Marie Lund

Cancer risk among patients with myotonic muscular dystrophy.

CONTEXT Myotonic muscular dystrophy (MMD) is an autosomal-dominant multisystem neuromuscular disorder characterized by unstable nucleotide repeat expansions. Case reports have suggested that MMD patients may be at increased risk of malignancy, putative risks that have never been quantified. OBJECTIVE To quantitatively evaluate cancer risk in patients with MMD, overall and by sex and age. DESIGN, SETTING, AND PARTICIPANTS We identified 1658 patients with an MMD discharge diagnosis in the Swedish Hospital Discharge Register or Danish National Patient Registry between 1977 and 2008. We linked these patients to their corresponding cancer registry. Patients were followed up from date of first MMD-related inpatient or outpatient contact to first cancer diagnosis, death, emigration, or completion of cancer registration. MAIN OUTCOME MEASURES Risks of all cancers combined and by anatomic site, stratified by sex and age. RESULTS One hundred four patients with an inpatient or outpatient discharge diagnosis of MMD developed cancer during postdischarge follow-up. This corresponds to an observed cancer rate of 73.4 per 10,000 person-years in MMD vs an expected rate of 36.9 per 10,000 person-years in the general Swedish and Danish populations combined (standardized incidence ratio [SIR], 2.0; 95% CI, 1.6-2.4). Specifically, we observed significant excess risks of cancers of the endometrium (n = 11; observed rate, 16.1/10,000 person-years; SIR, 7.6; 95% CI, 4.0-13.2), brain (n = 7; observed rate, 4.9/10,000 person-years; SIR, 5.3; 95% CI, 2.3-10.4), ovary (n = 7; observed rate, 10.3/10,000 person-years; SIR, 5.2; 95% CI, 2.3-10.2), and colon (n = 10; observed rate, 7.1/10,000 person-years; SIR, 2.9; 95% CI, 1.5-5.1). Cancer risks were similar in women and men after excluding genital organ tumors (SIR, 1.9; 95% CI, 1.4-2.5, vs SIR, 1.8; 95% CI, 1.3-2.5, respectively; P = .81 for heterogeneity; observed rates, 64.5 and 47.7 per 10,000 person-years in women and men, respectively). The same pattern of cancer excess was observed first in the Swedish and then in the Danish cohorts, which were studied sequentially and initially analyzed independently. CONCLUSION Patients with MMD identified from the Swedish and Danish patient registries were at increased risk of cancer both overall and for selected anatomic sites.

Use of macrolides in mother and child and risk of infantile hypertrophic pyloric stenosis: nationwide cohort study

Objective To assess the association between use of macrolide antibiotics in mothers and infants from pregnancy onset until 120 days after birth and infantile hypertrophic pyloric stenosis (IHPS). Design Nationwide register based cohort study. Setting Denmark, 1996-2011. Participants 999 378 liveborn singletons and linked individual level information on macrolide prescriptions (maternal use during pregnancy, n=30 091; maternal use after birth, n=21 557; use in infants, n=6591), surgery for IHPS, and potential confounders. Main outcome measures Surgery for IHPS by three categories of macrolide use: in mothers during pregnancy, in mothers after birth, and in infants after birth. Results 880 infants developed IHPS (0.9 cases per 1000 births). Compared with infants with no use of macrolides, the adjusted rate ratio for IHPS in infants with use of macrolides during days 0 to 13 after birth was 29.8 (95% confidence interval 16.4 to 54.1) and during days 14 to 120 was 3.24 (1.20 to 8.74); the corresponding absolute risk differences were 24.4 (95% confidence interval 13.0 to 44.1) and 0.65 (0.06 to 2.21) cases per 1000 infants exposed to macrolides, respectively. The rate ratio for maternal use of macrolides for days 0 to 13 after birth was 3.49 (1.92 to 6.34) and for days 14 to 120 was 0.70 (0.26 to 1.90); the corresponding absolute risk differences were 2.15 (0.82 to 4.64) and −0.11 (−0.26 to 0.31). The rate ratios for maternal use of macrolides during pregnancy were 1.02 (0.65 to 1.59) for weeks 0 to 27 and 1.77 (0.95 to 3.31) for weeks 28 to birth; the corresponding absolute risk differences were 0.01 (−0.31 to 0.50) and 0.67 (−0.06 to 2.02). Conclusions Treatment of young infants with macrolide antibiotics was strongly associated with IHPS and should therefore only be administered if potential treatment benefits outweigh the risk. Maternal use of macrolides during the first two weeks after birth was also associated with an increased risk of IHPS. A possible association was also found with use during late pregnancy.

Cardiac involvement in myotonic dystrophy: a nationwide cohort study

AIMS To quantify the association between myotonic dystrophy (DM) and cardiac disease in a nationwide cohort. METHODS AND RESULTS We identified a nationwide cohort of 1146 DM patients (period 1977-2011) using the National Patient Registry (NPR) and a subcohort of 485 patients who had undergone genetic testing for DM1. Information on incident cardiac diseases was obtained from the NPR. We estimated standardized incidence ratios (SIRs) of cardiac disease compared with the background population, overall and according to selected diagnostic subgroups (cardiomyopathy, heart failure, conduction disorders, arrhythmias, and device implantation). In the DM cohort, SIR for any cardiac disease was 3.42 [95% confidence interval (CI) 3.01-3.86]; for a cardiac disease belonging to the selected subgroups 6.91 (95% CI: 5.93-8.01) and for other cardiac disease 2.59 (95% CI: 2.03-3.25). For a cardiac disease belonging to the selected subgroups, the risk was particularly high in the first year after DM diagnosis [SIR 15.4 (95% CI: 10.9-21.3)] but remained significantly elevated in subsequent years [SIR 6.07 (95% CI: 5.11-7.16]). The risk was higher in young cohort members [e.g. 20-39 years: SIR 18.1 (95% CI: 12.3-25.8)] compared with older [e.g. 60-79 years: SIR 3.99 (95% CI: 2.98-5.23)] but remained significantly increased in all age categories. Results were similar in separate analyses of the genetically confirmed DM1 patients. CONCLUSION Myotonic dystrophy is strongly associated with cardiac disease. The risk is pronounced in the young and remains elevated throughout life, stressing the importance of lifelong cardiac follow-up from time of DM diagnosis.

Clinical Implications of P-Glycoprotein Modulation in Drug–Drug Interactions

Drug–drug interactions (DDIs) occur commonly and may lead to severe adverse drug reactions if not handled appropriately. Considerable information to support clinical decision making regarding potential DDIs is available in the literature and through various systems providing electronic decision support for healthcare providers. The challenge for the prescribing physician lies in sorting out the evidence and identifying those drugs for which potential interactions are likely to become clinically manifest. P-glycoprotein (P-gp) is a drug transporting protein that is found in the plasma membranes in cells of barrier and elimination organs, and plays a role in drug absorption and excretion. Increasingly, P-gp has been acknowledged as an important player in potential DDIs and a growing body of information on the role of this transporter in DDIs has become available from research and from the drug approval process. This has led to a clear need for a comprehensive review of P-gp-mediated DDIs with a focus on highlighting the drugs that are likely to lead to clinically relevant DDIs. The objective of this review is to provide information for identifying and interpreting evidence of P-gp-mediated DDIs and to suggest a classification for individual drugs based on both in vitro and in vivo evidence (substrates, inhibitors and inducers). Further, various ways of handling potential DDIs in clinical practice are described and exemplified in relation to drugs interfering with P-gp.

Risk of cancer in relatives of patients with myotonic dystrophy: a population-based cohort study.

Myotonic dystrophies (DM) are autosomal dominantly inherited neuromuscular disorders caused by unstable nucleotide repeat expansions. DM and cancer have been associated, but the pathogenesis behind the association remains unclear. It could relate to derived effects of the DM genotype in which case non‐DM relatives of DM patients would not be expected to be at increased risk of cancer. To elucidate this, a population‐based cohort study investigating risk of cancer in relatives of DM patients was conducted.

Concomitant use of low-dose methotrexate and NSAIDs and the risk of serious adverse events among patients with rheumatoid arthritis

Case reports and pharmacokinetic studies have suggested that concomitant use of low‐dose methotrexate and nonsteroidal anti‐inflammatory drugs (NSAIDs) may be associated with increased risk of methotrexate toxicity. This study aimed to investigate the risk of serious adverse events associated with concomitant use of low‐dose methotrexate and NSAIDs, compared with use of methotrexate alone, among patients with rheumatoid arthritis.

Genome-wide association study of Hirschsprung disease detects a novel low-frequency variant at the RET locus

Hirschsprung disease (HSCR) is a congenital disorder with a population incidence of ~1/5000 live births, defined by an absence of enteric ganglia along variable lengths of the colon. HSCR genome-wide association studies (GWAS) have found common associated variants at RET, SEMA3, and NRG1, but they still fail to explain all of its heritability. To enhance gene discovery, we performed a GWAS of 170 cases identified from the Danish nationwide pathology registry with 4717 controls, based on 6.2 million variants imputed from the haplotype reference consortium panel. We found a novel low-frequency variant (rs144432435), which, when conditioning on the lead RET single-nucleotide polymorphism (SNP), was of genome-wide significance in the discovery analysis. This conditional association signal was replicated in a Swedish HSCR cohort with discovery plus replication meta-analysis conditional odds ratio of 6.6 (P = 7.7 × 10−10; 322 cases and 4893 controls). The conditional signal was, however, not replicated in two HSCR cohorts from USA and Finland, leading to the hypothesis that rs144432435 tags a rare haplotype present in Denmark and Sweden. Using the genome-wide complex trait analysis method, we estimated the SNP heritability of HSCR to be 88%, close to estimates based on classical family studies. Moreover, by using Lasso (least absolute shrinkage and selection operator) regression we were able to construct a genetic HSCR predictor with a area under the receiver operator characteristics curve of 76% in an independent validation set. In conclusion, we combined the largest collection of sporadic Hirschsprung cases to date (586 cases) to further elucidate HSCR’s genetic architecture.

Comparative effectiveness and safety of apixaban, dabigatran, and rivaroxaban in patients with non-valvular atrial fibrillation

BACKGROUND The comparative effectiveness and safety of individual direct oral anticoagulants (DOACs) in clinical practice is largely unknown. The study objectives were to compare effectiveness and safety of DOACs in patients with non-valvular atrial fibrillation (NVAF). METHODS Based on nationwide registers we established a population-based historical cohort study of 12,638 new users of standard dose DOACs (apixaban 5 mg twice daily, dabigatran 150 mg twice daily and rivaroxaban 20 mg once daily) with NVAF in Denmark, July 2013 to March 2016. Patients were matched on propensity scores in a 1:1 ratio comparing apixaban vs. dabigatran (for a total of 6470 patients), apixaban vs. rivaroxaban (7352 patients), and rivaroxaban vs. dabigatran (5440 patients). Hazard ratios (HRs) for stroke or systemic embolism (effectiveness outcome) and major bleeding (safety outcome) were estimated. RESULTS In propensity-matched comparisons of the risk of stroke or systemic embolism, the HRs were 1.27 (95% confidence interval [CI], 0.82-1.96) for apixaban vs. dabigatran, 1.25 (95% CI, 0.87-1.79) for apixaban vs. rivaroxaban, and 1.17 (95% CI, 0.69-1.96) for rivaroxaban vs. dabigatran. For the risk of major bleeding, the HRs were 0.94 (95% CI, 0.62-1.41) for apixaban vs. dabigatran, 0.88 (95% CI, 0.64-1.22) for apixaban vs. rivaroxaban, and 1.35 (95% CI, 0.91-2.00) for rivaroxaban vs. dabigatran. CONCLUSIONS Among patients with NVAF in routine clinical practice, there were no statistically significant differences in risk of stroke or systemic embolism or major bleeding in propensity-matched comparisons between apixaban, dabigatran, and rivaroxaban used in standard doses. While analyses indicate that more than moderate differences can be excluded, smaller differences cannot be ruled out.

Concomitant use of statins and macrolide antibiotics and risk of serious renal events: A nationwide cohort study

BACKGROUND Concomitant use of statins metabolized by the cytochrome P450 isoenzyme 3A4 (CYP3A4) and CYP3A4-inhibiting macrolide antibiotics may confer an increased risk of renal failure. We investigated the risk of serious renal events associated with concomitant use of such statins and such macrolides. METHODS In a nationwide register-based cohort study (Denmark, 1999-2017), we identified 906,423 new users (40-79 years old), of CYP3A4-metabolized statins. In propensity score-matched analyses, we compared the risk of serious renal events during episodes of concomitant use of statins and CYP3A4-inhibiting macrolides (n = 71,521) with episodes of use of statins alone (n = 285,488) and, as the primary analysis, with episodes of concomitant use of statins and an active comparator (penicillin V, n = 139,446). Using proportional hazards regression, we estimated hazard ratios (HRs) for serious renal events within 30 days of start of follow-up. RESULTS We observed 25 serious renal events during concomitant use of statins and macrolides (incidence rate [IR], 4.9 per 1000 person-years). Compared with use of statins alone (50 events; IR, 2.3), concomitant use of statins and macrolides was associated with a significantly increased risk of serious renal events (HR 2.16, 95% confidence interval [CI] 1.33, 3.49). Compared with concomitant use of statins and penicillin V (52 events; IR, 5.3), however, we observed no increased risk (HR 0.93, 95% CI 0.58, 1.49). CONCLUSIONS In this nationwide cohort study concomitant use of statins and macrolides was not associated with a significantly increased risk of serious renal events.

Authors' reply to de Vries.

We thank de Vries for his valuable comments about our study.1 2 He states that the finding of an incidence rate ratio of 29.8 (95% confidence interval 16.4 to 54.1) for exposure from infant macrolide use during the first two weeks after birth is “either a very strong association or too good to be true.” This association …