after approval, as has been recently required by EU law and the German Medicines Act. Despite its large size, a single healthcare database may include insufficient patients for the study of a very small number of drug-exposed patients or the investigation of very rare drug risks. For that reason, in the United States, efforts have been made to work on models that provide the linkage of data from different electronic healthcare databases for monitoring the safety of medicines after authorization in (i) the Sentinel Initiative and (ii) the Observational Medical Outcomes Partnership (OMOP). In July 2014, the pilot project Mini-Sentinel included a total of 178 million people from 18 different US databases. The merging of the data is based on a distributed data network with a common data model. In the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance (ENCEPP) there has been no comparable merging of data from different databases; however, first experiences have been gained in various EU drug safety projects. In Germany, the data of the statutory health insurance providers constitute the most important resource for establishing a large healthcare database. Their use for this purpose has so far been severely restricted by the Code of Social Law (Section 75, Book 10). Therefore, a reform of this section is absolutely necessary.

Mortality in the German Pharmacoepidemiological Research Database (GePaRD) compared to national data in Germany: results from a validation study

Background

Electronic healthcare databases are of increasing importance in health research and mortality is one of the most relevant outcomes. However, data in these databases need to be validated, since they are often generated for reimbursement purposes. The aims of this study were to compare mortality figures from the German Pharmacoepidemiological Research Database (GePaRD) on an aggregated level with external data from the Federal Statistical Office of Germany (FSOG) and to assess consistency of records of death from core data and hospital data within GePaRD.

Methods

The study population comprised insurants of four statutory health insurances providing data for GePaRD with either continuous insurance coverage from January 1^st to December 31^st 2006 or until death. The sex-specific mortality rate, stratified and standardized by age, and the percentage of hospital deaths among all deaths was compared with data from the FSOG. Furthermore, the agreement between the dates of death according to hospital data and core data was assessed within GePaRD.

Results

The study population comprised 12,033,622 insurants. Compared to FSOG data, the age-standardised mortality rate in GePaRD was 21 % and 29 % lower in women and men, respectively. Regional analyses also indicated lower mortality rates in all federal states except for Bremen, where the age-standardised mortality rate was similar to FSOG data for both sexes. The percentage of hospital deaths among all deaths corresponded well with external data. The proportion of inpatient deaths also recorded in the health insurance core data was 98.5 %. Furthermore, 94 % of dates of death documented in hospital agreed with the dates of death according to the health insurance core data.

Conclusions

The lower mortality rates in almost all federal states might result from the higher socioeconomic status of the GePaRD study population compared to the overall population in Germany. In the federal state of Bremen, where socioeconomic representativeness is higher due to additional inclusion of two local health insurances, the mortality rates were in good accordance with external data. Agreement of the percentage of hospital deaths among all deaths between GePaRD and national statistics suggested completeness of outpatient mortality information.

Development of a mother-child database for drug exposure and adverse event detection in the Military Health System

PURPOSE

The aim of this study was to develop a mother-child linked database consisting of all eligible active duty military personnel, retirees, and their dependents in order to conduct medication-related analyses to improve the safety and quality of care in the Military Health System (MHS).

METHODS

Eligible women of reproductive age with at least one pregnancy-related encounter between January 2005 and December 2013 receiving care in the MHS were included in the study population. Building on previously published algorithms, we used pregnancy-related diagnostic and procedure codes, parameterized temporal constraints, and data elements unique to the MHS to identify pregnancies ending in live births, stillbirth, spontaneous abortion, or ectopic pregnancy. Pregnancies ending in live births were matched to presumptive offspring using birth dates and family-based sponsorship identification. Antidepressant and antiepileptic use during pregnancy was evaluated using electronic pharmacy data.

RESULTS

Algorithms identified 755,232 women who experienced 1,099,648 complete pregnancies with both pregnancy care encounter and pregnancy outcome. Of the 924,320 live birth pregnancies, 827,753 (90.0%) were matched to offspring. Algorithms also identified 5,663 stillbirths, 11,358 ectopic pregnancies, and 169,665 spontaneous abortions. Among the matched singleton live birth pregnancies, 7.1% of mothers were dispensed an antidepressant at any point during pregnancy, usually a selective serotonin reuptake inhibitor, (75.3%), whereas 1.3% of mothers were dispensed an antiepileptic drug.

Methodological challenges in using routinely collected health data to investigate long-term effects of medication use during pregnancy

To date, the investigation of teratogenic effects of medications has largely focused on physical alterations present at birth (i.e. malformations) as opposed to functional alterations (i.e. neurodevelopment, metabolic function) that may not be apparent at birth but could influence an individual's health and risk of disease in later life. The use of routinely collected health data represents one approach to better identifying, quantifying, and understanding the long-term risks or benefits of medication use during pregnancy. As such, the objective of this review was to identify and explore opportunities and challenges associated with using routinely collected health data to examine long-term effects of medication use during pregnancy. Drawing on published research several key methodological issues associated with their use in investigating long-term outcomes are reviewed. While significant opportunities exist to make greater use of routinely collected health data, there are a number of key challenges. Identified challenges relate to aspects of study design and analysis, and include obtaining access to data, the ability to match records across datasets and over long periods of time, how medication exposures are ascertained and classified, issues around loss to follow-up how outcomes are ascertained and classified, and the careful interpretation of results in light of study and data limitations. Understanding key challenges associated with using routinely collected health data to investigate long-term effects of medication use during pregnancy is essential in supporting their appropriate use and interpretation, which will contribute to improving the quality of research undertaken and ensure the reliability of results obtained.

HPV vaccine uptake after introduction of the vaccine in Germany: an analysis of administrative data

In Germany, vaccination against human papilloma virus (HPV) has been recommended by the German Standing Vaccination Committee (STIKO) for girls aged 12-17 years since March 2007. The vaccine is free of charge for this age group. Additionally, some statutory health insurance providers (SHI) offer reimbursement for women aged 18-26 years. Currently available information on the uptake or coverage of HPV vaccination is limited to specific regions, age groups, or study populations. This report describes the HPV vaccine uptake in 2008 for females aged 12-26 years in Germany on a broad regional level based on data from one large SHI. HPV vaccinations were identified by outpatient codes used for reimbursement of vaccine administration. Vaccine uptake was calculated by dividing the number of females, who received at least one HPV vaccine dose by the number of female insurees in the respective age group. The overall study population consisted of 317 234 females, of whom 77 350 received at least one HPV vaccine dose in 2008. Vaccine uptake was 32.2% in the recommended age group, with a peak age at 14-16 years. In the age group of females aged 18-26 years, where HPV vaccination was not officially recommended by the STIKO, uptake was 12.3%. Vaccine uptake in 2008 reflects an early stage after the recommendation of HPV vaccination in 2007. Future changes in vaccine uptake should be further and more promptly monitored.

Guillain-Barre syndrome, influenza, and influenza vaccination: the epidemiologic evidence

Guillain-Barré syndrome (GBS) is the most common cause of acute flaccid paralysis worldwide, and is thought to be immune-mediated. It is preceded by upper respiratory or gastrointestinal infection in about two-thirds of cases and is associated with some viral infections, including influenza. GBS has also been associated with the 1976 swine-influenza vaccine. Thereafter, some studies have shown a small increased risk of GBS following receipt of seasonal and 2009 H1N1 monovalent influenza vaccines. Studies over the years have also shown an increased risk of GBS following influenza infection, and the magnitude of risk is several times greater than that following influenza vaccination. Because GBS is rare, and even rarer following vaccination, it is difficult to estimate precise risk. We try to shed light on the complex relationship of GBS and its association with influenza and influenza vaccines over the past 35 years.

Antipsychotic drug use and the risk of venous thromboembolism in elderly patients with dementia

The aim of this study was to investigate the association between the use of antipsychotics and the risk of venous thromboembolism (VTE) in elderly patients with dementia. Based on data from the German Pharmacoepidemiological Research Database, a nested case-control study was conducted within a cohort of 72,591 patients with dementia aged at least 65 years at cohort entry. Cases were patients with a hospitalization due to VTE. Up to 4 controls were matched to each case according to age, sex, health insurance, and calendar time of the VTE. Users of antipsychotics were classified into current or former users, and in addition, all current users were categorized as prevalent or new users. For a further analysis, we distinguished between users of either conventional or atypical antipsychotics or concurrent users of both conventional and atypical antipsychotics. Multivariate conditional logistic regression was applied to calculate odds ratios (ORs) of VTE for all user groups compared with nonusers. The case-control data set comprised 1028 VTE cases and 4109 controls. An increased risk of VTE was found for current users (OR, 1.23; 95% confidence interval [CI], 1.01-1.50) and for users of a combination of atypical and conventional antipsychotics (OR, 1.62; 95% CI, 1.15-2.27). In current users, only new use was associated with an increased risk (OR, 1.63; 95% CI, 1.10-2.40). Increased attention to clinical signs of VTE should be paid during the first 3 months of treatment with antipsychotics and in patients receiving both conventional and atypical agents, especially if other risk factors for VTE exist.

Evaluation of pregnancy outcome records in the German Pharmacoepidemiological Research Database (GePaRD)

PURPOSE

Routine health care data are a valuable source for the assessment of risks of drugs during pregnancy. Therefore, the aim of the current analysis was the evaluation of pregnancy outcome records in German health insurance data.

METHODS

We used the German Pharmacoepidemiologic Research Database including data of more than 15 million insurants (about 18% of the German population). Among 10-49 year-old women, we identified six categories of pregnancy outcomes: term births, preterm births, stillbirths, induced abortions, spontaneous abortions and ectopic pregnancies. In order to assess the validity of these records, we have set our results in relation to representative data for the corresponding outcomes in Germany. We also investigated whether pregnancy markers (diagnoses, procedures or medical services which indicate an existing pregnancy) can be used to identify pregnancies.

RESULTS

In total, we identified 94 261 pregnancy outcomes in 2005. The percentage of births outside hospital (1.2%) and of preterm births (11.6%), the rate of stillbirths (3 per 1000 live births) and the rate of ectopic pregnancies (20 per 1000 live births) agreed well with representative data for Germany. Compared to epidemiological data, the occurrence of spontaneous abortions was underestimated (5.4% of all pregnancies). There were 4.1 induced abortions per 100 live births, compared to 18.1 in national data. Positive predictive values and sensitivities of markers varied across marker categories and for different pregnancy outcomes.

CONCLUSIONS

Completeness of pregnancy outcomes recorded in the database varied by pregnancy outcome. This should be taken into account in studies of drug safety in pregnancy.

Regional variation in caesarean deliveries in Germany and its causes

BACKGROUND

Determinants of regional variation in caesarean sections can contribute explanations for the observed overall increasing trend of caesarean sections. We assessed which mechanism explains the higher rate of caesarean sections in the former West than East Germany: a more liberal use of caesarean sections in the case of relative indications or more common caesarean sections without indications.

METHODS

We used a health insurance database from all regions of Germany with approximately 14 million insured individuals (about 17% of the total population in Germany). We selected women who gave birth in the years 2004 to 2006 and identified indications for caesarean section on the basis of hospital diagnoses in 30 days around birth. We classified pregnancies into three groups: those with strong indications for caesarean section (based on classification of absolute indications recommended by the Unmet Obstetrics Need network), those with moderate indications (other indications increasing the probability of caesarean section) and those with no indications. We investigated the percentage of caesarean sections among all births, presence of strong or moderate indications in all pregnancies, the probability of caesarean sections in the presence of indications and the fraction of caesarean sections attributable to strong, moderate and no indications.

RESULTS

In total, 294,841 births from 2004-2006 were included in the analysis. In the former West Germany, 30% births occurred by caesarean section, while in the former East Germany the caesarean section rate was 22%. Proportions of pregnancies with strong and moderate indications for caesarean section were similar in both regions. For strong indications the probability of caesarean section was similar in East and West Germany, but the probability of caesarean section among women with moderate indications was substantially higher in the former West Germany. Caesarean sections were also more common among women with no indications in the former West (8%) than in the former East (4-5%). The higher probability of caesarean section in the case of strong or moderate indications in the former West than in the East explained 87% of the difference between section rates in these two regions, while caesarean sections without indications contributed to only 13% of the difference observed.

CONCLUSIONS

The observed difference between caesarean section rates in the former East and West Germany was most likely due to different medical practice in handling relative indications.

Twin and sibling studies using health insurance data: the example of attention deficit/hyperactivity disorder (ADHD)

Background and Aims

Twin studies are used to assess the contribution of genetic factors to the aetiology of diseases. To show the feasibility of such research on the basis of health insurance data, we analysed twin and sibling data on the attention deficit/hyperactivity disorder (ADHD) in the German Pharmacoepidemiological Research Database (GePaRD).

Methods

The GePaRD consists of data from four statutory health insurances, including around 17% of the total population of Germany. Among those insured in 2005, we identified 286,653 non-twin sibling pairs and 12,486 twin pairs. Each pair consisted of an index child (6 to 12 years old) and a co-sibling of equal age or up to five years older. ADHD cases were identified by hospital or ambulatory ICD-10 diagnoses (F90.0 or F90.1) and prescriptions. We estimated tetrachoric correlations, percentage of concordant pairs, concordance rates, and heritability. Weighted estimates for the indirect assessment of mono- and dizygotic pairs were derived.

Results

Tetrachoric correlations were highest for twin pairs of the same sex (males: 0.85, 95% CI 0.81–0.89; females: 0.81, 95% CI 0.73–0.88) and lowest for opposite-sex non-twin sibling pairs (0.43, 95% CI 0.41–0.45). Heritability estimates were 0.88 (95% CI: 0.79–0.97) for males and 0.77 (95% CI: 0.60–0.95) for females.

Conclusions

The study clearly reproduced the well-known strong genetic component in the aetiology of ADHD. This approach could be used for further assessments of genetic components in other diseases.

Age-specific prevalence, incidence of new diagnoses, and drug treatment of attention-deficit/hyperactivity disorder in Germany

OBJECTIVE

The purpose of this study was to estimate the prevalence and incidence of new diagnoses of attention-deficit/hyperactivity disorder (ADHD) and assess drug treatment of ADHD in the 3-17 year age group in Germany.

METHOD

We analysed data from the German Pharmacoepidemiological Research Database (GePaRD) for the years 2004-2006. The GePaRD includes claim records of 14,000,000 members of four statutory health insurances, representing 17% of the German population. The assessment of ADHD diagnoses was based on International Classification of Diseases version 10 (ICD-10) codes in outpatient and hospital data.

RESULTS

In 2005, the age-standardized prevalence and incidence of new diagnoses were 2.5% and 9/1000 person-years, respectively. Both measures were 3-4 times higher for males than for females. Incidence of new ADHD diagnoses increased linearly up to the age of 8 years for boys and 9 years for girls and decreased abruptly thereafter. In the calendar quarter of the initial ADHD diagnosis, 9.4% (95% confidence interval [CI] 8.9-9.8%) received methylphenidate or atomoxetine and 36.8% (95% CI 36.1-37.6%) received at least one prescription of either drug within the first year. Initiation of drug treatment and choice of drug were similar for both sexes.

CONCLUSIONS

ADHD is a common condition among children and youth in Germany. There are substantial differences by sex in the prevalence and incidence of new ADHD diagnoses, but only a small difference in drug treatment among those diagnosed with ADHD. A relatively low percentage of children receives drug treatment in the first year after the initial diagnosis of ADHD.