Biomedical subjects

Per K Andersen

Publications and source records attributed to Per K Andersen.

13 recordsLinked to original sources

PubMed2007

No increased risk of developing Alzheimer disease in patients with glaucoma.

PURPOSE: To investigate whether primary open-angle glaucoma (POAG) is associated with increased risk of developing Alzheimer disease (AD). METHODS: In a nationwide case register linkage study of patients with hospital admission or outpatient contact during the period from 1977 to 2001 in Denmark, the rate of subsequent AD for patients with a diagnosis of POAG was compared with the rate for patients with primary angle-closure glaucoma (PACG), cataract, and osteoarthritis (OA) and with the rate for the general population. RESULTS: A total of 11,721 patients with a diagnosis of POAG (including normal tension glaucoma), 5975 patients with PACG, 162,640 patients with cataract, and 230,208 patients with OA were identified in the registers. Patients with POAG did not have increased rate of subsequent AD compared to patients with PACG, cataract, or OA or compared with the general population. CONCLUSIONS: POAG was not associated with increased risk of developing AD. It cannot be excluded that this negative finding is due to diagnostic misclassification as register data were used.

Aged↗

PubMed2006

The risk of affective disorders in patients with adrenocortical insufficiency.

OBJECTIVE: To investigate the risk of affective disorders among patients hospitalised with adrenocortical insufficiency in the study period: 1977-1999. METHOD: Using data from Danish registers, two study cohorts were identified by their ICD diagnoses at discharge from hospital: one comprising all patients with a first hospital admission with an index diagnosis of adrenocortical insufficiency; the other a control cohort comprising all patients with a first hospital admission with an index diagnosis of osteoarthritis. Subsequent admissions to psychiatric hospital wards with discharge ICD diagnoses of affective disorders were used as events of interest. Rates of readmission were estimated using Poisson regression models in survival analyses. Age, sex, duration of time after index discharge, and calendar time were included as co-variables. The primary analysis included all patients with adrenocortical insufficiency. Thereafter, the subgroup of patients with primary adrenocortical insufficiency (Addison's disease) was investigated separately in a secondary analysis. RESULTS: A study sample of 989 patients with adrenocortical insufficiency and 124,854 patients with osteoarthritis was identified. Eight hundred and fifty-two patients were subsequently readmitted with a diagnosis of affective disorder. Patients with adrenocortical insufficiency had a 2.68 (95% CI: 1.62-4.42) times greater rate of affective disorders and a 2.12 (95% CI: 1.16-3.86) times greater rate of depressive disorder when compared with the rate for patients with osteoarthritis. Patients with Addison's disease had a 2.14 (95% CI: 1.14-4.03) times greater rate of affective disorders, and a 1.71 (95% CI: 0.81-3.63) times greater rate of depressive disorder compared with the rate of patients with osteoarthritis. CONCLUSION: Patients with adrenocortical insufficiency may be at increased risk of developing severe affective disorders. Conventional replacement therapy with hydrocortisone may not be sufficient to ensure the psychiatric well-being of these patients.

Addison Disease↗

PubMed2006

Do antidepressants precipitate youth suicide?: a nationwide pharmacoepidemiological study.

The association between treatment with Selective serotonin reuptake inhibitors (SSRIs) and suicide in children and adolescents on the individual and ecological level were examined in a nationwide Danish pharmacoepidemiological register-linkage study including all persons aged 10-17 years treated with antidepressants during the period 1995-1999 (n=2,569) and a randomly selected control population (n=50,000). A tripartite approach was used. In Part 1, changes in youth suicide and use of antidepressants were examined. In Part 2, we made an assessment of youth suicide characteristics. In Part 3, we analysed the relative risk (RR) of suicide according to antidepressant treatment corrected for psychiatric hospital contact to minimize the problem of confounding by indication. The use of SSRIs among children and adolescents increased substantially during the study period, but the suicide rate remained stable (Part 1). Among 42 suicides nationally aged 10-17 years at death, none was treated with SSRIs within 2 weeks prior to suicide (Part 2). There was an increased rate of suicide associated with SSRIs (RR=4.47), however, not quite significant (95% CI: 0.95-20.96), when adjusted for severity of illness (Part 3). Conclusively, we were not able to identify an association between treatment with SSRIs and completed suicide among children and adolescents.

Adolescent↗

PubMed2006

Do antidepressants prevent suicide?

As in many developed countries, the use of antidepressants in Denmark has been substantially increasing during recent years, coinciding with a decreasing suicide rate. We aimed to investigate the relationship between treatment with antidepressants and suicide on individualized data from a nationwide study comprising an observational cohort study with linkage of registers of all prescribed antidepressants and recorded suicides in Denmark during the period 1995-99. A total of 438 625 patients who purchased at least one prescription of antidepressants and 1073 862 individuals from the general population were included in the study. Patients who continued treatment with selective serotonin reuptake inhibitors (SSRIs) (i.e. who purchased SSRIs twice or more) had a decreased rate of suicide compared with patients who purchased SSRIs once only [rate ratio (RR)=0.63; 95% confidence interval (CI)=0.56-0.71]. Furthermore, the rate of suicide decreased consistently with the number of prescriptions. Similarly, among patients treated with newer antidepressants other than SSRIs, the rate of suicide was decreased compared with the rate for patients who purchased other newer antidepressants once only (RR=0.70; 95% CI=0.52-0.94). Continued antidepressant treatment with SSRIs or other newer antidepressants is found to be associated with a reduced risk of suicide.

Adolescent↗

PubMed2005

Sudden cardiovascular death following myocardial infarction: the importance of left ventricular systolic dysfunction and congestive heart failure.

BACKGROUND: To study the prognostic information of congestive heart failure (CHF) and left ventricular systolic dysfunction regarding sudden and non-sudden cardiovascular death (SCD and non-SCD) in patients with acute myocardial infarction (MI), as this may indicate the potential benefit of implantable defibrillators. METHODS: Data from consecutive patients with acute MI screened in 1990-92 for the TRAndolapril Cardiac Evaluation (TRACE) study were entered into a registry. A total of 5502 patients were alive 30 days after the MI and were followed for up to 4 years with respect to cause of death. SCD was defined as cardiovascular death within 1 h of onset of symptoms. An echocardiography was performed 1-6 days after the admission and evaluated centrally using the wall motion index (WMI). RESULTS: Half of the patients had CHF and 17% of the patients had WMI < or =1.0 (corresponding to an ejection fraction < or =0.30). During follow-up 431 patients died from SCD and 606 from non-SCD. The risk ratios for SCD and non-SCD associated with WMI < or =1.0 were 3.17 and 2.95, transient CHF 2.01 and 1.46, and permanent CHF 3.71 and 4.42, respectively. No risk factor was a specific marker of SCD or non-SCD. The 3-year probability of SCD was 7.9% for patients with transient CHF, 13.3% for permanent CHF, and 15.5% for WMI < or =1.0. CONCLUSIONS: CHF and low WMI identify a relevant proportion of patients with MI who are at high absolute risk of SCD. This study indicates the relevance of defibrillators in consecutive post-MI patients with left ventricular dysfunction or clinical signs of heart failure.

Aged↗

PubMed2005

A class of goodness of fit tests for a copula based on bivariate right-censored data.

The copula of a bivariate distribution, constructed by making marginal transformations of each component, captures all the information in the bivariate distribution about the dependence between two variables. For frailty models for bivariate data the choice of a family of distributions for the random frailty corresponds to the choice of a parametric family for the copula. A class of tests of the hypothesis that the copula is in a given parametric family, with unspecified association parameter, based on bivariate right censored data is proposed. These tests are based on first making marginal Kaplan-Meier transformations of the data and then comparing a non-parametric estimate of the copula to an estimate based on the assumed family of models. A number of options are available for choosing the scale and the distance measure for this comparison. Significance levels of the test are found by a modified bootstrap procedure. The procedure is used to check the appropriateness of a gamma or a positive stable frailty model in a set of survival data on Danish twins.

Algorithms↗

PubMed2005

Increased risk of developing affective disorder in patients with hypothyroidism: a register-based study.

BACKGROUND: Links between thyroid function and depression have been noted in many contexts. We assessed whether hospitalization with hypothyroidism was a risk factor for developing affective disorder. METHODS: We conducted a prospective cohort study using historical data from Danish registers. The observational period was 1977-1999. Three study cohorts were identified: all patients with a first hospital admittance with the resulting index discharge diagnoses hypothyroidism, osteoarthritis, or nontoxic goiter. A later hospitalization with a resulting discharge diagnosis of affective disorder was used as event of interest, and rates of readmission were estimated and compared using competing risk models in survival analyses. FINDINGS: We identified 165,307 patients discharged with an index diagnosis. In the observational period, 1041 events occurred. An index diagnosis of hypothyroidism was associated with an increased risk of hospitalization with affective disorder when compared to the control diseases. The risk of hospitalization with affective disorder was greatest in the first year after index hospitalization. CONCLUSION: Patients hospitalized with hypothyroidism have a greater risk of readmission with depression or bipolar disorder than control patients. This renders epidemiologic support to theories linking thyroid dysfunction with mood disturbances.

Adult↗

PubMed2005

Increased risk of affective disorder following hospitalisation with hyperthyroidism - a register-based study.

OBJECTIVE: The pattern of comorbidity between thyroid disorders and affective disorder is not fully known. We assessed whether hospitalisation with hyperthyroidism was a risk factor for hospitalisation with affective disorder and evaluated the temporal relationship between these events. DESIGN: A historical prospective cohort study comparing patients with hyperthyroidism with patients with non-toxic goitre or osteoarthritis, using existing data from Danish registers. The observational period was from 1 January 1977 to 31 December 1999. METHODS: Three study cohorts were identified by their International Classification of Diseases (ICD) diagnoses at discharge from hospital and consisted of all patients with a first hospital admission with the index diagnoses of hyperthyroidism, osteoarthritis, or non-toxic goitre. Later admissions to psychiatric hospital wards with discharge ICD diagnoses of affective disorder were used as events of interest. Rates of re-admission were estimated using competing risks models in survival analyses. Age, sex, substance abuse, and calendar time were included as co-variables. RESULTS: A study sample of 183 647 patients discharged with an index diagnosis was identified. In total 1374 events occurred in the observational period. An index diagnosis of hyperthyroidism was associated with an increased risk of hospitalisation with affective disorder for both sexes and for all age-bands investigated, compared with the other index diagnoses. The risk was greatest in the first six months after index hospitalisation (rate ratio, 95% confidence interval: 3.60 (2.58-5.04)). CONCLUSIONS: Patients hospitalised with hyperthyroidism are at greater risk of re-admission with depressive disorder or bipolar disorder than control patients. This suggests that hyperthyroidism is associated with long-term mood disturbances.

Adult↗

PubMed2004

SAS macros for estimation of the cumulative incidence functions based on a Cox regression model for competing risks survival data.

When considering competing risks survival data, the cause specific hazard functions are often modelled by the proportional hazards Cox regression model. First, we present how to estimate the parameters in this model when some of the covariates are allowed to have exactly the same effect on several causes of failure. In many cases, the focus is not on the parameter estimates, but rather on the probability of observing a failure from a specific cause for individuals with specified covariate values. These probabilities, the cumulative incidences, are not simple functions of the parameters and they are, so far, not provided by the standard statistical software packages. We present two SAS macros: a SAS macro named CumInc for estimation of the cumulative incidences and a SAS macro named CumIncV for estimation of the cumulative incidences and the variances of the estimated cumulative incidences. The use of the macros is demonstrated through an example.

Proportional Hazards Models↗

PubMed2003

Nonlinear relation between alcohol intake and high-density lipoprotein cholesterol level: results from the Copenhagen City Heart Study.

BACKGROUND: It has been suggested that the level of high-density lipoprotein cholesterol (HDL-C) in the blood can be used as a marker of recent alcohol intake. However, before using HDL-C as a predictor of alcoholism, the relation between alcohol intake and HDL-C in the entire range of consumption must be explored. Most studies model the relation between alcohol intake and HDL-C linearly, although a threshold effect is expected. The objective of this study was to evaluate the shape of the relation between intake of alcohol and HDL-C and to determine whether there are differential effects of beer, wine, and spirits on HDL-C and whether they remain after adjusting for total alcohol. METHOD: The relation between alcohol intake and HDL-C was investigated by means of generalized additive models using data from the Copenhagen City Heart Study. RESULTS: A nonlinear effect of alcohol improved the model fit significantly, and the nonlinearity of alcohol was highly significant in both men and women. The relation was concave: HDL-C was stable in men and women who drank more than approximately 35 and 20 drinks per week, respectively. We found a significant nonlinear term of wine on HDL-C in men after adjustment for total alcohol intake. CONCLUSIONS: There was a concave relation between alcohol intake and HDL-C, indicating a threshold effect of alcohol on HDL-C. The association between wine and HDL-C in men after adjusting for total alcohol intake may be due to residual lifestyle confounding.

Adult↗

PubMed2002

Major depressive disorder in Parkinson's disease: a register-based study.

OBJECTIVE: To investigate whether patients with Parkinson's disease (PD) were at an increased risk of developing major depression compared with patients having other medical illnesses with a comparable degree of disability. METHOD: Case register linkage study of Danish Psychiatric Central Register (DPCR)and Danish National Hospital Register (DNHR). Three study cohorts were identified: all patients with PD, osteoarthritis, and diabetes. The rate of discharge diagnosis of depression on re-admission was estimated using competing risks models in survival analyses. The rates for patients with PD were compared with those of patients with osteoarthritis, and diabetes. RESULTS: The study sample identified 211 245 patients in the hospital registers with one of the index diagnoses. An increased incidence of developing depression was found for women and men throughout their lifetime when this incidence was compared with the control groups. CONCLUSION: The findings support the hypothesis that depression in patients with PD is a consequence of brain dysfunction.

Adult↗

PubMed2002

Preoperative endoscopic stent placement before pancreaticoduodenectomy: a meta-analysis of the effect on morbidity and mortality.

BACKGROUND: Pancreaticoduodenectomy is the only potentially curative treatment for peripapillary pancreatic tumors. However, postoperative morbidity and mortality are high, and different approaches have been tried to improve results, such as preoperative biliary drainage in patients with jaundice. This meta-analysis investigated the effect on postoperative outcome of preoperative biliary drainage by endoscopic biliary stent placement in patients who are jaundiced and who have peripapillary pancreatic tumors. METHODS: A Medline search for the period 1985 to 2001 was performed. Eight retrospective studies and 2 prospective randomized controlled trials were included. Selection criteria for the primary analysis were as follows: patients with peripapillary pancreatic cancer, endoscopic stent placement versus no stent, radical surgery, and assessment of postoperative morbidity and mortality. A secondary analysis included both radical and palliative surgery. RESULTS: In the primary analysis, 337 patients underwent preoperative endoscopic biliary stent placement, and 412 patients had no endoscopic biliary stent placement (controls). The overall odds ratio for postoperative complications (stent vs. no stent) is estimated as 0.79: 95% CI [0.36, 1.73] and the estimated odds ratio for postoperative mortality is 0.81: 95% CI [0.33, 1.99]. In the secondary analysis, 1008 patients underwent preoperative EBS versus 720 control patients. The odds ratio for postoperative complications in this analysis was 0.93: 95% CI [0.65, 1.33] and for postoperative mortality is 1.12: 95% CI [0.62, 2.01]. CONCLUSION: No evidence was found of either a positive or adverse effect of preoperative endoscopic biliary stent placement on the outcome of surgery in patients with pancreatic cancer.

Confidence Intervals↗

PubMedDate not supplied

Energy adjustment methods applied to alcohol analyses.

When alcohol consumption is related to outcome, associations between alcohol type and health outcomes may occur simply because of the ethanol in the beverage type. When one analyzes the consequences of consumption of beer, wine, and spirits, the total alcohol intake must therefore be taken into account. However, owing to the linear dependency between total alcohol intake and the alcohol content of each beverage type, the effects cannot be separated from each other or from the effect of ethanol. In nutritional epidemiology, similar problems regarding intake of macronutrients and total energy intake have been addressed, and four methods have been proposed to solve the problem: energy partition, standard, density, and residual. The aim of this study was to evaluate the usefulness of the energy adjustment methods in alcohol analyses by using coronary heart disease as an example. Data obtained from the Copenhagen City Heart Study were used. The standard and energy partition methods yielded similar results for continuous, and almost similar results for categorical, alcohol variables. The results from the density method differed, but nevertheless were concordant with these. Beer and wine drinkers, in comparison with findings for nondrinkers, had lower risk of coronary heart disease. Except for the case of men drinking beer, the effect seemed to be associated with drinking one drink per week. The standard method derives influence of substituting alcohol types at constant total alcohol intake and complements the estimates of adding consumption of a particular alcohol type to the total intake. For most diseases, the effect of ethanol predominates over that of substances in the beverage type, which makes the density method less relevant in alcohol analyses.

Adult↗