Risk Assessment of Acute, All-Cause 30-Day Readmission in Patients Aged 65+: a Nationwide, Register-Based Cohort Study.

BACKGROUND: Hospital readmission is considered an adverse health outcome in older people, adding additional pressure on clinical resources within health care services. Despite numerous studies on risk factors for readmissions, studies find different strengths of respective determinants and there is a need to explore and identify patterns of risk factors in larger cohorts. OBJECTIVE: Exploring and identifying patterns of risk factors for acute, all-cause 30-day readmission in a Danish cohort of patients aged 65+. DESIGN: Register-based cohort study using individual-level linkable information on demographics, social determinants, clinical conditions, health care utilization, and provider determinants obtained from primary and secondary health care. PARTICIPANTS: Historic cohort of 1,267,752 admissions in 479,854 patients, aged 65+, discharged from Danish public hospitals from January 2007 to September 2010. MAIN MEASURES: We included patient-level variables and admission-level variables. Outcome was acute, all-cause 30-day readmission. Data was analyzed by univariable and multivariable logistic regression. Strength of associations was analyzed using Wald test statistics. Receiver operating characteristic (ROC) analysis was used for quantification of predictive ability. For validation, we used split-sample design. KEY RESULTS: Acute admission and number of days since previous hospital discharge were factors strongly associated with readmission. Patients at risk of future readmission suffered from comorbidity, consumed more drugs, and were frequent users of in- and outpatient health care services in the year prior to the index admission. Factors related to index admission were only weakly associated with readmission. The predictive ability was 0.709 (0.707-0.711) for acute readmission. CONCLUSIONS: In a general population of older people, we found that pre-hospital factors rather than hospital factors account for increased risk of readmission and are dominant contributors to predict acute all-cause 30-day readmission. Therefore, risk for excess readmission should be shared across sectors and focus the care trajectory over time rather than distinct care episodes.

Significant association between the use of different proton pump inhibitors and microscopic colitis: a nationwide Danish case-control study.

BACKGROUND: Microscopic colitis causes chronic watery diarrhoea and has previously been associated with the use of proton pump inhibitors. AIM: To explore the association between proton pump inhibitor use and microscopic colitis, including its dependency on timing, dose and choice of proton pump inhibitor. METHODS: Within a 10-year period, we identified 10 652 patients with a first-time diagnosis of microscopic colitis, including 6254 (59%) with collagenous colitis and 4398 (41%) with lymphocytic colitis. All microscopic colitis cases were histologically confirmed in the Danish Pathology Register. Information on proton pump inhibitor use was obtained from the Danish Prescription Register. In this case-control study, we estimated the adjusted odds ratios (aOR) for the association between proton pump inhibitor use and risk of microscopic colitis using conditional logistic regression while adjusting for potential confounders. RESULTS: We found strong associations between current proton pump inhibitor use and both collagenous colitis (aOR 6.98; 95% CI: 6.45-7.55) and lymphocytic colitis (aOR 3.95; 95% CI: 3.60-4.33). This association was observed with all PPIs. The strongest association was with the current use of lansoprazole for both collagenous colitis (aOR 15.74; 95% CI: 14.12-17.55) and lymphocytic colitis (aOR 6.87; 95% CI: 6.00-7.86). When considering timing, ORs were highest for current use of proton pump inhibitor and lower for recent or past exposure. No clear dose-response pattern was observed. CONCLUSIONS: We found a strong association between microscopic colitis and ongoing use of proton pump inhibitors, especially lansoprazole.

Description of OPRA: A Danish database designed for the analyses of risk factors associated with 30-day hospital readmission of people aged 65+ years.

AIMS: To describe the construction of the Older Person at Risk Assessment (OPRA) database, the ability to link this database with existing data sources obtained from Danish nationwide population-based registries and to discuss its research potential for the analyses of risk factors associated with 30-day hospital readmission. METHODS: We reviewed Danish nationwide registries to obtain information on demographic and social determinants as well as information on health and health care use in a population of hospitalised older people. The sample included all people aged 65+ years discharged from Danish public hospitals in the period from 1 January 2007 to 30 September 2010. We used personal identifiers to link and integrate the data from all events of interest with the outcome measures in the OPRA database. The database contained records of the patients, admissions and variables of interest. RESULTS: The cohort included 1,267,752 admissions for 479,854 unique people. The rate of 30-day all-cause acute readmission was 18.9% ( n=239,077) and the overall 30-day mortality was 5.0% ( n=63,116). CONCLUSIONS: The OPRA database provides the possibility of linking data on health and life events in a population of people moving into retirement and ageing. Construction of the database makes it possible to outline individual life and health trajectories over time, transcending organisational boundaries within health care systems. The OPRA database is multi-component and multi-disciplinary in orientation and has been prepared to be used in a wide range of subgroup analyses, including different outcome measures and statistical methods.

The epidemiology of microscopic colitis: a 10-year pathology-based nationwide Danish cohort study.

OBJECTIVE: Microscopic colitis (MC) includes two main types: collagenous colitis (CC) and lymphocytic colitis (LC). Previous studies have indicated an increasing incidence, but these have mainly been based on regional databases. We found it important to study the epidemiology based on a comprehensive nationwide cohort. MATERIAL AND METHODS: We studied the epidemiological data of MC in Denmark from 2002 to 2011. The cohort consisted of all patients with a recorded diagnosis of either CC or LC in the Danish Pathology Register during the study period. Data on all patients with a registered colon biopsy were also included. RESULTS: A total of 7777 patients, 4749 (61%) with CC and 3028 (39%) with LC, were identified. Over the study period, the annual incidence of diagnosed cases of CC increased from 2.9/10(5) to 14.9/10(5) and of LC from 1.7/10(5) to 9.8/10(5). In 2011, the incidence of MC was 24.7/10(5) inhabitants. The age-specific incidence showed that the risk of both CC and LC increased with age. The female/male ratio, distribution of the type of colitis and mean age at diagnosis were relatively stable during the study period. The annual number of registered colon biopsies in the pathology register increased from 21.583 in 2002 to 39.733 in 2011, indicating an increased diagnostic activity. CONCLUSION: In a nationwide cohort study, the incidence of CC and LC continued to increase from 2002 to 2011. An increased diagnostic activity could in part explain the increase in the number of diagnosed cases.

Drug exposure and risk of microscopic colitis: a nationwide Danish case-control study with 5751 cases.

BACKGROUND: Previous small studies have indicated that commonly prescribed drugs may be associated with microscopic colitis (MC). With an increasing incidence of MC, it is important to explore the association between exposure to proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs, statins, and selective serotonin reuptake inhibitors and MC in a larger setting. METHODS: Case-control study based on nationwide Danish registries. The study included all patients with MC diagnosis during the period 2005 to 2011. One hundred sex- and age-matched controls per case were randomly selected among the Danish population. Prescriptions were recorded in a Prescription Register in the year before the first recorded MC diagnosis. Effect measure is the adjusted odds ratio (OR) of collagenous colitis (CC) and lymphocytic colitis (LC) according to prescriptions of PPIs, nonsteroidal anti-inflammatory drugs, statins, and selective serotonin reuptake inhibitors. Within the control group, we identified a subgroup with MC-free colonic biopsies. RESULTS: We identified 3474 patients with CC and 2277 with LC and found a positive association between redemption of prescriptions for PPIs and both CC (OR = 7.04; 95% confidence interval, 6.55-7.56) and LC (OR = 3.37; 95% confidence interval, 3.08-3.69). Among patients with MC-free colon biopsies in the control group, the association between PPIs and CC was strongly positive (OR = 3.47; 95% confidence interval, 3.08-3.89). Adding this parameter to the model attenuated all of the associations, but they remained positive for PPIs versus CC and selective serotonin reuptake inhibitors versus LC. CONCLUSIONS: We found positive associations between exposure to all 4 medication classes and MC. Variations in endoscopic frequency by drug category indicate a potential impact of bias.

Febrile seizures and cognitive function in young adult life: a prevalence study in Danish conscripts.

OBJECTIVE: To examine the association between febrile seizures and cognitive performance in early adulthood. STUDY DESIGN: This is a population-based study using data linked from health-care databases and conscript records of Danish men born from 1977 to 1983. The association between febrile seizures and cognitive function, measured with the Boerge Prien validated group intelligence test, was examined overall and by age of seizure, adjusted for potential confounders. The analysis was restricted to men without a known history of epilepsy (n = 18 276). RESULTS: Of the 18 276 eligible conscripts, 507 (2.8%) had a record of hospitalization with febrile seizures. Compared with conscripts with no such record, the adjusted prevalence ratio for having a Boerge Prien score in the bottom quartile was 1.08 (95% CI, 0.94-1.25). The adjusted prevalence ratios were 1.38 (95% CI, 1.07-1.79) for febrile seizures with an onset age of 3 months to <1 year, 0.98 (95% CI, 0.80-1.18) for febrile seizures with an onset age of 1 to 2 years, and 1.14 (95% CI, 0.79-1.66) for an onset age of 3 to 5 years. CONCLUSIONS: Overall, there was little association between febrile seizures and cognitive function.

Disease activity in pregnant women with Crohn's disease and birth outcomes: a regional Danish cohort study.

OBJECTIVES: CD is associated with increased risk of adverse birth outcomes, but existing studies have not assessed the impact of disease activity during pregnancy. We examined the impact of disease activity on birth outcomes: LBW, preterm birth, LBW at term, and CAs. METHODS: All births by CD women in North Jutland County, Denmark, from January 1, 1977 to December 31, 2005, were evaluated in a cohort study based on linkage between the Danish National Registry of Patients and the Medical Birth Registry. After identification of all births by CD women, review of medical records allowed collection of clinical details (including disease activity and drug therapy during pregnancy). The exposed cohort (N = 71) constituted pregnancies with low/moderate-high disease activity during pregnancy, and the unexposed cohort (N = 86) those with inactive disease. Logistic regression analyses were used to estimate the adjusted relative risks (with 95% confidence intervals) for adverse birth outcomes associated with disease activity in CD pregnancies. In subanalysis, we examined the impact of moderate-high activity. RESULTS: In women with disease activity, the adjusted risks of LBW, LBW at term, preterm birth, and CAs were 0.2 (0.0-2.6), 0.4 (0.0-3.7), 2.4 (0.6-9.5), and 0.8 (0.2-3.8), respectively. The crude risk of preterm birth was 3.4 (1.1-10.6) in those with moderate-high disease activity. CONCLUSIONS: Disease activity during pregnancy only increased the risk of preterm birth (especially in those with high disease activity). Further research is needed to assess the critical impact of disease activity in larger cohorts of CD women.

HbA1c in early diabetic pregnancy and pregnancy outcomes: a Danish population-based cohort study of 573 pregnancies in women with type 1 diabetes.

OBJECTIVE: To assess the association between first-trimester HbA(1c) (A1C) and the risk of adverse pregnancy outcomes in type 1 diabetic pregnancies. RESEARCH DESIGN AND METHODS: We identified all pregnant diabetic women in a Danish county from 1985 to 2003. A1C values from first trimester were collected, and pregnancy outcome was dichotomized as good (i.e., babies surviving the 1st month of life without major congenital abnormalities) and adverse (i.e., spontaneous and therapeutic abortion, stillbirth, neonatal death, or major congenital abnormalities detected within the 1st month). The prevalence of adverse outcomes was calculated according to quintiles of A1C. We computed receiver operating characteristic and lowess curve estimates and fitted logistic regression models to calculate prevalence odds ratio while adjusting for confounding by White class and smoking status. RESULTS: Of 573 pregnancies, 165 (29%) terminated with adverse outcomes. The prevalence of adverse outcomes varied sixfold from 12% (95% CI 7.2-17) in the lowest to 79% (60-91) in the highest quintile of A1C exposure. From A1C levels >7%, we found an almost linear association between A1C and risk of adverse outcome, whereby a 1% increase in A1C corresponded to 5.5% (3.8-7.3) increased risk of adverse outcome. CONCLUSIONS: Starting from a first-trimester A1C level slightly <7%, there is a dose-dependent association between A1C and the risk of adverse pregnancy outcome without indication of a plateau, below which the association no longer exits. A1C, however, seems to be of limited value in predicting outcome in the individual pregnancy.

Increase in incidence and prevalence of inflammatory bowel disease in northern Denmark: a population-based study, 1978-2002.

OBJECTIVES: Although incidence rates of inflammatory bowel disease have been reported worldwide, few long-term population-based studies with current time-trend analyses exist. We therefore examined time trends in the incidence rate of inflammatory bowel disease in a 25-year study period, and estimated the prevalence in 2002. All patients diagnosed between 1978 and 2002 were included as incident cases (n=2,326) and all patients living in North Jutland County on 31 December 2002 were used to estimate prevalent cases (n=2,205). METHODS: Medical records of all patients diagnosed with ulcerative colitis and Crohn's disease in the North Jutland County Hospital Discharge Registry were reviewed to examine if the diagnostic criteria were fulfilled. Age-specific and gender-specific standardized incidence rates were calculated. RESULTS: For ulcerative colitis, incidence rates in women increased from 8.3 (95% confidence interval (CI): 6.7-9.9) in 1978-1982 to 17.0 (95% CI: 14.7-19.3) per 100,000 person-years in 1998-2002. The corresponding figures for men were 7.7 (95% CI: 6.1-9.3) and 16.7 (95% CI: 14.4-18.8) per 100,000 person-years. For Crohn's disease, the incidence rates in women increased from 4.1 (95% CI: 3.0-5.2) in 1978-1982 to 10.7 (95% CI: 8.8-12.5) per 100,000 person-years in 1998-2002. The corresponding figures for men were 3.2 (95% CI: 2.1-4.2) and 8.5 (95% CI: 6.9-10.2) per 100,000 person-years. The prevalence of ulcerative colitis and Crohn's disease was 294 and 151 per 100,000 inhabitants, respectively. CONCLUSIONS: A marked and parallel increase was seen in both ulcerative colitis and Crohn's disease in both genders during the last 25 years, with a corresponding high prevalence of both diseases.

Drug use among fathers around time of conception: two register based surveys from Denmark and The Netherlands.

STUDY OBJECTIVE: Despite the increasing attention for the role of paternal exposures around the period of conception, there is no factual information about drug utilisation of fathers. Therefore, the aim of this study was to describe the drugs dispensed to fathers around conception, using pharmacy dispensing data of community pharmacies in Denmark and The Netherlands. DESIGN AND SETTING: Using pharmacy dispensing data from the Pharmaco-epidemiological Prescription Database of North Jutland in Denmark and the InterAction database in The Netherlands, we examined the prescriptions reimbursed in the half year before conception of 56,735 Danish fathers from 1991 to 2000, and 5859 Dutch fathers from 1995 to 2000. MAIN RESULTS: One third of all fathers had taken up prescriptions for at least one drug in the half year before conception, both in Denmark and in The Netherlands. In the majority of fathers only one type of drug was dispensed, but in both countries at least 5% of all fathers had redeemed three or more types of drugs. The main drugs purchased by fathers in Denmark and The Netherlands were antibiotics (14.3 and 6.3% of all fathers, respectively), analgesics (6.1 and 7.6%), antihistamines (2.0 and 2.0%) and anti-ulcer drugs (1.6 and 2.5%). CONCLUSION: A large proportion of fathers used drugs around the time of conception. This finding emphasises the importance of safety information on therapeutic drugs with respect to potential paternal teratogenicity.

A population-based cohort study of mortality among adults prescribed paracetamol in Denmark.

OBJECTIVE: We examined overall and cause-specific mortality in a population-based cohort of individuals prescribed paracetamol. We evaluated rates of death due to liver and renal disease, cancer, and other major causes of death. METHOD: Using the population-based pharmacoepidemiology prescription database of North Jutland County, Denmark, we identified nearly 50,000 persons receiving prescriptions for paracetamol from 1989 to 1995 and evaluated mortality through 1996. Standardized mortality ratios (SMRs) for 18 specific causes of death were computed for persons prescribed paracetamol compared with persons among the general population of the county. RESULTS: SMRs were elevated regardless of cause of death, with a nearly doubled overall death rate among persons prescribed paracetamol. The mortality ratios were highest within 1 year of paracetamol prescription and tended to decline with increasing follow-up, especially for cancers. The magnitudes of the excess mortality risks for liver and renal diseases were not materially higher than for other causes of death. CONCLUSION: Paracetamol is a first-line analgesic for patients with a wide variety of chronic or serious illnesses and therefore is associated with increased rates of nearly all causes of death. The findings are an example of confounding by indication. Paracetamol may be a drug most prone to this form of bias in pharmacoepidemiologic studies. Future observational studies reporting adverse effects of paracetamol must thoroughly evaluate confounding by indication before making causal inferences.

Predictive value and completeness of the registration of congenital abnormalities in three Danish population-based registries.

AIMS: The predictive value and completeness of data on congenital abnormalities (CAs) collected in three administrative health registries in the County of North Jutland, Denmark were compared. METHODS: The study included all singleton liveborn infants in the county during the period 1991-94 (n = 24,147). All infants recorded as having a CA in either the Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), or the National Registry of Congenital Abnormalities (NRCA) were identified, and the recordings in each registry were compared. Infants recorded in at least two registries were considered correctly diagnosed with a CA for the sake of the analyses. The predictive value was defined as the number of infants correctly diagnosed with a CA in the registry divided by the total number of infants recorded with a CA in the registry. In all cases with recording in one registry only, the predictive value of the registration with CA diagnosis was assessed through a review of a sample of medical records. The completeness was defined as the number of correctly diagnosed CAs in the registry divided by the total number of identified CAs. RESULTS: The predictive value and completeness were calculated as 89.1% (85.3-92.8) and 32.3% (28.9-35.7) in the MBR; 88.2% (85.9-90.5) and 89.9% (87.7-92.1) in the HDR; and 99.6% (98.9-100.0) and 36.0% (32.5-39.5) in the NRCA. CONCLUSIONS: The HDR seems to have a predictive value and completeness that are acceptable for general surveillance and epidemiological research regarding CAs. The NRCA may be suitable for case-control studies owing to a high predictive value.