Lars Pedersen

Aarhus University Hospital, Aarhus, Central Jutland, Denmark

Are you Lars Pedersen?

Claim your profile

Publications (205)1390.36 Total impact

  • No preview · Article · Jan 2016 · Stroke

  • No preview · Article · Jan 2016 · European Heart Journal: Acute Cardiovascular Care
  • Source

    Full-text · Article · Jan 2016 · Clinical Epidemiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The prognostic impact of preadmission use of calcium channel blockers (CCBs) and beta blockers (BBs) on stroke mortality remains unclear. We aimed to examine whether preadmission use of CCBs or BBs was associated with improved short-term mortality following ischemic stroke, intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). We conducted a nationwide population-based cohort study using Danish medical registries. We identified all patients with a first-time inpatient diagnosis of stroke between 2004 and 2012 and their comorbidities. We defined CCB/BB use as current use, former use, or non-use. Current use was further classified as new or long-term use. We used Cox regression modeling to compute 30-day mortality rate ratios (MRRs) with 95% confidence intervals (CIs), controlling for potential confounders. We identified 100,043 patients with a first-time stroke. Of these, 83,736 (83.7%) patients had ischemic stroke, 11,779 (11.8%) had ICH, and 4,528 (4.5%) had SAH. Comparing current users of CCBs or BBs with non-users, we found no association with mortality for ischemic stroke [adjusted 30-day MRR = 0.99 (95% CI: 0.94-1.05) for CCBs and 1.01 (95% CI: 0.96-1.07) for BBs], ICH [adjusted 30-day MRR = 1.05 (95% CI: 0.95-1.16) for CCBs and 0.95 (95% CI: 0.87-1.04) for BBs], or SAH [adjusted 30-day MRR = 1.05 (95% CI: 0.85-1.29) for CCBs and 0.89 (95% CI: 0.72-1.11) for BBs]. Former use of CCBs or BBs was not associated with mortality. Preadmission use of CCBs or BBs was not associated with 30-day mortality following ischemic stroke, ICH, or SAH.
    Full-text · Article · Dec 2015 · BMC Neurology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background & aims: Sessile serrated adenomas/polyps (SSA/Ps) and traditional serrated adenomas (TSAs) are now distinguished from hyperplastic polyps and recognized as precursors to colorectal cancer (CRC). We studied CRC risks associated with serrated polyps. Methods: Using Danish databases (1977-2009), we conducted a nationwide population-based case-control study nested within individuals who had received colonoscopies (n=272,342), and identified 2045 CRC cases and 8105 CRC-free individuals (controls). For each case and control, we identified the first colorectal polyp(s) biopsied or excised during or after initial colonoscopy, and obtained tissue blocks for hyperplastic lesions. Four expert pathologists reviewed these lesions using current terminology for serrated polyps. We used logistic regression to compute odds ratios (ORs) to associate risk of CRC with polyp type and estimated absolute risks by multiplying the risk in patients with no polyps by these ORs. Results: Seventy-nine cases and 142 controls had SSA/Ps (OR, 3.07; 95% confidence interval [CI], 2.30-4.10). SSA/Ps with cytology markers of dysplasia were associated with a particularly high OR (4.76; 95% CI, 2.59-8.73). Women with SSA/P had higher risk for CRC than men with SSA/P (OR for women, 5.05; 95% CI, 3.05-8.37 vs OR for men, 2.18; 95% CI, 1.24-3.82); patients with SSA/P proximal to the splenic flexure had the highest risk for CRC (OR, 12.42; 95% CI, 4.88-31.58). The OR for CRC was 4.84 in the 14 cases vs 17 controls with TSAs (95% CI, 2.36-9.93), 2.51 in the 757 cases vs 1698 controls with conventional adenomas (95% CI, 2.25-2.80), and 1.30 in the 55 cases vs 235 controls with hyperplastic polyps (95% CI, 0.96-1.77). The 10 year risk for CRC was 4.4% for patients with SSA/P with dysplasia, 4.5% for patients with TSAs, and 2.3% for patients with conventional adenomas. Conclusion: Patients with SSA/P or TSA are at increased risk for CRC; their level of risk is similar to or higher than that of patients with conventional adenomas.
    No preview · Article · Dec 2015 · Gastroenterology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mycosis fungoides (MF) and parapsoriasis display increased inflammation, which may be associated with increased risk of arterial cardiovascular events. The aim of this Danish nationwide population-based cohort study was to assess the relative risk (RR) of acute myocardial infarction (AMI) or stroke in patients with MF and parapsoriasis. In patients with MF, the RR of AMI or stroke was 1.0 (95% confidence interval (95% CI) 0.7-1.3). In the second half of the study period, the RR was 1.8 (95% CI 1.1-2.9) during the first 5 years of follow-up. In men with parapsoriasis, the RR of AMI or stroke was 1.7 (95% CI 1.1-2.7) within the first 5 years of follow-up, whereas the RR of AMI during the first 5 years of follow-up was 2.0 (95% CI 1.2-3.4). In conclusion, patients with MF and parapsoriasis have an increased RR of AMI or stroke within the first 5 years of follow-up.
    No preview · Article · Nov 2015 · Acta Dermato-Venereologica
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: The Danish National Patient Registry (DNPR) is one of the world's oldest nationwide hospital registries and is used extensively for research. Many studies have validated algorithms for identifying health events in the DNPR, but the reports are fragmented and no overview exists. Objectives: To review the content, data quality, and research potential of the DNPR. Methods: We examined the setting, history, aims, content, and classification systems of the DNPR. We searched PubMed and the Danish Medical Journal to create a bibliography of validation studies. We included also studies that were referenced in retrieved papers or known to us beforehand. Methodological considerations related to DNPR data were reviewed. Results: During 1977-2012, the DNPR registered 8,085,603 persons, accounting for 7,268,857 inpatient, 5,953,405 outpatient, and 5,097,300 emergency department contacts. The DNPR provides nationwide longitudinal registration of detailed administrative and clinical data. It has recorded information on all patients discharged from Danish nonpsychiatric hospitals since 1977 and on psychiatric inpatients and emergency department and outpatient specialty clinic contacts since 1995. For each patient contact, one primary and optional secondary diagnoses are recorded according to the International Classification of Diseases. The DNPR provides a data source to identify diseases, examinations, certain in-hospital medical treatments, and surgical procedures. Long-term temporal trends in hospitalization and treatment rates can be studied. The positive predictive values of diseases and treatments vary widely (<15%-100%). The DNPR data are linkable at the patient level with data from other Danish administrative registries, clinical registries, randomized controlled trials, population surveys, and epidemiologic field studies - enabling researchers to reconstruct individual life and health trajectories for an entire population. Conclusion: The DNPR is a valuable tool for epidemiological research. However, both its strengths and limitations must be considered when interpreting research results, and continuous validation of its clinical data is essential.
    Preview · Article · Nov 2015 · Clinical Epidemiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Bisphosphonate use has been associated with increased risk of fatal stroke. We examined the association between preadmission use of oral bisphosphonates and 30-day mortality following hospitalization for stroke. Patients and methods: We conducted a nationwide population-based cohort study using medical databases and identified all patients in Denmark with a first-time hospitalization for stroke between 1 July 2004 and 31 December 2012 (N=100,043). Cox regression was used to compute adjusted hazard ratios as a measure of 30-day mortality rate ratios (MRRs) associated with bisphosphonate current use (prescription filled within 90 days prior to the stroke) or recent use (prescription filled in the 90-180 days prior to the stroke). Current use was further classified as new or long-term use. Results: We found 51,982 patients with acute ischemic stroke (AIS), 11,779 with intracerebral hemorrhage (ICH), 4,528 with subarachnoid hemorrhage (SAH), and 31,754 with unspecified stroke. Absolute 30-day mortality risks were increased among current vs nonusers of bisphosphonates for AIS (11.9% vs 8.5%), ICH (43.2% vs 34.5%), SAH (40.3% vs 23.2%), and unspecified strokes (18.8% vs 14.0%). However, in adjusted analyses, current bisphosphonate use did not increase 30-day mortality from AIS (MRR, 0.87; 95% confidence interval [CI]: 0.75, 1.01); ICH (MRR, 1.05; 95% CI: 0.90, 1.23); SAH (MRR, 1.15; 95% CI: 0.83, 1.61); or unspecified stroke (MRR, 0.94; 95% CI: 0.81, 1.09). Likewise, no association with mortality was found for recent use. Adjusted analyses by type of bisphosphonate showed increased mortality following stroke among new users of etidronate (MRR, 1.40; 95% CI: 1.01, 1.93) and reduced mortality after AIS among current users of alendronate (MRR, 0.87; 95% CI: 0.74, 1.02). Conclusion: We found no overall evidence that preadmission bisphosphonate use increases 30-day mortality following stroke.
    Full-text · Article · Sep 2015 · Clinical Epidemiology

  • No preview · Article · Sep 2015 · Diabetologia
  • [Show abstract] [Hide abstract]
    ABSTRACT: Disclosures: All authors have completed the ICMJE Form for Disclosure of Potential Conflicts of Interest. None of the authors have any personal conflict of interest of relevance to the manuscript. Centre for Pharmacoepidemiology at Karolinska institutet and the Department of Clinical Epidemiology at Aarhus University Hospital receive financial support from several pharmaceutical companies. The study was independently developed from a post-authorization safety study commissioned by the European Medicines Agency through Janssen Biotech. The company did not participate in study design, interpretation of the data or the decision to submit the manuscript.
    No preview · Article · Sep 2015

  • No preview · Article · Sep 2015 · Annals of Neurology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aims of this work were to assess glycaemic control in metformin users receiving their first add-on glucose-lowering therapy and to examine the real-life effectiveness of different add-on drugs. We carried out a population-based cohort study using healthcare databases in northern Denmark during 2000-2012. We included 4,734 persons who initiated metformin monotherapy and added another glucose-lowering drug within 3 years. Attainment of recommended HbA1c goals within 6 months of add-on was investigated, using Poisson regression analysis adjusted for age, sex, baseline HbA1c, diabetes duration, complications and Charlson Comorbidity Index. Median metformin treatment duration at intensification was 12 months (interquartile range [IQR] 4-23 months) and pre-intensification HbA1c was 8.0% (IQR 7.2-9.2%) (64 [IQR 55-77] mmol/mol). Median HbA1c dropped 1.2% (13 mmol/mol) with a sulfonylurea (SU) add-on, 0.8% (9 mmol/mol) with a dipeptidyl peptidase-4 (DPP-4) inhibitor, 1.3% (14 mmol/mol) with a glucagon-like peptide-1 (GLP-1) receptor agonist, 0.9% (10 mmol/mol) with other non-insulin drugs and 2.4% (26 mmol/mol) with insulin. Compared with SU add-on, attainment of HbA1c <7% (<53 mmol/mol) was higher with GLP-1 receptor agonists (adjusted RR [aRR] 1.10; 95% CI 1.01, 1.19) and lower with DPP-4 inhibitors (aRR 0.94; 95% CI 0.89, 0.99), other drugs (aRR 0.86; 95% CI 0.77, 0.96) and insulin (aRR 0.88; 95% CI 0.77, 0.99). The proportion of metformin add-on users who attained HbA1c <7% (<53 mmol/mol) increased from 46% in 2000-2003 to 59% in 2010-2012, whereas attainment of HbA1c <6.5% (<48 mmol/mol) remained 30% among patients aged <65 years without comorbidities. Among early type 2 diabetes patients receiving their first metformin add-on treatment, HbA1c reduction with different non-insulin drugs is similar to, and comparable with, that observed in randomised trials, yet 41% do not achieve HbA1c <7% (<53 mmol/mol) within 6 months.
    Full-text · Article · Aug 2015 · Diabetologia

  • No preview · Article · Aug 2015 · Annals of Neurology
  • Source

    Full-text · Article · Jul 2015 · Diabetes care
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Few data exist on the occurrence of metastatic basal cell carcinoma (mBCC). To identify all cases of mBCC in Denmark over a 14-year period. We searched the Danish National Patient Registry covering all Danish hospitals, the Danish Cancer Registry, the National Pathology Registry and the Causes of Death Registry during the period 1997 to 2010 for potential cases of mBCC registered according to the International classification of diseases ICD-10 and the International Systemized Nomenclature of Medicine (SNOMED). We identified 126,627 patients with a history of primary basal cell carcinoma (BCC) in the registries during the 14-year study period. Using case identifications from the four registries, a total of 170 potential mBCC cases were identified. However, after a pathology review, only five cases could be confirmed, of which three were basosquamous carcinomas. The 14-year cumulative incidence proportion of mBCC was 0.0039% (95% CI 0.0016-0.0083) among individuals with a history of previous BCC (n = 126,627) and 0.0001% (95% CI 0.0000-0.0002) in the general population. MBCC is a rare disease and only a small proportion of potential cases identified in automated clinical databases or registries can be confirmed by pathology and medical record review.
    Full-text · Article · Jun 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It is unknown if splanchnic venous thrombosis is a marker of occult cancer and a prognostic factor for cancer survival. Using Danish medical registries, we conducted a nationwide cohort study including all patients with first-time splanchnic venous thrombosis (n=1,191) between 1994 and 2011. We followed the patients for subsequent cancer diagnoses and calculated absolute risks and standardized incidence ratios (SIRs). We formed a matched comparison cohort of cancer patients without splanchnic venous thrombosis, and assessed the prognostic impact of splanchnic venous thrombosis on cancer survival by applying the Kaplan-Meier methods and Cox regression. We followed the patients for a median of 1.6 years, and found that splanchnic venous thrombosis was marker of occult cancer. The three-month cancer risk was 8.0% and the SIR was 33 (95% confidence interval: 27-40), compared to the general population. Increased risk was mainly found for liver cancer (risk=3.5%; SIR=1805), pancreatic cancer (risk=1.5%; SIR=256), and myeloproliferative neoplasms (risk=0.7%; SIR=764). The overall SIR remained twofold increased after one or more years of follow-up. Splanchnic venous thrombosis was also a prognostic factor for survival in patients with liver and pancreatic cancer. The clinical impact may be more thorough diagnostic work-up in patients presenting with splanchnic venous thrombosis. Copyright © 2015 American Society of Hematology.
    Preview · Article · Jun 2015 · Blood
  • Source

    Full-text · Article · Jun 2015 · Epidemiology (Cambridge, Mass.)
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed to validate a predefined algorithm for osteonecrosis of the jaw (ONJ) among cancer patients in the Danish National Registry of Patients and to assess the nature of clinical information recorded in medical charts of ONJ patients. We identified potential ONJ cases recorded in 2005-2010 among cancer patients at the hospital Departments of Oral and Maxillofacial Surgery (DOMS) in three Danish regions, using a set of codes from the International Classification of Diseases, 10th revision (ICD-10). We abstracted DOMS charts of the potential cases, had the ONJ status adjudicated by an expert ONJ adjudication committee (ONJAC), and computed positive predictive values. For patients with ONJAC-confirmed ONJ, we abstracted the charts for information on ONJ clinical course. Sensitivity of the algorithm was computed using a separate sample of 101 known ONJ cases accrued in 2005-2011. We identified 212 potential ONJ cases, of which 197 (93%) had charts available for abstraction. Eighty-three potential cases were confirmed by ONJAC, with a positive predictive value of 42% (95% confidence interval [CI] 35%-49%). DOMS charts of these 83 cases contained complete information on ONJ clinical course. Information about antiresorptive treatment was recorded for 84% of the patients. Among the 101 known ONJ cases, 74 had at least one prespecified ICD-10 code recorded in the Danish National Registry of Patients within ±90 days of the ONJ diagnosis (sensitivity 73%; 95%CI [64%-81%]). The predefined algorithm is not adequate for monitoring ONJ in pharmacovigilance studies. Additional case-finding approaches, coupled with adjudication, are necessary to estimate ONJ incidence accurately. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    No preview · Article · May 2015 · Pharmacoepidemiology and Drug Safety
  • [Show abstract] [Hide abstract]
    ABSTRACT: Parkinson's disease (PD) may be caused by an enteric neurotropic pathogen entering the brain through the vagal nerve, a process that may take over 20 years. We investigated the risk of PD in patients who underwent vagotomy, and hypothesized that truncal vagotomy is associated with a protective effect, while super-selective vagotomy has a minor effect. We constructed cohorts of all patients in Denmark who underwent vagotomy during 1977-1995 and a matched general population cohort, by linking Danish registries. We used Cox regression to compute hazard ratios (HRs) for PD and corresponding 95% confidence intervals [CIs], adjusting for potential confounders. Risk of PD was decreased in patients who underwent truncal [HR = 0.85, 95% CI= 0.56-1.27; follow-up of >20 years: HR = 0.58, 95% CI: 0.28-1.20] compared to super-selective vagotomy. Risk of PD was also decreased following truncal vagotomy when compared to the general population cohort [overall adjusted HR = 0.85, 95% CI 0.63-1.14; follow-up >20 years, adjusted HR = 0.53 [95% CI: 0.28-0.99]. In patients who underwent super-selective vagotomy, risk of PD was similar to the general population [HR = 1.09, 95% CI: 0.84-1.43; follow-up of >20 years: HR = 1.16, 95% CI: 0.80-1.70]. The statistical precision of the risk estimates was limited. Results were consistent after external adjustment for unmeasured confounding by smoking. Full truncal vagotomy is associated with a decreased risk for subsequent PD, suggesting that the vagal nerve may be critically involved in the pathogenesis of PD. This article is protected by copyright. All rights reserved. © 2015 American Neurological Association.
    No preview · Article · May 2015 · Annals of Neurology
  • [Show abstract] [Hide abstract]
    ABSTRACT: To examine time trends in early glycemic control in patients with type 2 diabetes in real life between 2000 and 2012. We used population-based medical databases to ascertain achieved glycemic control associated with initial glucose-lowering treatment in patients with incident type 2 diabetes in Northern Denmark. Success in reaching glycated hemoglobin (HbA1c ) goals within 3-6 months was examined by regression analysis. Among 38,418 patients, 91% started with oral glucose-lowering drugs in monotherapy. Metformin initiation increased from 32% in 2000-2003 to 90% of all patients in 2010-2012. Pre-treatment HbA1c levels decreased from 8.9% (interquartile range (IQR), 7.6%-10.7%) in 2000-2003 to 7.0% (IQR, 6.5%-8.1%) in 2010-2012. More patients achieved an HbA1c target <7% (<53 mmol/mol) in 2010-2012 than in 2000-2003 (80% vs. 60%, adjusted relative risk (aRR) = 1.10 [95% CI 1.08-1.13]), and more achieved an HbA1c <6.5% (<48 mmol/mol) (53% vs. 37%, aRR = 1.07 [95% CI: 1.03-1.11]), with similar success rates observed among patients <65 years without comorbidities. Achieved HbA1c levels were similar for different initiation therapies, with reductions of 0.8% (from 7.3% to 6.5%) on metformin, 1.5% (8.1% to 6.6%) on sulfonylurea, 4.0% (10.4% to 6.4%) on non-insulin combination therapies, and 3.8% (10.3% to 6.5%) on insulin monotherapy. Pre-treatment HbA1c in incident type 2 diabetes patients has decreased substantially, likely related to earlier detection and treatment in accordance with changing guidelines. Achieved glycemic control has improved, but 20% of patients still do not attain an HbA1c <7% within the first 6 months of initial treatment. This article is protected by copyright. All rights reserved.
    No preview · Article · Apr 2015 · Diabetes Obesity and Metabolism

Publication Stats

5k Citations
1,390.36 Total Impact Points


  • 2001-2015
    • Aarhus University Hospital
      • Department of Clinical Epidemiology
      Aarhus, Central Jutland, Denmark
  • 2000-2015
    • Aarhus University
      • • Department of Clinical Epidemiology
      • • Department of Epidemiology and Social Medicine
      Aarhus, Central Jutland, Denmark
  • 2008-2011
    • Boston University
      • Department of Epidemiology
      Boston, Massachusetts, United States
  • 2001-2009
    • Aalborg University Hospital
      Ålborg, North Denmark, Denmark
  • 2004
    • Odense University Hospital
      Odense, South Denmark, Denmark