Showing papers by "Anders H. Riis published in 2013"

Registration of acute medical hospital admissions in the Danish National Patient Registry: a validation study

Abstract: BACKGROUND In recent years, the number of acute hospital admissions has increased and this has imposed both organizational and financial strains on the health care system. Consequently, it is of crucial importance that we have valid data on admission types in the administrative databases in order to provide data for health care planning and research. OBJECTIVE To examine the validity of registration of acute admissions among medical patients in the Danish National Patient Registry (DNPR) using medical record reviews as the reference standard. METHODS We used the nationwide DNPR to identify a sample of 160 medical patients admitted to a hospital in the North Denmark Region during 2009. Data on admission type was obtained from the DNPR and confirmed by a medical record review. We computed positive predictive values, sensitivity, and specificity including 95% confidence intervals (CI) using the medical record review as the reference standard. RESULTS Among the 160 medical inpatients identified in the DNPR, 128 were registered with an acute admission, and 32 were registered with a nonacute admission. Two medical records could not be located. Thus, the analyses included 158 medical patients. Among the 127 patients registered with acute admission, 124 were confirmed to be correctly classified. Correspondingly, 28 of the 31 patients with a registered nonacute admission were confirmed to be correctly classified. The overall positive predictive value of the acute admissions among medical patients was 97.6% (95% CI, 93.8%-99.3%). Sensitivity was 97.6% (95% CI, 93.8%-99.3%) and specificity was 90.3% (95% CI, 76.4%-97.2%). CONCLUSION The registration of acute admission among medical patients in the DNPR has high validity.

Correlates of menstrual cycle characteristics among nulliparous Danish women

Abstract: Objective We examined the association between lifestyle factors and menstrual cycle characteristics among nulliparous Danish women aged 18-40 years who were participating in an Internet-based prospective cohort study of pregnancy planners. Methods We used cross-sectional data collected at baseline to assess the association of age, body mass index (BMI), physical activity, alcohol and caffeine consumption, and smoking with the prevalence of irregular cycles, short (≤25 days) and long (≥33 days) cycles, and duration and amount of menstrual flow. We used log-binomial and multinomial logistic regression to estimate prevalence ratios and 95% confidence intervals. Results Low physical activity and heavy alcohol consumption were associated with an increased prevalence of irregular periods. High BMI, smoking, and caffeine and alcohol consumption were related to an increased prevalence of short menstrual cycles and heavy menstrual bleeding. Women in their mid-to-late thirties had shorter and lighter menstrual flow, but a lower prevalence of irregular cycles, compared with women 18-25 years of age. Discussion In this study, increased age, high BMI, and sedentary behavior were associated with menstrual-pattern irregularities. These factors may influence the balance and level of endogenous hormones conducive to optimal menstrual function.

Pre-gravid oral contraceptive use and time to pregnancy: a Danish prospective cohort study

Abstract: STUDY QUESTION: Is there an association between oral contraceptive (OC) use (age at the start of use duration of use ethinylestradiol dose and generation) and time to pregnancy (TTP)? SUMMARY ANSWER: Although OC use was associated with a transient delay in the return of fertility we found no evidence that long-term OC use deleteriously affects fecundability. WHAT IS KNOWN ALREADY: Studies using retrospective data on TTP have reported a short-term delay in the return of fertility after OC use. However little is known about the long-term OC use and TTP. STUDY DESIGN SIZE DURATION: Data were derived from Snart Gravid.dk a prospective cohort study that enrolled participants from 1 June 2007 to 31 May 2010. The final study population consisted of 3727 women. PARTICIPANTS SETTING METHODS: Eligible women were Danish pregnancy planners aged 18-40 years who completed a baseline questionnaire and bimonthly follow-up questionnaires until conception or for 12 months whichever came first. Cohort retention was 80%. We used proportional probability regression models to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs) with adjustment for potential confounders. MAIN RESULTS AND ROLE OF CHANCE: Compared with barrier methods the use of OCs as the last contraception method before attempting to conceive was associated with a short-term delay in return of fertility (FR = 0.87 95% CI: 0.79-0.96). Longer term OC use was associated with higher fecundability: compared with OC use for less than 2 years; FRs were 0.98 (95% CI: 0.83-1.15) for 2-3 years 1.16 (95% CI: 0.98-1.37) for 4-5 years 1.10 (95% CI: 0.93-1.29) for 6-7 years 1.17 (95% CI: 0.99-1.38) for 8-9 years 1.23 (95% CI: 1.04-1.46) for 10-11 years and 1.28 (95% CI: 1.07-1.53) for >/=12 years of OC use. LIMITATIONS REASONS FOR CAUTION: Because this was a non-experimental study where study volunteers provided information about their history of contraceptive use at baseline and were followed prospectively to assess their waiting times to pregnancy there was some potential for error in the reporting of OC use and TTP. Nevertheless participants reported data on OC use before the occurrence of pregnancy thereby reducing the potential for systematic bias. WIDER IMPLICATIONS OF THE FINDINGS: Women who have used OCs for many years should be reassured as there was no evidence that long-term OC use has a deleterious affects on fecundability. Both short- and long-term OC users are likely to experience a transient delay in conception compared with those discontinuing barrier methods. STUDY FUNDING: This study was supported by the National Institute of Child Health and Human Development (R21050264) and the Danish Medical Research Council (271-07-0338). The authors declare that there are no conflicts of interest.

Use of systemic glucocorticoids and the risk of colorectal cancer

Abstract: Summary Background Systemic glucocorticoids are potent immunosuppressants, potentially facilitating carcinogenesis Studies examining glucocorticoids and colorectal cancer risk are few Aim To investigate the association between use of systemic glucocorticoids and colorectal cancer risk, both overall and by cancer stage (localised versus metastatic) Methods We conducted a nested population-based case–control study in Northern Denmark (18 million people) using medical registries The study included 14 158 patients with a first-time diagnosis of colorectal cancer from 1991 through 2010 Using risk set sampling, we identified 141 580 population controls, matched on age and gender Logistic regression models were used to compute odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for covariates Results Frequent use of systemic glucocorticoids (defined as >2 prescriptions) was not associated with overall colorectal cancer risk [adjusted OR (aOR) = 093 (95% CI: 085–100)], compared with never/rare use (≤2 prescriptions) Associations according to duration of use and doses (quartiles of cumulative prednisolone equivalents) were also near the null Examining colorectal cancer by stage, no substantial associations were found between long-term use (>5 years) of high-dose (>5500 mg) systemic glucocorticoids and localised [aOR = 112 (95% CI: 081–155)] or metastatic [aOR = 082 (95% CI: 059–114)] cancer Conclusion Despite immunological and metabolic effects of frequent use of systemic glucocorticoids, which would be expected to increase colorectal cancer risk, we found no substantial association between the two

Rosiglitazone use and post-discontinuation glycaemic control in two European countries, 2000-2010.

Abstract: Objectives To evaluate the impact of risk minimisation policies on the use of rosiglitazone-containing products and on glycaemic control among patients in Denmark and the UK. Design, setting and participants We used population-based data from the Aarhus University Prescription Database (AUPD) in northern Denmark and from the General Practice Research Database (GPRD) in the UK. Main outcome measures We examined the use of rosiglitazone during its entire period of availability on the European market (2000–2010) and evaluated changes in the glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) levels among patients discontinuing this drug. Results During 2000–2010, 2321 patients with records in AUPD used rosiglitazone in northern Denmark and 25 428 patients with records in GPRD used it in the UK. The proportion of rosiglitazone users among all users of oral hypoglycaemic agents peaked at 4% in AUPD and at 15% in GPRD in May 2007, the month of publication of a meta-analysis showing increased cardiovascular morbidity associated with rosiglitazone use. 12 months after discontinuation of rosiglitazone-containing products, the mean change in HbA1c was −0.16% (95% CI −3.4% to 3.1%) in northern Denmark and −0.17% (95% CI −0.21% to 0.13%) in the UK. The corresponding mean changes in FPG were 0.01 mmol/L (95% CI −7.3 to 7.3 mmol/L) and 0.03 mmol/L (95% CI −0.22 to 0.28 mmol/L). Conclusions Publication of evidence concerning the potential cardiovascular risks of rosiglitazone was associated with an irreversible decline in the use of rosiglitazone-containing products in Denmark and the UK. The mean changes in HbA1c and FPG after drug discontinuation were slight.

Clopidogrel use and short-term mortality after peptic ulcer bleeding: a population-based cohort study.

Abstract: Clopidogrel therapy increases bleeding risk, but whether it influences short-term mortality after peptic ulcer bleeding (PUB) is unknown. The objective was to examine whether clopidogrel use at the time of PUB increases 30-day mortality. We conducted this cohort study in northern Denmark (population 1.7 million). We used the Danish National Patient Registry, covering all hospitals, to identify all patients with a first-ever inpatient diagnosis of endoscopically or surgically confirmed PUB between 1998 and 2008 and their comorbidities. From the prescription database in the region, we ascertained the use of clopidogrel at the time of admission (current use) or before admission (former use) and use of concurrent medications. We obtained mortality data from the Danish Civil Registration System. We used regression modeling to compute mortality rate ratios (MRRs) with 95% confidence intervals (CIs), controlling for potential confounders. We identified 6951 patients with bleeding peptic ulcers. At admission, 122 (1.8%) were current users of clopidogrel, 143 (2.1%) were former users, and 6686 (96.2%) were nonusers. Thirty-day mortality was 5.7% for current users, 7.0% for former users, and 8.0% for nonusers. The adjusted 30-day MRR was reduced in both current and former users, compared with nonusers (MRR = 0.72, 95% CI 0.34, 1.52 and MRR = 0.71, 95% CI 0.38, 1.32, respectively). There was no notable modification of the association within gender or age strata. Although the use of clopidogrel increases the risk of PUB, former use and current use of clopidogrel were not associated with increased short-term mortality after admission for this condition.