TL;DR: The CPRD primary care database is a rich source of health data for research, including data on demographics, symptoms, tests, diagnoses, therapies, health-related behaviours and referrals to secondary care, but researchers must be aware of the complexity of routinely collected electronic health records.
Abstract: The Clinical Practice Research Datalink (CPRD) is an ongoing primary care database of anonymised medical records from general practitioners, with coverage of over 11.3 million patients from 674 practices in the UK. With 4.4 million active (alive, currently registered) patients meeting quality criteria, approximately 6.9% of the UK population are included and patients are broadly representative of the UK general population in terms of age, sex and ethnicity. General practitioners are the gatekeepers of primary care and specialist referrals in the UK. The CPRD primary care database is therefore a rich source of health data for research, including data on demographics, symptoms, tests, diagnoses, therapies, health-related behaviours and referrals to secondary care. For over half of patients, linkage with datasets from secondary care, disease-specific cohorts and mortality records enhance the range of data available for research. The CPRD is very widely used internationally for epidemiological research and has been used to produce over 1000 research studies, published in peer-reviewed journals across a broad range of health outcomes. However, researchers must be aware of the complexity of routinely collected electronic health records, including ways to manage variable completeness, misclassification and development of disease definitions for research.
TL;DR: The definition of prevalent diabetes from UK Biobank baseline data has external validity, and it is recommended that specific primary care Read codes should be used for incident diabetes to ensure precision.
Abstract: Objectives
UK Biobank is a UK-wide cohort of 502,655 people aged 40–69, recruited from National Health Service registrants between 2006–10, with healthcare data linkage. Type 2 diabetes is a key exposure and outcome. We developed algorithms to define prevalent and incident diabetes for UK Biobank. The algorithms will be implemented by UK Biobank and their results made available to researchers on request.
Methods
We used UK Biobank self-reported medical history and medication to assign prevalent diabetes and type, and tested this against linked primary and secondary care data in Welsh UK Biobank participants. Additionally, we derived and tested algorithms for incident diabetes using linked primary and secondary care data in the English Clinical Practice Research Datalink, and ran these on secondary care data in UK Biobank.
Results and Significance
For prevalent diabetes, 0.001% and 0.002% of people classified as “diabetes unlikely” in UK Biobank had evidence of diabetes in their primary or secondary care record respectively. Of those classified as “probable” type 2 diabetes, 75% and 96% had specific type 2 diabetes codes in their primary and secondary care records. For incidence, 95% of people with the type 2 diabetes-specific C10F Read code in primary care had corroborative evidence of diabetes from medications, blood testing or diabetes specific process of care codes. Only 41% of people identified with type 2 diabetes in primary care had secondary care evidence of type 2 diabetes. In contrast, of incident cases using ICD-10 type 2 diabetes specific codes in secondary care, 77% had corroborative evidence of diabetes in primary care. We suggest our definition of prevalent diabetes from UK Biobank baseline data has external validity, and recommend that specific primary care Read codes should be used for incident diabetes to ensure precision. Secondary care data should be used for incident diabetes with caution, as around half of all cases are missed, and a quarter have no corroborative evidence of diabetes in primary care.
TL;DR: The prevalence of people consulting for shoulder problems in primary care is substantially lower than community-based estimates of shoulder pain and most referrals occur within 3 months of initial presentation, but only a minority of patients are referred to orthopaedic specialists or rheumatologists.
Abstract: Objectives To estimate the national prevalence and incidence of adults consulting for a shoulder condition and to investigate patterns of diagnosis, treatment, consultation and referral 3 yr after initial presentation. Methods Prevalence and incidence rates were estimated for 658469 patients aged 18 and over in the year 2000 using a primary care database, the IMS Disease Analyzer-Mediplus UK. A cohort of 9215 incident cases was followed-up prospectively for 3 yr beyond the initial consultation. Results The annual prevalence and incidence of people consulting for a shoulder condition was 2.36% [95% confidence interval (CI) 2.32-2.40%] and 1.47% (95% CI 1.44-1.50%), respectively. Prevalence increased linearly with age whilst incidence peaked at around 50 yr then remained static at around 2%. Around half of the incident cases consulted once only, while 13.6% were still consulting with a shoulder problem during the third year of follow-up. During the 3 yr following initial presentation, 22.4% of patients were referred to secondary care, 30.8% were prescribed non-steroidal anti-inflammatory drugs and 10.6% were given an injection by their general practitioner (GP). GPs tended to use a limited number of generalized codes when recording a diagnosis; just five of 426 possible Read codes relating to shoulder conditions accounted for 74.6% of the diagnoses of new cases recorded by GPs. Conclusions The prevalence of people consulting for shoulder problems in primary care is substantially lower than community-based estimates of shoulder pain. Most referrals occur within 3 months of initial presentation, but only a minority of patients are referred to orthopaedic specialists or rheumatologists. GPs may lack confidence in applying precise diagnoses to shoulder conditions.
TL;DR: These data quantify the consistent and strong relationships between BMI and prospectively recorded diagnoses of NAFLD/NASH and emphasize the importance of weight reduction strategies for prevention and management ofNAFLD.
Abstract: The relationship between rising body mass index (BMI) and prospective risk of non-alcoholic fatty liver disease (NAFLD) / non-alcoholic steatohepatitis (NASH) is virtually absent.Determine the extent of the association between BMI and risk of future NAFLD diagnosis, stratifying by sex and diabetes.Two prospective studies using Humedica and THIN with 1.54 and 4.96 years of follow-up respectively.Electronic health record databases Participants: Patients with had a recorded BMI measurement between 15-60kg/m(2), and smoking status, and one year of active status prior to baseline BMI. Patients with a diagnosis or history of chronic diseases were excluded.None Main Outcome Measure: Recorded diagnosis of NAFLD/NASH during follow-up (Humedica ICD-9 code 571.8, and read codes for NAFLD and NASH in THIN).Hazard ratios (HR) were calculated across BMI categories using BMI of 20-22.5kg/m2 as the reference category, adjusting for age, sex and smoking status. Risk of recorded NAFLD/NASH increased linearly with BMI and was approximately 5-fold higher in Humedica (HR=4.78, 95% CI 4.17-5.47) and 9-fold higher in THIN (HR=8.93, 7.11-11.23) at a BMI of 30-32.5 kg/m(2) rising to around 10-fold higher in Humedica (HR=9.80, 8.49-11.32) and 14-fold higher in THIN (HR=14.32, 11.04-18.57) in the 37.5-40 kg/m(2) BMI category. Risk of NAFLD/NASH was approximately 50% higher in men, and approximately double in those with diabetes.These data quantify the consistent and strong relationships between BMI and prospectively recorded diagnoses of NAFLD/NASH and emphasize the importance of weight reduction strategies for prevention and management of NAFLD.
TL;DR: The extent of resource utilisation by patients classed as having chronic wounds within Wales using linked routine data – available through the Secure Anonymised Information Linkage (SAIL) database – to estimate the costs associated with the management of these patients by the NHS in Wales is determined.
Abstract: Chronic wounds are known to represent a significant burden to patients and National Health Service (NHS) alike. However, previous attempts to estimate the costs associated with the management of chronic wounds have been based on literature studies or broad estimates derived from incidence rates and extrapolations from relatively small-scale studies. The aim of this study is therefore to determine the extent of resource utilisation by patients classed as having chronic wounds within Wales using linked routine data – available through the Secure Anonymised Information Linkage (SAIL) database – to estimate the costs associated with the management of these patients by the NHS in Wales. The SAIL database brings together, and anonymously links, a wide range of person-based data from general practitioner (GP) practices within Wales, which includes primary and secondary care consultations to create an encrypted anonymised linking field for each individual. This linkage allows the patient pathway to be tracked through the NHS system both retrospectively and prospectively from a specific reference date. The estimated costs were derived by extrapolating to an all-Wales level from the results gleaned from the SAIL database using the respective READ codes to capture relevant patients with chronic wounds. The number of patients identified as having chronic wounds within the SAIL database was 78 090, which equates to 190 463 across Wales as a whole and a prevalence of 6% of the Welsh population. The total cost of managing patients with chronic wounds in Wales amounted to £328·8 million – an average cost of £1727 per patient and 5·5% of total expenditure on the health service in Wales. A relatively few READ codes represented a significant proportion of expenditure, with diabetic foot ulcers, leg ulcers, foot ulcers, varicose eczema, bed sores and postoperative wound care constituting 93% of total expenditure. When a more conservative perspective was used in relation to classification of chronic wounds, the total cost amounted to £303 million. However, these are likely to be underestimates because of the lack of information for patients with treatments lasting over 6 months and not including patients who might have entered the health care system of wound management elsewhere – such as patients contracting pressure ulcers in hospitals and having surgical wound infections.