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Asthma

Evangelos Kontopantelis, Ivan Olier, Claire Planner, David Reeves, Darren M Ashcroft, Linda Gask, Tim Doran, Sioban Reilly

Type
Disease or Syndrome
ID
PH500
Version ID
1000
Data Sources
Valid event data range
01/04/2000 - 31/03/2012
Sex
Female, Male
Agreement Date
2015-12-16
Coding system
Read codes v2 OXMIS codes
Tags /Collections
ClinicalCodes Repository Phenotype Library

Definition

The database:

The CPRD is a large computerised database of anonymised primary care medical records. It contains complete patient information for participating practices, with the healthcare events (diagnoses, treatments, referrals, tests and prescriptions) recorded using coding systems (Read coding for diagnoses). Practice characteristics are described in detail elsewhere. The database is broadly representative of the UK population, although larger practices are over-represented. Practices need to meet prespecified data entry quality criteria to be defined as ‘up to research standard’, and for each study year, our main sample included all CPRD practices that were classed as such for the whole year. We also generated two data sets to test the sensitivity of our findings. First, we included all practices contributing data across the entire study period. Second, we included a subsample of 50 practices, representative of UK practices in terms of area deprivation, and practice list size.

Defining people with SMI and controls:

Information was extracted for the period 1 April 2000 to 31 March 2012 and aggregated into 12 yearly ‘bins’, to correspond with financial years 2000/2001–2011/2012. We used Read codes to identify the presence of SMI. First, we identified relevant keywords (or key-stubs) and codes, for example ‘paranoi’ and ‘E100.00’ (simple schizophrenia). Next, the CPRD was searched for codes that matched the list in either the code or the description field. Finally, the matched code list was reviewed by clinical experts and a final conservative list of codes was agreed. A similar process was used to define comorbidities (hypertension, asthma, hypothyroidism, osteoarthritis, chronic kidney disease, coronary heart disease, epilepsy, chronic obstructive pulmonary disease, cancer, stroke, heart failure, rheumatoid arthritis, dementia and psoriasis). All code lists we used are available from http://www.clinicalcodes.org. All conditions, bar asthma, were treated as unresolvable (ie, permanent). Within each year, all patients registered with a CPRD practice for the whole year and aged 18 or over were eligible for inclusion. The final SMI Read code list was used to identify cases of SMI, which were then grouped into three broad subcategories, in line with the diagnoses used when compiling primary care QOF SMI registers: schizophrenia; affective psychoses (bipolar disorder or other unspecified affective psychosis); other types of psychosis. In the event that an individual received more than one SMI diagnosis over the study period, we used the last available diagnosis to retrospectively ‘correct’ the original diagnosis (ie, we assumed that the latest diagnosis was the correct one). Within each year, each SMI case was then matched on age, sex and practice to five randomly selected patients not associated with SMI up until that time point. More details on the extraction of the cohort have been provided elsewhere,21 and a flow chart of the data extraction process is available in the online appendix figure A2.

Defining consultation type:

We defined a ‘consultation’ as involving direct contact between a patient and a healthcare professional within the primary care setting. We divided consultations into two main categories: face-to-face (our primary outcome), and by telephone (see online appendix table A1). We also constructed a third ‘other’ grouping of all other activities that are captured by the ‘consultation type’ codes within the CPRD. This includes mail/email contact, third party consultations (including referrals), secondary care episodes, other administrative tasks and consultations of unknown content. This group is highly heterogeneous and includes many activities that cannot be classed as consultations. However, we decided to use this grouping as an aggregate secondary outcome since it can potentially provide insight into the overall workload associated with patient care in the primary care context. We decided against breaking down the ‘other’ group in more subcategories as we are very doubtful regarding the reliability and across practice consistency of the coding within these ‘other’ categories. In instances where a patient had two or more consultations within a day, we conservatively assumed a single consultation took place, to reduce the likelihood of including duplicate records.

Publications

  • Evangelos Kontopantelis, Ivan Olier, Claire Panner, David Reeves, Darren M Ashcroft, Linda Gask, Tim Doran, Siobhan Reilly, Primary care consultation rates among people with and without severe mental illness a UK cohort study using the Clinical Practice Research Datalink. BMJ Open, 5 (e008650), 2015.

Clinical Code List

Rows: 40
Code Description Entity type Coding System (OXMIS Read) Category
173A.00 Exercise induced asthma res21: Asthma Read diagnostic
173c.00 Occupational asthma res21: Asthma Read diagnostic
173d.00 Work aggravated asthma res21: Asthma Read diagnostic
1780.00 Aspirin induced asthma res21: Asthma Read diagnostic
1O2..00 Asthma confirmed res21: Asthma Read diagnostic
663V000 Occasional asthma res21: Asthma Read diagnostic
663V100 Mild asthma res21: Asthma Read diagnostic
663V200 Moderate asthma res21: Asthma Read diagnostic
663V300 Severe asthma res21: Asthma Read diagnostic
663j.00 Asthma - currently active res21: Asthma Read diagnostic
H312000 Chronic asthmatic bronchitis res21: Asthma Read diagnostic
H33..00 Asthma res21: Asthma Read diagnostic
H33..11 Bronchial asthma res21: Asthma Read diagnostic
H330.00 Extrinsic (atopic) asthma res21: Asthma Read diagnostic
H330.11 Allergic asthma res21: Asthma Read diagnostic
H330.12 Childhood asthma res21: Asthma Read diagnostic
H330.13 Hay fever with asthma res21: Asthma Read diagnostic
H330.14 Pollen asthma res21: Asthma Read diagnostic
H330000 Extrinsic asthma without status asthmaticus res21: Asthma Read diagnostic
H330011 Hay fever with asthma res21: Asthma Read diagnostic
H330100 Extrinsic asthma with status asthmaticus res21: Asthma Read diagnostic
H330111 Extrinsic asthma with asthma attack res21: Asthma Read diagnostic
H330z00 Extrinsic asthma NOS res21: Asthma Read diagnostic
H331.00 Intrinsic asthma res21: Asthma Read diagnostic
H331.11 Late onset asthma res21: Asthma Read diagnostic
H331000 Intrinsic asthma without status asthmaticus res21: Asthma Read diagnostic
H331100 Intrinsic asthma with status asthmaticus res21: Asthma Read diagnostic
H331111 Intrinsic asthma with asthma attack res21: Asthma Read diagnostic
H331z00 Intrinsic asthma NOS res21: Asthma Read diagnostic
H332.00 Mixed asthma res21: Asthma Read diagnostic
H334.00 Brittle asthma res21: Asthma Read diagnostic
H33z.00 Asthma unspecified res21: Asthma Read diagnostic
H33z.11 Hyperreactive airways disease res21: Asthma Read diagnostic
H33z200 Late-onset asthma res21: Asthma Read diagnostic
H33zz00 Asthma NOS res21: Asthma Read diagnostic
H33zz11 Exercise induced asthma res21: Asthma Read diagnostic
H33zz12 Allergic asthma NEC res21: Asthma Read diagnostic
H35y600 Sequoiosis (red-cedar asthma) res21: Asthma Read diagnostic
H35y700 Wood asthma res21: Asthma Read diagnostic
H47y000 Detergent asthma res21: Asthma Read diagnostic
Rows: 23
Code Description Entity type Coding System (OXMIS Read) Category
3052AT PSYCHOGENIC ASTHMA res21: Asthma OXMIS diagnostic
493 ASTHMA res21: Asthma OXMIS diagnostic
493 AA ASTHMA ACUTE res21: Asthma OXMIS diagnostic
493 AB ASTHMA ATTACK res21: Asthma OXMIS diagnostic
493 AD ASTHMA OCCASIONAL res21: Asthma OXMIS diagnostic
493 AE ASTHMA SEASONAL res21: Asthma OXMIS diagnostic
493 AI ASTHMA SEVERITY MILD res21: Asthma OXMIS diagnostic
493 AJ ASTHMA SEVERITY MODERATE res21: Asthma OXMIS diagnostic
493 AK ASTHMA SEVERITY SEVERE res21: Asthma OXMIS diagnostic
493 BD ASTHMA AND BRONCHITIS res21: Asthma OXMIS diagnostic
493 BR BRONCHIAL ASTHMA res21: Asthma OXMIS diagnostic
493 C CROUP ASTHMATIC res21: Asthma OXMIS diagnostic
493 CH CHILDHOOD ASTHMA res21: Asthma OXMIS diagnostic
493 EA ASTHMA EXERCISE INCLUDED res21: Asthma OXMIS diagnostic
493 EB ASTHMA EXERCISE INDUCED res21: Asthma OXMIS diagnostic
493 EP ASTHMA EPISODIC res21: Asthma OXMIS diagnostic
493 GR ASTHMA ALLERGIC GRASS res21: Asthma OXMIS diagnostic
493 GS ASTHMA POLLEN INITIATED res21: Asthma OXMIS diagnostic
493 HT INTRINSIC ASTHMA res21: Asthma OXMIS diagnostic
493 JC CHRONIC ASTHMA res21: Asthma OXMIS diagnostic
493 NA NOCTURNAL ASTHMA res21: Asthma OXMIS diagnostic
691 TM ECZEMA WITH ASTHMA res21: Asthma OXMIS diagnostic
L4930LO LATE ONSET ASTHMA res21: Asthma OXMIS diagnostic

API

To Export Phenotype Details:

Format API
XML site_root/api/v1/public/phenotypes/PH500/version/1000/detail/?format=xml
JSON site_root/api/v1/public/phenotypes/PH500/version/1000/detail/?format=json
R Package

# Download here

library(ConceptLibraryClient)


# Connect to API

client = connect_to_API(public=TRUE)


# Get details of phenotype

details = get_phenotype_detail_by_version('PH500', '1000', api_client=client)

To Export Phenotype Code List:

Format API
XML site_root/api/v1/public/phenotypes/PH500/version/1000/export/codes/?format=xml
JSON site_root/api/v1/public/phenotypes/PH500/version/1000/export/codes/?format=json
CSV site_root/phenotypes/PH500/version/1000/export/codes/
R Package

# Download here

library(ConceptLibraryClient)


# Connect to API

client = connect_to_API(public=TRUE)


# Get codelists of phenotype

codelists = get_phenotype_code_list('PH500', '1000', api_client=client)

Version History

Version
ID
Name Owner Publish date
1000 Asthma ieuan.scanlon 2021-10-06 currently shown

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