The predictive value of ICD-10 diagnostic coding used to assess Charlson comorbidity index conditions in the population-based Danish National Registry of Patients

Epidemiology of systemic mastocytosis in Denmark

Mastocytosis is a heterogeneous group of diseases characterized by abnormal proliferation of mast cells. Systemic mastocytosis (SM), in which abnormal mast cells are present in tissues beyond the skin, is divided into seven subcategories with varying degrees of severity and prognosis. Very little is known about the epidemiology of SM and its subcategories. This retrospective cohort study of 548 adults with SM diagnosed 1997-2010 was constructed using linked Danish national health registries. The most common subtype of mastocytosis was indolent SM (including urticaria pigmentosa) (n = 450; 82%), followed by SM with subtype unknown (n = 61; 11%), SM with associated clonal haematological non-mast cell lineage disease (n = 24; 4%), aggressive SM (n = 8; 2%), and mast cell leukaemia (n = 5; 1%). The incidence rate for SM (all subtypes including urticaria pigmentosa) was 0·89 per 100 000 per year. Cumulative incidence was 12·46 per 100 000, and the 14-year limited-duration prevalence as of 1 January, 2011 was 9·59 per 100 000. This nationwide cohort from Denmark is the first population-based epidemiological study of mastocytosis. In this cohort of patients aged 15 years and older, SM was found to be overall relatively rare with notable variation by subtype for patient characteristics, survival and epidemiological measures.

Validity of the International Classification of Diseases, 10th revision discharge diagnosis codes for hyponatraemia in the Danish National Registry of Patients

OBJECTIVE

To examine the validity of the International Classification of Diseases, 10th revision (ICD-10) codes for hyponatraemia in the nationwide population-based Danish National Registry of Patients (DNRP) among inpatients of all ages.

DESIGN

Population-based validation study.

SETTING

All somatic hospitals in the North and Central Denmark Regions from 2006 through 2011.

PARTICIPANTS

Patients of all ages admitted to hospital (n=819 701 individual patients) during the study period. The patient could be included in the study more than once, and our study did not restrict to patients with serum sodium measurements (total of n=2 186 642 hospitalisations).

MAIN OUTCOME MEASURE

We validated ICD-10 discharge diagnoses of hyponatraemia recorded in the DNRP, using serum sodium measurements obtained from the laboratory information systems (LABKA) research database as the gold standard. One sodium value <135 mmol/L measured at any time during hospitalisation confirmed the diagnosis. We estimated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for ICD-10 codes for hyponatraemia overall and for cut-off points for increasing hyponatraemia severity.

RESULT

An ICD-10 code for hyponatraemia was recorded in the DNRP in 5850 of the 2 186 642 hospitalisations identified. According to laboratory measurements, however, hyponatraemia was present in 306 418 (14%) hospitalisations. Sensitivity of hyponatraemia diagnoses was 1.8% (95% CI 1.7% to 1.8%). For sodium values <115 mmol/L, sensitivity was 34.3% (95% CI 32.6% to 35.9%). The overall PPV was 92.5% (95% CI 91.8% to 93.1%) and decreased with increasing hyponatraemia severity. Specificity and NPV were high for all cut-off points (≥99.8% and ≥86.2%, respectively). Patients with hyponatraemia without a corresponding ICD-10 discharge diagnosis were younger and had higher Charlson Comorbidity Index scores than patients with hyponatraemia with a hyponatraemia code in the DNRP.

CONCLUSIONS

ICD-10 codes for hyponatraemia in the DNRP have high specificity but very low sensitivity. Laboratory test results, not discharge diagnoses, should be used to ascertain hyponatraemia.

Existing data sources for clinical epidemiology: Aarhus University Clinical Trial Candidate Database, Denmark

Denmark is facing a reduction in clinical trial activity as the pharmaceutical industry has moved trials to low-cost emerging economies. Competitiveness in industry-sponsored clinical research depends on speed, quality, and cost. Because Denmark is widely recognized as a region that generates high quality data, an enhanced ability to attract future trials could be achieved if speed can be improved by taking advantage of the comprehensive national and regional registries. A “single point-of-entry” system has been established to support collaboration between hospitals and industry. When assisting industry in early-stage feasibility assessments, potential trial participants are identified by use of registries to shorten the clinical trial startup times. The Aarhus University Clinical Trial Candidate Database consists of encrypted data from the Danish National Registry of Patients allowing an immediate estimation of the number of patients with a specific discharge diagnosis in each hospital department or outpatient specialist clinic in the Central Denmark Region. The free access to health care, thorough monitoring of patients who are in contact with the health service, completeness of registration at the hospital level, and ability to link all databases are competitive advantages in an increasingly complex clinical trial environment.

Approaches to ascertaining comorbidity information: validation of routine hospital episode data with clinician-based case note review

Background

In clinical practice, research, and increasingly health surveillance, planning and costing, there is a need for high quality information to determine comorbidity information about patients. Electronic, routinely collected healthcare data is capturing increasing amounts of clinical information as part of routine care. The aim of this study was to assess the validity of routine hospital administrative data to determine comorbidity, as compared with clinician-based case note review, in a large cohort of patients with chronic kidney disease.

Methods

A validation study using record linkage. Routine hospital administrative data were compared with clinician-based case note review comorbidity data in a cohort of 3219 patients with chronic kidney disease. To assess agreement, we calculated prevalence, kappa statistic, sensitivity, specificity, positive predictive value and negative predictive value. Subgroup analyses were also performed.

Results

Median age at index date was 76.3 years, 44% were male, 67% had stage 3 chronic kidney disease and 31% had at least three comorbidities. For most comorbidities, we found a higher prevalence recorded from case notes compared with administrative data. The best agreement was found for cerebrovascular disease (κ = 0.80) ischaemic heart disease (κ = 0.63) and diabetes (κ = 0.65). Hypertension, peripheral vascular disease and dementia showed only fair agreement (κ = 0.28, 0.39, 0.38 respectively) and smoking status was found to be poorly recorded in administrative data. The patterns of prevalence across subgroups were as expected and for most comorbidities, agreement between case note and administrative data was similar. Agreement was less, however, in older ages and for those with three or more comorbidities for some conditions.

Conclusions

This study demonstrates that hospital administrative comorbidity data compared moderately well with case note review data for cerebrovascular disease, ischaemic heart disease and diabetes, however there was significant under-recording of some other comorbid conditions, and particularly common risk factors.

Association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use prior to major elective surgery and the risk of acute dialysis

Background

Some studies but not others suggest angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use prior to major surgery associates with a higher risk of postoperative acute kidney injury (AKI) and death.

Methods

We conducted a large population-based retrospective cohort study of patients aged 66 years or older who received major elective surgery in 118 hospitals in Ontario, Canada from 1995 to 2010 (n = 237,208). We grouped the cohort into ACEi/ARB users (n = 101,494) and non-users (n = 135,714) according to whether the patient filled at least one prescription for an ACEi or ARB (or not) in the 120 days prior to surgery. Our study outcomes were acute kidney injury treated with dialysis (AKI-D) within 14 days of surgery and all-cause mortality within 90 days of surgery.

Results

After adjusting for potential confounders, preoperative ACEi/ARB use versus non-use was associated with 17% lower risk of post-operative AKI-D (adjusted relative risk (RR): 0.83; 95% confidence interval (CI): 0.71 to 0.98) and 9% lower risk of all-cause mortality (adjusted RR: 0.91; 95% CI: 0.87 to 0.95). Propensity score matched analyses provided similar results. The association between ACEi/ARB and AKI-D was significantly modified by the presence of preoperative chronic kidney disease (CKD) (P value for interaction < 0.001) with the observed association evident only in patients with CKD (CKD - adjusted RR: 0.62; 95% CI: 0.50 to 0.78 versus No CKD: adjusted RR: 1.00; 95% CI: 0.81 to 1.24).

Conclusions

In this cohort study, preoperative ACEi/ARB use versus non-use was associated with a lower risk of AKI-D, and the association was primarily evident in patients with CKD. Large, multi-centre randomized trials are needed to inform optimal ACEi/ARB use in the peri-operative setting.

Medical emergency team activation: performance of conventional dichotomised criteria versus national early warning score

BACKGROUND

To activate the hospital's medical emergency team (MET), either conventional dichotomised activation criteria or an early warning scoring system may be used. The relative performance of these different activation patterns to discriminate high risk patients in a heterogenic general ward population after adjustment for multiple confounding factors has not been evaluated. We aimed to evaluate the dichotomised activation criteria used at our institution and the recently published national early warning score (NEWS, United Kingdom).

MATERIALS AND METHODS

Prospective point prevalence study at a university hospital in Finland. On two separate days, the vital signs of all adult patients without treatment limitations were measured. Data on cumulative comorbidity (Charlson comorbidity index), age, gender, admission characteristics and subsequent mortality were collected. Univariate and multivariate logistic regression models were used for unadjusted and adjusted performance testing.

RESULTS

The cohort consisted of 615 patients. The dichotomised activation criteria were not associated with in-hospital serious adverse events (odds ratio 1.87, 95% confidence interval 0.55-6.30) or 30-day mortality (2.13, 0.79-5.72) after adjustments. For a NEWS of seven or more (the suggested trigger level for immediate MET activation), the adjusted odds ratios for the above mentioned outcomes were 7.45 (2.39-23.3) and 11.4 (4.40-29.6), respectively. Unlike the dichotomised activation criteria, NEWS was also independently associated with a higher 60- and 180-day mortality after adjustments.

CONCLUSIONS

NEWS discriminates high risk patients in a heterogenic general ward population independently of multiple confounding factors. The conventional dichotomised activation criteria were not able to detect high risk patients.

Pre-admission use of glucocorticoids and 30-day mortality following colorectal cancer surgery: a population-based Danish cohort study

BACKGROUND

Previous studies indicate that pre-admission glucocorticoids increase the risk of perioperative complications.

AIM

To examine whether pre-admission use of glucocorticoids affects 30-day mortality after colorectal cancer (CRC) surgery.

METHODS

We conducted a nationwide population-based cohort study by linking Danish medical registries. All residents in Denmark who underwent CRC surgery from 2001 to 2011 were included. We characterised subjects who filled their most recent glucocorticoid prescription ≤90, 91-365 and >365 days before their surgery date as prevalent, recent and former users, respectively. Prevalent users were subgrouped into new (first-ever prescription ≤90 days before surgery date) and continuing users. We estimated 30-day cumulative mortality by the Kaplan-Meier method and corresponding mortality rate ratios (MRRs) using Cox proportional hazard regression, adjusting for potential confounders.

RESULTS

Of the 34 641 CRC patients included, 3966 (11.5%) had filled one or more prescriptions of glucocorticoids within the year before the surgery date. Thirty-day mortality among prevalent users of oral glucocorticoids was 15.0% vs. 7.3% among non-users [MRR = 1.28; 95% confidence interval (CI): 1.03, 1.58]. Among new users, the 30-day mortality was 17.8% (MRR = 1.92; 95% CI: 1.30, 2.83) while it was 14.2% among continuing users (MRR = 1.13; 95% CI: 0.88, 1.44). No associations were found for recent or former use of oral glucocorticoids nor for use of inhaled, intestinal-acting, and mixed glucocorticoids.

CONCLUSIONS

Prevalent use, particulary new use, of oral glucocorticoids was associated with markedly increased 30-day mortality after colorectal cancer surgery compared to patients not exposed to any glucocorticoids.

Influence of comorbidity on cancer patients' rehabilitation needs, participation in rehabilitation activities and unmet needs: a population-based cohort study

PURPOSE

This study aims to investigate possible associations between cancer survivors' comorbidity status and their (1) need for rehabilitation, (2) participation in rehabilitation activities and (3) unmet needs for rehabilitation in a 14-month period following date of diagnosis.

METHODS

We performed a population-based cohort study including incident cancer patients diagnosed from 1 October 2007 to 30 September 2008 in two regions in Denmark. Fourteen months after diagnosis, participants completed a questionnaire measuring different aspects and dimensions of rehabilitation. Individual information on comorbidity was based on hospital contacts from 1994 and until diagnosis, subsequently classified according to the Charlson comorbidity index. Logistic regression analyses were used to explore the association between comorbidity and outcomes for rehabilitation. Analyses were conducted overall and stratified for gender, age and cancer type.

RESULTS

A total of 3,439 patients responded (70%). Comorbidity at all levels was statistically significant associated with a physical rehabilitation need, and moderate to severe comorbidity was statistically significant associated with a need in the emotional, family-oriented and financial areas as well as participation in physical-related rehabilitation activities. Stratified analyses showed that significant results in most cases were related to being older than 65 years or having colorectal or prostate cancer.

CONCLUSIONS

Comorbidity at all levels was significantly associated with needs for physical rehabilitation. Moderate to severe comorbidity was further associated with other areas of need and participation in physical area activities. This should be taken into account when planning rehabilitation interventions for cancer survivors. Differences among subgroups could help target interventions and should be explored further.

Mortality and molecular epidemiology associated with extended-spectrum β-lactamase production in Escherichia coli from bloodstream infection

Background

The rate of infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is growing worldwide. These infections are suspected to be related to increased mortality. We aimed to estimate the difference in mortality due to bloodstream infections (BSIs) with ESBL-positive and ESBL-negative E. coli isolates and to determine the molecular epidemiology of our ESBL-positive isolates.

Materials and methods

We performed a cohort study on consecutive patients with E. coli BSI between 2008 and 2010 at the Charité University Hospital. Collected data were ESBL production, basic demographic parameters, and underlying diseases by the Charlson comorbidity index (CCI). The presence of ESBL genes was analyzed by polymerase chain reaction (PCR) and sequencing. Phylogenetic groups of ESBL-positive E. coli were determined by PCR. Risk factors for mortality were analyzed by multivariable regression analysis.

Results

We identified 115 patients with BSI due to E. coli with ESBL phenotype and 983 due to ESBL-negative E. coli. Fifty-eight percent (n=67) of the ESBL-positive BSIs were hospital-acquired. Among the 99 isolates that were available for PCR screening and sequencing, we found mainly 87 CTX-M producers, with CTX-M-15 (n=55) and CTX-M-1 (n=21) as the most common types. Parameters significantly associated with mortality were age, CCI, and length of stay before and after onset of BSI.

Conclusion

The most common ESBL genotypes in clinical isolates from E. coli BSIs were CTX-M-15 (58%) and CTX-M-1 (22%). ESBL production in clinical E. coli BSI isolates was not related to increased mortality. However, the common occurrence of hospital-acquired BSI due to ESBL-positive E. coli indicates future challenges for hospitals.

Comorbidity in adult bone sarcoma patients: a population-based cohort study

Background. Comorbidity is an important prognostic factor for survival in different cancers; however, neither the prevalence nor the impact of comorbidity has been investigated in bone sarcoma. Methods. All adult bone sarcoma patients from western Denmark treated at the Aarhus Sarcoma Centre in the period from 1979 to 2008 were identified through a validated population-based database. Charlson Comorbidity Index scores were computed, using discharge diagnoses from the Danish National Patient Registry. Survival was assessed as overall and disease-specific mortality. The impact of comorbidity was examined as rates according to the level of comorbidity as well as uni- and multivariately using proportional hazard models. Results. A total of 453 patients were identified. The overall prevalence of comorbidity was 19%. The prevalence increased with age and over the study period. In patients with Ewing/osteosarcoma, comorbidity was not associated with an increased overall or disease-specific mortality. However, patients with bone sarcomas other than Ewing/osteosarcoma had increased overall mortality. Independent prognostic factors for disease-specific survival were age, tumor size, stage at diagnosis, soft tissue involvement, grade, and surgery. Conclusion. The prevalence of comorbidity in bone sarcoma patients is low. Comorbidity impaired survival in patients with non-Ewing/nonosteosarcoma, histology. This emphasizes the importance of not only treating the sarcoma but also comorbidity.

Decreasing incidence rates of bacteremia: a 9-year population-based study

BACKGROUND

Numerous studies have shown that the incidence rate of bacteremia has been increasing over time. However, few studies have distinguished between community-acquired, healthcare-associated and nosocomial bacteremia.

METHODS

We conducted a population-based study among adults with first-time bacteremia in Funen County, Denmark, during 2000-2008 (N = 7786). We reported mean and annual incidence rates (per 100,000 person-years), overall and by place of acquisition. Trends were estimated using a Poisson regression model.

RESULTS

The overall incidence rate was 215.7, including 99.0 for community-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. During 2000-2008, the overall incidence rate decreased by 23.3% from 254.1 to 198.8 (3.3% annually, p < .001), the incidence rate of community-acquired bacteremia decreased by 25.6% from 119.0 to 93.8 (3.7% annually, p < .001) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p < .001). The incidence rate of healthcare-associated bacteremia remained stable. The most common microorganisms were Escherichia coli (28.3%), Staphylococcus aureus (12.3%), coagulase-negative staphylococci (10.0%) and Streptococcus pneumoniae (9.1%). Regardless of place of acquisition, the proportion of bacteremias caused by enterococci increased (p < .05) and the proportion caused by coagulase-negative staphylococci decreased (p < .05).

CONCLUSIONS

The incidence rates of community-acquired and nosocomial bacteremia decreased substantially over time.

Management of anastomotic leakage in a nationwide cohort of colonic cancer patients

BACKGROUND

The mortality associated with anastomotic leakage (AL) after colonic cancer surgery is high and management often results in permanent fecal diversion. Preservation of bowel continuity in combination with proximal loop diversion (salvage) may reduce the number of permanent ostomies without jeopardizing safety.

STUDY DESIGN

This nationwide study used prospective data from the database of the Danish Colorectal Cancer Group, the National Patient Registry, and patient files. Patients with AL requiring surgery (grade C) were categorized according to the type of surgical treatment as anastomotic takedown with an end-ostomy or salvage. Thirty-day mortality, long-term mortality, and permanent ostomy rates were analyzed using multivariable logistic and Cox regression analyses.

RESULTS

Anastomotic leakage occurred in 593 of 9,333 patients (6.4%), of whom 507 with grade C were included. Takedown and salvage were undertaken in 433 (85.4%) and 74 (14.6%) patients, respectively. Salvage was performed more frequently for Hinchey I-II or minor anastomotic defects and resulted in increased likelihood of stoma reversal (adjusted hazard ratio 3.24, 95% CI 2.04 to 5.16, p < 0.001), corresponding to a risk of permanent fecal diversion of 16.8%, compared with 54.5% after takedown. Adjusted mortality rates were comparable between the groups. A second episode of AL after stoma reversal occurred more frequently in patients with end-ileostomies (10 of 64) than in patients with end-colostomies (1 of 64) or loop-ileostomies (3 of 36), p = 0.017.

CONCLUSIONS

Patients with Hinchey I-II and small anastomotic defect were safely managed by anastomotic salvage, which reduced the risk of permanent fecal diversion. Anastomotic salvage is a viable option for this subset of patients.

The direct and indirect impact of comorbidity on the survival of patients with non-small cell lung cancer: a combination of survival, staging and resection models with missing measurements in covariates

OBJECTIVE

To examine the direct and indirect impact of comorbidity on the survival.

DESIGN

A historical cohort study.

SETTING

Denmark.

PARTICIPANTS

All patients with non-small cell lung cancer who were registered in the Danish Lung Cancer Registry in 2010.

MAIN OUTCOME MEASURES

The influence of comorbidity on stage misclassification, probability of resection and survival.

RESULTS

It was estimated that the comorbidity influences the probability of resection with OR 0.65 and 95% credible interval (0.54; 0.79), the staging process with OR 1.08 and 95% credible interval (0.96; 1.20), and the survival process with HR 1.08 and 95% credible interval (1.02; 1.14).

CONCLUSIONS

We found that comorbidity has a significant indirect effect on survival mediated by the resection process and a slightly direct effect on mortality.

Mortality and postoperative care pathways after emergency gastrointestinal surgery in 2904 patients: a population-based cohort study

BACKGROUND

Emergency major gastrointestinal (GI) surgery carries a considerable risk of mortality and postoperative complications. Effective management of complications and appropriate organization of postoperative care may improve outcome. The importance of the latter is poorly described in emergency GI surgical patients. We aimed to present mortality data and evaluate the postoperative care pathways used after emergency GI surgery.

METHODS

A population-based cohort study with prospectively collected data from six Capital Region hospitals in Denmark. We included 2904 patients undergoing major GI laparotomy or laparoscopy surgery between January 1, 2009, and December 31, 2010. The primary outcome measure was 30 day mortality.

RESULTS

A total of 538 patients [18.5%, 95% confidence interval (CI): 17.1-19.9] died within 30 days of surgery. In all, 84.2% of the patients were treated after operation in the standard ward, with a 30 day mortality of 14.3%, and 4.8% were admitted to the intensive care unit (ICU) after a median stay of 2 days (inter-quartile range: 1-6). When compared with 'admission to standard ward', 'admission to standard ward before ICU admission' and 'ICU admission after surgery' were independently associated with 30 day mortality; odds ratio 5.45 (95% CI: 3.48-8.56) and 3.27 (95% CI: 2.45-4.36), respectively.

CONCLUSIONS

Mortality in emergency major GI surgical patients remains high. Failure to allocate patients to the appropriate level of care immediately after surgery may contribute to the high postoperative mortality. Future research should focus on improving risk stratification and evaluating the effect of different postoperative care pathways in emergency GI surgery.

Use of antibiotics for urinary tract infection in women undergoing surgery for urinary incontinence: a cohort study

OBJECTIVE

To describe the use of antibiotics for urinary tract infection (UTI) before and after surgery for urinary incontinence (UI); and for those with use of antibiotics before surgery, to estimate the risk of treatment for a postoperative UTI, relative to those without use of antibiotics before surgery.

DESIGN

A historical population-based cohort study.

SETTING

Denmark.

PARTICIPANTS

Women (age ≥18 years) with a primary surgical procedure for UI from the county of Funen and the Region of Southern Denmark from 1996 throughout 2010. Data on redeemed prescriptions of antibiotics ±365 days from the date of surgery were extracted from a prescription database.

MAIN OUTCOME MEASURES

Use of antibiotics for UTI in relation to UI surgery, and the risk of being a postoperative user of antibiotics for UTI among preoperative users.

RESULTS

A total of 2151 women had a primary surgical procedure for UI; of these 496 (23.1%) were preoperative users of antibiotics for UTI. Among preoperative users, 129 (26%) and 215 (43.3%) also redeemed prescriptions of antibiotics for UTI within 0-60 and 61-365 days after surgery, respectively. Among preoperative non-users, 182 (11.0%) and 235 (14.2%) redeemed prescriptions within 0-60 and 61-365 days after surgery, respectively. Presurgery exposure to antibiotics for UTI was a strong risk factor for postoperative treatment for UTI, both within 0-60 days (adjusted OR, aOR=2.6 (95% CI 2.0 to 3.5)) and within 61-365 days (aOR=4.5 (95% CI 3.5 to 5.7)).

CONCLUSIONS

1 in 4 women undergoing surgery for UI was treated for UTI before surgery, and half of them had a continuing tendency to UTIs after surgery. Use of antibiotics for UTI before surgery was a strong risk factor for antibiotic use after surgery. In women not using antibiotics for UTI before surgery only a minor proportion initiated use after surgery.

Impact of gender, co-morbidity and social factors on labour market affiliation after first admission for acute coronary syndrome. A cohort study of Danish patients 2001-2009

Background

Over the last decades survival after acute coronary syndrome (ACS) has improved, leading to an increasing number of patients returning to work, but little is known about factors that may influence their labour market affiliation. This study examines the impact of gender, co-morbidity and socio-economic position on subsequent labour market affiliation and transition between various social services in patients admitted for the first time with ACS.

Methods

From 2001 to 2009 all first-time hospitalisations for ACS were identified in the Danish National Patient Registry (n = 79,714). For this population, data on sick leave, unemployment and retirement were obtained from an administrative register covering all citizens. The 21,926 patients, aged 18–63 years, who had survived 30 days and were part of the workforce at the time of diagnosis were included in the analyses where subsequent transition between the above labour market states was examined using Kaplan-Meier estimates and Cox proportional hazards models.

Findings

A total of 37% of patients were in work 30 days after first ACS diagnosis, while 55% were on sick leave and 8% were unemployed. Seventy-nine per cent returned to work once during follow-up. This probability was highest among males, those below 50 years, living with a partner, the highest educated, with higher occupations, having specific events (NSTEMI, and percutaneous coronary intervention) and with no co-morbidity. During five years follow-up, 43% retired due to disability or voluntary early pension. Female gender, low education, basic occupation, co-morbidity and having a severer event (invasive procedures) and receiving sickness benefits or being unemployed 30 days after admission were associated with increased probability of early retirement.

Conclusion

About half of patients with first-time ACS stay in or return to work shortly after the event. Women, the socially disadvantaged, those with presumed severer events and co-morbidity have lower rates of return.

Peripheral artery disease is a coronary heart disease risk equivalent among both men and women: results from a nationwide study

AIMS

Lower extremity peripheral artery disease (PAD) has been proposed as a 'coronary heart disease (CHD) risk equivalent'. We aimed to examine whether PAD confers similar risk for mortality as incident myocardial infarction (MI) and whether risk differs by gender.

METHODS

Using nationwide Danish administrative registries (2000-2008), we identified patients aged ≥40 years with incident PAD (PAD only, n = 35,628), incident PAD with a history of MI (PAD + MI, n = 7029), and incident MI alone (MI alone, n = 71,115).

RESULTS

Patients with PAD only tended to be younger, female, and have less comorbidity than the other groups. During follow up (median 1051 d, IQR 384-1938), we found that MI-alone patients had greater risk of adverse outcomes in the acute setting (first 90 d); however, the PAD-only and PAD + MI groups had higher long-term mortality at 7 years than those with MI alone (47.8 and 60.4 vs. 36.4%, respectively; p < 0.0001). After adjustment, the PAD-only and PAD + MI groups had a higher long-term risk for mortality [hazard ratio (HR) 1.47, 95% confidence interval (CI) 1.44-1.51; and HR 1.65, 95% CI 1.58-1.72, respectively], cardiovascular mortality (HR 1.30, 95% CI 1.26-1.34; and HR 1.71, 95% CI 1.62-1.80, respectively), and composite of death, MI, and ischaemic stroke, 95% CI HR, 1.38, 95% CI 1.36-1.42; and HR 1.68, 95% CI 1.61-1.75, respectively). The greater long-term risks of PAD were seen for both women and men.

CONCLUSIONS

Both women and men with incident PAD have greater long-term risks of total and cardiovascular mortality vs. those with incident MI. PAD should be considered a CHD risk equivalent, warranting aggressive secondary prevention.

Development and validation of a comorbidity scoring system for patients with cirrhosis

BACKGROUND & AIMS

At least 40% of patients with cirrhosis have comorbidities that increase mortality. We developed a cirrhosis-specific comorbidity scoring system (CirCom) to help determine how these comorbidities affect mortality and compared it with the generic Charlson Comorbidity Index.

METHODS

We used data from nationwide health care registries to identify Danish citizens diagnosed with cirrhosis in 1999-2008 (n = 12,976). They were followed through 2010 and characterized by 34 comorbidities. We used Cox regression to assign severity weights to comorbidities with an adjusted mortality hazard ratio (HR) ≥ 1.20. Each patient's CirCom score was based on, at most, 2 of these comorbidities. Performance was measured with Harrell's C statistic and the Net Reclassification Index (NRI) and results were compared with those obtained using the Charlson Index (based on 17 comorbidities). Findings were validated in 2 separate cohorts of patients with alcohol-related cirrhosis or chronic hepatitis C.

RESULTS

The CirCom score included chronic obstructive pulmonary disease, acute myocardial infarction, peripheral arterial disease, epilepsy, substance abuse, heart failure, nonmetastatic cancer, metastatic cancer, and chronic kidney disease; 24.2% of patients had 1 or more of these, and mortality correlated with the CirCom score. Patients' CirCom score correlated with their Charlson Comorbidity Index (Kendall's τ = 0.57; P < .0001). Compared with the Charlson Index, the CirCom score increased Harrell's C statistic by 0.6% (95% confidence interval: 0.3%-0.8%). The NRI for the CirCom score was 5.2% (95% confidence interval: 3.7%-6.9%), and the NRI for the Charlson Index was 3.6% (95% confidence interval: 2.3%-5.0%). Similar results were obtained from the validation cohorts.

CONCLUSIONS

We developed a scoring system to predict mortality among patients with cirrhosis based on 9 comorbidities. This system had higher C statistic and NRI values than the Charlson Comorbidity Index, and is easier to use. It could therefore be a preferred method to predict death or survival of patients and for use in epidemiologic studies.

Mortality in elderly ICU patients: a cohort study

BACKGROUND

The population is aging. We examined changes in the proportion of elderly (≥ 80 years) intensive care unit (ICU) patients during 2005-2011 and the association between age and mortality controlling for preexisting morbidity.

METHODS

Through the Danish National Patient Registry, we identified a cohort of 49,938 ICU admissions (47,596 patients) in Northern Denmark from 2005 to 2011. Patients were subdivided in age groups (15-49, 50-64, 65-79 and ≥ 80 years) and calendar year. We estimated 30-day and 31-365-day mortality and mortality rate ratios (MRRs), stratified by admission type (medical and elective/acute surgical patients). Mortality was compared between age groups adjusting for sex and preexisting morbidity using 50-64-year-olds as reference.

RESULTS

The proportion of elderly patients increased from 11.7% of all ICU patients in 2005 to 13.8% in 2011. Among the elderly, the 30-day mortality was 43.7% in medical, 39.6% in acute surgical, and 11.6% in elective surgical ICU patients. The corresponding adjusted 30-day MRRs compared with the 50-64-year-olds were 2.7 [95% confidence interval (CI) 2.5-3.0] in medical, 2.7 (95% CI 2.4-3.0) in acute surgical, and 5.2 (95% CI 4.1-6.6) in elective surgical ICU patients. The 31-365-day mortality among elderly patients was 25.4% in medical, 26.9% in acute, and 11.9% in elective surgical ICU patients, corresponding to adjusted MRRs of 2.5 (95% CI 2.1-2.9), 2.2 (95% CI 1.9-2.5), and 1.9 (95% CI 1.6-2.3), respectively.

CONCLUSIONS

During 2005-2011, there was an 18% increase in the proportion of elderly ICU patients. Advancing age is associated with increased mortality even after controlling for preexisting morbidity.

Cognitive test scores in young men and subsequent risk of type 2 diabetes, cardiovascular morbidity, and death

BACKGROUND

The association between cognitive scores in young adulthood and long-term cardiometabolic risks remains unclear.

METHODS

Using population-based registries, we followed 6502 military conscripts from their 22nd birthday until death, emigration, or 55 years of age. We calculated risks and hazard ratios (HRs) associating quartiles of cognitive scores (very high, high, moderate, and low) with type 2 diabetes, hypertension, myocardial infarction, stroke, venous thromboembolism, and death before age 55 years.

RESULTS

The 33-year risk of the combined outcome was inversely associated with cognitive scores (26% for low and 16% for very high scores). Compared with very high scores, the HR for the combined outcome was 1.20 (95% confidence interval = 1.02, 1.41) for high, 1.43 (1.22, 1.68) for moderate, and 1.67 (1.43, 1.95) for low scores. Similar HRs were observed for individual outcomes.

CONCLUSION

Low cognitive score in young adulthood was a strong predictor for type 2 diabetes, cardiovascular morbidity, and death before 55 years of age.

Use of symptom-relieving drugs before and after surgery for urinary incontinence in women: a cohort study

OBJECTIVE

To describe the use of symptom-relieving drugs (antimuscarinic drugs or duloxetine) before and after surgery for urinary incontinence (UI); and for those with use of antimuscarinic drugs or duloxetine before surgery, to estimate the risk of being a postoperative user, relative to those without use before surgery.

DESIGN

A historical population-based cohort study.

SETTING

Denmark.

PARTICIPANTS

Women ≥18 years with a first-time surgical procedure for UI from the county of Funen, Denmark between 1 January 1996 and 31 December 2006, extended to the Region of Southern Denmark from 1 January 2007 to the end of 2010. For these women, data on redeemed prescriptions ±365 days of date of surgery were extracted.

MAIN OUTCOME MEASURES

Effect of preoperative use of antimuscarinic drugs or duloxetine on the risk of being a postoperative user of these drugs.

RESULTS

Of 2151 women with a first-time surgical procedure for UI, 358 (16.6%) were preoperative users of antimuscarinic drugs or duloxetine and 1793 were not (83.4%). A total of 110 (30.7%) of the preoperative users also redeemed prescriptions for these drugs within 0-60 days after surgery, and 152 (42.5%) of the preoperative users redeemed prescriptions for these drugs within 61-365 days after surgery. Among preoperative non-users, 25 (1.4%) and 145 (8.1%) redeemed prescriptions within 0-60 and 61-365 days after surgery, respectively. Presurgery exposure to antimuscarinic drugs or duloxetine was a strong risk factor of postoperative drug use, both within 0-60 days (adjusted OR=33.0, 95% CI 20.0 to 54.7) and 61-365 days (OR=7.2, 95% CI 5.4 to 9.6).

CONCLUSIONS

A substantial number of women will continue to be prescribed symptom-relieving drugs after surgery for UI within a year of follow-up. Only a minority of preoperative non-users initiated usage of symptom-relieving drugs after surgery. Compared with other factors included in the regression model, preoperative use of antimuscarinic drugs or duloxetine was the strongest risk factor for postoperative use.

The influence of comprehensive geriatric assessment on drug therapy in elderly patients

BACKGROUND

Comprehensive geriatric assessment of hospitalised patients implies optimising patients' medical treatment, and good coordination between hospital and general practice is essential for the quality of the drug treatment. Only a few studies have investigated the continuation of patients' medication from primary care to hospital and back again to primary care.

OBJECTIVES

To describe changes of drug therapy during hospital stay in a geriatric ward and the following acceptance of these changes in primary cares after discharge.

METHODS

An observational register study following 1,550 geriatric patients' pharmacological treatment longitudinally across hospital stay, by linkage of a primary care prescription database and hospital medical records. The medication regimens for the individual patients were compared at three cross sections: primary care before hospitalisation, during hospital stay and primary care after hospitalisation, analysed according to drug therapy, co-morbidity, functionality and outpatient follow-up.

RESULTS

Patients were using an average of 8.2 drugs before hospital admission, of which an average of 0.9 drugs per patient was discontinued or switched during hospitalisation. An average of 1.7 new drugs per patient was initiated by the hospital physicians. After discharge, 63.9 % of the changes initiated by hospital physicians were continued in primary care. Of new drugs initiated in hospital 42.7 % were accepted in primary care.

CONCLUSIONS

A relatively small proportion of drugs was switched or discontinued and the average number of drugs increased during hospital stay. Of these changes, two thirds were accepted in primary care after discharge and less than half of newly initiated drugs were continued in primary.

Comorbidity and survival of Danish ovarian cancer patients from 2000-2011: a population-based cohort study

OBJECTIVE

To examine the prevalence of comorbidity among patients diagnosed with epithelial ovarian cancer in the Central Denmark Region and to study the impact of comorbidity on cancer survival over time.

METHODS

We included women recorded with a first-time diagnosis of epithelial ovarian cancer in the Danish National Registry of Patients in the Central Denmark region between 2000 and 2011. We followed their survival through the Danish Civil Registration System. We estimated 1- and 5-year survival overall and stratified by Charlson Comorbidity Index score. We used Cox proportional hazard regression analyses to compute adjusted mortality rate ratios (MRRs) within different calendar time periods overall and by comorbidity level.

RESULTS

We identified 1,540 patients. In 2000-2002, 25% of the newly diagnosed ovarian cancer patients had a comorbidity diagnosis compared with 35% in 2009-2011. Median age increased from 61 to 66 years. One-year overall survival changed from 73% (95% confidence interval [CI]: 69-78) in 2000-2002 to 69% (95% CI: 63-73) in 2009-2011, corresponding to an age- and comorbidity-adjusted MRR of 1.03 (95% CI: 0.79-1.36). Five-year survival changed only slightly during the study period, from 37% (95% CI: 32-42) in 2000-2002 to 39% (95% CI: 34-44) in 2009-2011. In patients with Charlson score ≥3, 1-year survival changed from 63% (95% CI: 35-81) in 2000-2002 to 41% (95% CI: 24-57) in 2003-2005 and thereafter stabilized. One-year survival changed from 56% (95% CI: 44-66) to 64% (95% CI: 53-74) in patients with Charlson score 1-2. Compared with Charlson score 0, adjusted 1-year MRRs for Charlson score ≥3 were 1.44 (95% CI: 0.62-3.36) in 2000-2002 and 2.11 (95% CI: 1.27-3.51) in 2009-2011, whereas adjusted 1-year MRRs for Charlson score 1-2 changed from 2.04 (95% CI: 1.33-3.14) in 2000-2002 to 1.09 (95% CI: 0.69-1.71) in 2009-2011.

CONCLUSION

Comorbidity increased among ovarian cancer patients over time and was associated with poor survival. One- and 5-year overall survivals changed only little and an expected decrease in survival, following increased prevalence of comorbidity and increasing age of patients, may have been counteracted by more aggressive surgery.

Comorbidity and survival of Danish lung cancer patients from 2000-2011: a population-based cohort study

Objective

To examine lung cancer survival and the impact of comorbidity in the Central Denmark Region from 2000 to 2011.

Methods

We performed a population-based cohort study of lung cancer patients diagnosed during four 3-year calendar periods (2000–2002, 2003–2005, 2006–2008, and 2009–2011) in the Central Denmark Region. The Danish National Registry of Patients was used to identify 9,369 incident lung cancer patients, and to obtain data on their Charlson comorbidity index score, categorized as no (score = 0), medium (score = 1–2), or high (score ≥3) level comorbidity. We calculated 1- and 5-year survival in different calendar time periods overall, and by age, sex, and level of comorbidity, and used Cox regression to compute mortality rate ratios (MRR) for each level of comorbidity versus no comorbidity in different calendar time periods.

Results

Overall 1-year survival increased from 31% in 2000–2002 to 37% in 2009–2011, while the 5-year survival increased from 10% in 2000–2002 to predicted 13% in 2009–2011 with the largest improvement observed for women and patients less than 80 years. The adjusted 1-year MRR in patients with high comorbidity compared with those without comorbidity was 1.23 (95% confidence interval [CI]: 1.05–1.46) in 2000–2002 and 1.35 (95% CI: 1.17–1.56) in 2009–2011. The corresponding adjusted 5-year MRRs were 1.21 (95% CI: 1.04–1.40) in 2000–2002 and 1.26 (95% CI: 1.11–1.42) in 2009–2011.

Conclusion

Lung cancer patients’ survival increased from 2000 to 2011 in the Central Denmark Region, most prominently for women under 80 years and patients with no, or medium level of comorbidity. Their prognosis remained nonetheless dismal with overall 5-year survival of 13%, and comorbidity remained a negative prognostic factor.

Comorbidity and survival of Danish patients with colon and rectal cancer from 2000-2011: a population-based cohort study

Objective

To evaluate recent trends in the prevalence and impact of comorbidity on colorectal cancer (CRC) survival in the Central Region of Denmark.

Material and methods

Using the Danish National Registry of Patients, we identified 5,777 and 2,964 patients with a primary colon or rectal cancer, respectively, from 2000 through 2011. We estimated survival according to Charlson Comorbidity Index scores and computed mortality rate ratios (MRRs) using Cox proportional hazard regression analysis, adjusting for age and sex.

Results

More than one-third of CRC patients had comorbidity at diagnosis. During the study period, 1-year survival increased substantially in colon cancer patients with Charlson score 0 (72% to 80%) and modestly for Charlson score 3+ patients (43% to 46%). Using colon cancer patients with Charlson score 0 as reference, adjusted 1-year MRRs in patients with Charlson score 3+ were 2.19 (95% confidence interval [CI]: 1.57–3.05) in 2000–2002 and 2.56 (95% CI: 1.96–3.35) in 2009–2011. One-year survival after rectal cancer improved from 81% to 87% in patients with Charlson score 0 and from 56% to 60% in Charlson score 3+. Corresponding MRRs in patients with Charlson 3+ were 2.21 (95% CI: 1.33–3.68) in 2000–2002 and 3.09 (95% CI: 1.91–5.00) in 2009–2011 using Charlson score 0 as reference. Five-year MRRs did not differ substantially from 1-year MRRs.

Conclusion

Comorbidity was common among CRC patients and was associated with poorer prognosis. We observed improved survival from 2000 to 2011 for all comorbidity levels, with least improvement for colon cancer patients with comorbid conditions.

Comorbidity and survival of Danish prostate cancer patients from 2000-2011: a population-based cohort study

Objective

We investigated temporal changes in overall survival among prostate cancer (PC) patients and the impact of comorbidity on all-cause mortality.

Methods

We conducted a population-based cohort study in the Central Denmark Region (1.2 million inhabitants). Using medical registries, we identified 7,654 PC patients with first-time PC diagnosis within the period 2000–2011 and their corresponding comorbidities within 10 years prior to the PC diagnosis. We estimated 1- and 5-year survival in four consecutive calendar periods using a hybrid analysis and plotted Kaplan–Meier survival curves. We used Cox proportional hazards regression to compute 1- and 5-year age-adjusted mortality rate ratios (MRRs) for different comorbidity levels. All estimates are reported with their corresponding 95% confidence intervals (CI).

Results

The annual number of PC cases doubled over the 12-year study period. Men aged <70 years accounted for the largest proportional increase (from 33% to 47%). The proportion of patients within each comorbidity category remained constant over time. One-year survival increased from 82% (CI: 80%–84%) in 2000–2002 to 92% (CI: 90%–93%) in 2009–2011, while 5-year survival increased from 43% (CI: 40%–46%) to 65% (CI: 62%–67%) during the same time intervals. Improvements in 5-year survival were most prominent among patients aged <80 years and among those with no comorbidity (from 51% to 73%) and medium comorbidity (from 32% to 54%). Improvements in survival were much smaller for those with high comorbidity (from 33% to 39%). The 1-year age-adjusted MRR for patients with high comorbidity (relative to patients with no comorbidity) increased over time from 1.84 (CI: 1.19–2.84) to 3.67 (CI: 2.49–5.41), while the 5-year age-adjusted MRR increased from 1.73 (CI: 1.34–2.23) to 2.38 (CI: 1.93–2.94).

Conclusion

Overall survival of PC improved substantially during 2000–2011, although primarily among men with low comorbidity. All-cause mortality was highest among PC patients with high comorbidity, and their relative 1- and 5-year mortality increased over time compared to those without comorbidity.

Comorbidity and survival of Danish breast cancer patients from 2000-2011: a population-based cohort study

Objective

Previous studies have suggested that breast cancer survival in Denmark has improved, primarily in cancer patients without comorbidity. We therefore conducted a population-based cohort study to examine recent temporal changes in survival and mortality among breast cancer patients with different extents of comorbidity.

Methods

We used population-based medical and administrative registries to identify breast cancer patients diagnosed between 2000 and 2011 in the Central Denmark Region. We defined comorbid diseases according to the Charlson Comorbidity Index (CCI), including a history of hospitalization for comorbid disease up to 10 years before breast cancer diagnosis. We studied the impact of comorbidities on overall 1- and 5-year survival in different calendar time periods, using a hybrid analysis for survival prediction in the most recent calendar periods.

Results

We included 9,329 breast cancer patients. The proportion of patients within different comorbidity categories remained stable from 2000 to 2011. One-year survival improved from 91% in 2000–2002 to 95% in 2009–2011, while 5-year survival improved from 72% to a predicted 78%. During the entire study period, comorbidity was a strong predictor of the survival of breast cancer patients. However, we observed improvements over time in 1- and 5-year survival for all comorbidity groups. During the 12-year study period, the estimated 5-year survival for patients with a high comorbidity disease burden (CCI score ≥3) increased from 25% to a predicted 50%, and their 5-year age-adjusted mortality hazard ratio (HR) fell from 4.0 (95% confidence interval [CI]: 3.0, 5.4) to 2.7 (95% CI: 2.0, 3.6), respectively, compared with patients with no comorbid disease.

Conclusion

Survival of breast cancer patients diagnosed in the Central Denmark Region improved from 2000 to 2011, regardless of the extent of comorbid disease.

Temporal trends in stroke admissions in Denmark 1997-2009

Background

The Stroke burden is increasing in many populations where health institutions may experience more patients. We wanted to examine whether incidence rates and absolute number of hospitalized stroke patients remained stable in Denmark during a 13 years period where exposure to major stroke risk factors decreased, changes in stroke treatment was implemented, and the age of the population increased.

Methods

The Danish National Patient Register was used to identify all subjects 25 years of age or above admitted with a first time stroke in Denmark from 1997–2009. Incidence rates (IRs) and age-adjusted Poisson regression analyses were used to examine trends in age-, gender- and stroke subtype (ischaemic or unspecified).

Results

During the 13-year observation period there were 53.5 million person-years at risk (PY) and a total of 84,626 male and 84,705 female stroke patients were admitted to Danish hospitals. The IRs of hospitalized strokes per 1000 PY was 3.21 (95% confidence interval [CI] 3.16-3.27) in 1997, 3.85 (95% CI 3.79-3.91) in 2003 and 3.22 (95% CI 3.16-3.28) in 2009, respectively.

Incidence rate ratios of hospitalized stroke events adjusted for age in the period 2007–2009 compared to 1997–2000 were 0.89 (95% CI 0.87- 0.91) for men and 0.92 (95% CI 0.90-0.94) for women.

The incidence of hospitalized unspecified strokes decreased from 1997 to 2009 whereas there was a steep rise in incidence for hospitalization with specified ischemic stroke during this period.

Conclusion

This study found a constant rate of stroke hospitalization in Denmark from 1997–2009. The overall rate of hospitalized strokes adjusted for age decreased during this period.

Comorbid diseases interact with breast cancer to affect mortality in the first year after diagnosis--a Danish nationwide matched cohort study

Background

Survival of breast cancer patients with comorbidity, compared to those without comorbidity, has been well characterized. The interaction between comorbid diseases and breast cancer, however, has not been well-studied.

Methods

From Danish nationwide medical registries, we identified all breast cancer patients between 45 and 85 years of age diagnosed from 1994 to 2008. Women without breast cancer were matched to the breast cancer patients on specific comorbid diseases included in the Charlson comorbidity Index (CCI). Interaction contrasts were calculated as a measure of synergistic effect on mortality between comorbidity and breast cancer.

Results

The study included 47,904 breast cancer patients and 237,938 matched comparison women. In the first year, the strongest interaction between comorbidity and breast cancer was observed in breast cancer patients with a CCI score of ≥4, which accounted for 29 deaths per 1000 person-years. Among individual comorbidities, dementia interacted strongly with breast cancer and accounted for 148 deaths per 1000 person-years within one year of follow-up. There was little interaction between comorbidity and breast cancer during one to five years of follow-up.

Conclusions

There was substantial interaction between comorbid diseases and breast cancer, affecting mortality. Successful treatment of the comorbid diseases or the breast cancer can delay mortality caused by this interaction in breast cancer patients.

Use of benzodiazepines or benzodiazepine related drugs and the risk of cancer: a population-based case-control study

AIM

Studies of the carcinogenic potential of benzodiazepines and related drugs (BZRD) have been equivocal. A recent study reported a 35% excess cancer risk among users of hypnotics, including benzodiazepines.

METHOD

Using Danish nationwide registers, we conducted a matched case-control study of the association between BZRD and cancer risk. During 1 January 2002 and 31 December 2009, we identified 152 510 cases with a first time cancer who were matched (1:8) by age and gender to 1,220,317 cancer-free controls. A new-user design was applied by excluding all subjects who had used anxiolytics, hypnotics or sedatives during the first 2 years of available prescription data (1995-6). Odds ratios (ORs) with 95% confidence intervals (CI) were estimated using conditional logistic regression, adjusting for potential confounders. In the primary analysis, long term use of BZRD was defined by a cumulative amount of ≥500 defined daily doses of BZRD within a period of 1 to 5 years prior to the index date.

RESULTS

The adjusted OR for cancer associated with BZRD use was 1.09 (95% CI 1.04, 1.14). ORs were close to unity for most cancer sites, except stomach 1.40 (95% CI 1.05, 1.88), oesophagus 1.43 (95% CI 1.01, 2.02), liver 1.81 (95% CI 1.18, 2.80), lung 1.38 (95% CI 1.23, 1.54), pancreas 1.35 (95% CI 1.02, 1.79) and kidney 1.39 (95% CI 1.01, 1.91). For tobacco-related cancers, the OR was 1.15 (95% CI 1.09, 1.22) and for the remaining cancer sites 1.01 (95% CI 0.94, 1.08). Sub-group analyses revealed only small differences between different levels of exposure or different patient subgroups.

CONCLUSION

BZRD use was not associated with an overall increase in cancer risk, except for what is likely explained by minor lifestyle confounding, e.g. smoking.

Risk of colorectal cancer in patients with acute myocardial infarction and stroke: a nationwide cohort study

BACKGROUND

An association between colorectal cancer and acute myocardial infarction (AMI) and stroke has been suggested, but evidence is conflicting.

METHOD

We conducted a population-based cohort study (1978-2010) of the association between AMI/stroke and colorectal cancer by linking nationwide Danish registries. We calculated standardized incidence ratios (SIR) of colorectal cancer after AMI/stroke as the ratios of observed to expected incidence.

RESULTS

A total of 297,523 patients with AMI (median age, 69.4 years; 64% men) were followed for a median of 3.1 years (range, 0-33 years) and 4,387 developed colorectal cancer [SIR, 1.08; 95% confidence interval (CI), 1.05-1.11; P < 0.001]. In the first year of follow-up, the SIR was 1.85 (95% CI, 1.73-1.98; P < 0.001), whereas it was 0.98 (95% CI, 0.95-1.02; P = 0.318) in the second and subsequent years. We followed 246,998 patients with stroke (median age, 72.4 years; 52% men) for a median of 2.9 years (range, 0-33 years) and 3,035 developed colorectal cancer (SIR, 1.04; 95% CI, 1.00-1.07; P = 0.053). In the first year of follow-up, the SIR was 1.42 (95% CI, 1.31-1.53; P < 0.001), whereas it was 0.96 (95% CI, 0.93-1.00; P = 0.072) thereafter. We found no difference between the SIRs for ischemic and hemorrhagic stroke. The increased one-year relative risks for AMI and stroke corresponded to a 0.3% absolute risk.

CONCLUSIONS

Our findings reflect detection of occult cancer at the time of the vascular event. The lack of increased risk after one year suggests that an association based on shared risk factors or chronic inflammation is unlikely.

IMPACT

In patients with AMI/stroke, the diagnostic workup including screening for colorectal cancer should follow that of the general population.

Does comorbidity interact with colorectal cancer to increase mortality? A nationwide population-based cohort study

BACKGROUND

It is unknown whether comorbidity interacts with colorectal cancer (CRC) to increase the rate of mortality beyond that explained by the independent effects of CRC and comorbid conditions.

METHODS

We conducted a cohort study (1995-2010) of all Danish CRC patients (n=56963), and five times as many persons from the general population (n=271670) matched by age, gender, and specific comorbidities. To analyse comorbidity, we used the Charlson Comorbidity Index (CCI) scores. We estimated standardised mortality rates per 1000 person-years, and calculated interaction contrasts as a measure of the excess mortality rate not explained by the independent effects of CRC or comorbidities.

RESULTS

Among CRC patients with a CCI score=1, the 0-1 year mortality rate was 415 out of 1000 person-years (95% confidence interval (CI): 401, 430) and the interaction accounted for 9.3% of this rate (interaction contrast=39 out of 1000 person-years, 95% CI: 22, 55). For patients with a CCI score of 4 or more, the interaction accounted for 34% of the mortality (interaction contrast=262 out of 1000 person-years, 95% CI: 215, 310). The interaction between CRC and comorbidities had limited influence on mortality beyond 1 year after diagnosis.

CONCLUSION

Successful treatment of the comorbidity is pivotal and may reduce the mortality attributable to comorbidity itself, and also the mortality attributable to the interaction.

Preadmission metformin use and mortality among intensive care patients with diabetes: a cohort study

Introduction

Metformin has anti-inflammatory and anti-thrombotic effects that may improve the outcome of critical illness, but clinical data are limited. We examined the impact of preadmission metformin use on mortality among intensive care unit (ICU) patients with type 2 diabetes.

Methods

We conducted this population-based cohort study among all persons admitted to the 17 ICUs in Northern Denmark (population approximately 1.8 million). We focused on all patients with type 2 diabetes who were admitted to the ICUs between January 2005 and December 2011. Through individual-level linkage of population-based medical databases, type 2 diabetes was identified using a previously validated algorithm including hospital diagnoses, filled prescriptions for anti-diabetic drugs, and elevated HbA1c levels. Metformin use was identified by filled prescriptions within 90 days before admission. Covariates included surgery, preadmission morbidity, diabetes duration, and concurrent drug use. We computed 30-day mortality and hazard ratios (HRs) of death using Cox regression adjusted for covariates, both overall and after propensity score matching.

Results

We included 7,404 adult type 2 diabetes patients, representing 14.0% of 52,964 adult patients admitted to the ICUs. Among type 2 diabetes patients, 1,073 (14.5%) filled a prescription for metformin as monotherapy within 90 days before admission and 1,335 (18.0%) received metformin in combination with other anti-diabetic drugs. Thirty-day mortality was 17.6% among metformin monotherapy users, 17.9% among metformin combination therapy users, and 25.0% among metformin non-users. The adjusted HRs were 0.80 (95% confidence interval (CI): 0.69, 0.94) for metformin monotherapy users and 0.83 (95% CI: 0.71, 0.95) for metformin combination therapy users, compared to non-users. Propensity-score-matched analyses yielded the same results. The association was evident across most subgroups of medical and surgical ICU patients, but most pronounced in elderly patients and in patients with well-controlled diabetes. Former metformin use was not associated with decreased mortality.

Conclusions

Preadmission metformin use was associated with reduced 30-day mortality among medical and surgical intensive care patients with type 2 diabetes.

Hospitalization rate and 30-day mortality among patients with status asthmaticus in Denmark: a 16-year nationwide population-based cohort study

Objective

Current data on hospitalization and prognosis of acute asthma and status asthmaticus are inconclusive. We aim to analyze the rate of first-time hospitalizations for status asthmaticus among patients of all ages, the proportion admitted to intensive care units (ICU), and the 30-day mortality over a 16-year period.

Methods

In this population-based cohort study, we used medical registries to identify all first-time status asthmaticus hospitalizations in Denmark from 1996 through 2011. Data on comorbidities were also obtained. We computed yearly hospitalization rates overall and by gender and age groups, and estimated the proportion requiring ICU admission. We estimated 30-day age- and gender-standardized mortality. We examined potential misclassification from acute exacerbation of chronic obstructive pulmonary disease (COPD) by excluding patients with preexisting or concurrent COPD.

Results

Of the 5,001 patients identified with a first-time status asthmaticus hospitalization, 50.5% were male, 40.3% were <15 years old, and 12.4% had comorbidity. The hospitalization rate increased from 48.0 per 1,000,000 person-years (PY) (95% confidence interval [CI]: 45.1–51.1 PY) during 1996–1999 to 70.1 per 1,000,000 PY (95% CI: 66.7–73.7 PY) during 2008–2011. This may be explained by an increased hospitalization rate of children. The standardized 30-day mortality risk declined from 3.3% (95% CI: 2.5%–4.1%) in 1996–1999 to 1.5% (95% CI: 0.9%–2.1%) in 2008–2011. During 2005–2011, 10.1% of status asthmaticus patients were admitted to the ICU. Hospitalization rates and mortality risk decreased by excluding 939 patients also registered with COPD, but overall temporal changes did not change.

Conclusion

From 1996 to 2011, status asthmaticus hospitalization rate increased but remained below 100 hospitalizations per 1,000,000 PY. Thirty-day mortality risk was halved to less than 2%.

Characteristics and survival of interval and sporadic colorectal cancer patients: a nationwide population-based cohort study

OBJECTIVES

Colorectal cancers (CRCs) diagnosed relatively soon after a colonoscopy are referred to as interval CRCs. It is not clear whether interval CRCs arise from prevalent lesions missed at colonoscopy or represent specific aggressive biology leading to poor survival.

METHODS

Using Danish population-based medical registries (2000-2009), we investigated patients with "interval" CRC diagnosed within 1-5 years of a colonoscopy, and compared them with cases with colonoscopy ≥10 years before diagnosis and to "sporadic" CRCs with no colonoscopy before diagnosis. Multivariate logistic regression was used to explore the association between clinical, demographic, and comorbidity characteristics and interval CRC. We assessed survival using Kaplan-Meier methods and mortality rate ratios (MRRs) using Cox regression, adjusting for covariates including the Charlson Comorbidity Index (CCI 0, 1-2, 3+).

RESULTS

The comparison of the 982 interval CRCs to the 358 patients with CRC ≥10 years after colonoscopy revealed nearly similar characteristics and mortality. In the comparison with the 35,704 sporadic CRCs, interval cases were slightly older (74 vs. 71 years), more likely to be female (54 vs. 48%), have comorbidities (CCI3+: 28 vs. 15%), have proximal tumors (38 vs. 22%), and tumors with mucinous histology (9.1 vs. 7.0%), but stage was similar (metastatic 23 vs. 24%). In logistic regression analysis, female sex, localized stage at diagnosis, proximal tumor location, and high comorbidity burden were factors independently associated with interval CRC. The 1-year survival was 68% (95% confidence interval (CI): 65%, 71%) in interval and 71% (95% CI: 70%, 71%) in sporadic cases, with an adjusted MRR of 0.92 (95% CI 0.82, 1.0). After 5 years, survival was 41% (95% CI: 37%, 44%) in interval and 43% (95% CI: 42%, 43%) in sporadic cases, and the adjusted 2-5 year MRR was 1.0 (95% CI 0.88, 1.2).

CONCLUSIONS

Clinical characteristics and survival among interval CRCs did not suggest aggressive biology, but rather that the majority represented missed lesions.

Effect of socioeconomic status on mortality after bacteremia in working-age patients. A Danish population-based cohort study

Objectives

To examine the effect of socioeconomic status (SES) on mortality in patients with bacteremia and the underlying factors that may mediate differences in mortality.

Methods

We conducted a population-based cohort study in two Danish regions. All patients 30 to 65 years of age with first time bacteremia from 2000 through 2008 were identified in a population-based microbiological bacteremia database (n = 8,653). Individual-level data on patients’ SES (educational level and personal income) and comorbid conditions were obtained from public and medical registries. We used Cox regression to examine mortality within 30 days after bacteremia with and without cumulative adjustment for potential mediators.

Results

Bacteremia patients of low SES were more likely to live alone and be unmarried than patients of high SES. They also had more pre-existing comorbidity, more substance abuse, more Staphylococcus aureus and nosocomial infections, and more admissions to small nonteaching hospitals. Overall, 1,374 patients (15.9%) died within 30 days of follow-up. Patients of low SES had consistently higher mortality after bacteremia than those of high SES crude hazard ratio for low vs. high education, 1.38 [95% confidence interval (CI), 1.18–1.61]; crude hazard ratio for low-income vs. high-income tertile, 1.58 [CI, 1.39–1.80]. Adjustment for differences in social support, pre-existing comorbidity, substance abuse, place of acquisition of the infection, and microbial agent substantially attenuated the effect of SES on mortality (adjusted hazard ratio for low vs. high education, 1.15 [95% CI, 0.98–1.36]; adjusted hazard ratio for low-income vs. high-income tertile, 1.29 [CI, 1.12–1.49]). Further adjustment for characteristics of the admitting hospital had minimal effect on observed mortality differences.

Conclusions

Low SES was strongly associated with increased 30-day mortality after bacteremia. Less social support, more pre-existing comorbidity, more substance abuse, and differences in place of acquisition and agent of infection appeared to mediate much of the observed disparities in mortality.

Risk of human papillomavirus-related cancers among kidney transplant recipients and patients receiving chronic dialysis--an observational cohort study

Background

Individuals with end-stage renal disease (ESRD) have excess risk of various cancer types. However, the total burden of human papillomavirus-related cancers remains unknown.

Methods

We performed a nationwide observational cohort study during 1994–2010.

For each person with ESRD, we sampled 19 population controls (without ESRD) matched on age, gender and municipality. Participants were followed until first diagnosis of human papillomavirus-related cancer, death, emigration, or 31 December 2010, whichever came first.

Human papillomavirus-related cancers were extracted from Danish medical administrative databases. We considered cancers of the cervix, vulva, vagina, penis, anus, and subsets of head and neck cancers as human papillomavirus-related. We calculated incidence rates of human papillomavirus-related cancer and used Poisson regression to identify risk factors for human papillomavirus-related cancer.

Results

Among 12,293 persons with ESRD and 229,524 population controls we identified 62 and 798 human papillomavirus-related cancers, respectively. Incidence rates of human papillomavirus-related- cancer were 102 per 100,000 person-years (95% confidence interval [CI]; 79.5-131) among persons with ESRD and 40.8 per 100,000 person-years (95% CI; 38.1-43.7) among population controls. ESRD patients had 4.54 (95% CI, 2.48-8.31) fold increased risk of anal cancer and 5.81 fold (95% CI; 3.36-10.1) increased risk of vulvovaginal cancer. Adjusted for age, comorbidity, and sex, ESRD patients had 2.41 (95% CI; 1.83-3.16) fold increased risk of any human papillomavirus-related cancer compared with population controls. Compared with dialysis patients renal transplant recipients had an age-adjusted non-significant 1.53 (95% CI, 0.91-2.58) fold higher risk of human papillomavirus-related cancer.

Conclusions

Persons with ESRD have excess risk of potentially vaccine-preventable human papillomavirus-related cancers.

Hospitalization with acute exacerbation of chronic obstructive pulmonary disease and associated health resource utilization: a population-based Danish cohort study

OBJECTIVE

Health resource utilization (HRU) and outcomes associated with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are not well described. Therefore, a population-based cohort study was conducted to characterize patients hospitalized with AECOPD with regard to HRU, mortality, recurrence, and predictors of readmission with AECOPD.

METHODS

Using Danish healthcare databases, this study identified COPD patients with at least one AECOPD hospitalization between 2005-2009 in Northern Denmark. Hospitalized AECOPD patients' HRU, in-hospital mortality, 30-day, 60-day, 90-day, and 180-day post-discharge mortality and recurrence risk, and predictors of readmission with AECOPD in the year following study inclusion were characterized.

RESULTS

This study observed 6612 AECOPD hospitalizations among 3176 prevalent COPD patients. Among all AECOPD hospitalizations, median length of stay was 6 days (interquartile range [IQR] 3-9 days); 5 days (IQR 3-9) among those without ICU stay and 11 days (IQR 7-20) among the 8.6% admitted to the ICU. Mechanical ventilation was provided to 193 (2.9%) and non-invasive ventilation to 479 (7.2%) admitted patients. In-hospital mortality was 5.6%. Post-discharge mortality was 4.2%, 7.8%, 10.5%, and 17.4% at 30, 60, 90, and 180 days, respectively. Mortality and readmission risk increased with each AECOPD hospitalization experienced in the first year of follow-up. Readmission at least twice in the first year of follow-up was observed among 286 (9.0%) COPD patients and was related to increasing age, male gender, obesity, asthma, osteoporosis, depression, myocardial infarction, diabetes I and II, any malignancy, and hospitalization with AECOPD or COPD in the prior year.

LIMITATIONS

The study included only hospitalized AECOPD patients among prevalent COPD patients. Furthermore, information was lacking on clinical variables.

CONCLUSION

These findings indicate that AECOPD hospitalizations are associated with substantial mortality and risk of recurrence.

Accuracy of the Charlson index comorbidities derived from a hospital electronic database in a teaching hospital in Saudi Arabia

Hospital management and researchers are increasingly using electronic databases to study utilization, effectiveness, and outcomes of healthcare provision. Although several studies have examined the accuracy of electronic databases developed for general administrative purposes, few studies have examined electronic databases created to document the care provided by individual hospitals. In this study, we assessed the accuracy of an electronic database in a major teaching hospital in Eastern Province, Saudi Arabia, in documenting the 17 comorbidities constituting the Charlson index as recorded in paper charts by care providers. Using the hospital electronic database, the researchers randomly selected the data for 1,019 patients admitted to the hospital and compared the data for accuracy with the corresponding paper charts. Compared with the paper charts, the hospital electronic database did not differ significantly in prevalence for 9 conditions but differed from the paper charts for 8 conditions. The kappa (K) values of agreement ranged from a high of 0.91 to a low of 0.09. Of the 17 comorbidities, the electronic database had substantial or excellent agreement for 10 comorbidities relative to paper chart data, and only one showed poor agreement. Sensitivity ranged from a high of 100.0 percent to a low of 6.0 percent. Specificity for all comorbidities was greater than 93 percent. The results suggest that the hospital electronic database reasonably agrees with patient chart data and can have a role in healthcare planning and research. The analysis conducted in this study could be performed in individual institutions to assess the accuracy of an electronic database before deciding on its utility in planning or research.

Candida infection and cancer risk: a Danish nationwide cohort study

BACKGROUND

Candida species infection may be associated with increased cancer risk.

METHODS

We linked data from the nationwide medical registries and examined the incidence of various cancers in patients with a first-time hospital presentation with candida infection. We computed the cumulative incidence of cancer and standardized incidence ratios (SIRs) of cancer overall, immune-related cancers, and specific cancer types by comparing observed versus expected incidences based on age-, sex-, and anatomical site-specific incidence rates.

RESULTS

Among 21,247 candida-infected patients, we identified 1534 cancers during a combined follow-up of 187,993 years (standardized incidence ratio (SIR)=1.6 (95% confidence interval (CI): 1.5-1.7)). The 1- and 10-year risks of cancer were 2.6%, and 8.3%, respectively. In the first year after a candida diagnosis, the SIR for cancer was 3.7 (95% CI: 3.4-4.0). In the second and subsequent years of follow-up, the SIRs were 1.2 (95% CI: 1.1-1.3) for any cancer and 1.4 (95% CI 1.2-1.7) for immune-related cancers. The risk of mouth and throat cancers remained more than 3-fold increased in the second and subsequent years of follow-up.

CONCLUSIONS

Hospital presentation with candida infection is associated with increased short- and long-term cancer risk.

Identification of acute myocardial infarction from electronic healthcare records using different disease coding systems: a validation study in three European countries

OBJECTIVE

To evaluate positive predictive value (PPV) of different disease codes and free text in identifying acute myocardial infarction (AMI) from electronic healthcare records (EHRs).

DESIGN

Validation study of cases of AMI identified from general practitioner records and hospital discharge diagnoses using free text and codes from the International Classification of Primary Care (ICPC), International Classification of Diseases 9th revision-clinical modification (ICD9-CM) and ICD-10th revision (ICD-10).

SETTING

Population-based databases comprising routinely collected data from primary care in Italy and the Netherlands and from secondary care in Denmark from 1996 to 2009.

PARTICIPANTS

A total of 4 034 232 individuals with 22 428 883 person-years of follow-up contributed to the data, from which 42 774 potential AMI cases were identified. A random sample of 800 cases was subsequently obtained for validation.

MAIN OUTCOME MEASURES

PPVs were calculated overall and for each code/free text. 'Best-case scenario' and 'worst-case scenario' PPVs were calculated, the latter taking into account non-retrievable/non-assessable cases. We further assessed the effects of AMI misclassification on estimates of risk during drug exposure.

RESULTS

Records of 748 cases (93.5% of sample) were retrieved. ICD-10 codes had a 'best-case scenario' PPV of 100% while ICD9-CM codes had a PPV of 96.6% (95% CI 93.2% to 99.9%). ICPC codes had a 'best-case scenario' PPV of 75% (95% CI 67.4% to 82.6%) and free text had PPV ranging from 20% to 60%. Corresponding PPVs in the 'worst-case scenario' all decreased. Use of codes with lower PPV generally resulted in small changes in AMI risk during drug exposure, but codes with higher PPV resulted in attenuation of risk for positive associations.

CONCLUSIONS

ICD9-CM and ICD-10 codes have good PPV in identifying AMI from EHRs; strategies are necessary to further optimise utility of ICPC codes and free-text search. Use of specific AMI disease codes in estimation of risk during drug exposure may lead to small but significant changes and at the expense of decreased precision.

Multisystem morbidity and mortality in Cushing's syndrome: a cohort study

CONTEXT

Cushing's syndrome (CS) is associated with hypercoagulability, insulin resistance, hypertension, bone loss, and immunosuppression. To date, no adequately large cohort study has been performed to assess the multisystem effects of CS.

OBJECTIVE

We aimed to examine the risks for mortality, cardiovascular disease, fractures, peptic ulcers, and infections in CS patients before and after treatment.

DESIGN

Population-based cohort study.

SETTING

Source population was the entire population of Denmark (1980 to 2010). Data were obtained from the Danish National Registry of Patients and the Danish Civil Registration System.

PATIENTS

Benign CS of adrenal or pituitary origin and a matched population comparison cohort were included.

OUTCOME MEASURES

We used Cox regression, and computed hazard ratios (HR) with 95% confidence intervals (95% CI). Morbidity was investigated in the 3 years before diagnosis; morbidity and mortality were assessed during complete follow-up after diagnosis and treatment.

RESULTS

Included were 343 CS patients and 34 300 controls. Mortality was twice as high in CS patients (HR 2.3, 95%CI 1.8-2.9) compared with controls. Patients with CS were at increased risk for venous thromboembolism (HR 2.6, 95%CI 1.5-4.7), myocardial infarction (HR 3.7, 95%CI 2.4-5.5), stroke (HR 2.0, 95%CI 1.3-3.2), peptic ulcers (HR 2.0, 95%CI 1.1-3.6), fractures (HR 1.4, 95%CI 1.0-1.9), and infections (HR 4.9, 95%CI 3.7-6.4). This increased multimorbidity risk was present before diagnosis. Mortality and risk of myocardial infarction remained elevated during long-term follow-up. Mortality and risks for acute myocardial infarction, venous thromboembolism, stroke, and infections were similarly increased in adrenal and pituitary CS.

CONCLUSIONS

Despite the apparently benign character of the disease, CS is associated with clearly increased mortality and multisystem morbidity, even before diagnosis and treatment.

Chronic heart failure and risk of hospitalization with pneumonia: a population-based study

BACKGROUND

Chronic heart failure may increase risk of pneumonia due to alveoli flooding and reduced microbial clearance. We examined whether chronic heart failure is a risk factor for pneumonia-related hospitalization.

METHODS

In this large population-based case-control study we identified adult patients with a first-time primary or secondary discharge diagnosis of viral or bacterial pneumonia between 1994 and 2008, using health care databases in Northern Denmark. For each case, ten sex- and age-matched population controls were selected from Denmark's Civil Registration System. We used conditional logistic regression to compute relative risk (RR) for pneumonia-related hospitalization among persons with and without pre-existing heart failure, overall and stratified by medical treatment. We controlled for a wide range of comorbidities, socioeconomic markers and immunosuppressive treatment.

RESULTS

The study included 67,162 patients with a pneumonia-related hospitalization and 671,620 population controls. The adjusted OR for pneumonia-related hospitalization among persons with previous heart failure was 1.81 (95% confidence interval (CI): 1.76-1.86) compared with other individuals. The adjusted pneumonia RR was lower for heart failure patients treated with thiazides only (adjusted OR=1.56, 95% CI: 1.46-1.67), as compared with patients whose treatment included loop-diuretics and digoxin as a marker of increased severity (adjusted OR=1.95, 95% CI: 1.85-2.06) or both loop-diuretics and spironolactone (adjusted OR=2.02, 95% CI: 1.90-2.15). The population-attributable risk of pneumonia hospitalizations caused by heart failure in our population was 6.2%.

CONCLUSIONS

Patients with chronic heart failure, in particular those using loop diuretics, have markedly increased risk of hospitalization with pneumonia.

Lower reoperation rate for cemented hemiarthroplasty than for uncemented hemiarthroplasty and internal fixation following femoral neck fracture: 12- to 19-year follow-up of patients aged 75 years or more

BACKGROUND AND PURPOSE

Elderly patients with displaced femoral neck fractures are commonly treated with a hemiarthroplasty (HA), but little is known about the long-term failure of this treatment. We compared reoperation rates for patients aged at least 75 years with displaced femoral neck fractures treated with either internal fixation (IF), cemented HA, or uncemented HA (with or without hydroxyapatite coating), after 12-19 years of follow-up.

METHODS

4 hospitals with clearly defined guidelines for the treatment of 75+ year-old patients with a displaced femoral neck fracture were included. Cohort 1 (1991-1993) with 180 patients had undergone IF; cohort 2 (1991-1995) with 203 patients had received an uncemented bipolar Ultima HA stem (Austin-Moore); cohort 3 (1991-1995) with 209 patients had received a cemented Charnley-Hastings HA; and cohort 4 (1991-1998) with 158 patients had received an uncemented hydroxyapatite-coated Furlong HA. Data were retrieved from patient files, from the region-based patient administrative system, and from the National Registry of Patients at the end of 2010. We performed survival analysis with adjustment for comorbidity, age, and sex.

RESULTS

Cemented HA had a reoperation rate (RR) of 5% and was used as reference in the Cox regression analysis, which showed significantly higher hazard ratios (HRs) for IF (HR = 3.8, 95% CI: 1.9-7.5; RR = 18%), uncemented HA (HR = 2.2, CI: 1.1-4.5; RR = 11%) and uncemented hydroxyapatite-coated HA (HR = 3.6, CI: 1.8-7.4; RR = 16%).

INTERPRETATION

Cemented HA has a superior long-term hip survival rate compared to IF and uncemented HA (with and without hydroxyapatite coating) in patients aged 75 years or more with displaced femoral neck fractures.

Socioeconomic status in HCV infected patients - risk and prognosis

Background and aims

It is unknown whether socioeconomic status (SES) is a risk factor for hepatitis C virus (HCV) infection or a prognostic factor following infection.

Methods

From Danish nationwide registries, we obtained information on three markers of SES: employment, income, and education. In a case control design, we examined HCV infected patients and controls; conditional logistic regression was employed to obtain odds ratios (ORs) for HCV infection for each of the three SES markers, adjusting for the other two SES markers, comorbidity, and substance abuse. In a cohort design, we used Cox regression analysis to compute mortality rate ratios (MRRs) for each of the three SES markers, adjusting for the other two SES markers, comorbidity level, age, substance abuse, and gender.

Results

When compared to employed persons, ORs for HCV infection were 2.71 (95% confidence interval [CI]: 2.24–3.26) for disability pensioners and 2.24 (95% CI: 1.83–2.72) for the unemployed. When compared to persons with a high income, ORs were 1.64 (95% CI: 1.34–2.01) for low income persons and 1.19 (95% CI: 1.02–1.40) for medium income persons. The OR was 1.35 (95% CI: 1.20–1.52) for low education (no more than basic schooling). When compared to employed patients, MRRs were 1.71 (95% CI: 1.22–2.40) for unemployed patients and 2.24 (95% CI: 1.63–3.08) for disability pensioners. When compared to high income patients, MRRs were 1.47 (95% CI: 1.05–2.05) for medium income patients and 1.64 (95% CI: 1.13–2.34) for low income patients. Educational status was not associated with mortality.

Conclusion

Low SES was associated with an increased risk of HCV infection and with poor prognosis in HCV infected patients.

The impact of comorbidity and stage on prognosis of Danish melanoma patients, 1987-2009: a registry-based cohort study

BACKGROUND

Comorbid conditions may play an important role in the prognosis of melanoma patients but have received little attention.

METHODS

Using data from Danish registries, we identified patients diagnosed with melanoma from 1987 to 2009. We estimated the prevalence of comorbidity and calculated mortality rate ratios and interaction risks between melanoma and comorbidity. For every melanoma patient, 10 individuals were selected for comparison. Individuals in the comparison cohort were matched to their corresponding melanoma patients on age, gender, and exact prevalent comorbidities.

RESULTS

We included 23 476 patients, 81% of whom had no comorbidity. Higher prevalence of comorbidity was associated with more advanced cancer stage. The standardised mortality rate increased with increasing level of comorbidity in both cohorts and was consistently higher among melanoma patients. Melanoma and comorbidity interacted to increase the mortality rate. The highest proportional excess was seen in melanoma patients with comorbidity score 3, in whom interaction accounted for 77 deaths per 1000 person-years (40% of the total rate). We stratified by cancer stage and found that the interaction was markedly concentrated in patients with distant metastases.

CONCLUSION

Interaction between melanoma and comorbidity was primarily concentrated in patients with distant metastases, which raises the possibility that comorbidity is associated with delay of melanoma diagnosis, advanced cancer stage, and less aggressive melanoma treatment.