Cause-specific mortality in COPD subpopulations: a cohort study of 339 647 people in England

BACKGROUND

Identifying correlates of cause-specific mortality in patients with chronic obstructive pulmonary disease (COPD) may aid the targeting of therapies to reduce mortality. We determined factors associated with causes of death in a primary care COPD population.

METHODS

Clinical Practice Research Datalink Aurum was linked to Hospital Episode Statistics and death certificate data. People with COPD alive between 1 January 2010 and 1 January 2020 were included. Patient characteristics were defined before the start of follow-up: (a) frequency and severity of exacerbations; (b) emphysema or chronic bronchitis; (c) Global Obstructive Lung Disease (GOLD) groups A-D; and (d) airflow limitation. We used Cox Proportional Hazards regression and competing risks to investigate the association between patient characteristics and risk of all-cause, COPD and cardiovascular (CV) mortality.

RESULTS

339 647 people with COPD were included of which 97 882 died during follow-up (25.7% COPD related and 23.3% CV related). Airflow limitation, GOLD group, exacerbation frequency and severity, and COPD phenotype were associated with all-cause mortality. Exacerbations, both increased frequency and severity, were associated with COPD-related mortality (≥2 exacerbations vs none adjusted HR: 1.64, 1.57-1.71; 1 severe vs none adjusted HR: 2.17, 2.04-2.31, respectively). Patients in GOLD groups B-D had a higher risk of COPD and CV mortality compared with GOLD group A (GOLD group D vs group A, adjusted HR for COPD mortality: 4.57, 4.23-4.93 and adjusted HR for CV mortality: 1.53, 1.41-1.65). Increasing airflow limitation was also associated with both COPD and CV mortality (GOLD 4 vs 1, adjusted HR: 12.63, 11.82-13.51 and adjusted HR: 1.75, 1.60-1.91, respectively).

CONCLUSION

Poorer airflow limitation, worse functional status and exacerbations had substantial associations with risk of all-cause mortality. Differing results for CV and COPD-related mortality suggests interventions to prevent mortality may need to target particular characteristics or time points in the disease course.

Exploring the impact of varying definitions of exacerbations of chronic obstructive pulmonary disease in routinely collected electronic medical records

BACKGROUND

Validity of exposure and outcome measures in electronic medical records is vital to ensure robust, comparable study findings however, despite validation studies, definitions of variables used often differ. Using exacerbations of chronic obstructive pulmonary disease (COPD) as an example, we investigated the impact of potential misclassification of different definitions commonly used in publications on study findings.

METHODS

A retrospective cohort study was performed. English primary care data from the Clinical Practice Research Datalink Aurum database with linked secondary care data were used to define a population of COPD patients ≥40 years old registered at a general practice. Index date was the date eligibility criteria were met and end of follow-up was 30/12/19, death or end of data collection. Exacerbations were defined using 6 algorithms based on definitions commonly used in the literature, including one validated definition. For each algorithm, the proportion of frequent exacerbators (≥2 exacerbations/year) and exacerbation rates were described. Cox proportional hazard regression was used to investigate each algorithm on the association between heart failure and risk of COPD exacerbation.

FINDINGS

A total of 315,184 patients were included. Baseline proportion of frequent exacerbators varied from 2.7% to 15.3% depending on the algorithm. Rates of exacerbations over follow-up varied from 19.3 to 66.6 events/100 person-years. The adjusted hazard ratio for the association between heart failure and exacerbation varied from 1.45, 95% confidence intervals 1.42-1.49, to 1.01, 0.98-1.04.

INTERPRETATION

The use of high validity definitions and standardisation of definitions in electronic medical records is crucial to generating high quality, robust evidence.

Mortality in non-exacerbating COPD: a longitudinal analysis of UK primary care data

INTRODUCTION

Non-exacerbating patients with chronic obstructive pulmonary disease (COPD) are a less studied phenotype. We investigated clinical characteristics, mortality rates and causes of death among non-exacerbating compared with exacerbating patients with COPD.

METHODS

We used data from the Clinical Practice Research Datalink, Hospital Episode Statistics and Office for National Statistics between 1 January 2004 and 31 December 2018. Ever smokers with a COPD diagnosis with minimum 3 years of baseline information were included. We compared overall using Cox regression and cause-specific mortality rates using competing risk analysis, adjusted for age, sex, deprivation, smoking status, body mass index, GOLD stage and comorbidities. Causes of death were identified using International Classification of Diseases-10 codes.

RESULTS

Among 67 516 patients, 17.3% did not exacerbate during the 3-year baseline period. Mean follow-up was 4 years. Non-exacerbators were more likely to be male (63.3% vs 52.4%, p<0.001) and less often had a history of asthma (33.9% vs 43.6%, p<0.001) or FEV1<50% predicted (23.7 vs 31.8%) compared with exacerbators. Adjusted HR for overall mortality in non-exacerbators compared with exacerbators was 0.62 (95% CI 0.56 to 0.70) in the first year of follow-up and 0.87 (95% CI 0.83 to 0.91) thereafter. Non-exacerbating patients with COPD died less of respiratory causes than exacerbators (29.2% vs 40.3%) and more of malignancies (29.4% vs 23.4%) and cardiovascular diseases (26.2% vs 22.9%). HRs for malignant and circulatory causes of death were increased after the first year of follow-up.

DISCUSSION

In this primary care cohort, non-exacerbators showed distinct clinical characteristics and lower mortality rates. Non-exacerbators were equally likely to die of respiratory, malignant or cardiovascular diseases.

Frequency and severity of respiratory infections prior to COPD diagnosis and risk of subsequent postdiagnosis COPD exacerbations and mortality: EXACOS-UK health care data study

OBJECTIVE

Little is known about how lower respiratory tract infections (LRTIs) before chronic obstructive pulmonary disease (COPD) are associated with future exacerbations and mortality. We investigated this association in patients with COPD in England.

METHODS

Clinical Practice Research Datalink Aurum, Hospital Episode Statistics and Office of National Statistics data were used. Start of follow-up was patient's first ever COPD diagnosis date and a 1-year baseline period prior to start of follow-up was used to find mild LRTIs (general practice (GP) events/no antibiotics), moderate LRTIs (GP events+antibiotics) and severe LRTIs (hospitalised). Patients were categorised as having: none, 1 mild only, 2+ mild only, 1 moderate, 2+ moderate and 1+ severe. Negative binomial regression modelled the association between baseline LRTIs and subsequent COPD exacerbations and Cox proportional hazard regression was used to investigate mortality.

RESULTS

In 215 234 patients with COPD, increasing frequency and severity of mild and moderate LRTIs were associated with increased rates of subsequent exacerbations compared with no recorded LRTIs (1 mild adjusted IRR 1.16, 95% CI 1.14 to 1.18, 2+ mild IRR 1.51, 95% CI 1.46 to 1.55, 1 moderate IRR 1.81, 95% CI 1.78 to 1.85, 2+ moderate IRR 2.55, 95% CI 2.48 to 2.63). Patients with 1+ severe LRTI (vs no baseline LRTIs) also showed an increased rate of future exacerbations (adjusted IRR 1.75, 95% CI, 1.70 to 1.80). This pattern of association was similar for risk of all-cause and COPD-related mortality; however, patients with 1+ severe LRTIs had the highest risk of all-cause and COPD mortality.

CONCLUSION

Increasing frequency and severity of LRTIs prior to COPD diagnosis were associated with increasing rates of subsequent exacerbations, and increasing risk of all-cause and COPD-related mortality.

Inhaled Corticosteroids and Risk of Cardiovascular Disease in Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Regression

Background

Previous studies have reported mixed associations between inhaled corticosteroids (ICSs) and cardiovascular disease (CVD) in people with chronic obstructive pulmonary disease (COPD). Using updated literature, we investigated the association between ICS-containing medications and CVD in COPD patients, stratified by study-related factors.

Methods

We searched MEDLINE and EMBASE for studies that reported effect estimates for the association between ICS-containing medications and the risk of CVD in COPD patients. CVD outcomes specifically included heart failure, myocardial infarction, and stroke-related events. We conducted a random-effects meta-analysis and a meta-regression to identify effect-modifying study-related factors.

Results

Fifteen studies met inclusion criteria and investigated the association between ICS-containing medications and the risk of CVD. Pooled results from our meta-analysis showed a significant association between ICS-containing medication and reduced risk of CVD (hazard ratio 0.87, 95% confidence intervals 0.78 to 0.97). Study follow-up time, non-ICS comparator, and exclusion of patients with previous CVD modified the association between ICS use and risk of CVD.

Conclusions

Overall, we found an association between ICS-containing medications and reduced risk of CVD in COPD patients. Results from the meta-regression suggest that subgroups of COPD patients may benefit from ICS use more than others and further work is needed to determine this.

Differences in severe exacerbations rates and healthcare utilisation in COPD populations in the UK and France

Introduction

Chronic obstructive pulmonary disease (COPD) is a leading cause of mortality in Europe; however, it is important to understand how clinical practice patterns differ between countries and how this might relate to disease outcomes, to identify ways of improving local disease management. We aimed to describe and compare the management of patients with COPD in the UK and France between 2008 and 2017.

Methods

We used data from the Clinical Practice Research Datalink GOLD and Hospital Episode Statistics in the UK and the Echantillon Généraliste des Bénéficiaire in France to identify patients with COPD each year between 2008 and 2017. We compared patient characteristics, all-cause mortality and COPD exacerbations each year between 2008 and 2017 for patients in the UK and France separately. Health care utilisation and COPD exacerbations in 2017 were compared between France and the UK using t-tests and χ² tests.

Results

Patients with COPD were similar in gender and comorbidities in both countries. Incidence of COPD exacerbations remained stable in the UK and France between 2007 and 2017. In 2017, the proportion of all-cause and COPD-related hospitalisations was greater in the UK than in France (43.9% vs 32.8% and 8.3% vs 4.9%, respectively; p<0.001) as was the proportion of patients visiting accident and emergency (A&E) (39.8% vs 16.2%, respectively; p<0.001). In addition, the mean length of stay in hospital for COPD-related causes was shorter in the UK than in France (6.2 days (SD 8.4) vs 10.5 days (SD 9.1), respectively; p<0.001).

Discussion

Overall, UK patients were more likely to go to A&E, be hospitalised for COPD-related causes and stay in hospital for fewer days after being admitted for COPD-related reasons compared with patients in France, illustrating a difference in health-seeking behaviours and access to healthcare.

Frequency and Severity of Exacerbations of COPD Associated with Future Risk of Exacerbations and Mortality: A UK Routine Health Care Data Study

Background

Studies have shown that chronic obstructive pulmonary disease (COPD) exacerbation events are related to future events; however, previous literature typically reports frequent vs infrequent exacerbations per patient-year and no studies have investigated increasing number of severe exacerbations in relation to COPD outcomes.

Objective

To investigate the association between baseline frequency and severity of exacerbations and subsequent mortality and exacerbation risk in a COPD cohort.

Methods

Clinical Practice Research Datalink (CPRD) Aurum and Hospital Episode Statistics data were used to identify patients registered at general practices in the UK, who had a diagnosis of COPD, were over the age of 40 years, were smokers or ex-smokers and had data recorded from 2004 onwards. Frequency and severity of exacerbations in the baseline year were identified as moderate exacerbations (general practice events) and severe exacerbations (hospitalised events). Patients were categorised as having: none, 1 moderate only, 2 moderate only, 3+ moderate only, 1 severe (and any moderate), 2 severe (and any moderate), and 3+ severe (and any moderate exacerbations). Poisson regression was used to investigate the association between baseline exacerbation frequency/severity and exacerbation events and mortality over follow-up.

Results

Overall, 340,515 COPD patients were included. Patients had higher rates of future exacerbations with increasing frequency and severity of baseline exacerbations compared to no baseline exacerbations. Adjusted incidence rate ratios (IRR) for patients with 1, 2, and 3+ moderate exacerbations compared to 0 exacerbations were 1.70 (95% CI 1.66–1.74), 2.31 (95% CI 2.24–2.37), and 3.52 (95% CI 3.43–3.62), respectively. Patients with increased frequency of baseline exacerbations were more likely to die from all-cause, COPD-related, and cardiovascular-related mortality in a graduated fashion.

Conclusion

Increasing number and severity of exacerbations were associated with increasing risk of subsequent exacerbations, all-cause mortality and COPD-related mortality. Even a single moderate event increases the risk of future events, illustrating that every exacerbation counts.

295 Ear Conditions in Adult Patients with Learning Disabilities and Autism: A New Approach to Outpatient Management

Introduction

Patients with learning disability and autism (PwLDA) are a priority group for care quality and outcomes improvement in the NHS Long Term Plan. The aim of this project was to establish a new standard of care for PwLDA in our otology department.

Method

We first conducted a retrospective analysis of PwLDA who accessed routine adult otology clinics (RCs) between August-October 2020. We assessed achievement in four broad outcome domains: i) documentation of patient-specific special needs; ii) examination of ears; iii) assessment of hearing; iv) completion of hospital passport. We then formed a multidisciplinary team (MDT), which introduced specialised MDT-clinics (SCs) for PwLDA with otology conditions. These SCs were continuously improved by incorporating reasonable adjustments. We subsequently performed a retrospective analysis of PwLDA reviewed in the initial four months of SCs. This enabled a comparison between the type of clinic, RCs or SCs, and the achievement of specific outcomes. This interaction was statistically analysed using Chi-squared test.

Results

A mean of 7.7 and 5.0 PwLDA per month were booked into RCs and SCs respectively. Type of clinic had a significant effect on achievement of outcomes in domains i. and iv. (χ2 (1)&gt;10.3; p&lt;0.005) favouring attendance at SCs. There was no significant interaction for these variables in domains ii. and iii.

Conclusions

This is the first dedicated otology MDT service for PwLDA in the UK. Overall, these results demonstrate an improvement following implementation of the SCs. This innovative work establishes a new MDT-clinic outpatient model for PwLDA who suffer with ear- and hearing-related conditions.

Deriving a Standardised Recommended Respiratory Disease Codelist Repository for Future Research

Background

Electronic health record (EHR) databases provide rich, longitudinal data on interactions with healthcare providers and can be used to advance research into respiratory conditions. However, since these data are primarily collected to support health care delivery, clinical coding can be inconsistent, resulting in inherent challenges in using these data for research purposes.

Methods

We systematically searched existing international literature and UK code repositories to find respiratory disease codelists for asthma from January 2018, and chronic obstructive pulmonary disease and respiratory tract infections from January 2020, based on prior searches. Medline searches using key terms provided in article lists. Full-text articles, supplementary files, and reference lists were examined for codelists, and codelists repositories were searched. A reproducible methodology for codelists creation was developed with recommended lists for each disease created based on multidisciplinary expert opinion and previously published literature.

Results

Medline searches returned 1126 asthma articles, 70 COPD articles, and 90 respiratory infection articles, with 3%, 22% and 5% including codelists, respectively. Repository searching returned 12 asthma, 23 COPD, and 64 respiratory infection codelists. We have systematically compiled respiratory disease codelists and from these derived recommended lists for use by researchers to find the most up-to-date and relevant respiratory disease codelists that can be tailored to individual research questions.

Conclusion

Few published papers include codelists, and where published diverse codelists were used, even when answering similar research questions. Whilst some advances have been made, greater consistency and transparency across studies using routine data to study respiratory diseases are needed.

Predicting Future Health Risk in COPD: Differential Impact of Disease-Specific and Multi-Morbidity-Based Risk Stratification

Objective

Multi-morbidity contributes to mortality and hospitalisation in COPD, but it is uncertain how this interacts with disease severity in risk prediction. We compared contributions of multi-morbidity and disease severity factors in modelling future health risk using UK primary care healthcare data.

Methods

Health records from 103,955 patients with COPD identified from the Clinical Practice Research Datalink were analysed. We compared area under the curve (AUC) statistics for logistic regression (LR) models incorporating disease indices with models incorporating categorised comorbidities. We also compared these models with performance of The John Hopkins Adjusted Clinical Groups^® System (ACG) risk prediction algorithm.

Results

LR models predicting all-cause mortality outperformed models predicting hospitalisation. Mortality was best predicted by disease severity (AUC & 95% CI: 0.816 (0.805–0.827)) and prediction was enhanced only marginally by the addition of multi-morbidity indices (AUC & 95% CI: 0.829 (0.818–0.839)). The model combining disease severity and multi-morbidity indices was a better predictor of hospitalisation (AUC & 95% CI: 0.679 (0.672–0.686)). ACG-derived LR models outperformed conventional regression models for hospitalisation (AUC & 95% CI: 0.697 (0.690–0.704)) but not for mortality (AUC & 95% CI: 0.816 (0.805–0.827)).

Conclusion

Stratification of future health risk in COPD can be undertaken using clinical and demographic data recorded in primary care, but the impact of disease severity and multi-morbidity varies depending on the choice of health outcome. A more comprehensive risk modelling algorithm such as ACG offers enhanced prediction for hospitalisation by incorporating a wider range of coded diagnoses.

Potential impact of diabetes prevention on mortality and future burden of dementia and disability: a modelling study

AIMS/HYPOTHESIS

Diabetes is associated with an increased risk of dementia. We estimated the potential impact of trends in diabetes prevalence upon mortality and the future burden of dementia and disability in England and Wales.

METHODS

We used a probabilistic multi-state, open cohort Markov model to integrate observed trends in diabetes, cardiovascular disease and dementia to forecast the occurrence of disability and dementia up to the year 2060. Model input data were taken from the English Longitudinal Study of Ageing, Office for National Statistics vital data and published effect estimates for health-state transition probabilities. The baseline scenario corresponded to recent trends in obesity: a 26% increase in the number of people with diabetes by 2060. This scenario was evaluated against three alternative projected trends in diabetes: increases of 49%, 20% and 7%.

RESULTS

Our results suggest that changes in the trend in diabetes prevalence will lead to changes in mortality and incidence of dementia and disability, which will become visible after 10-15 years. If the relative prevalence of diabetes increases 49% by 2060, expected additional deaths would be approximately 255,000 (95% uncertainty interval [UI] 236,000-272,200), with 85,900 (71,500-101,600) cumulative additional cases of dementia and 104,900 (85,900-125,400) additional cases of disability. With a smaller relative increase in diabetes prevalence (7% increase by 2060), we estimated 222,200 (205,700-237,300) fewer deaths, and 77,000 (64,300-90,800) and 93,300 (76,700-111,400) fewer additional cases of dementia and disability, respectively, than the baseline case of a 26% increase in diabetes.

CONCLUSIONS/INTERPRETATION

Reducing the burden of diabetes could result in substantial reductions in the incidence of dementia and disability over the medium to long term.

The DNA sequence and analysis of human chromosome 6

Chromosome 6 is a metacentric chromosome that constitutes about 6% of the human genome. The finished sequence comprises 166,880,988 base pairs, representing the largest chromosome sequenced so far. The entire sequence has been subjected to high-quality manual annotation, resulting in the evidence-supported identification of 1,557 genes and 633 pseudogenes. Here we report that at least 96% of the protein-coding genes have been identified, as assessed by multi-species comparative sequence analysis, and provide evidence for the presence of further, otherwise unsupported exons/genes. Among these are genes directly implicated in cancer, schizophrenia, autoimmunity and many other diseases. Chromosome 6 harbours the largest transfer RNA gene cluster in the genome; we show that this cluster co-localizes with a region of high transcriptional activity. Within the essential immune loci of the major histocompatibility complex, we find HLA-B to be the most polymorphic gene on chromosome 6 and in the human genome.

Small bowel cancer in western Canada

Based on incident cases of small intestinal cancers in the four western Canadian provinces reported in the population-based cancer registries of British Columbia, Alberta, Saskatchewan and Manitoba we evaluated the descriptive epidemiological characteristics such as age, sex and subsite distribution of adenocarcinomas, carcinoids, lymphomas and sarcomas for the period 1975-1989. The distribution of adenocarcinomas, carcinoids and lymphomas presented a clear trend along the length of the small bowel. Most of the adenocarcinomas (54.7%) occurred in the duodenum and their relative frequency decreased in aboral direction: 29.9% in the jejunum and 16.0% in the ileum. The carcinoids showed an opposite trend, an increasing relative frequency in aboral direction: 3.9% in the duodenum, 9.2% in the jejunum and 86.7% in the ileum. Lymphomas were more frequent in the ileum (49.5%) compared to jejunum (29.4%) and duodenum (21.0%). Most sarcomas occurred along the jejunum (46.7%). The mean and median ages of lymphoma and sarcoma patients were significantly lower compared to adenocarcinoma and carcinoid cases. There was no difference in mean and median age by gender in the adenocarcinoma and carcinoid categories, but in the lymphoma and sarcoma groups males were significantly younger than females.

Sleeping body temperatures in 3-4 month old infants

Rectal, skin, and ambient temperatures were continuously recorded overnight from 3-4 month old normal infants in their home cots under conditions of room temperature and wrapping chosen freely by parents. It was found that rectal temperature was above 37 degrees C when infants were put down, but fell rapidly to 36.4 degrees C within one and a half hours, then stabilised for a few hours before rising steadily. This pattern was tied more closely to the time of putting down than time of day. The extent and rate of temperature fall did not correlate with any feature of the thermal environment. We also found that skin temperature changed much less than rectal temperature over the night, and for the first two hours in the cot there was no relation between skin and rectal temperature. There is therefore a well organised, endogenous rhythm of temperature in 4 month old infants.

The thermal environment in which 3-4 month old infants sleep at home

The thermal insulation of clothing and wrapping (tog value), room temperature, and body temperature was measured for 3-4 month old infants sleeping in their home cots under conditions chosen freely by parents during a cold winter. We found that ambient temperature averaged 18.4 degrees C when infants were put down, but fell by an average of 4.4 degrees C during the night. Minimum room temperature correlated with outside temperature, but most rooms were heated to some degree; smaller babies were kept in warmer rooms. The tog value of clothing before putting the baby down averaged 5.1, supplemented by 9.6 tog units of wrapping in the cot--a 188% increase for a 4.4 degrees C drop in temperature. Total tog of clothing and wrapping correlated negatively with minimum room temperature; smaller born babies tended to be more heavily wrapped. Despite the large increase in insulation in the cot, most babies maintained normal body temperatures.