ObjectiveTo assess the association between the use of sodium glucose cotransporter 2 (SGLT2) inhibitors and seven serious adverse events of current concern.DesignRegister based cohort study.SettingSweden and Denmark from July 2013 to December 2016.ParticipantsA propensity score matched cohort of 17 213 new users of SGLT2 inhibitors (dapagliflozin, 61%; empagliflozin, 38%; canagliflozin, 1%) and 17 213 new users of the active comparator, glucagon-like peptide 1 (GLP1) receptor agonists.Main outcome measuresThe primary outcomes were lower limb amputation, bone fracture, diabetic ketoacidosis, acute kidney injury, serious urinary tract infection, venous thromboembolism, and acute pancreatitis, as identified from hospital records. Hazard ratios and 95% confidence intervals were estimated by using Cox proportional hazards models.ResultsUse of SGLT2 inhibitors, as compared with GLP1 receptor agonists, was associated with an increased risk of lower limb amputation (incidence rate 2.7 v 1.1 events per 1000 person years, hazard ratio 2.32, 95% confidence interval 1.37 to 3.91) and diabetic ketoacidosis (1.3 v 0.6, 2.14, 1.01 to 4.52) but not with bone fracture (15.4 v 13.9, 1.11, 0.93 to 1.33), acute kidney injury (2.3 v 3.2, 0.69, 0.45 to 1.05), serious urinary tract infection (5.4 v 6.0, 0.89, 0.67 to 1.19), venous thromboembolism (4.2 v 4.1, 0.99, 0.71 to 1.38) or acute pancreatitis (1.3 v 1.2, 1.16, 0.64 to 2.12).ConclusionsIn this analysis of nationwide registers from two countries, use of SGLT2 inhibitors, as compared with GLP1 receptor agonists, was associated with an increased risk of lower limb amputation and diabetic ketoacidosis, but not with other serious adverse events of current concern.

ObjectiveTo investigate whether oral fluoroquinolone use is associated with an increased risk of aortic aneurysm or dissection.DesignNationwide historical cohort study using linked register data on patient characteristics, filled prescriptions, and cases of aortic aneurysm or dissection.SettingSweden, July 2006 to December 2013.Participants360 088 treatment episodes of fluoroquinolone use (78%ciprofloxacin) and propensity score matched comparator episodes of amoxicillin use (n=360 088).Main outcome measuresCox regression was used to estimate hazard ratios for a first diagnosis of aortic aneurysm or dissection, defined as admission to hospital or emergency department for, or death due to, aortic aneurysm or dissection, within 60 days from start of treatment.ResultsWithin the 60 day risk period, the rate of aortic aneurysm or dissection was 1.2 cases per 1000 person years among fluoroquinolone users and 0.7 cases per 1000 person years among amoxicillin users. Fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection (hazard ratio 1.66 (95% confidence interval 1.12 to 2.46)), with an estimated absolute difference of 82 (95% confidence interval 15 to 181) cases of aortic aneurysm or dissection by 60 days per 1 million treatment episodes. In a secondary analysis, the hazard ratio for the association with fluoroquinolone use was 1.90 (1.22 to 2.96) for aortic aneurysm and 0.93 (0.38 to 2.29) for aortic dissection.ConclusionsIn a propensity score matched cohort, fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection. This association appeared to be largely driven by aortic aneurysm.

Azithromycin use was not associated with an increased risk of death from cardiovascular causes in a general population of young and middle-aged adults. (Funded by the Danish Medical Research Council.).

Objective To assess the risk of serious adverse events after vaccination of adolescent girls with quadrivalent human papillomavirus (qHPV) vaccine.Design Register based cohort study. Setting Denmark and Sweden, October 2006 to December 2010.Participants 997 585 girls aged 10-17, among whom 296 826 received a total of 696 420 qHPV vaccine doses.Main outcome measures Incident hospital diagnosed autoimmune, neurological, and venous thromboembolic events (53 different outcomes) up to 180 days after each qHPV vaccine dose. Only events with at least five vaccine exposed cases were considered for further assessment. Rate ratios adjusted for age, country, calendar year, and parental country of birth, education, and socioeconomic status were estimated, comparing vaccinated and unvaccinated person time. For outcomes where the rate ratio was significantly increased, we regarded three criteria as signal strengthening: analysis based on 20 or more vaccine exposed cases (reliability), rate ratio 3.0 or more (strength), and significantly increased rate ratio in country specific analyses (consistency). We additionally assessed clustering of events in time and estimated rate ratios for a risk period that started on day 181.Results Among the 53 outcomes, at least five vaccine exposed cases occurred in 29 and these were analysed further. Whereas the rate ratios for 20 of 23 autoimmune events were not significantly increased, exposure to qHPV vaccine was significantly associated with Behcet's syndrome, Raynaud's disease, and type 1 diabetes. Each of these three outcomes fulfilled only one of three predefined signal strengthening criteria. Furthermore, the pattern of distribution in time after vaccination was random for all three and the rate ratios for these outcomes in the period from day 181 after vaccination were similar to the rate ratios in the primary risk period. The rate ratios for five neurological events were not significantly increased and there were inverse associations with epilepsy (rate ratio 0.66, 95% confidence interval 0.54 to 0.80) and paralysis (0.56, 0.35 to 0.90). There was no association between exposure to qHPV vaccine and venous thromboembolism (0.86, 0.55 to 1.36).Conclusions This large cohort study found no evidence supporting associations between exposure to qHPV vaccine and autoimmune, neurological, and venous thromboembolic adverse events. Although associations for three autoimmune events were initially observed, on further assessment these were weak and not temporally related to vaccine exposure. Furthermore, the findings need to be interpreted considering the multiple outcomes assessed.

In this Danish nationwide study, exposure to TNF-α antagonists among patients with IBD was not associated with an increased risk of cancer over a median follow-up of 3.7 years among those exposed. An increased risk associated with longer-term accumulated doses and follow-up cannot be excluded.

Objective To estimate the risks of major congenital malformations in the offspring of mothers who are underweight (body mass index (BMI) <18.5), overweight (BMI 25 to <30), or in obesity classes I (BMI 30 to <35), II (35 to <40), or III (≥40) compared with offspring of normal weight mothers (BMI 18.5 to <25) in early pregnancy. Design Population based cohort study. Setting Nationwide Swedish registries. Participants 1 243 957 liveborn singleton infants from 2001 to 2014 in Sweden. Data on maternal and pregnancy characteristics were obtained by individual record linkages. Exposure Maternal BMI at the first prenatal visit. Main outcome measures Offspring with any major congenital malformation, and subgroups of organ specific malformations diagnosed during the first year of life. Risk ratios were estimated using generalised linear models adjusted for maternal factors, sex of offspring, and birth year. Results A total of 43 550 (3.5%) offspring had any major congenital malformation, and the most common subgroup was for congenital heart defects (n=20 074; 1.6%). Compared with offspring of normal weight mothers (risk of malformations 3.4%), the proportions and adjusted risk ratios of any major congenital malformation among the offspring of mothers with higher BMI were: overweight, 3.5% and 1.05 (95% confidence interval 1.02 to 1.07); obesity class I, 3.8% and 1.12 (1.08 to 1.15), obesity class II, 4.2% and 1.23 (1.17 to 1.30), and obesity class III, 4.7% and 1.37 (1.26 to 1.49). The risks of congenital heart defects, malformations of the nervous system, and limb defects also progressively increased with BMI from overweight to obesity class III. The largest organ specific relative risks related to maternal overweight and increasing obesity were observed for malformations of the nervous system. Malformations of the genital and digestive systems were also increased in offspring of obese mothers. Conclusions Risks of any major congenital malformation and several subgroups of organ specific malformations progressively increased with maternal overweight and increasing severity of obesity. For women who are planning pregnancy, efforts should be encouraged to reduce adiposity in those with a BMI above the normal range.

We did not detect a significant association between maternal use of SSRIs during pregnancy and autism spectrum disorder in the offspring. On the basis of the upper boundary of the confidence interval, our study could not rule out a relative risk up to 1.61, and therefore the association warrants further study. (Funded by the Danish Health and Medicines Authority.).

Febrile seizures represent a recognized serious adverse event following measles, mumps, and rubella (MMR) vaccination. We conducted a series of genome-wide association scans comparing children with MMR-related febrile seizures, children with febrile seizures unrelated to vaccination, and controls with no history of febrile seizures. Two loci were distinctly associated with MMR-related febrile seizures, harboring the interferon-stimulated gene IFI44L (rs273259; P = 5.9×10−12 vs. controls; P =1.2×10−9 vs. MMR-unrelated febrile seizures) and the measles virus receptor CD46 (rs1318653; P = 9.6×10−11 vs. controls; P = 1.6×10−9 vs. MMR-unrelated febrile seizures). Furthermore, four loci were associated with febrile seizures in general implicating the sodium channel genes SCN1A (rs6432860; P = 2.2×10−16) and SCN2A (rs3769955; P = 3.1×10−10), a TMEM16 family gene (TMEM16C; rs114444506; P = 3.7×10−20), and a region associated with magnesium levels (12q21.33; rs11105468; P = 3.4×10−11). Finally, functional relevance of TMEM16C was demonstrated with electrophysiological experiments in wild-type and knockout rats.