Review of codelists used to define hypertension in electronic health records and development of a codelist for research.

BACKGROUND AND AIMS: Hypertension is a leading risk factor for cardiovascular disease. Electronic health records (EHRs) are routinely collected throughout a person's care, recording all aspects of health status, including current and past conditions, prescriptions and test results. EHRs can be used for epidemiological research. However, there are nuances in the way conditions are recorded using clinical coding; it is important to understand the methods which have been applied to define exposures, covariates and outcomes to enable interpretation of study findings. This study aimed to identify codelists used to define hypertension in studies that use EHRs and generate recommended codelists to support reproducibility and consistency. ELIGIBILITY CRITERIA: Studies included populations with hypertension defined within an EHR between January 2010 and August 2023 and were systematically identified using MEDLINE and Embase. A summary of the most frequently used sources and codes is described. Due to an absence of Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) codelists in the literature, a recommended SNOMED CT codelist was developed to aid consistency and standardisation of hypertension research using EHRs. FINDINGS: 375 manuscripts met the study criteria and were eligible for inclusion, and 112 (29.9%) reported codelists. The International Classification of Diseases (ICD) was the most frequently used clinical terminology, 59 manuscripts provided ICD 9 codelists (53%) and 58 included ICD 10 codelists (52%). Informed by commonly used ICD and Read codes, usage recommendations were made. We derived SNOMED CT codelists informed by National Institute for Health and Care Excellence guidelines for hypertension management. It is recommended that these codelists be used to identify hypertension in EHRs using SNOMED CT codes. CONCLUSIONS: Less than one-third of hypertension studies using EHRs included their codelists. Transparent methodology for codelist creation is essential for replication and will aid interpretation of study findings. We created SNOMED CT codelists to support and standardise hypertension definitions in EHR studies.

Determining prescriptions in electronic healthcare record data: methods for development of standardized, reproducible drug codelists.

Objective: To develop a standardizable, reproducible method for creating drug codelists that incorporates clinical expertise and is adaptable to other studies and databases. Materials and Methods: We developed methods to generate drug codelists and tested this using the Clinical Practice Research Datalink (CPRD) Aurum database, accounting for missing data in the database. We generated codelists for: (1) cardiovascular disease and (2) inhaled Chronic Obstructive Pulmonary Disease (COPD) therapies, applying them to a sample cohort of 335 931 COPD patients. We compared searching all drug dictionary variables (A) against searching only (B) chemical or (C) ontological variables. Results: In Search A, we identified 165 150 patients prescribed cardiovascular drugs (49.2% of cohort), and 317 963 prescribed COPD inhalers (94.7% of cohort). Evaluating output per search strategy, Search C missed numerous prescriptions, including vasodilator anti-hypertensives (A and B:19 696 prescriptions; C:1145) and SAMA inhalers (A and B:35 310; C:564). Discussion: We recommend the full search (A) for comprehensiveness. There are special considerations when generating adaptable and generalizable drug codelists, including fluctuating status, cohort-specific drug indications, underlying hierarchical ontology, and statistical analyses. Conclusions: Methods must have end-to-end clinical input, and be standardizable, reproducible, and understandable to all researchers across data contexts.

Prevalence of Chronic Obstructive Pulmonary Disease in England from 2000 to 2019.

Background: There is considerable variation in reported chronic obstructive pulmonary disease (COPD) prevalence internationally, partly due to differing definitions in use. Accurate estimates of disease prevalence are important for allocation of health-care resources, yet UK estimates of COPD prevalence have not been updated for a decade. We calculated yearly COPD prevalence in England between 2000 and 2019 using different definitions of COPD. Methods: We used routinely collected primary care electronic healthcare record (EHR) data from the Clinical Practice Research Datalink (CPRD) Aurum database linked with secondary care data from the Hospital Episode Statistics (HES) Admitted Patient Care (APC) database. Mid-year point prevalence was calculated yearly from 2000 to 2019 in English adults aged ≥40 years using 5 definitions: (i) validated COPD, (ii) Quality and Outcomes Framework (QOF) COPD, (iii) COPD symptoms, inhaler prescription, and no asthma diagnosis, (iv) hospitalisation with COPD as any diagnosis, (v) hospitalisation with COPD as primary or secondary diagnosis. Prevalence was further stratified by gender, age group, and region. Results: A total of 12,745,793 people were included over the 20-year period. Annual cohort sizes ranged from 4,373,538 in 2000 to 6,159,496 in 2019. Estimates of COPD prevalence increased every year from 2000 and the difference in estimated prevalence between the validated and QOF definitions has grown over time. In 2019, a COPD prevalence of 4.9% was found using validated events in either primary or secondary care (definition 1 or definition 5). Additionally, including potentially undiagnosed cases (definition 3) in the COPD definition produced an increased prevalence of 6.7%. Conclusion: Common definitions of COPD (eg, QOF codes), may underestimate the true prevalence. The extent of this underestimate has increased over time and could lead to under-allocation of resources where need is estimated based on these definitions. Standardisation of COPD coding in routine EHRs and metrics such as spirometry is key to accurate disease monitoring.

Comparison of COPD primary care in England, Scotland, Wales, and Northern Ireland.

Currently the National Asthma and COPD audit programme (NACAP) only undertakes audit of COPD primary care in Wales due to its near complete data coverage. We aimed to determine if the quality of COPD primary care in the other UK nations is comparable with Wales. We found that English, Scottish, and Northern Irish practices were significantly worse than Welsh practices at recording coded lung function parameters used in COPD diagnosis (ORs: 0.51 [0.43-0.59], 0.29 [0.23-0.36], 0.42 [0.31-0.58], respectively) and referring appropriate patients for pulmonary rehabilitation (ORs: 0.10 [0.09-0.11], 0.12 [0.11-0.14], 0.22 [0.19-0.25], respectively). Completing national audits of primary care in Wales only may have led to improvements in care, or at least improvements in the recording of care in Wales that are not occurring elsewhere in the UK. This highlights the potential importance of audit in improving care quality and accurate recording of that care.

"NEWS2" as an Objective Assessment of Hospitalised COPD Exacerbation Severity.

Introduction: There is currently no accepted way to risk-stratify hospitalised exacerbations of chronic obstructive pulmonary disease (COPD). We hypothesised that the revised UK National Early Warning Score (NEWS2) calculated at admission would predict inpatient mortality, need for non-invasive ventilation (NIV) and length-of-stay. Methods: We included data from 52,284 admissions for exacerbation of COPD. Data were divided into development and validation cohorts. Logistic regression was used to examine relationships between admission NEWS2 and outcome measures. Predictive ability of NEWS2 was assessed using area under receiver operating characteristic curves (AUC). We assessed the benefit of including other baseline data in the prediction models and assessed whether these variables themselves predicted admission NEWS2. Results: 53% of admissions had low risk, 24% medium risk and 23% a high risk NEWS2 in the development cohort. The proportions dying as an inpatient were 2.2%, 3.6% and 6.5% by NEWS2 risk category, respectively. The proportions needing NIV were 4.4%, 9.2% and 18.0%, respectively. NEWS2 was poorly predictive of length-of-stay (AUC: 0.59[0.57-0.61]). In the external validation cohort, the AUC (95% CI) for NEWS2 to predict inpatient death and need for NIV were 0.72 (0.68-0.77) and 0.70 (0.67-0.73). Inclusion of patient demographic factors, co-morbidity and COPD severity improved model performance. However, only 1.34% of the variation in admission NEWS2 was explained by these baseline variables. Conclusion: The generic NEWS2 risk assessment tool, readily calculated from simple physiological data, predicts inpatient mortality and need for NIV (but not length-of-stay) at exacerbations of COPD. NEWS2 therefore provides a classification of hospitalised COPD exacerbation severity.

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.

Does pay-for-performance improve patient outcomes in acute exacerbation of COPD admissions?

BACKGROUND: The COPD Best Practice Tariff (BPT) is a pay-for-performance scheme in England that incentivises review by a respiratory specialist within 24 hours of admission and completion of a list of key care components prior to discharge, known as a discharge bundle, for patients admitted with acute exacerbation of COPD (AECOPD). We investigated whether the two components of the COPD BPT were associated with lower 30-day mortality and readmission in people discharged following AECOPD. METHODS: Longitudinal study of national audit data containing details of AECOPD admissions in England and Wales between 01 February 2017 and 13 September 2017. Data were linked with national admissions and mortality data. Mixed-effects logistic regression, using a random intercept for hospital to adjust for clustering of patients, was used to determine the relationship between the COPD BPT criteria (combined and separately) and 30-day mortality and readmission. Models were adjusted for age, sex, socioeconomic status, length of stay, smoking status, Charlson comorbidity index, mental illness and requirement for oxygen or noninvasive ventilation during admission. RESULTS: 28 345 patients discharged from hospital following AECOPD were included. 37% of admissions conformed to the two COPD BPT criteria. No relationship was observed between BPT conforming admissions and 30-day mortality (OR: 1.09 (95% CI 0.92 to 1.29)) or readmissions (OR: 0.96 (95% CI 0.90 to 1.02)). No relationship was observed between either of the individual COPD BPT components and 30-day mortality or readmissions. However, a specialist review at any time during admission was associated with lower inpatient mortality (OR: 0.69 (95% CI 0.58 to 0.81)). CONCLUSION: Completion of the combined COPD BPT criteria does not appear associated with a reduction in 30-day mortality or readmission. However, specialist review was associated with reduced inpatient mortality. While it is difficult to argue that discharge bundles do not improve care, this analysis questions whether the pay-for-performance model improves mortality or readmissions.

Predictors of pulmonary rehabilitation completion in the UK.

INTRODUCTION: Pulmonary rehabilitation has been shown to improve dyspnoea, fatigue, quality of life and exercise capacity in individuals with chronic obstructive pulmonary disease (COPD). Our aim was to determine the characteristics of people with COPD associated with completion of pulmonary rehabilitation. METHODS: This was a cross-sectional analysis of 7060 people with COPD enrolled in pulmonary rehabilitation between January 1, 2017 and March 31, 2017. Data were from a UK national audit of COPD care. Factors associated with pulmonary rehabilitation completion were determined using mixed effects logistic regression with a random intercept for pulmonary rehabilitation service. Factors chosen for assessment based on clinical judgement and data availability were age, sex, country, socioeconomic status, body mass index, referral location, programme type, start within 90 days, smoking status, oxygen therapy, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage, Medical Research Council (MRC) dyspnoea grade, any exercise test and any health status questionnaire. RESULTS: 4635 (66%) people with COPD completed a pulmonary rehabilitation programme. People that were aged ≥60 years, resident in Wales, referred within 90 days, an ex- or never-smoker, received an exercise test, or received a health status questionnaire had significantly greater odds of completing pulmonary rehabilitation. People that were in the most deprived quintile, underweight or very severely obese, enrolled in a rolling rather than a cohort programme, had a higher GOLD stage and had a higher MRC grade had significantly lower odds of completing pulmonary rehabilitation. CONCLUSIONS: People with COPD were more likely to complete pulmonary rehabilitation when best practice guidelines were followed. People with more severe COPD symptoms and those enrolled in rolling rather than cohort programmes were less likely to complete pulmonary rehabilitation. Referring people with COPD in the earlier stages of disease, ensuring programmes follow best practice guidelines and favouring cohort over rolling programmes could improve rates of pulmonary rehabilitation completion.

Predictors of Referral to Pulmonary Rehabilitation from UK Primary Care.

Background: A large proportion of people with COPD are not referred to pulmonary rehabilitation (PR) despite its proven benefits. No previous studies have examined predictors of referral to PR. Objective: To determine the characteristics of people with COPD associated with referral to PR. Methods: Cross-sectional analysis of a primary care cohort of 82,696 Welsh people with COPD generated as part of a UK national audit of COPD care. Data represent care received by patients as of 31/03/2017. Referral to PR was defined as any code in the patient record indicating referral to PR in the last 3 years. Potential predictors of referral to PR were chosen based on clinical judgement and data availability. Independent predictors of PR referral were determined using backward stepwise mixed-effects logistic regression with a random effect for practice. Variables assessed were: age, gender, deprivation, MRC recorded in past year, MRC grade, smoking status recorded in past year, smoking status, number of exacerbations in past year, inhaled therapy prescription, influenza vaccination, and comorbidities of diabetes, hypertension, coronary heart disease, stroke, heart failure, lung cancer, asthma, bronchiectasis, depression, anxiety, severe mental illness, osteoporosis, and painful condition. Results: A total of 13,297 people (16%) with COPD were referred from primary care for PR. Patients with a comorbidity of bronchiectasis or depression, MRC recorded in the last year, higher MRC grade, more exacerbations in the last year, a greater level of inhaled therapy, an influenza vaccination, or were an ex-smoker had significantly higher odds of referral to PR. Patients that were older, female, more deprived, or had a comorbidity of diabetes, asthma, or painful condition had significantly lower odds of referral to PR. Conclusion: Generally appropriate patients are being prioritised for PR referral; however, it is concerning that women, current smokers, and more deprived patients appear to have lower odds of referral.