Antibiotic use during pregnancy in Sweden: A nationwide utilization study covering 2007-2019

INTRODUCTION

Antibiotics are often prescribed during pregnancy. Assessing the current state of prenatal antibiotic use is therefore imperative for optimizing prescribing and identifying emerging research priorities. The study aimed to describe recent trends and patterns in antibiotic use during pregnancy among women who gave birth in Sweden, including user characteristics.

MATERIAL AND METHODS

Population-based descriptive study using linked nationwide registers. All pregnancies delivered in Sweden from 2007 to 2019 were included. Prevalence of use was defined as the percentage of pregnancies during which at least one prescription forantibiotics was filled. Temporal trends in the prevalence of antibiotic use by calendar year, trimester and weeks of gestation were assessed from time series graphs.

RESULTS

Prescriptions for systemic antibiotics were filled in 20.7% of 1 434 431 pregnancies overall, decreasing from 24.7% in 2007 to 18.0% in 2019. Phenoxymethylpenicillin (8.5%), pivmecillinam (6.5%), nitrofurantoin (4.7%), amoxicillin (1.6%) and cefadroxil (1.5%) use were the most prevalent. Their use decreased over the 13-year period, except for pivmecillinam, which increased from 4.0% to 7.4%. Prevalence of use was highest in the second trimester (9.5%), with weekly trends peaking at 13 and 34 weeks of gestation. Compared with non-users, antibiotic users more often belonged to the youngest and oldest age strata, carried multipleton pregnancies, had delivered before, had attained a lower education level and smoked in early pregnancy. A higher body mass index, asthma, chronic renal disease and diabetes mellitus were more prevalent among antibiotic users than among non-users.

CONCLUSIONS

Although outpatient antibiotic use during pregnancy in Sweden has been declining, one in five pregnancies was exposed to systemic antibiotics.

Psykiske lidelser og plager ved vedvarende opioidbruk for langvarige ikke-kreftrelaterte smerter – en registerstudie

Background

Knowledge of mental disorders among patients with persistent opioid use for the treatment of chronic non-cancer pain is essential, as mental disorders and symptoms can exacerbate or perpetuate pain and impact on the ability of patients to manage their illness. We have studied the prevalence of mental disorders and symptoms, including substance use disorders, in patients with persistent opioid use in 2019.

Material and method

Persons ≥ 18 years with persistent opioid use and persons ≥ 18 years with at least one registered mental disorder in the specialist healthcare service in 2019 were included. Data were retrieved from national health registries in Norway. Patients who received opioids reimbursed for the treatment of chronic pain were compared with those who received opioids without reimbursement.

Results

The prevalence of mental disorders and symptoms was 34 % among 14 403 persons who received reimbursed opioids, and 42 % among 38 001 persons who received opioids without reimbursement. This is equivalent to a two to threefold increase in prevalence compared to the general population. There was a particularly higher prevalence of anxiety disorders and substance use disorders. The prevalence of mental disorders and symptoms was highest in the age group 18-44 years (49-55 %).

Interpretation

Among patients with persistent opioid use, a large proportion had mental disorders and symptoms, which are known risk factors for developing problematic opioid use and opioid use disorder.

Patterns of filled prescriptions and the association with risk of drug-induced death. A population-based nested case-control register study

PURPOSE

Opioid analgesics (OA) and other pharmaceuticals have been associated with drug-induced deaths. However, there is a lack of knowledge regarding patterns of use of these pharmaceuticals in the population and regarding such associations. We identify and describe subgroups of people with different patterns of filled prescriptions of OA and other relevant pharmaceuticals and examine associations with drug-induced deaths. In addition, we estimate the proportion of drug-induced deaths with a filled OA prescription and OA as cause of death.

METHODS

A Norwegian population-based nested case-control register study with cases (drug-induced deaths 2010-2018, N = 2388) and population controls matched for age, gender and year of inclusion (N = 21 465). Patterns of filled prescriptions for opioid analgesics (OA), benzodiazepines and benzodiazepine-related drugs, gabapentinoids, ADHD medication and antidepressants/antipsychotics were explored by k-means cluster analysis. Associations with drug-induced deaths were estimated by conditional logistic regression adjusted for sociodemographic characteristics. Overlap of filled OA prescriptions and OA as cause of death was estimated.

RESULTS

Five clusters were identified: 'few prescriptions', 'weak OA', 'ADHD medication', 'sedative/psychiatric morbidity' and 'strong OA'. The 'strong OA' cluster had higher socioeconomic status compared to the other groupings. The risk of drug-induced death was also highest in this cluster (OR = 35.5; CI 25.6-49.3) and, for 68% (CI 64-73) of cases, filled prescriptions for OA was indicated as the underlying cause of death.

CONCLUSIONS

The cluster analysis identified a subgroup with filled prescriptions of OA and other pharmaceuticals and a higher socioeconomic status than other subgroups. This subgroup had a high risk of drug-induced death that needs to be addressed.

Recognition and management of children and adolescents with conduct disorder: a real-world data study from four western countries

BACKGROUND

Conduct disorders (CD) are among the most frequent psychiatric disorders in children and adolescents, with an estimated worldwide prevalence in the community of 2-4%. Evidence-based psychological outpatient treatment leads to significant improvement in about two-thirds of cases. However, there seems to be considerable variation in rates of CD diagnoses and implementation of evidence-based interventions between nations. The aim of this study was to compare administrative prevalence and treatment patterns for CD in children and adolescents seen in health care systems across four Western countries (Denmark, Germany, Norway, and the USA).

METHODS

Cross-sectional observational study using healthcare data to identify children and adolescents (aged 0-19 years) with an ICD-10 code for CD within the calendar year 2018. Within each country's study population, the prevalence of CD, psychiatric comorbidity, psychopharmacological treatment, and psychiatric hospitalisation was calculated.

RESULTS

The prevalence of diagnosed CD differed 31-fold between countries: 0.1% (Denmark), 0.3% (Norway), 1.1% (USA) and 3.1% (Germany), with a male/female ratio of 2.0-2.5:1. The rate of psychiatric comorbidity ranged from 69.7 to 86.1%, with attention-deficit/hyperactivity disorder being most common. Between 4.0% (Germany) and 12.2% (USA) of youths with a CD diagnosis were prescribed antipsychotic medication, and 1.2% (Norway) to 12.5% (Germany) underwent psychiatric hospitalisation.

CONCLUSION

Recognition and characteristics of youths diagnosed with CD varied greatly by country. In some countries, the administrative prevalence of diagnosed CD was markedly lower than the average estimated worldwide prevalence. This variation might reflect country-specific differences in CD prevalence, referral thresholds for mental health care, diagnostic tradition, and international variation in service organisation, CD recognition, and availability of treatment offers for youths with CD. The rather high rates of antipsychotic prescription and hospitalisation in some countries are remarkable, due to the lack of evidence for these therapeutic approaches. These findings stress the need of prioritising evidence-based treatment options in CD. Future research should focus on possible reasons for inter-country variation in recognition and management of CD, and also address possible differences in patient-level outcomes.

Comparative Risk of Major Congenital Malformations With Antiseizure Medication Combinations vs Valproate Monotherapy in Pregnancy

BACKGROUND AND OBJECTIVES

Valproate should be avoided in pregnancy, but it is the most effective drug for generalized epilepsies. Alternative treatment may require combinations of other drugs. Our objectives were to describe first trimester use of antiseizure medication (ASM) combinations that are relevant alternatives to valproate and determine whether specific combinations were associated with a lower risk of major congenital malformations (MCM) compared with valproate monotherapy.

METHODS

We conducted a population-based cohort study using linked national registers from Denmark, Finland, Iceland, Norway, and Sweden and administrative health care data from the United States and New South Wales, Australia. We described first trimester use of ASM combinations among pregnant people with epilepsy from 2000 to 2020. We compared the risk of MCM after first trimester exposure to ASM combinations vs valproate monotherapy and low-dose valproate plus lamotrigine or levetiracetam vs high-dose valproate (≥1,000 mg/d). We used log-binomial regression with propensity score weights to calculate adjusted risk ratios (aRRs) and 95% CIs for each dataset. Results were pooled using fixed-effects meta-analysis.

RESULTS

Among 50,905 pregnancies in people with epilepsy identified from 7.8 million total pregnancies, 788 used lamotrigine and levetiracetam, 291 used lamotrigine and topiramate, 208 used levetiracetam and topiramate, 80 used lamotrigine and zonisamide, and 91 used levetiracetam and zonisamide. After excluding pregnancies with use of other ASMs, known teratogens, or a child diagnosed with MCM of infectious or genetic cause, we compared 587 exposed to lamotrigine-levetiracetam duotherapy and 186 exposed to lamotrigine-topiramate duotherapy with 1959 exposed to valproate monotherapy. Pooled aRRs were 0.41 (95% CI 0.24-0.69) and 1.26 (0.71-2.23), respectively. Duotherapy combinations containing low-dose valproate were infrequent, and comparisons with high-dose valproate monotherapy were inconclusive but suggested a lower risk for combination therapy. Other combinations were too rare for comparative safety analyses.

DISCUSSION

Lamotrigine-levetiracetam duotherapy in first trimester was associated with a 60% lower risk of MCM than valproate monotherapy, while lamotrigine-topiramate was not associated with a reduced risk. Duotherapy with lamotrigine and levetiracetam may be favored to treat epilepsy in people with childbearing potential compared with valproate regarding MCM, but whether this combination is as effective as valproate remains to be determined.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that in people with epilepsy treated in the first trimester of pregnancy, the risk of major congenital malformations is lower with lamotrigine-levetiracetam duotherapy than with valproate alone, but similar with lamotrigine-topiramate.

Fatal drug overdoses in individuals treated pharmacologically for chronic pain: a nationwide register-based study

INTRODUCTION

Chronic pain patients may be at an increased risk for drug overdoses as a result of comorbid psychiatric disorders and treatment with risk-increasing prescription medications, such as opioids. We aimed to characterise fatal drug overdoses and investigate factors associated with the deaths among individuals who had been treated pharmacologically for chronic pain.

METHODS

We included all individuals who received analgesics reimbursed for chronic pain in Norway during 2010-9 (n=569 047). Among this population, we identified all individuals with drug overdoses as cause of death (cases). Extracting data from national registries on diagnoses, filled prescriptions, and socioeconomic variables, we used a nested case-control design to compare the cases with age- and sex-matched controls from the study population.

RESULTS

Overall, 623 (0.11%) individuals in the study population died of an overdose. Most, 66.8%, had overdosed accidentally, and 61.9% as a result of pharmaceutically available opioids. Compared with the controls (n=62 245), overdoses overall were associated strongly with substance use disorders (adjusted odds ratio 7.78 [95% confidence interval 6.20-9.77]), use of combinations of opioids, benzodiazepines and related drugs and gabapentinoids (4.60 [3.62-5.85]), previous poisoning with pharmaceuticals (2.78 [2.20-3.51]), and with living alone the last year of life (2.11 [1.75-2.54]). Intentional overdoses had a stronger association with previous poisonings with pharmaceuticals whereas accidental overdoses were strongly associated with substance use disorders.

CONCLUSIONS

This study shows the need for better identification of overdose and suicide risk in individuals treated for chronic pain. Extra caution is needed when treating complex comorbid disorders, especially with overdose risk-increasing medications.

Socioeconomic risk factors for long-term opioid use: A national registry-linkage study

BACKGROUND

Opioid use has increased substantially as a treatment for chronic pain, although harms from long-term opioid therapy outweigh the benefits. More knowledge about factors associated with long-term opioid use is needed. We aimed to investigate the association between socioeconomic status and long-term opioid use in the period 2010-2019.

METHODS

This was a nested case-control study in which the cases were all persons ≥18 years with long-term opioid use, that is use of opioids for more than 3 months (N = 215,642). Cases were matched on gender, age and index year (first long-term use period) with four controls who filled at least one opioid prescription, but never developed long-term opioid use in the study period (N = 862,568). We performed a logistic regression analysis adjusted for relevant confounders, stratified on age groups (18-67 years and 68 years and above).

RESULTS

In the younger age group, long-term opioid use was associated with low education (adjusted odds ratio, aOR = 1.54; 95% confidence interval, CI [1.51-1.57]), low income (1.33 [1.31-1.36]), being unemployed (1.40 [1.38-1.42]) and receiving disability pension (1.36 [1.33-1.38]). Weaker associations were found for living in a single-person household or in a dense geographical area. Similar associations were found for the older age group.

CONCLUSION

We found that low socioeconomic status was associated with long-term opioid use both among people in working age and older people. These results indicate a need for social and financial support for non-pharmacological treatment of chronic pain among people with lower socioeconomic status.

SIGNIFICANCE

This study shows that people with low socioeconomic status are at higher risk of developing long-term opioid use. In the clinical setting, physicians should consider socioeconomic status when prescribing opioids for chronic pain. Non-pharmacological treatment options funded by public health services should be prioritized to those with low socioeconomic status as long-term opioid use in chronic pain patients is not recommended.

Prescription high-risk polysubstance use among opioid maintenance treatment patients

BACKGROUND

Among individuals receiving buprenorphine or methadone as opioid maintenance treatment (OMT), concomitant use of other central nervous system depressants, including prescription drugs, can increase risk of overdose. We aimed to 1) determine the prevalence of use of high-risk prescription drugs (opioid analgesics, benzodiazepines, benzodiazepine-related drugs, and gabapentinoids) among OMT patients, 2) calculate its associations with different mental health and pain-related diagnoses, and 3) compare prevalence of concomitant use with the general population.

METHODS

A national sample comprising all individuals filling at least one prescription of OMT drugs in Norway in 2019 was formed. Healthcare registry data were linked to investigate high-risk prescription drug use and different diagnoses. We calculated one-year prevalence of use, amount dispensed in defined daily doses (DDDs), and the number of prescribers for the different high-risk prescription drugs. Logistic regression was used to determine associations (adjusted odds ratios; aOR, 95% confidence intervals (CIs)) between diagnoses and use. Prevalence of use was calculated both in the OMT patient sample and the general population.

RESULTS

Among the OMT patient sample (n=7,299), 47.6% (n=3,476) filled prescriptions for benzodiazepines. For each high-risk prescription drug group, there was a median of 1-2 prescribers. Musculoskeletal diagnoses were the strongest factor for concomitant high-risk prescription drug use for both males (aOR 3.23, CI: 2.72-3.85) and females (aOR 3.07, CI: 2.42- 3.90). The 1-year prevalence of benzodiazepine use was 11.4 times higher for males and 7.1 times higher for females in OMT than the general population. The amount in DDDs was higher for every drug for OMT patients than the general population, particularly for benzodiazepines.

CONCLUSIONS

OMT patients frequently filled prescriptions for high-risk drugs, and in higher dosages than the general population. However, we found little evidence of 'doctor shopping.' Given that these prescription drugs carry overdose risk, particularly when combined with OMT drugs, our findings emphasize the continued need for education and caution to both prescribers and patients on their concomitant use with OMT.

Gender differences in physical morbidity in opioid agonist treatment patients: population-based cohort studies from the Czech Republic and Norway

BACKGROUND

Physical diseases represent a significant burden for opioid agonist treatment (OAT) patients. This study described physical morbidity in two national cohorts of OAT patients focusing on gender differences.

METHODS

This population-based cohort study linking multiple health registers investigated physical diseases (ICD-10) in patients receiving OAT in the Czech Republic (N = 4,280) and Norway (N = 11,389) during 2010-2019. Gender-stratified analysis was performed.

RESULTS

Overall, we found a large burden of physical morbidity across gender groups in OAT patients. In the Czech Republic and Norway, women in OAT had a significantly higher prevalence of physical diseases across most diagnostic chapters, notably genitourinary diseases and neoplasms. Injuries/external causes and infectious/parasitic diseases were among the most common diseases in both women and men. Viral hepatitis accounted for over half of infectious morbidity in women and men in both cohorts.

CONCLUSIONS

Our findings support the need for early screening, detection, and treatment of diseases and conditions across organ systems and the integration of health promotion activities to reduce physical morbidity in OAT patients. The gender differences underline the need for a tailored approach to address specific medical conditions.

Cause-Specific Mortality among Patients in Treatment for Opioid Use Disorder in Multiple Settings: A Prospective Comparative Cohort Study

INTRODUCTION

Among people receiving current or previous opioid maintenance treatment (OMT), the leading cause of premature death is an opioid overdose. However, other causes of mortality remain high in this group. An understanding of causes of deaths across multiple settings can be useful in informing more comprehensive prevention responses. The aim of this study was to describe all non-overdose causes of death in three national cohorts (Czechia, Denmark, and Norway) among OMT patients and to explore associations of non-overdose mortality with age and gender.

METHODS

This prospective comparative cohort study used national mortality registry databases for OMT patients from Czechia (2000-2019), Denmark (2000-2018), and Norway (2010-2019). Crude mortality rates and age-standardized mortality rates (ASMRs) were calculated as deaths per 1,000 person years for cause-specific mortality.

RESULTS

In total, 29,486 patients were included, with 5,322 deaths recorded (18%). We found variations in causes of death among the cohorts and within gender and age groups. The leading non-overdose causes of death were accidents in Czechia and Denmark, and neoplasms in Norway. Cardiovascular deaths were highest in Czechia, particularly for women in OMT (ASMR 3.59 vs. 1.24 in Norway and 1.87 in Denmark).

CONCLUSION

This study found high rates of preventable death among both genders and all age groups. Different demographic structures, variations in risk exposure, as well as variations in coding practices can explain the differences. The findings support increased efforts towards screening and preventative health initiatives among OMT patients specific to the demographic characteristics in different settings.

Prenatal opioid exposure and risk of asthma in childhood: a population-based study from Denmark, Norway, and Sweden

Background: Opioids may modulate the immune function through opioid receptors on immune cells. Long-term consequences of prenatal opioid exposure on the immune system, such as childhood asthma, are unknown. Objectives: To investigate whether prenatal opioid exposure is associated with the risk of childhood asthma. Methods: Cohort study using linked nationwide registers in Denmark (1996-2015), Norway (2005-2015), and Sweden (2006-2013). Children born by mothers who were chronic opioid analgesics users before pregnancy (n = 14,764) or who were receiving opioid maintenance therapy (OMT) before or during pregnancy (n = 1,595) were identified based on information from each of the medical birth registers and prescription registers. Long-term opioid analgesics exposed children were compared to short-term exposed or unexposed, whereas OMT exposed children were compared to OMT unexposed. Asthma among children ≥1 years of age was defined as two or more filled prescriptions of antiasthmatic medication within 365 days, or a diagnosis of asthma. Hazard ratios (HRs) were calculated using Cox proportional hazards regression with attained age as the time scale. Inverse probability of treatment weights based on propensity scores were applied to adjust for measured confounders. Individual level data from Norway and Sweden were pooled, whereas individual level data from Denmark were analyzed separately. For the opioid analgesics comparisons, adjusted HRs (aHR) from the combined Norwegian/Swedish data and the Danish data were pooled in a fixed-effects meta-analysis. Results: For the opioid analgesics cohort, no increased risk of asthma was observed in long-term exposed children neither compared with unexposed [aHR = 0.99 (95% CI 0.87-1.12)], nor compared with short-term exposed [aHR = 0.97 (0.86-1.10)]. No increased risk of asthma was observed in OMT exposed compared with OMT unexposed children [Norway/Sweden: aHR = 1.07 (0.60-1.92), Denmark: aHR = 1.25 (0.87-1.81)]. Results from sensitivity analyses, where potential misclassification of the outcome and misclassification of OMT exposure were assessed, as well as starting follow-up at 6 years of age, showed that the estimates of association were generally robust. Conclusion: We found no association between prenatal exposure to opioids and risk of childhood asthma. Results were consistent across two different opioid exposure groups with different confounder distributions.

Mental disorder prevalence in chronic pain patients using opioid versus non-opioid analgesics: A registry-linkage study

BACKGROUND

Chronic pain and mental disorders are leading causes of disability worldwide. Individuals with chronic pain are more likely to experience mental disorders compared to individuals without chronic pain, but large-scale estimates are lacking. We aimed to calculate overall prevalence of mental health diagnoses from primary and secondary care among individuals treated for chronic pain in 2019 and to compare prevalence among chronic pain patients receiving opioid versus non-opioid analgesics, according to age and gender.

METHODS

It is a population-based cohort study. Linked data from nationwide health registers on dispensed drugs and diagnoses from primary (ICPC-2) and secondary (ICD-10) health care. Chronic pain patients were identified as all patients over 18 years of age filling at least one prescription of an analgesic reimbursed for non-malignant chronic pain in both 2018 and 2019 (N = 139,434, 69.3% women).

RESULTS

Prevalence of any mental health diagnosis was 35.6% (95% confidence interval: 35.4%-35.9%) when sleep diagnoses were included and 29.0% (28.8%-29.3%) when excluded. The most prevalent diagnostic categories were sleep disorders (14% [13.8%-14.2%]), depressive and related disorders (10.1% [9.9%-10.2%]) and phobia and other anxiety disorders (5.7% [5.5%-5.8%]). Prevalence of most diagnostic categories was higher in the group using opioids compared to non-opioids. The group with the highest overall prevalence was young women (18-44 years) using opioids (50.1% [47.2%-53.0%]).

CONCLUSIONS

Mental health diagnoses are common in chronic pain patients receiving analgesics, particularly among young individuals and opioid users. The combination of opioid use and high psychiatric comorbidity suggests that prescribers should attend to mental health in addition to somatic pain.

SIGNIFICANCE

This large-scale study with nation-wide registry data supports previous findings of high psychiatric burden in chronic pain patients. Opioid users had significantly higher prevalence of mental health diagnoses, regardless of age and gender compared to users of non-opioid analgesics. Opioid users with chronic pain therefore stand out as a particularly vulnerable group and should be followed up closely by their physician to ensure they receive sufficient care for both their mental and somatic symptoms.

Prenatal exposure to pregabalin, birth outcomes and neurodevelopment - a population-based cohort study in four Nordic countries

INTRODUCTION

Pregabalin is an antiepileptic drug frequently prescribed to pregnant women. Risks of adverse birth and postnatal neurodevelopmental outcomes following prenatal exposure to pregabalin are uncertain.

OBJECTIVE

To investigate the association between prenatal exposure to pregabalin and the risks of adverse birth and postnatal neurodevelopmental outcomes.

METHODS

This study was conducted using population-based registries in Denmark, Finland, Norway, and Sweden (2005-2016). We compared pregabalin exposure against no exposure to antiepileptics and against active comparators lamotrigine and duloxetine. We obtained pooled propensity score-adjusted estimates of association using fixed-effect and Mantel-Haenszel (MH) meta-analyses.

RESULTS

The total number of pregabalin-exposed births was 325/666,139 (0.05%) in Denmark, 965/643,088 (0.15%) in Finland, 307/657,451 (0.05%) in Norway, and 1275/1,152,002 (0.11%) in Sweden. The adjusted prevalence ratios (aPRs) with 95% confidence interval (CI) following pregabalin exposure versus no exposure were 1.14 (0.98-1.34) for major congenital malformations and 1.72 (1.02-2.91) for stillbirth, which attenuated to 1.25 (0.74-2.11) in MH meta-analysis. For the remaining birth outcomes, the aPRs were close to or attenuated toward unity in analyses using active comparators. Adjusted hazard ratios (95% CI) contrasting prenatal pregabalin exposure versus no exposure were 1.29 (1.03-1.63) for ADHD and attenuated when using active comparators, 0.98 (0.67-1.42) for autism spectrum disorders, and 1.00 (0.78-1.29) for intellectual disability.

CONCLUSIONS

Prenatal exposure to pregabalin was not associated with low birth weight, preterm birth, small for gestational age, low Apgar score, microcephaly, autism spectrum disorders, or intellectual disability. On the basis of the upper value of the 95% confidence interval, increased risks greater than 1.8 were unlikely for any major congenital malformation and ADHD. For stillbirth and most groups of specific major congenital malformations, the estimates attenuated in MH meta-analysis.

Maternal and Early-Life Exposure to Antibiotics and the Risk of Autism and Attention-Deficit Hyperactivity Disorder in Childhood: a Swedish Population-Based Cohort Study

INTRODUCTION

Antibiotics represent the most common type of medication used during pregnancy and infancy. Antibiotics have been proposed as a possible factor in changes in microbiota composition, which may play a role in the aetiology of autism and attention deficit/hyperactivity disorder (ADHD). Our aim was to investigate the association between maternal and early-life antibiotic use and autism and ADHD in childhood.

METHODS

This Swedish nation-wide population-based cohort study included all first live singleton births (N = 483,459) between January 2006 and December 2016. The association of dispensed antibiotics with autism and ADHD in children aged ≤ 11 years was estimated by applying multivariable logistic regression and generalised estimating equations models.

RESULTS

Of the mothers, 25.9% (n = 125,106) were dispensed ≥1 antibiotic during the exposure period (from 3 months pre-conception to delivery), and 41.6% (n = 201,040) of the children received ≥ 1 antibiotic in early life (aged ≤ 2 years). Penicillin was the most prescribed antibiotic class (17.9% of mothers, 38.2% of children). Maternal antibiotic use was associated with an increased risk of autism [odds ratio (OR) = 1.16, 95% confidence interval (CI) 1.09-1.23] and ADHD (OR = 1.29, 95% CI 1.21-1.36) in childhood. Early-life exposure to antibiotics showed an even stronger association [autism (OR = 1.46, 95% CI 1.38-1.55); ADHD (OR = 1.90, 95% CI 1.80-2.00)]. Both maternal and childhood-exposure sub-analyses suggested a dose-response relationship.

CONCLUSION

Maternal and early-life antibiotic use was associated with an increased risk of autism and ADHD in childhood. However, differences were noted by exposure period and antibiotic classes.

Comparative Safety of Antiseizure Medication Monotherapy for Major Malformations

OBJECTIVE

This study was undertaken to examine the comparative safety of antiseizure medication (ASM) monotherapy in pregnancy with respect to risk of major congenital malformations (MCMs), overall and by MCM subtype.

METHODS

We conducted a population-based cohort study using national health register data from Denmark, Finland, Iceland, Norway, and Sweden (1996-2020). We compared pregnancies with first trimester exposure to lamotrigine monotherapy to ASM-unexposed, carbamazepine, valproate, oxcarbazepine, levetiracetam, and topiramate to lamotrigine monotherapy, and stratified monotherapy groups by dose. The outcome was nongenetic MCM and specific subtypes. We estimated adjusted risk ratios (aRRs) and 95% confidence intervals (CIs) with log-binomial regression and propensity score weights.

RESULTS

There was a higher crude risk of any MCM in pregnancies exposed to lamotrigine monotherapy (n = 8,339) compared to ASM-unexposed pregnancies (n = 4,866,362), but not after confounder adjustment (aRR = 0.97, 95% CI = 0.87-1.08). Compared to lamotrigine, there was an increased risk of malformations associated with valproate (n = 2,031, aRR = 2.05, 95% CI = 1.70-2.46) and topiramate (n = 509, aRR = 1.81, 95% CI = 1.26-2.60), which increased in a dose-dependent manner. We found no differences in malformation risk for carbamazepine (n = 2,674, aRR = 0.91, 95% CI = 0.72-1.15), oxcarbazepine (n = 1,313, aRR = 1.09, 95% CI = 0.83-1.44), or levetiracetam (n = 1,040, aRR = 0.78, 95% CI = 0.53-1.13). Valproate was associated with several malformation subtypes, including nervous system, cardiac, oral clefts, clubfoot, and hypospadias, whereas lamotrigine and carbamazepine were not.

INTERPRETATION

Topiramate is associated with an increased risk of MCM similar to that associated with valproate, but lower doses may mitigate the risks for both drugs. Conversely, we found no increased risks for lamotrigine, carbamazepine, oxcarbazepine, or levetiracetam, which is reassuring. ANN NEUROL 2023;93:551-562.

In-utero antibiotic exposure and subsequent infections in infancy: a register-based cohort study with sibling analysis

BACKGROUND

Prenatal antibiotic use, the ensuing maternal dysbiosis, and subsequent acquisition of altered microbiota in early life have been linked to the offspring's increased susceptibility to childhood infections. However, infection risks during the first year of life associated with in-utero antibiotic exposure have not been comprehensively explored.

OBJECTIVE

To investigate the associations between exposure to antibiotics in utero and subsequent infections during infancy and whether such associations differ by antibiotic class.

STUDY DESIGN

All data were retrieved from Swedish population-based registers. Singletons live-born between 2006 and 2018 were followed up from birth to their first birthday. Exposure was maternal filling of at least 1 antibiotic prescription between the last menstrual period and delivery. Outcomes were the infants' antimicrobial prescription fills, incident infections diagnosed in specialist care, and deaths with infections indicated as underlying or contributing causes ("infection-related deaths"). Birth year, birth season, maternal age, place of residence, parity, comorbidity indicator, body mass index, proxies for general health status, education level, and smoking status were considered covariates. Poisson regression was used to estimate crude and adjusted incidence rate ratios with 95% confidence intervals for the number of antimicrobial prescriptions filled to the infant. Cox regression was used to estimate crude and adjusted hazard ratios with 95% confidence intervals for incident infections diagnosed in specialist care and at death. Sibling analyses were used to account for shared familial factors. Sensitivity of the results to exposure definition and perinatal factors prognostic for the outcomes were assessed in supplementary analyses.

RESULTS

Of 1,347,018 infants in the full cohort, 294,657 (21.9%) were exposed to antibiotics in utero. There were 677,430 antimicrobial prescriptions filled (1.380 per 1000 person-days), 423,705 incident infections diagnosed in specialist care (0.870 per 1000 person-days), and 2800 infection-related deaths (0.006 deaths per 1000 person-days) during follow-up. Compared to unexposed, infants exposed to antibiotics in utero had higher rates of antimicrobial prescription fills (adjusted incidence rate ratio, 1.34; 95% confidence interval, 1.33-1.34), incident infections diagnosed in specialist care (adjusted hazard ratio, 1.28; 95% confidence interval, 1.27-1.29), and infection-related mortality (adjusted hazard ratio, 1.15; 95% confidence interval, 1.05-1.25). For antimicrobial prescriptions and infections diagnosed in specialist care, associations were consistent across most antibiotic classes but were attenuated in the sibling analyses: adjusted incidence rate ratio of 1.05 (95% confidence interval, 1.04-1.06) and adjusted hazard ratio of 1.05 (95% confidence interval, 1.03-1.07), respectively. No association with infant mortality was found in the sibling cohort (adjusted hazard ratio, 0.93; 95% confidence interval, 0.81-1.08).

CONCLUSION

The minor associations between exposure to antibiotics in utero and infections during infancy were partly explained by shared familial factors and did not differ across frequently used antibiotic classes.

Cohort Description: Preventing an Opioid Epidemic in Norway - Focusing on Treatment of Chronic Pain (POINT) - A National Registry-Based Study

AIM

The POINT project aims to provide evidence to optimise chronic pain management, prevent adverse consequences of opioids, and improve chronic pain patients' pain relief, functional capacity, and quality of life. We describe the outline of the project and its work packages. More specifically, we describe a cohort of persons with chronic pain and a cohort of long-term opioid users identified from a national registry linkage.

DATA SOURCES

The project utilises data from nationwide healthcare and population registers in Norway. Using the Norwegian Prescription Database, we identified a cohort of persons who have been dispensed drugs reimbursed for chronic pain and a cohort of persons who used opioids long term from 2010 to 2019. Data from the Norwegian Registry for Primary Health Care and the Norwegian Patient Registry (2008-2019), Cancer Registry (1990-2018) Cause of Death Registry (2010-2019) and demographic and socioeconomic registers from Statistics Norway (2010-2019) were linked to the cohorts.

STUDY POPULATION

There were 568,869 participants with chronic pain. Sixty-three percent of the cohort was women, and the mean age was 57.1 years. There were 336,712 long-term opioid users (58.6% women; 60.9 years). In chronic pain and long-term opioid user cohorts, the most frequent musculoskeletal diagnosis was back pain diagnosed in primary care (27.6% and 30.7%). Psychiatric diagnoses were also common.

MAIN VARIABLES

Upcoming studies will utilise psychiatric and somatic diagnoses from the patient registers, drug use from the prescription register, causes of death, demographics, and socioeconomic status (eg, education, income, workability, immigrant status) as exposures or outcomes.

CONCLUSION AND FUTURE PLANS

The two cohorts have numerous pain-related diagnoses, especially in the musculoskeletal system, and noticeably frequent somatic and psychiatric morbidity. The POINT project also includes later work packages that explore prescriber and patient perspectives around safe and effective treatment of chronic pain.

Antimicrobial use in Sweden during the COVID-19 pandemic: prescription fill and inpatient care requisition patterns

Background

Increased and inappropriate antimicrobial use are the key drivers of the emergence of antimicrobial resistance, and there have been widespread concerns around potential antimicrobial misuse, overuse and their consequences during the COVID-19 pandemic. To better understand the impact of the pandemic on antimicrobial use, particularly in light of the resurgence of COVID-19 cases since the summer of 2020, we assessed trends in antimicrobial prescription fills and hospital requisitions in Sweden during 2020 against those of preceding years.

Methods

We performed a descriptive study using population-based data from the Swedish Prescribed Drug Register and the Swedish e-Health Agency. The weekly number of prescriptions filled and the total volume sold to inpatient care institutions in defined daily doses (DDDs) per 1000 inhabitants for systemic antibacterials (Anatomical Therapeutic Chemical therapeutic subgroup J01 excluding J01XX), antimycotics (J02), antivirals (J05) and antiprotozoals (P01) were computed and evaluated from time series graphs. A time series linear regression with ordinary least squares (OLS) estimation was used to model 2015–2019 data and predict the expected number of prescriptions filled and volumes sold in DDDs per 1000 inhabitants during 2020 with 95% confidence limits.

Results

From mid-March 2020, the weekly rate of antibiotic and antiprotozoal prescriptions filled plummeted to unprecedentedly low levels for the rest of the year; while unprecedentedly high numbers of antiviral prescriptions were filled weekly between mid-February and mid-March 2020. There was a net reduction in annual dispensing of antibiotics by 17%; of antiprotozoals by 21%; and of antivirals by 0.3% during 2020 compared to 2019. Inpatient care requisitions of antiprotozoals and antibiotics surged to 6-year highs during March 2020, resulting in a 127% increase in DDDs of antiprotozoals sold from 2019. The volume of antibiotics and antivirals sold to inpatient care institutions in 2020 decreased by 3% and 13% compared to 2019, respectively.

Conclusions

The overall decline in antimicrobial prescriptions filled in Sweden during 2020 were in part, collateral dividends of the COVID-19 pandemic.

Supplementary information

The online version contains supplementary material available at 10.1186/s12879-022-07405-3.

Prescription opioids among older adults: ten years of data across five countries

BACKGROUND

Opioid use has increased globally in the recent decade. Although pain remains a significant problem among older adults, susceptibility to opioid-related harms highlights the importance of careful opioid therapy monitoring on individual and societal levels. We aimed to describe the trends of prescription opioid utilisation among residents aged ≥65 in all Nordic countries during 2009-2018.

METHODS

We conducted cross-sectional measurements of opioid utilisation in 2009-2018 from nationwide registers of dispensed drugs in Denmark, Finland, Iceland, Norway, and Sweden. The measures included annual opioid prevalence, defined daily doses (DDDs) per 1000 inhabitants per day (DIDs), and morphine milligram equivalents (MMEs) per user per day.

RESULTS

From 2009 to 2018, an average of 808,584 of adults aged ≥65 used opioids yearly in all five countries; an average annual prevalence of 17.0%. During this time period, the prevalence decreased in Denmark, Norway, and Sweden due to declining codeine and/or tramadol use. Iceland had the highest opioid prevalence in 2009 (30.2%), increasing to 31.7% in 2018. In the same period, DIDs decreased in all five countries, and ranged from 28.3 in Finland to 58.5 in Denmark in 2009, and from 23.0 in Finland to 54.6 in Iceland in 2018. MMEs/user/day ranged from 4.4 in Iceland to 19.6 in Denmark in 2009, and from 4.6 in Iceland to 18.8 in Denmark in 2018. In Finland, Norway, and Sweden, MMEs/user/day increased from 2009 to 2018, mainly due to increasing oxycodone utilisation.

CONCLUSIONS

The stable or decreasing opioid utilisation prevalence among a majority of older adults across the Nordic countries coincides with an increase in treatment intensity in 2009-2018. We found large cross-national differences despite similarities across the countries' cultures and healthcare systems. For the aged population, national efforts should be placed on improving pain management and monitoring future trends of especially oxycodone utilisation.

Vedvarende bruk av opioider og samtidig bruk av andre vanedannende legemidler

BACKGROUND

Long-term use of opioids may have undesirable consequences. We have investigated long-term opioid use in patient groups that were prescribed opioids for various indications (chronic pain, palliative care, other (white prescriptions, not generally covered by the Norwegian National Insurance Scheme)) as well as the groups' concomitant use of some other addictive medications.

MATERIAL AND METHOD

Persons registered in the Norwegian Prescription Database with at least one filled prescription of an opioid in the period 2011-19 were included. Long-term use in a calendar year was defined as the dispensing of > 180 defined daily doses or > 4 500 mg oral morphine equivalents distributed over at least 3 periods of 3 months.

RESULTS

The number of long-term opioid users was 50 422 in 2011 and 59 996 in 2019 (10.1 and 10.7 % of all opioid users). The number who received opioids on blue prescription (partly covered by the Norwegian National Insurance Scheme) for chronic pain increased in the period by 9 952 persons, but the majority (n=38 006, 63.3 %) continued to receive opioids exclusively on white prescription in 2019. A total of 15 623 (41.1 %) and 14 881 (39.2 %), respectively, of the long-term opioid users who received opioids solely on white prescription in 2019 also received benzodiazepines and Z-hypnotics in the same year. Of the 23 967 long-term users who also received benzodiazepines, 88 % were dispensed opioids and benzodiazepines on the same day at least once in 2019.

INTERPRETATION

Prolonged prescribing of opioids on white prescription and concurrent prescribing of other addictive drugs may indicate undesirable use with no clear indication.

Describing long-term opioid use utilizing Nordic Prescription Registers - A Norwegian example

Previous studies have defined long-term opioid use in varying ways, decreasing comparability, reproducibility, and clinical applicability of the research. Based on recommendations from recent systematic reviews, we aimed to develop a methodology to estimate the prevalence of use persisting more than three months utilizing one of the Nordic prescription registers. We used the Norwegian Prescription Register (NorPD) to extract data on all opioid dispensations between 1 January 2004 and 31 October 2019. New users of opioids (washout 365 days) were defined as long-term users if they fulfilled two criteria: 1) they had ≥2 dispensations of opioids, 91-180 days apart; 2) days 0-90 included ≥90 dispensed administration units (e.g., tablets) of opioids. Overall, there were 2,543,224 new users of opioids during the study period. Of these, 354,666 (13.9%) fulfilled the criteria for long-term opioid use at least once. Compared with those who did not fulfill the criteria (short-term users), long-term users were older, more likely women, and used tramadol, oxycodone, and buprenorphine more frequently as their first opioid. In conclusion, we found that 1/7 of opioid users continued use longer than 3 months. Future outcome research should identify the clinically most important dose requirements for long-term opioid use criteria.

Individuals Dying of Overdoses Related to Pharmaceutical Opioids Differ from Individuals Dying of Overdoses Related to Other Substances: A Population-Based Register Study

BACKGROUND

Pharmaceutical opioid (PO) overdose deaths have increased in many Western countries. There are indications that those dying from a PO overdose differ from those dying from other types of overdoses. These differences might pose a challenge as the majority of current preventive measures are tailored toward those with the characteristics of "conventional" overdose deaths.

OBJECTIVE

We investigated differences in the characteristics of persons who died from PO overdoses compared to all other overdoses.

MATERIAL AND METHODS

Using the Norwegian Cause of Death Registry, we retrieved information on overdoses classified according to ICD-10 and identified PO overdoses (T40.2; T40.4) and all other overdoses (T40.X; T43.6) in 2010-2019. By linking data from nationwide registers, we analyzed data on opioid dispensations and the history of mental and behavioral disorders. 1,224 persons were registered with PO overdoses and 1,432 persons with other overdoses.

RESULTS

Persons in the PO overdose group were older and were more frequently women (35.0% vs. 20.5%) than persons with other overdoses. They had a higher prevalence of chronic pain (35.8% vs. 13.2%), history of cancer (8.1% vs. 1.8%), filled prescriptions of analgetic opioids more frequently the month before death (38.8% vs. 12.0%), and used threefold higher doses of prescribed opioids compared to individuals in all other overdose group (66 vs. 26 oral morphine equivalents/day). In the PO overdose group, oxycodone and fentanyl were more frequently dispensed, while codeine was more frequently dispensed in the other overdose groups. A lower proportion of those in the PO overdose group had recorded diagnoses of substance use disorders, schizophrenia, and hyperkinetic disorder compared to the other overdose groups.

CONCLUSION

Persons dying from overdoses on POs often differ from the population targeted by existing prevention strategies, as they are more frequently older women with chronic pain and using high doses of prescription opioids.

Bruk av andre vanedannende legemidler blant opioidbrukere med langvarige smerter

Bakgrunn: Opioider for behandling av langvarige smerter kan forskrives på blå resept, men bør ikke brukessamtidig med andre vanedannende legemidler.Hensikt: Å undersøke bruk av opioider på blå resept i perioden 2009-2019, samt å studere bruk av andre vanedannendelegemidler (benzodiazepiner og z-hypnotika) blant dem som fikk opioider på blå resept i 2019.Metode: Data ble hentet fra Reseptregisteret. En prevalent opioidbruker i 2019 ble definert som en person medminst én utlevering av et smertestillende opioid på blå resept for langvarige smerter også i 2018. Bruk av andrevanedannende legemidler ble definert som minst én utlevering av et annet vanedannende legemiddel i løpet avsamme år.Resultater: Totalt 18 443 personer (67% kvinner) fikk utlevert opioider på blå resept i 2019, en økning fra5 568 i 2009 via 10 693 i 2016 og 16 133 i 2017. Av de 18 443 var 14 202 (77%) prevalente opioidbrukere.Blant de prevalente brukerne fikk 88% utlevert 100 mg orale morfinekvivalenter (OMEQ) eller mindre perdag. Totalt fikk 54% av de prevalente opioidbrukerne utlevert minst ett annet vanedannende legemiddel i 2019.Z-hypnotika var oftest forekommende blant de som brukte 100 mg OMEQ eller mindre per dag, mens benzodiazepineralene eller i kombinasjon med z-hypnotika dominerte blant opioidbrukerne som fikk utlevert merenn 100 mg OMEQ per dag. Mengden utlevert av andre vanedannende legemidler økte med mengden opioiderbrukt per dag. En større andel kvinner enn menn fikk utlevert andre vanedannende legemidler i 2019.Konklusjon: Studien indikerer at bruk av andre vanedannende legemidler forekommer hos en stor andel avdem som får forskrevet opioider på blå resept. Dette er tegn på et uheldig forskrivningsmønster som børstuderes nærmere.

An 11-year nationwide registry-linkage study of opioid maintenance treatment in pregnancy in Norway

Aim: We aimed to describe opioid maintenance treatment (OMT) to pregnant women in Norway and study thebackground characteristics of the pregnant women compared to the general population of pregnant women andto a previous clinical cohort study of OMT in pregnancy.Methods: Population-based cohort study with linked data from the Norwegian Medical Birth Registry, theNorwegian Prescription Database, the Norwegian Patient Registry, and Statistics Norway. The study populationconsisted of women giving birth between 2005-2015 in Norway. We defined OMT pregnancies as pregnancieswhere the woman was dispensed OMT medications (methadone, buprenorphine, or buprenorphine/naloxone) at least once during pregnancy.Results: The study population consisted of 420,808 women with 645,440 pregnancies ending in a live birth inNorway in 2005-2015 (the general pregnant population). Of these, 261 women (0.6‰) had altogether 306OMT pregnancies. The mean number of pregnancies was 28 OMT pregnancies per year and quite stable duringthe study period. Women with OMT pregnancies were older, smoked tobacco more frequently, had lowereducation, and fewer of them had a partner, compared to the general population of pregnant women. In mostpregnancies, the women were treated with buprenorphine (n=183 (59.8%)), while in 120 (39.2%) pregnancies,the woman received methadone. From 2008, buprenorphine replaced methadone as the most frequently useddrug. In only 38 (12.4%) pregnancies, OMT treatment was initiated in pregnancy. In 201 (66%) pregnancies,the woman used OMT medications in all trimesters. For these women, the mean amount of dispensed drug was3.4 DDD/day (85 mg/day) in pregnancy for methadone and 1.9 DDD/day (15.2 mg/day) for buprenorphine.Conclusion: The number of OMT pregnancies per year has been low and stable in the period 2005-2015.Following Norwegian recommendations, there has been a shift from treatment with methadone towardsbuprenorphine. The women receiving OMT during pregnancy had more risk factors for adverse outcomes thanthe general pregnant population but were quite similar to the previous clinical cohort.

Cardiovascular Risk in Users of Mirabegron Compared with Users of Antimuscarinic Treatments for Overactive Bladder: Findings from a Non-Interventional, Multinational, Cohort Study

INTRODUCTION

During clinical trials, mirabegron, a β3-adrenoreceptor agonist, was associated with increased vital signs vs placebo in patients with overactive bladder.

OBJECTIVE

The purpose of this study was to compare incidence rates of adverse cardiovascular (CV) outcomes following mirabegron or antimuscarinic use.

METHODS

We conducted an observational post-marketing safety study utilising real-world data. The study population was identified within five sources: Danish and Swedish National Registers, Clinical Practice Research Datalink (UK), Optum (USA) and Humana (USA). Episodes of time when patients were new users of mirabegron or antimuscarinics (October 2012-December 2018) were sourced from prescriptions and matched on propensity scores. Occurrences of major adverse cardiovascular events (MACE), acute myocardial infarction (AMI), stroke, CV mortality and all-cause mortality were identified. Outcome incidence rates and hazard ratios from Cox models were estimated.

RESULTS

Overall, 152,026 mirabegron and 152,026 antimuscarinic episodes were matched. The population consisted of 63.1% women and 72.6% were ≥ 65 years old. There were no appreciable differences in the incidence rates of MACE, AMI or stroke between users of mirabegron and antimuscarinics. Incidence rates of CV mortality (hazard ratio 0.83, 95% confidence interval 0.73-0.95) and all-cause mortality (hazard ratio 0.80, 95% confidence interval 0.76-0.84) were no higher with mirabegron vs antimuscarinics. Results restricted to episodes at high risk for CV events or stratified by age (< 65 years, ≥ 65 years) or prior overactive bladder medication use were consistent with overall findings.

CONCLUSIONS

This large, multinational study found no higher risk of MACE, AMI, stroke, CV mortality or all-cause mortality among users of mirabegron relative to users of antimuscarinics.

Use of intravenous iron and risk of anaphylaxis: A multinational observational post-authorisation safety study in Europe

PURPOSE

This post-authorisation safety study estimated the risk of anaphylaxis in patients receiving intravenous (IV) iron in Europe, with interest in iron dextran and iron non-dextrans. Studies conducted in the United States have reported risk of anaphylaxis to IV iron ranging from 2.0 to 6.8 per 10 000 first treatments.

METHODS

Cohort study of IV iron new users, captured mostly through pharmacy ambulatory dispensing, from populations covered by health and administrative data sources in five European countries from 1999 to 2017. Anaphylaxis events were identified through an algorithm that used parenteral penicillin as a positive control.

RESULTS

A total of 304 210 patients with a first IV iron treatment (6367 iron dextran), among whom 13-16 anaphylaxis cases were identified and reported as a range to comply with data protection regulations. The pooled unadjusted incidence proportion (IP) ranged from 0.4 (95% confidence interval [CI], 0.2-0.9) to 0.5 (95% CI, 0.3-1.0) per 10 000 first treatments. No events were identified at first dextran treatments. There were 231 294 first penicillin treatments with 30 potential cases of anaphylaxis (IP = 1.2; 95% CI, 0.8-1.7 per 10 000 treatments).

CONCLUSION

We found an IP of anaphylaxis from 0.4 to 0.5 per 10 000 first IV iron treatments. The study captured only a fraction of IV iron treatments administered in hospitals, where most first treatments are likely to happen. Due to this limitation, the study could not exclude a differential risk of anaphylaxis between iron dextran and iron non-dextrans. The IP of anaphylaxis in users of penicillin was consistent with incidences reported in the literature.

A study of cancer occurrence in users of mirabegron and antimuscarinic treatments for overactive bladder

OBJECTIVE

This post-authorization safety study (EU PAS Register Number: EUPAS16088) was designed to compare the incidence of cancer outcomes in patients treated with mirabegron versus antimuscarinic medications.

METHODS

Cohorts of mirabegron initiators during 2012-2018 were propensity-score matched to antimuscarinic medication initiators within real-world data sources (Danish National Registers, Swedish National Registers, Clinical Practice Research Datalink [UK], Optum [US], and Humana [US]). Incident cancer cases were identified during follow-up from direct linkage to cancer registers or validated through medical record review or through physician questionnaires. Comparisons of sex-specific composite cancer outcomes (cancer of the lung/bronchus, colon/rectum, melanoma of skin, urinary bladder, non-Hodgkin lymphoma, kidney/renal pelvis, pancreas, prostate in men and breast and uterus in women) were made overall and for person-time in the first year and after the first year following start of treatment, for all ages and for the subgroup ≥65 years.

RESULTS

Among the 80,637 mirabegron initiators matched to 169,885 antimuscarinic medication initiators, 68% were at least 65 years of age and 66% were women. Over 5000 incident cancer cases were observed overall. Incidence rates were higher for men than women for composite and individual cancer outcomes. The pooled fixed effects hazard ratios for composite cancer outcomes (all ages) were 1.05 (95% confidence interval [CI]: 0.98-1.14) for women and 1.06 (95% CI: 0.98-1.14) for men. Results were similar in persons ≥65 years.

CONCLUSIONS

The results suggest no association between mirabegron use and risk of cancer, compared with antimuscarinic medications, in either men or women. Registration: EU PAS Register Number: EUPAS16088.

Risk of common infections among individuals with psoriasis in Sweden: A nationwide cohort study comparing secukinumab to ustekinumab

Purpose

To determine risk of respiratory tract infections, urinary tract infections and candidiasis in secukinumab users compared to ustekinumab users among individuals with psoriasis in Sweden.

Methods

This was a Swedish population‐based register‐linked new‐user cohort study on individuals with psoriasis and psoriasis arthritis treated with secukinumab (2015‐2017) and ustekinumab (2009‐2017). Ever‐never exposure definition was used, that is, each individual's follow‐up time was attributed to the drug they were first exposed to. Risk of severe respiratory and urinary tract infections and candidiasis (diagnosis codes from out‐patient specialist visits and in‐patient hospitalisations) and respiratory and urinary tract infections treated in primary care (proxied by dispensation of antibiotics) was determined by adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox regression. We also give crude incidence rates and rate ratios.

Results

In total, 1955 new users of secukinumab (n = 848) and ustekinumab (n = 1107) were identified. There was a slightly increased risk of respiratory and urinary tract infections treated in primary care among secukinumab users compared to ustekinumab users (HR: 1.22, 95% CI: 1.03‐1.43). Non‐significant differences in estimated risk of severe respiratory and urinary tract infections (HR: 0.96, 95% CI: 0.57‐1.61) and candidiasis (HR: 1.80, 95% CI: 0.84‐3.84) treated in the hospital setting were observed.

Conclusion

We observed a slightly increased risk of respiratory and urinary tract infections treated in primary care among secukinumab users compared to ustekinumab users. Larger studies with longer follow‐up are needed to draw conclusions on relative safety.

On the path towards universal coverage of hepatitis C treatment among people receiving opioid agonist therapy (OAT) in Norway: a prospective cohort study from 2013 to 2017

OBJECTIVES

We aimed to calculate cumulative hepatitis C virus (HCV) treatment coverage among individuals enrolled in opioid agonist therapy (OAT) in Norway between 2013 and 2017 and to document the treatment transition to direct-acting antiviral (DAA) agents. Moreover, we aimed to describe adherence to DAAs in the same cohort.

DESIGN

Prospective cohort, registry data.

SETTING

Specialist healthcare service (secondary) PARTICIPANTS AND OUTCOMES: This observational study was based on data from The Norwegian Prescription Database. We studied dispensed OAT and HCV treatment annually to calculate the cumulative frequency, and employed secondary sources to calculate prevalence, incidence and HCV treatment coverage from 2013 to 2017, among the OAT population. Factors associated with adherence to DAAs were identified a priori and subject to logistic regression.

RESULTS

10 371 individuals were identified with dispensed OAT, 1475 individuals of these were identified with dispensed HCV treatment. Annual HCV treatment coverage increased from 3.5% (95% CI: 3.2 to 4.4) in 2013 to 17% (95% CI: 17 to 20) in 2017, giving a cumulative HCV coverage among OAT patients in Norway of 38.5%. A complete shift to interferon-free treatment regimens occurred, where DAAs accounting for 32% of HCV treatments in 2013 and 99% in 2017. About two-thirds of OAT patients were considered adherent to their DAA regimens across all genotypes. High level of OAT continuity was associated with improved adherence to DAAs (adjusted OR 1.4, 95% CI: 1 to 2, p=0.035).

CONCLUSIONS

A large increase in HCV treatment coverage attributed by a complete shift to interferon-free regimens among the Norwegian OAT population has been demonstrated. However, treatment coverage is inadmissibly too low and a further substantial scale-up in HCV treatment is required to reach the universal targets of controlling and eliminating the HCV endemic.

In utero opioid exposure and risk of infections in childhood: A multinational Nordic cohort study

PURPOSE

There is an increasing number of children with in utero exposure to opioids. Knowledge about opioid safety in pregnancy, particularly for outcomes later in childhood is scarce. It has been suggested that opioids can modulate immune system and increase the risk of infections. Our goal was to study the impact of in utero opioid exposure on the immune system and the risk of infections in childhood.

METHODS

This population-based cohort study used nationwide registers from Denmark, Norway, and Sweden. Among pregnant women we identified users of opioids for two different indications, opioids used in opioid maintenance therapy (OMT) and opioids used for treatment of pain. We followed the exposed children and studied susceptibility for infections measured as number of antibiotic prescriptions expressed as Incidence rate ratios (IRRs) and diagnoses in specialist health care expressed as hazard ratios (HRs).

RESULTS

After adjustment we did not observe increased risk for filling antibiotic prescriptions in children exposed to OMT opioids compared with OMT discontinuers (IRR, 1.08; 95% CI 0.81-1.44 in Norway and Sweden, and IRR, 0.74; 95% CI 0.63-0.88 in Denmark), or for diagnosis of infection in specialist health care (HR 0.83; 95% CI 0.55-1.26 in Norway and Sweden, and 0.82; 95% CI 0.62-1.10 in Denmark).

CONCLUSIONS

In this population-based cohort study, we did not observe increased risk of infections among children prenatally exposed to OMT opioids when compared to OMT discontinuers, nor long-term analgesic opioids exposed when compared to short-term analgesic opioids exposed.

Potentially addictive drugs dispensing to patients receiving opioid agonist therapy: a register-based prospective cohort study in Norway and Sweden from 2015 to 2017

OBJECTIVES

To compare the use of benzodiazepines, z-hypnotics, gabapentinoids, opioids and centrally acting stimulants (CAS) among patients who had received opioid agonist therapy (OAT) in Norway and Sweden during the period 2015 - 2017.

DESIGN

A register-based prospective cohort study using information about dispensed drugs from the Norwegian Prescription Database and Swedish Prescribed Drug Register.

SETTING

Patients who were dispensed OAT opioids from pharmacies.

PARTICIPANTS

A total of 7176 Norwegian and 3591 Swedish patients on OAT were included.

OUTCOME MEASURES

The number and frequency of potentially addictive drugs dispensed were calculated for the two countries. The mean daily doses of dispensed benzodiazepines and z-hypnotics were summarised by calculating benzodiazepines in diazepam equivalents and z-hypnotics in zopiclone equivalents.

RESULTS

In 2017, 46% of patients in Norway, and 15% in Sweden, were dispensed a benzodiazepine. Moreover, 14% in Norway and 26% in Sweden received z-hypnotics. Gabapentinoids were dispensed to 10% of patients in Norway and 19% of patients in Sweden. In Norway, 6% and 12% of the patients received strong and weak non-OAT opioids, respectively, whereas in Sweden 10% were dispensed strong non-OAT opioids and 5% weak non-OAT opioids . CAS were dispensed to 4% in Norway and 18% in Sweden. The mean daily doses of benzodiazepines were 16 and 17 mg diazepam equivalents in Norway and Sweden, respectively. For z-hypnotics, the mean daily dose was 8 mg zopiclone equivalents in both countries. 'Benzodiazepines and z-hypnotics' was the most dispensed drug combination in 2017. Similar results were found in 2015 and 2016.

CONCLUSIONS

Nearly half of those patients who were dispensed an OAT opioid in Norway and Sweden were dispensed potentially addictive drugs. The differences identified between Norway and Sweden might be related to differences in eligibility guidelines and restrictions with respect to OAT.

Uptake and predictors of direct-acting antiviral treatment for hepatitis C among people receiving opioid agonist therapy in Sweden and Norway: a drug utilization study from 2014 to 2017

Background

Treatment with direct-acting antiviral agents (DAAs) offers an opportunity to eliminate hepatitis C virus (HCV) endemic among people who inject drugs (PWID) and people enrolled in opioid agonist therapy (OAT) programs. The objective of this study was to estimate and to compare HCV treatment uptake after the introduction of DAAs among patients receiving OAT in Sweden and Norway. We also aimed to evaluate predictors of DAAs treatment among OAT patients in both countries.

Methods

This observational study was conducted with data from The Swedish Prescribed Drug Register and The Norwegian Prescription Database. We studied dispensed medications to calculate HCV treatment among OAT patients from 2014 to 2017 in Sweden and Norway. HCV prevalence was estimated from primary and secondary sources. Dispensations of medicines from different therapeutic areas, which served as proxy for co-morbidities in 2017, were conditionally adjusted for age, gender, and OAT medications. Logistic regression was used to evaluate these parameters.

Results

In total 3529 individuals were identified with dispensed OAT in the Swedish cohort and 7739 individuals in the Norwegian cohort. HCV treatment was utilized by 407 persons in Sweden and 920 in Norway during the study period. Annual HCV and DAA treatment uptake increased in both countries. The estimated cumulative HCV treatment uptake at the end of 2017 was 31% in Norway and 28% in Sweden. DAA treatment was associated with increased age (aOR 1.8; 95% CI 1.0–3.2) and the dispensation of drugs used for diabetes (aOR 3.2; 95% CI 1.8–5.7) in Sweden. In Norway, lipid modifying agents and antibacterials were associated with decreased odds (aOR 0.4; 95%CI 0.2–0.9, aOR 0.8; 95%CI 0.6–1.0).

Conclusions

An increase in DAA treatment and HCV treatment uptake was observed among Swedish and Norwegian OAT patients whilst introducing new direct-acting antiviral treatment regimens. However, more than two thirds of the OAT population in Norway and Sweden were untreated at the beginning of 2018. A further scale-up is crucial in order to control and eliminate the HCV endemic among OAT patients.

Indirect Effects of Pneumococcal Childhood Vaccination in Individuals Treated With Immunosuppressive Drugs in Ambulatory Care: A Case-cohort Study

BACKGROUND

The extent to which iatrogenically-immunosuppressed individuals benefit from indirect effects of childhood vaccination with pneumococcal conjugate vaccines (PCVs) is unknown. We determined how the sequential introduction of PCV7 (2006) and PCV13 (2011) in the Norwegian childhood vaccination program has affected the epidemiology of invasive pneumococcal disease (IPD) in individuals treated with immunosuppressants in ambulatory care.

METHODS

We conducted a case-cohort study comprising 7926 IPD cases reported to the Norwegian Surveillance System for Communicable Diseases in 2005-2014 and 249998 individuals randomly selected from the National Registry in 2012. We defined immunosuppressive treatment groups based on dispensed prescriptions retrieved from the Norwegian Prescription Database. Incidences and age-adjusted relative risks (RR) were estimated.

RESULTS

IPD incidences decreased in all groups. The PCV13 incidence decreased by 5-12% across groups. The non-PCV13 incidence increased by 4-10%, mostly in individuals on chemotherapy (overlapping 95% confidence intervals). In the PCV13 era, the RR for IPD was highest (significant) and the percentage of cases caused by the polysaccharide vaccine PPV23 serotypes lowest (numerical) in individuals on chemotherapy (RR = 20.4, PPV23 = 52%), followed by individuals on corticosteroids (RR = 6.2, PPV23 = 64%), other immunosuppressants (RR = 5.6, PPV23 = 68%), and no immunosuppressants (RR = 1 [reference], PPV23 = 74%).

CONCLUSIONS

IPD incidences declined after PCV introduction in both immunocompetent and iatrogenically-immunosuppressed individuals, underscoring the benefit of childhood vaccination for the entire population. Still, individuals treated with immunosuppressants in ambulatory care are at increased risk of IPD caused by a more diverse group of serotypes.

Cardiovascular Safety of Prucalopride in Patients with Chronic Constipation: A Multinational Population-Based Cohort Study

Introduction

The serotonin 5-HT₄ receptor agonist prucalopride is approved in the European Union for the treatment of chronic constipation. This offered the unique opportunity to include real-world observational data on cardiovascular safety in the new drug application for approval of prucalopride in the USA.

Methods

This observational population-based cohort study (EUPAS9200) conducted in five data sources (three in the UK, one in Sweden, and one in Germany [which was subsequently excluded from the pooled analyses]) aimed to estimate the pooled adjusted incidence rate ratio for major adverse cardiovascular events (defined as hospitalization for non-fatal acute myocardial infarction or stroke, and in-hospital cardiovascular death) in adult initiators of prucalopride compared with initiators of polyethylene glycol 3350 (PEG) following a common protocol. Standardized incidence rates and incidence rate ratios of major adverse cardiovascular events were derived using propensity score stratification. Sensitivity analyses explored the impact of exposure definition, outcome categories, interim cancer, and unmeasured confounding.

Results

The pooled analyses included 5715 initiators of prucalopride and 29,372 initiators of PEG. Average duration of use was 175 days for prucalopride and 82 days for PEG. The pooled standardized incidence rate per 1000 person-years (95% confidence interval) of major adverse cardiovascular events was 6.57 (3.90–10.39) for patients initiating prucalopride and 10.24 (6.97–14.13) for PEG. The pooled adjusted incidence rate ratio for major adverse cardiovascular events was 0.64 (95% confidence interval 0.36–1.14). Results remained consistent in various sensitivity analyses.

Conclusions

The pooled incidence rate ratio estimate was consistent with no indication of an increased risk above the pre-specified safety threshold of 3.00 for major adverse cardiovascular events in patients with chronic constipation using prucalopride as compared with PEG.

Dispensation of attention deficit hyperactivity disorder (ADHD) medications in patients receiving opioid agonist therapy; a national prospective cohort study in Norway from 2015 to 2017

BACKGROUND

It is estimated that up to a third of patients on opioid agonist therapy (OAT) have attention deficit hyperactivity disorder (ADHD). Treatment by ADHD medication, including a centrally acting stimulant (CAS) or atomoxetine is one of the essential approaches. This study evaluates the use of dispensed ADHD medications in the Norwegian OAT population in the period from 2015 to 2017. Types and doses of ADHD medications, co-dispensations of other potentially addictive drugs like benzodiazepines, z-hypnotics, gabapentinoids, and non-OAT opioids, as well as direct-acting antivirals (DAA) against hepatitis C infection, are investigated.

METHODS

Information about all dispensed ADHD medication, OAT opioids, and the defined potentially addictive drugs were recorded from the Norwegian Prescription Database. Dispensation rates, the types, and the doses of dispensed ADHD medications were estimated by summarizing the number of dispensations, and the dispensed doses. Logistic regression analyses were employed to assess the associations between ADHD medication, and OAT opioid use, and dispensations of other potentially addictive drugs and DAAs against hepatitis C infection.

RESULTS

A total of 9235 OAT patients were included. The proportion of patients who were dispensed ADHD medication increased from 3.5 to 4.6% throughout the study period. The three most dispensed CAS were short- and intermediate-acting methylphenidate (55%), lisdexamphetamine (24%), and dexamphetamine (17%) in 2017. Buprenorphine, rather than methadone, as OAT opioid (adjusted odds ratio: 1.6, CI: 1.2-2.1) was associated with being dispensed ADHD medication. Among patients who received CAS and OAT opioids each calendar year, the dispensed doses of methylphenidate increased from 63 mg/day in 2015 to 76 mg/day in 2017 (p = 0.01). Sixty percent of patients receiving ADHD medications were also dispensed other addictive drugs concomitantly in 2017. Similar results were found in 2015 and 2016.

CONCLUSION

Co-prescription of ADHD medications was low among patients on OAT in Norway, considering a high prevalence of ADHD in this patient group. On the other hand, concurrent dispensations of multiple addictive drugs were common in this population. Understanding the underlying reasons for such prescribing is essential, and research on how to optimize ADHD medication of patients with ADHD receiving OAT is needed.

Prescribed opioid analgesic use developments in three Nordic countries, 2006–2017

Background and aims

While the Nordic countries have considerably stricter controls on opioid prescribing for chronic non-cancer pain than other countries, previous research has warned that prescription of strong opioids is increasing. This study examines consumption of and developments in dispensed prescribed opioids to individuals receiving ambulatory care from 2006 to 2017, using publicly available data from each of three Nordic countries’ national prescription registries.

Methods

Repeated, cross-sectional design. One-year prevalence of all dispensed prescribed opioids in ATC N02A group were reported for Norway, Denmark, and Sweden in the period 2006–2017 by gender. One-year prevalence of the weak opioids tramadol and codeine and the strong opioid oxycodone were then reported separately over this period for each country. The mean defined daily dose (DDD) per user per year, an estimate of the amount of opioids prescribed, was reported for each of the three opioids in 2016.

Results

Patterns of dispensed prescribed opioids differ greatly between 2006 and 2017 and between countries, with tramadol increasing in Norway, codeine declining across the board, and oxycodone increasing in all three countries. Norway exceeded Sweden and Denmark in prevalence of all dispensed prescribed opioids, with 12.1% of the female Norwegian population and 9.2% of the male Norwegian population dispensed at least one prescribed opioid as an outpatient in 2016. Norway’s high overall prevalence rates are tempered by dispensing the lowest mean doses of both weak opioids compared to Sweden. Similarly, Sweden dispenses the lowest mean doses of oxycodone but to the largest proportion of its population (3.0%).

Conclusions

Significant shifts have occurred in the dispensing of prescribed opioids in Norway, Sweden, and Denmark over the past 12 years. The increasing prevalence of oxycodone in all three countries should continue to be monitored. Prescription registries provide a wealth of publicly available data that can be used to monitor and to guide prescribing policies in a more knowledge-based direction.

Antidiabetic medication use during pregnancy: an international utilization study

OBJECTIVE

Diabetes in pregnancy and consequently the need for treatment with antidiabetic medication (ADM) has become increasingly prevalent. The prevalence and patterns of use of ADM in pregnancy from 2006 onward in seven different countries was assessed.

RESEARCH DESIGN AND METHODS

Data sources included individually linked data from the nationwide health registers in Denmark (2006-2016), Finland (2006-2016), Iceland (2006-2012), Norway (2006-2015), Sweden (2006-2015), state-wide administrative and claims data for New South Wales, Australia (2006-2012) and two US insurance databases: Medicaid Analytic eXtract (MAX; 2006-2012, public) and IBM MarketScan (2012-2015, private). The prevalence of ADM use was calculated as the proportion of pregnancies with at least one filled prescription of an ADM in the 90 days before pregnancy or within the three trimesters of pregnancy.

RESULTS

Prevalence of any ADM use in 5 279 231 pregnancies was 3% (n=147 999) and varied from under 2% (Denmark, Norway, and Sweden) to above 5% (Australia and US). Insulin was the most used ADM, and metformin was the most used oral hypoglycemic agent with increasing use over time in all countries. In 11.4%-62.5% of pregnancies with prepregnancy use, ADM (primarily metformin) was discontinued. When ADM treatment was initiated in late pregnancy for treatment of gestational diabetes mellitus, insulin was most often dispensed, except in the US, where glibenclamide was most often used.

CONCLUSIONS

Prevalence and patterns of use of ADM classes varied between countries and over time. While insulin remained the most common ADM used in pregnancy, metformin use increased significantly over the study period.

Mutations of DnaA-boxes in the oriR region increase replication frequency of the MiniR1-1 plasmid

BACKGROUND

The MiniR1-1 plasmid is a derivative of the R1 plasmid, a low copy cloning vector.

RESULTS

Nucleotide sequencing analysis shows that the MiniR1-1 plasmid is a 6316 bp circular double-stranded DNA molecule with an oriR1 (origin for replication). The plasmid carries the repA, tap, copA and bla genes, and genes for ORF1 and ORF2. MiniR1-1 contains eight DnaA-binding sites (DnaA-boxes). DnaA-box1 is in the oriR1 region and fully matched to the DnaA-box consensus sequence, and DnaA-box8, with one mismatch, is close to the copA gene. The presence of the MiniR1-1 plasmid leads to an accumulation of the D-period cells and an increase in cell size of slowly growing Escherichia coli cells, suggesting that the presence of MiniR1-1 delays cell division. Mutations in the MiniR1-1 DnaA-box1 and DnaA-box8 significantly increase the copy number of the plasmid and the mutations in DnaA-box1 also affect cell size. It is likely that titration of DnaA to DnaA-boxes negatively controls replication of the MiniR1-1 plasmid and delays cell division. Interestingly, DnaA weakly interacts with the initiator protein RepA in vivo.

CONCLUSION

DnaA regulates the copy number of MiniR1-1 as a negative factor through interacting with the RepA protein.

Trends in Resistance to Extended-Spectrum Cephalosporins and Carbapenems among Escherichia coli and Klebsiella spp. Isolates in a District in Western India during 2004-2014

Surveillance data on the level of resistant bacteria is needed to inform strategies to reduce the development and spread of antibiotic resistance. The aim of this study was to determine the non-susceptibility trends to extended-spectrum cephalosporins and carbapenems among Escherichia coli and Klebsiella spp. isolates from the district of Nashik in Western India during the period 2004-2014. Antibacterial susceptibility testing of clinical isolates was performed using Kirby-Bauer disc diffusion method to determine inhibitory zone diameters. The change in proportions of non-susceptible bacteria over calendar time was investigated with spline transformations in a logistic regression model. For the extended-spectrum cephalosporins, the proportions of non-susceptible E. coli and Klebsiella spp. isolates were above 78.4% and 84.9% throughout the study period, respectively. E. coli and Klebsiella spp. isolates exhibited carbapenem non-susceptibility levels as high as 76.9% and 84.1% respectively. The proportions of extended-spectrum betalactamase (ESBL)-producing isolates ranged from 38.3-85.9% in E. coli and from 45.1-93.1% in Klebsiella spp. Significantly higher proportions of non-susceptible and ESBL-producing isolates were found among isolates from inpatients compared to isolates from outpatients for both E. coli and Klebsiella spp. (p < 0.050). The high proportions of non-susceptible isolates observed show that there is great need to focus on optimal use of antibiotics to reduce the development of antibiotic resistance.

Self-reported data on medicine use in the Norwegian Mother and Child cohort study compared to data from the Norwegian Prescription Database

<p><em>Aims:</em> To study information on prescribed drug use (opioids, antidepressants and benzodiazepines (BZD)) recorded in the Norwegian Prescription Database (NorPD) and to compare this information with selfreported drug use among pregnant women in the Norwegian Mother and Child Cohort Study (MoBa).</p><p><em>Materials and methods:</em> The study population consisted of 28 479 women who participated in MoBa and who answered all questionnaires in pregnancy and whose pregnancy started after 1 March 2004. Data on dispensed drugs in NorPD were extracted for three different time windows: a) the pregnancy period, b) 30 days prior to pregnancy in addition to pregnancy, c) 60 days prior to pregnancy in addition to pregnancy. Data on self- reported drug use in MoBa were used as the reference standard in the validity analysis. Sensitivity and specificity were calculated.</p><p><em>Results:</em> Sensitivity of drug use as recorded in NorPD for the pregnancy period was highest for antidepressants (66.9%) and BZD-antiepileptics (100%) and lowest for BZD-anxiolytics (44.8%) and BZDhypnotics (27.8%). Expansion of the time windows for dispensed drugs in the NorPD to include intervals 30 and 60 days before pregnancy led to higher sensitivity, but lower specificity of all classes of drugs. For opioids, sensitivity increased from 48.8% to 53.6%, while specificity decreased from 98.7 to 97.6%. For antidepressants and BZD-anxiolytics, specificity decreased for both from 99.7 to 99.4%.</p><p><em>Conclusion:</em> Using self-reported data as reference standard, the prescription data provides valid information on current exposures to BZD-antiepileptics and antidepressants in pregnant women if time windows are selected with adequate consideration depending on the investigated problem. However, validity is lower for other benzodiazepines and opioids.</p>

DNA compaction in the early part of the SOS response is dependent on RecN and RecA

The nucleoids of undamaged Escherichia coli cells have a characteristic shape and number, which is dependent on the growth medium. Upon induction of the SOS response by a low dose of UV irradiation an extensive reorganization of the nucleoids occurred. Two distinct phases were observed by fluorescence microscopy. First, the nucleoids were found to change shape and fuse into compact structures at midcell. The compaction of the nucleoids lasted for 10-20 min and was followed by a phase where the DNA was dispersed throughout the cells. This second phase lasted for ~1 h. The compaction was found to be dependent on the recombination proteins RecA, RecO and RecR as well as the SOS-inducible, SMC (structural maintenance of chromosomes)-like protein RecN. RecN protein is produced in high amounts during the first part of the SOS response. It is possible that the RecN-mediated 'compact DNA' stage at the beginning of the SOS response serves to stabilize damaged DNA prior to recombination and repair.

Single transmembrane peptide DinQ modulates membrane-dependent activities

The functions of several SOS regulated genes in Escherichia coli are still unknown, including dinQ. In this work we characterize dinQ and two small RNAs, agrA and agrB, with antisense complementarity to dinQ. Northern analysis revealed five dinQ transcripts, but only one transcript (+44) is actively translated. The +44 dinQ transcript translates into a toxic single transmembrane peptide localized in the inner membrane. AgrB regulates dinQ RNA by RNA interference to counteract DinQ toxicity. Thus the dinQ-agr locus shows the classical features of a type I TA system and has many similarities to the tisB-istR locus. DinQ overexpression depolarizes the cell membrane and decreases the intracellular ATP concentration, demonstrating that DinQ can modulate membrane-dependent processes. Augmented DinQ strongly inhibits marker transfer by Hfr conjugation, indicating a role in recombination. Furthermore, DinQ affects transformation of nucleoid morphology in response to UV damage. We hypothesize that DinQ is a transmembrane peptide that modulates membrane-dependent activities such as nucleoid compaction and recombination.

Exposure of the bacterium Escherichia coli to DNA damaging agents induces the SOS response, which up-regulates gene functions involved in numerous cellular processes such as DNA repair, cell division, and replication. Most of the SOS regulated genes in E. coli have been characterized, but still there are several genes of unknown function. One of these uncharacterized genes is dinQ. In this work we characterize dinQ and two novel small RNAs, agrA and agrB, that regulate expression of dinQ. The DinQ peptide is localized in the inner membrane as a single transmembrane peptide of 27 amino acids. Small proteins of less than 50 amino acids are important in cellular processes such as regulation, signalling, and antibacterial action. Here we demonstrate that DinQ modulates recombination and transformation of nucleoid morphology in response to UV damage. Our results provide new insights into small hydrophobic peptides that could regulate important DNA metabolic processes dependent on the inner membrane of the cell.

Growth rate dependent numbers of SeqA structures organize the multiple replication forks in rapidly growing Escherichia coli

When the bacterium Escherichia coli is grown in rich medium, the replication and segregation periods may span two, three or four generations and cells may contain up to 24 replication forks. The newly synthesized, hemimethylated DNA at each fork is bound by SeqA protein. The SeqA-DNA structures form distinct foci that can be observed by immunofluorescence microscopy. The numbers of foci were lower than the numbers of replication forks indicating fork co-localization. The extent of co-localization correlated with the extent of replication cycle overlap in wild-type cells. No abrupt increase in the numbers of foci occurred at the time of initiation of replication, suggesting that new replication forks bind to existing SeqA structures. Manipulations with replication control mechanisms that led to extension or reduction of the replication period and number of forks, did not lead to changes in the numbers of SeqA foci per cell. The results indicate that the number of SeqA foci is not directly governed by the number of replication forks, and supports the idea that new DNA may be 'captured' by existing SeqA structures.

Specific N-terminal interactions of the Escherichia coli SeqA protein are required to form multimers that restrain negative supercoils and form foci

The Escherichia coli SeqA protein binds preferentially to hemimethylated DNA and is required for inactivation (sequestration) of newly formed origins. A mutant SeqA protein, SeqA4 (A25T), which is deficient in origin sequestration in vivo, was found here to have lost the ability to form multimers, but could bind as dimers with wild-type affinity to a pair of hemimethylated GATC sites. In vitro, binding of SeqA dimers to a plasmid first generates a topology change equivalent to a few positive supercoils, then the binding leads to a topology change in the "opposite" direction, resulting in a restraint of negative supercoils. Binding of SeqA4 mutant dimers produced the former effect, but not the latter, showing that a topology change equivalent to positive supercoiling is caused by the binding of single dimers, whereas restraint of negative supercoils requires multimerization via the N-terminus. In vivo, mutant SeqA4 protein was not capable of forming foci observed by immunofluorescence microscopy, showing that N-terminus-dependent multimerization is required for building SeqA foci. Overproduction of SeqA4 led to partially restored initiation synchrony, indicating that origin sequestration may not depend on efficient higher-order multimerization into foci, but do require a high local concentration of SeqA.