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Ischaemia Heart Disease

David Reeves, David A Springate, Darren M Ashcroft, Ronan Ryan, Tim Doran, Richard Morris, Ivan Olier, Evangelos Kontopantelis

Type
Disease or Syndrome
ID
PH620
Version ID
1240
Data Sources
Valid event data range
01/01/1996 - 17/12/20003
Sex
Female, Male
Agreement Date
2014-04-23
Coding system
Read codes v2
Tags /Collections
ClinicalCodes Repository Phenotype Library

Definition

Data:

CPRD and THIN obtain their data from practices using the Vision electronic record system, while QResearch obtains data from practices using EMIS software. We felt that comparisons would be most informative between databases drawing data from different capture systems. Across the time-period studied, two versions of EMIS were in use, the more common being the text-based EMIS LV system with navigation and data entry mainly via the keyboard; EMIS PCS, which is Windows-based with mouse control and drop-down menus, was introduced from 1999. Vision was Windows-based throughout the study period. A small-scale direct comparison of EMIS LV and Vision indicated that coded data entry, excepting prescribing information, was faster with Vision and that more items were likely to be coded. Practices running Vision have slightly higher achievement rates for most Quality and Outcomes Framework (QOF) indicators than practices running either version of EMIS, even after controlling for differences in practice and area characteristics. We had access to CPRD, and therefore chose to replicate a study previously conducted using QResearch. CPRD and QResearch both draw data from general practices spread throughout the UK—currently more than 600 practices each—and comparisons to the national age-gender structure and prevalence rates for common conditions mostly show good correspondence for both datasets. For practical reasons, we focused on studies of the effectiveness of medicinal interventions and, after assessing the available studies, chose to replicate an investigation into the effects of statins on the mortality of patients with ischaemic heart disease (IHD) by Hippisley-Cox and Coupland (H-C&C). The methodological details provided in the published paper were insufficient on their own to allow a close replication to be conducted, and we therefore obtained additional details from the authors. We requested purely factual information about the methods used and did not share any of our analyses or results. We replicated the methods of H-C&C as closely as possible, given the differences between the two databases. All of the methods described below, including the study period, variable specifications and analytical procedures, are exact replications of those used in the original study, unless indicated otherwise. We selected all practices in CPRD that provided up to standard (UTS) data (UTS is CPRD’s designation for data meeting their internal quality standards) for the whole of the period from 1 January 1996 to 17 December 2003. We next identified all patients with a first diagnosis of IHD within this period, based on the QOF business rules for 2004. We excluded patients whose IHD diagnosis fell within the first 3 months of registration with their general practice or was on or subsequent to their recorded date of death, or who were prescribed statins prior to first diagnosis. We extracted data for these patients from the date of IHD diagnosis up until 17 December 2003, or until the date of death or exit from the practice, or the last recorded date for practices that stopped providing data before 17 December 2003, giving a maximum possible length of follow-up postdiagnosis of just under 8 years.

Analysis:

The main outcome was all-cause mortality, identified through a record of death in the CPRD. Following H-C&C, we conducted two main analyses: (1) a cohort analysis and (2) a case-control analysis nested within the full cohort. All analyses were conducted using R. Following H-C&C, statistical significance was assessed using p<0.01 (two tailed), but 95% CIs are reported in tables and figures. We made an a priori decision not to attempt to ‘improve’ on the analysis conducted by H-C&C, as our specific aim was to determine whether the same results and conclusions would emerge from using identical methods on a different underlying dataset targeting the same population.

Cohort analysis:

The cohort analysis used a Cox proportional hazards model to examine the effect of statin use on patient survival, with survival time determined by the time (in days) between the date of first diagnosis and date of death. Patients who transferred out of their practice before death or who were still alive at the end of the study period were treated as censored observations. Statin exposure was used as a time-varying covariate, with the period of exposure from the date of first prescription to when the statin was stopped (estimated as the date of last prescription plus 90 days; intervening breaks in the use of statins were ignored), or if not stopped until the end of the study period, date of death or date of transfer out of practice. Covariates adjusted for in the analysis were year of diagnosis, gender, comorbidities (diabetes, hypertension, myocardial infarction, congestive cardiac failure and cancer), and age (coded as 0–44, 45–54, 55–64, 65–74, 75–84, 85–94 or ≥95), smoking (ever smoked, never smoked, not recorded) and body mass index (BMI; coded as <25, 25–30, >30 kg/m2) all at the date of diagnosis. The presence of each comorbidity was indicated by a diagnosis in the patient record (using the 2004 QOF business rules) and coded as present/not present at the date of IHD diagnosis. If smoking status or BMI was not recorded within 4 years prior to diagnosis of IHD, we coded it as missing. The analysis was undertaken using the R survival analysis package accounting for the clustering of patients by practice and using the Huber-White robust estimate of SE. The proportional hazards assumption was checked graphically and with a test for proportional hazards.

Nested case-control study:

The nested case-control analysis compared all patients from the cohort who died during the follow-up period (the cases) with a group of matched control patients (also with IHD) who did not die. For each case, we defined an ‘index date’ as the date of death. We then used an incidence density sampling procedure (as per the original study; personal correspondence) to randomly select four control patients for each case matched on gender, year of IHD diagnosis and age (coded in 5-year age-bands). General practice was not used as a matching variable. Controls were patients with IHD alive at the time their matched case died (including patients who themselves became cases at a later time-point). The incidence sampling procedure allowed the same patient to be selected as a control for more than one case, thus providing a full set of four controls for each case, while still producing unbiased estimates of risk. Statin exposure was based on the first and last prescription dates prior to the index date and coded into: (1) currently taking statins (last prescription was within 90 days of the index date); (2) previously took statins (last prescription more than 90 days prior to the index date) and (3) has never taken statins. We did this for all statins as a group and also separately for five different types of statin (atorvastatin, cerivastatin, fluvastatin, pravastatin and simvastatin). For ‘all statins’, the last prescription could be for a different statin type than the first; for individual statins, it had to be the same type. One further formulation, rosuvastatin, was in use that did not appear in the QResearch study. We included this in the ‘all statins’ group but did not analyse it individually as only 22 patients had received the statin. Analysis of the case-control study used conditional logistic regression accounting for the matching of cases with controls, to obtain ORs for the risk of death in relation to use of statins. We allowed for clustering by general practice and used a robust estimate of SE, in line with the cohort analysis. Covariates in the analysis were smoking status, BMI and comorbidities, specified as in the Cohort analysis but based on the index date rather than the date of diagnosis. Additional covariates in this analysis were the Townsend deprivation score for the practice postcode (in national quintiles; H-C&C used quintiles of patient-level Townsend scores) and use of β-blockers, aspirin, ACE inhibitors and calcium channel blockers, identified through the British National Formulary chapter codes in the patient record. Each medication was coded as either used or not used prior to the index date but after the date of IHD diagnosis. Interactions between use of statins and each of gender, age (less than 75 vs 75 and over) and diabetes were tested by adding interaction terms into the model.

Publications

  • David Reeves, David A Springate, Darren M Ashcroft, Ronan Ryan, Tim Doran, Richard Morris, Ivan Olier, Evangelos Kontopantelis, Can analyses of electronic patient records be independently and externally validated? The effect of statins on the mortality of patients with ischaemic heart disease: a cohort study with nested case–control analysis. BMJ Open, 4:e004952 2014.

Clinical Code List

Rows: 115
Code Description Entity type Category Coding System (Read)
G3...00 Ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G3...11 Arteriosclerotic heart disease Ischaemic Heart Disease diagnostic Read
G3...12 Atherosclerotic heart disease Ischaemic Heart Disease diagnostic Read
G3...13 IHD - Ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G30..00 Acute myocardial infarction Ischaemic Heart Disease diagnostic Read
G30..11 Attack - heart Ischaemic Heart Disease diagnostic Read
G30..12 Coronary thrombosis Ischaemic Heart Disease diagnostic Read
G30..13 Cardiac rupture following myocardial infarction (MI) Ischaemic Heart Disease diagnostic Read
G30..14 Heart attack Ischaemic Heart Disease diagnostic Read
G30..15 MI - acute myocardial infarction Ischaemic Heart Disease diagnostic Read
G30..16 Thrombosis - coronary Ischaemic Heart Disease diagnostic Read
G30..17 Silent myocardial infarction Ischaemic Heart Disease diagnostic Read
G300.00 Acute anterolateral infarction Ischaemic Heart Disease diagnostic Read
G301.00 Other specified anterior myocardial infarction Ischaemic Heart Disease diagnostic Read
G301000 Acute anteroapical infarction Ischaemic Heart Disease diagnostic Read
G301100 Acute anteroseptal infarction Ischaemic Heart Disease diagnostic Read
G301z00 Anterior myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G302.00 Acute inferolateral infarction Ischaemic Heart Disease diagnostic Read
G303.00 Acute inferoposterior infarction Ischaemic Heart Disease diagnostic Read
G304.00 Posterior myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G305.00 Lateral myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G306.00 True posterior myocardial infarction Ischaemic Heart Disease diagnostic Read
G307.00 Acute subendocardial infarction Ischaemic Heart Disease diagnostic Read
G307000 Acute non-Q wave infarction Ischaemic Heart Disease diagnostic Read
G307100 Acute non-ST segment elevation myocardial infarction Ischaemic Heart Disease diagnostic Read
G308.00 Inferior myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G309.00 Acute Q-wave infarct Ischaemic Heart Disease diagnostic Read
G30A.00 Mural thrombosis Ischaemic Heart Disease diagnostic Read
G30B.00 Acute posterolateral myocardial infarction Ischaemic Heart Disease diagnostic Read
G30X.00 Acute transmural myocardial infarction of unspecif site Ischaemic Heart Disease diagnostic Read
G30X000 Acute ST segment elevation myocardial infarction Ischaemic Heart Disease diagnostic Read
G30y.00 Other acute myocardial infarction Ischaemic Heart Disease diagnostic Read
G30y000 Acute atrial infarction Ischaemic Heart Disease diagnostic Read
G30y100 Acute papillary muscle infarction Ischaemic Heart Disease diagnostic Read
G30y200 Acute septal infarction Ischaemic Heart Disease diagnostic Read
G30yz00 Other acute myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G30z.00 Acute myocardial infarction NOS Ischaemic Heart Disease diagnostic Read
G31..00 Other acute and subacute ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G310.00 Postmyocardial infarction syndrome Ischaemic Heart Disease diagnostic Read
G310.11 Dressler's syndrome Ischaemic Heart Disease diagnostic Read
G311.00 Preinfarction syndrome Ischaemic Heart Disease diagnostic Read
G311.11 Crescendo angina Ischaemic Heart Disease diagnostic Read
G311.12 Impending infarction Ischaemic Heart Disease diagnostic Read
G311.13 Unstable angina Ischaemic Heart Disease diagnostic Read
G311.14 Angina at rest Ischaemic Heart Disease diagnostic Read
G311000 Myocardial infarction aborted Ischaemic Heart Disease diagnostic Read
G311011 MI - myocardial infarction aborted Ischaemic Heart Disease diagnostic Read
G311100 Unstable angina Ischaemic Heart Disease diagnostic Read
G311200 Angina at rest Ischaemic Heart Disease diagnostic Read
G311300 Refractory angina Ischaemic Heart Disease diagnostic Read
G311400 Worsening angina Ischaemic Heart Disease diagnostic Read
G311500 Acute coronary syndrome Ischaemic Heart Disease diagnostic Read
G311z00 Preinfarction syndrome NOS Ischaemic Heart Disease diagnostic Read
G312.00 Coronary thrombosis not resulting in myocardial infarction Ischaemic Heart Disease diagnostic Read
G31y.00 Other acute and subacute ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G31y000 Acute coronary insufficiency Ischaemic Heart Disease diagnostic Read
G31y100 Microinfarction of heart Ischaemic Heart Disease diagnostic Read
G31y200 Subendocardial ischaemia Ischaemic Heart Disease diagnostic Read
G31y300 Transient myocardial ischaemia Ischaemic Heart Disease diagnostic Read
G31yz00 Other acute and subacute ischaemic heart disease NOS Ischaemic Heart Disease diagnostic Read
G32..00 Old myocardial infarction Ischaemic Heart Disease diagnostic Read
G32..11 Healed myocardial infarction Ischaemic Heart Disease diagnostic Read
G32..12 Personal history of myocardial infarction Ischaemic Heart Disease diagnostic Read
G33..00 Angina pectoris Ischaemic Heart Disease diagnostic Read
G330.00 Angina decubitus Ischaemic Heart Disease diagnostic Read
G330000 Nocturnal angina Ischaemic Heart Disease diagnostic Read
G330z00 Angina decubitus NOS Ischaemic Heart Disease diagnostic Read
G331.00 Prinzmetal's angina Ischaemic Heart Disease diagnostic Read
G331.11 Variant angina pectoris Ischaemic Heart Disease diagnostic Read
G332.00 Coronary artery spasm Ischaemic Heart Disease diagnostic Read
G33z.00 Angina pectoris NOS Ischaemic Heart Disease diagnostic Read
G33z000 Status anginosus Ischaemic Heart Disease diagnostic Read
G33z100 Stenocardia Ischaemic Heart Disease diagnostic Read
G33z200 Syncope anginosa Ischaemic Heart Disease diagnostic Read
G33z300 Angina on effort Ischaemic Heart Disease diagnostic Read
G33z400 Ischaemic chest pain Ischaemic Heart Disease diagnostic Read
G33z500 Post infarct angina Ischaemic Heart Disease diagnostic Read
G33z600 New onset angina Ischaemic Heart Disease diagnostic Read
G33z700 Stable angina Ischaemic Heart Disease diagnostic Read
G33zz00 Angina pectoris NOS Ischaemic Heart Disease diagnostic Read
G34..00 Other chronic ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G340.00 Coronary atherosclerosis Ischaemic Heart Disease diagnostic Read
G340.11 Triple vessel disease of the heart Ischaemic Heart Disease diagnostic Read
G340.12 Coronary artery disease Ischaemic Heart Disease diagnostic Read
G340000 Single coronary vessel disease Ischaemic Heart Disease diagnostic Read
G340100 Double coronary vessel disease Ischaemic Heart Disease diagnostic Read
G342.00 Atherosclerotic cardiovascular disease Ischaemic Heart Disease diagnostic Read
G343.00 Ischaemic cardiomyopathy Ischaemic Heart Disease diagnostic Read
G344.00 Silent myocardial ischaemia Ischaemic Heart Disease diagnostic Read
G34y.00 Other specified chronic ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G34y000 Chronic coronary insufficiency Ischaemic Heart Disease diagnostic Read
G34y100 Chronic myocardial ischaemia Ischaemic Heart Disease diagnostic Read
G34yz00 Other specified chronic ischaemic heart disease NOS Ischaemic Heart Disease diagnostic Read
G34z.00 Other chronic ischaemic heart disease NOS Ischaemic Heart Disease diagnostic Read
G34z000 Asymptomatic coronary heart disease Ischaemic Heart Disease diagnostic Read
G35..00 Subsequent myocardial infarction Ischaemic Heart Disease diagnostic Read
G350.00 Subsequent myocardial infarction of anterior wall Ischaemic Heart Disease diagnostic Read
G351.00 Subsequent myocardial infarction of inferior wall Ischaemic Heart Disease diagnostic Read
G353.00 Subsequent myocardial infarction of other sites Ischaemic Heart Disease diagnostic Read
G35X.00 Subsequent myocardial infarction of unspecified site Ischaemic Heart Disease diagnostic Read
G36..00 Certain current complication follow acute myocardial infarct Ischaemic Heart Disease diagnostic Read
G360.00 Haemopericardium/current comp folow acut myocard infarct Ischaemic Heart Disease diagnostic Read
G361.00 Atrial septal defect/curr comp folow acut myocardal infarct Ischaemic Heart Disease diagnostic Read
G362.00 Ventric septal defect/curr comp fol acut myocardal infarctn Ischaemic Heart Disease diagnostic Read
G363.00 Ruptur cardiac wall w'out haemopericard/cur comp fol ac MI Ischaemic Heart Disease diagnostic Read
G364.00 Ruptur chordae tendinae/curr comp fol acute myocard infarct Ischaemic Heart Disease diagnostic Read
G365.00 Rupture papillary muscle/curr comp fol acute myocard infarct Ischaemic Heart Disease diagnostic Read
G366.00 Thrombosis atrium;auric append&vent/curr comp foll acute MI Ischaemic Heart Disease diagnostic Read
G38..00 Postoperative myocardial infarction Ischaemic Heart Disease diagnostic Read
G380.00 Postoperative transmural myocardial infarction anterior wall Ischaemic Heart Disease diagnostic Read
G381.00 Postoperative transmural myocardial infarction inferior wall Ischaemic Heart Disease diagnostic Read
G384.00 Postoperative subendocardial myocardial infarction Ischaemic Heart Disease diagnostic Read
G38z.00 Postoperative myocardial infarction; unspecified Ischaemic Heart Disease diagnostic Read
G3y..00 Other specified ischaemic heart disease Ischaemic Heart Disease diagnostic Read
G3z..00 Ischaemic heart disease NOS Ischaemic Heart Disease diagnostic Read

API

To Export Phenotype Details:

Format API
XML site_root/api/v1/public/phenotypes/PH620/version/1240/detail/?format=xml
JSON site_root/api/v1/public/phenotypes/PH620/version/1240/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('PH620', '1240', api_client=client)

To Export Phenotype Code List:

Format API
XML site_root/api/v1/public/phenotypes/PH620/version/1240/export/codes/?format=xml
JSON site_root/api/v1/public/phenotypes/PH620/version/1240/export/codes/?format=json
CSV site_root/phenotypes/PH620/version/1240/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('PH620', '1240', api_client=client)

Version History

Version
ID
Name Owner Publish date
1240 Ischaemia Heart Disease ieuan.scanlon 2021-10-06 currently shown

Export - export all codes into a csv file/JSON/XML for the current phenotype version.

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