MORGAM Manual

Data Transfer Format: Coronary Events Form: 22 Version: 4 Date: 14.04.2003

© National Institute for Health and Welfare and the MORGAM Project investigators Last updated: 14 April 2003 For more information, please contact Kari Kuulasmaa (firstname.lastname@thl.fi)

• Format specification
• Instructions
  • General instructions
  • Specific instructions for each item
• Updates

Format specification

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Instructions

The purpose of this transfer format is to provide an exact and common format for the MORGAM Participating Centres (MPCs) to transfer data on coronary events to the MONICA Data Centre (MDC). Data in the format specified here should be submitted to the MDC for as many coronary events as specified in Item COREV of the Data transfer format: coronary events inventory for each member of the MORGAM cohort (see specific instructions for item COREV of the "Data transfer format: coronary events inventory". The data should be sent through e-mail or on diskettes, not on paper forms.

The record format is ASCII fixed length and record size is 78 characters. The position of each data item in the record is given in column "COLUMNS" of this data transfer format. There should be one record of data for every member of each MORGAM cohort.

This format corresponds with the layout of the information on the electronic data file which is transferred, and need to correspond with the format of locally used paper forms or electronic files. Instructions for transferring the data are given in Section Data communication between the Participating Centres and the MDC. To avoid errors, special attention should be paid in extracting these data items from the local data set.

General Instructions

The ITEM NAME on the document is a computer variable name used for the item by the MDC.

Blank fields are not allowed in the record.

Instructions for making corrections to data that have already been sent to the MDC are given in Section Data communication between the Participating Centres and the MDC.

28-day period: Several places of the specific instructions refer to a "28-day period". Two dates are defined to belong to the same 28-day period, if the difference between the dates is less than 28 days. For example, if two events occurred on 1 January 1996 and 28 January 1996 they were within the same 28-day period, but they occurred on 1 January  and 29 January, they were not. Similarly, 24 January and 20 February are in the same 28-day period, but 24 January and 21 February are not.

Please contact the MDC for instructions if you cannot provide information as specified in this document or if you have any problems with the interpretation of the coding for any specific items.

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Specific instructions for each item

Follow these instructions carefully when creating a computer file for the data transfer from the MPC to the MDC.

Number 22 indicates the "Data transfer format - coronary events".

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Enter the version number from the heading of the "Data transfer format - coronary events" which you are using. If the version number of the data transfer format which you are using is not "4", these instructions do not correspond to the format you are using. Check from the hyperlink for "Data transfer format: coronary events" of URL: http://www.thl.fi/morgam/internal/manual/contents.htm that you are using the valid version of the format.

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Items CENTRE...SERIAL

These are key items used for merging the different records of the same individual. Please make sure that the codes are identical with those used for the same person in the "Data transfer format: MONICA survey data".

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This is a key item, which identifies the different coronary events of the person. For every event you must assign an event number, which can be any number between 01 and 99, with one restriction: The same person is not allowed to have more than one coronary event with the same event number. This number, together with the other key items, will be used to identify the event in any future communication between the MDC and the MPC.

Note: there is no need for a person's event numbers to be in the order of the date of the event. Therefore, you can assign the event number already at the stage when you start registering the event.

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The first two columns are for the month; code 01 - 12, or code 99 if the month is not known. Enter the year of birth, in full four characters, in the last four columns. If the year of birth is not known, which should be very rare, derive the year of birth from an estimate of the age.

This item is the same as item MBIRTH of "Data transfer format: MONICA survey data", and it will be used for double checking the key items. If you compile the data for this record from various sources, please extract the data for this item from a different source than for the MONICA survey record.

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This item is the same as item SEX of "Data transfer format: MONICA survey data", and it will be used for double checking the key items. If you compile the data for this record from various sources, please extract the data for this item from a different source than for the MONICA survey record.

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If the event was registered in the MONICA Project, enter here the MONICA coronary event serial number under which data were submitted to the MONICA Data Centre. The purpose of this item is to facilitate a comparison with the MONICA data for clarification of possible inconsistencies.
Code 9999999 if this event was not registered in MONICA or if the serial number is not easily available.

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For onset of clinically diagnosed angina pectoris (i.e. EVTYPE = 1), enter the date of the first recorded diagnosis. Note, however, that if the onset of angina pectoris was diagnosed later than 28 days before a cardiac revascularization or an acute coronary event with diagnostic category 1, 2, 3, 4 or 5 (see item DGNCAT below), the angina pectoris should not be registered (i.e. no Form 22 should be submitted for it).

For cardiac revascularization (i.e. EVTYPE = 2), enter the date when revascularization was done.

For an acute coronary event, (i.e. EVTYPE = 3), the date of event is the date of onset of the acute symptoms of the coronary event (or, in their absence, the fatal collapse of the person). Where the patient has vague or intermittent symptoms followed by prolonged more severe symptoms, followed by a call for medical help, the time of event will be the time of onset of the prolonged symptoms. Where several attacks of symptoms occur and each of these attacks could qualify as possible onset, the onset should be timed from the onset of the first typical event of chest pain lasting more than 20 minutes. Where the patient has vague or intermittent or otherwise atypical symptoms (see item SYMPT) before calling medical help, and then has typical symptoms after being seen, the time of the onset should be that of the symptoms that led to a medical consultation.

If events are extracted from computerized data base the date of event is estimated as the date of death or the date of hospital admission.

When a silent infarct is diagnosed, estimate the date of event as the date of diagnosis.

All acute coronary events following an acute coronary event within 28 days should be considered as the same event, and therefore only one event record should be submitted for them.

If there was an acute coronary event and a revascularization (i.e. EVTYPE = 4), enter the date of the first of these.

If the exact date is not known, use circumstantial evidence to estimate the most likely date. If person has not been seen for some time, and is found dead, with no circumstantial evidence of when the fatal event occurred, then estimate the time and date of event (and death) as intermediate between the time the person was last seen and the time the body was found.

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Enter here the type of event for which the record was prepared:
Code 1 for the onset of angina pectoris.
Code 2 for cardiac revascularization (PTCA, CABG or any other revascularization procedure).
Code 3 non-fatal and fatal acute coronary event (including hospitalized unstable angina) or silent myocardial infarction.
Code 4 if there is a cardiac revascularization within the 28-day period following an acute coronary event or if the coronary event was a complication of the revascularization. In such a case both the acute coronary event and the revascularization will be reported on the same coronary event record.

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Record the clinical diagnoses here according to the International Classification of Diseases, Injuries and Causes of Death (ICD) 8th, 9th or 10th Revision. Do not code Procedures or Operations as the codes for these are often indistinguishable for entirely different diseases. Code the 3-character code. For an ICD-8 or ICD-9 code starting with a letter, such as E or Y, you should enter the letter and the first two numbers of the code (e.g. for ICD-9 code E987, enter E98). If there are fewer than three disease codes, enter NNN in the unused CLIND fields.

Ordinarily these will be the major hospital discharge codes, but if none is available such as when a patient is managed at home, or discharge coding has not been done, the MPC should assign up to three ICD codes to the clinical diagnoses of the attending doctors. In general, code the clinical diagnoses in the sequence in which they appear on the discharge or other documents. However, make sure that the major reason for hospital admission appears first. If there are more than three diagnoses recorded, and the diagnosis that led to registration is not among the first three, then ensure that this diagnosis is coded in CLIND3.

For fatal events where both clinical diagnoses (e.g. hospital discharge diagnoses) and death certificate diagnoses are available, the clinical diagnoses should be coded here. The death certificate diagnoses will be coded in items DEATHD of the "Data transfer format: follow-up data". In cases of discrepancies between clinical diagnoses and death certificate diagnoses it is likely that in analyses death certificate diagnoses will be used.

If clinical diagnoses of the attending doctors are not available, code NNN in all three CLIND fields.

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Enter the code for the the ICD version which was used for coding items CLIND1 ... CLIND3

Code 1 if ICD Revision 8 was used.
Code 2 if ICD Revision 9 was used.
Code 3 if ICD Revision10 was used.
Code 8 if each of items CLIND1 ... CLIND3 are coded NNN. Codes 1, 2 and 3 are also acceptable in such a case.

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This item is needed to assess the fatality of the event and to join the mortality data of "Data transfer format: follow-up data" to the event.

The 28-day period is defined in the General instructions of this form. The period starts on the date specified in item EVDATE. Note that in cases where one or more acute coronary events occur during the 28 days' period, the events should be considered as the same event, and the counting of the 28 days' survival period must start from the date of onset of the first suspected event.

If the reason for the person's exit from the study is death (i.e. EXREAS of the follow-up data record has value "1"), then SURVIV = 2 if EXDATE - EVDATE < 28 days. The date of onset of the event and the date of death are covered in the instructions for EXDATE and EVDATE, and the survival status will be derived from their difference.

In the rare cases where EXDATE - EVDATE < 28 days, but the reason for the exit from the study is the end of the study follow-up period (i.e. EXREAS = 2), then code SURVIV according to the survival status at 28 days after EVDATE even if it is later than EXDATE. (Although the event will not be included in analyses where death is used as the end-point, the 28-day survival status is needed for deriving the MONICA diagnostic category. The death information of the "Data transfer format - follow-up data" will not be collected for such events.)

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Items APSOUR1...APSOUR3: Source of diagnosis of angina pectoris

If the MPC has collected data on the onset of angina pectoris, they can be submitted to the MDC using this form and coding EVTYPE = 1. The purpose of these items is to indicate the source or sources and reliability of the diagnosis. The items are ordered according to the reliability of the diagnosis, with APSOUR1 (medical record or drug reimbursement register) being considered most reliable and item APSOUR3 (interview with person) the least reliable.

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Code 1  (yes) if angina pectoris was decided on the basis of a review of medical records or if information of angina pectoris was extracted from hospital discharge register or drug reimbursement register.

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Code 1 (yes) if a clinician tells that the person has had angina pectoris.

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Code 1 (yes) if the subject tells that he or she has been told by a physician to have angina pectoris.

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Item REVTYPE: Type of revascularization

Code 1 if coronary angioplasty (with or without stenting) was done. If the PTCA was repeated within 28 days, submit only one event record.
Code 2 if coronary artery bypass surgery was done.
Code 3 if both PTCA and CABG were done within 28 days of each other.
Code 4 if other revascularization procedure  than conventional PTCA or CABG  was done.
Code 9 if there is information that revascularization was done, but the type of revascularization is not known.

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Items REVSOUR1 ... REVSOUR3: Source of data on revascularization

Code 1 (yes)  if the information was obtained by a review of the hospital records or from a hospital discharge register.

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Code 1 (yes) if the information was obtained from the patient's doctor, but the medical records were not seen.

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Code 1 (yes) if information about the revascularization was obtained only from the patient.

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Items CESOUR1 ... CESOUR7: Source of notification of acute coronary event

The purpose of these items is to indicate the sources of data for identification of acute coronary events at follow-up.

Code 1 (yes) if the MONICA coronary event register or other population-based coronary event register was used to monitor acute coronary events, and this event was found there.

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Code 1 (yes) if information on the event was extracted from a cause of death register.

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Code 1 (yes) if information on the event was obtained by review of the hospital record or from a hospital discharge register.

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Code 1 (yes) if the notification was obtained from the person's doctor.

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Code 1 (yes) if notification was obtained from the person.

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Code 1 (yes) if interval ECG was the only source of information about acute coronary event.

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Code 1 (yes) if notification was obtained from some other source e.g. from the person's relative, ..etc.

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Items DSOUR1 ... DSOUR5: Source of validation of the diagnosis of acute coronary event

The purpose of these items is to indicate sources of data for validation of the diagnosis of acute coronary event. Items DSOUR1...DSOUR5 have been constructed in such a way that exactly one of them should have code 1 for each acute coronary event.

Code 1 (yes) if the acute coronary event was validated using the MONICA criteria.

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Code 1 (yes) if diagnostic data was available and systematic review of this data was done using a predetermined algorithm, other than MONICA.

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Code 1 (yes) if hospital notes and/or necropsy report were seen but systematic review was not done.

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Code 1 (yes) if hospital discharge letter was available for evaluating the event.

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Code 1 (yes) if only hospital discharge diagnoses or ICD-codes, death certificate diagnoses or ICD-codes or final official death diagnoses or ICD-codes were available.

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Items SYMPT...THROMBD: Data on acute coronary event

Because each event lasts only 28 days the diagnostic criteria used must be from investigations or symptoms that refer to what happened within that 28 day survival period even though the results (such as necropsy or biochemical markers) may be reported later. The definition of the 28-day survival period has been given earlier.

The most severe findings during the 28-day survival period should always be recorded. This means that in case of recurrent events during the 28-day period symptoms should be coded "typical" if in any of the recurrent attacks the criteria for typical symptoms were met. Accordingly enzymes should be coded "Abnormal" if in any of the recurrent attacks the criteria for abnormal enzymes were met. This also means that symptoms, enzymes or other biochemical markers and ECG findings may refer to different attacks occurring within the 28-day period.

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The coding is identical with MONICA Manual, Part IV, Form 01, version 5, Item 12:

The patient may have one or more episodes of symptoms in the 28 days' survival period following the onset (see item EVDATE).

Code 1 (typical symptoms) when chest pain is present and characterized by:

1. duration of more than 20 minutes, and
2. no definite non-cardiac, or cardiac non-atherosclerotic cause.

Any synonym for pain is acceptable such as "pressure", "discomfort", "ache".

If a patient has an onset of acute symptoms that are not typical but subsequently (during the 28 days' survival period) has a recurrence of acute symptoms that are typical, then code the symptoms as 1 (typical). In such cases the date of onset, EVDATE, should be that of the first acute symptoms that led to medical consultation.

If a patient has symptoms that are typical, additional symptoms such as a shock, syncope and left ventricular failure will not make those symptoms atypical.

If symptoms are otherwise typical but the duration is not stated, then code 5 (inadequately described). The duration can be assumed to be 20 minutes and the symptoms considered as typical if there are statements in the history implying that the pain lasted while something else was going on, or until something else happened (such as arrival at hospital, cardiac arrest syncope, fatal collapse, administration of analgesic by medical attendant) or if the pain is described using words like "protracted" or "continuous", or if the pain continued despite self-administration of drugs.

Code 2 (atypical) means symptoms that were not typical but there was

1. one or more of the following conditions present
   • atypical pain
   • acute left ventricular failure
   • shock
   • syncope

Note: acute left ventricular failure, shock or syncope, do not convert otherwise typical symptoms into atypical ones.

AND

2. the absence of cardiac disease other than ischaemic heart disease

AND

3. no definite non-cardiac or cardiac non-atherosclerotic cause.

Atypical pain would be pain recorded as of short duration or intermittent with each bout lasting for less than 20 minutes, or pain at an unusual site (upper abdomen, arms, jaw, neck).

Acute left ventricular failure means that diagnosis was made clinically or that the patient became severely breathless suddenly. Chronic heart failure or breathlessness getting worse over several days would not qualify.

Fatal collapse should not be considered as syncope. Syncope should be reversible. Typical chest pain leading to syncope should be coded as typical (see above).

Code 3 (other symptoms) when symptoms are well described but do not satisfy the criteria for typical or atypical. Symptoms due to a definite non-cardiac cause or to a definite non-atherosclerotic cardiac cause (such as pericarditis) should be coded 3.

Code 4 (no symptoms) in non-fatal cases if the patient reported no symptoms in the attack, and in fatal cases if the eyewitnesses of the fatal collapse state that the individual was completely normal and uncomplaining before the moment of death.

Code 5 (inadequately described symptoms) for cases otherwise satisfying criteria for typical pain, but in which the duration of the pain is not described, so that it is not possible to classify the symptoms as typical.

Code 8 (irrelevant) if EVTYPE = 1 or 2.

Code 9 (insufficient data) if information on the presence or character of symptoms is inadequate to allocate another code.

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The coding instructions are given in the MONICA Manual, Part IV, Section 1.2.4.

Code 8 (irrelevant) if EVTYPE = 1 or 2.

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The coding is identical with MONICA Manual, Part IV, Form 01, version 5, Item 14:

Each MPC should find out and define, with the help of their local hospital laboratories, (a) the cardiac enzyme tests employed, and (b) the upper limit of normal for each test in each laboratory.

For quality control, record the actual enzyme test values on the coronary event forms of your MPC, although those values are not transmitted to the Data Centre.

Code 1 (abnormal) if at least one reading is more than twice the upper limit of normal when measured within 72 hours or within 3 calendar days of onset of symptoms, admission to hospital, or of any recurrence of acute symptoms during the 28-day follow-up period from the original date of onset.

Code 2 (equivocal) when serum enzyme levels are raised but to less than twice the upper limit of normal, when measured within the relevant time period.

Code 3 (non-specific) if serum enzyme levels are raised to more than twice the upper limit of normal, but there are probable explanations other than myocardial infarction, such as liver disease, infections, defibrillation or surgery.

Code 4 (normal) when the enzyme tests are done within the relevant time period and reported adequately and the levels are within the limits of normal.

Code 5 (incomplete) where tests are done but not within 72 hours of onset of acute symptoms or any recurrence.

Code 8 (irrelevant) if EVTYPE = 1 or 2.

Code 9 (insufficient data) when serum enzyme tests have not been done or are unavailable.

Note: MPCs differ in the coding of serum enzyme results which are more than twice the limit of normal although taken more than 72 hours or three calendar days from the onset. Some centres code these as 5 (incomplete). Others, because of the difficulty of ascertaining recurrence of symptoms, and because some cardiac enzymes may remain elevated for this time or longer, code them 1 (abnormal). They reserve code 5 (incomplete) for tests done out of time that were either within normal limits or below twice the upper limit of normal. This is a rare problem and centres should make their own rules explicit and stick to them, but the abnormal option is generally preferred.

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If troponin or other nonenzymatic marker test of cardiac injury is employed, MPC should find out and define the upper limit of normal for each test in each laboratory.

Code 1 (diagnostically elevated) if at least one reading is raised over the upper limit of normal irrespective the time of measurement after onset of symptoms, after the admission to hospital, or after any recurrence of acute symptoms during the 28-day follow-up period from the original date of onset.

Code 2 (measured, but not diagnostically elevated) when the tests are done within the relevant time period and reported adequately and the levels are within the limits of normal.

Code 8 (irrelevant) if EVTYPE = 1 or 2.

Code 9 (insufficient data) when troponin or other nonenzymatic markers of cardiac injury are not employed or the results are otherwise unavailable.

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The coding is identical with MONICA Manual, Part IV, Form 01, version 5, Item 15:

Code 1 (definite) if, recorded at necropsy there was, visible to the naked eye

1. myocardial infarction:

and/or

2. recent occlusion of a coronary artery (from antemortem thrombus or haemorrhage into an atheromatous plaque or embolism):

Code 2 (equivocal) when the necropsy record does not show definite evidence (as above) nor does it record any non-cardiac or cardiac, non-atherosclerotic disease causing death but there is

1. old myocardial infarction (scar):

and/or

2. occlusion or severe stenosis (greater than 50% reduction of lumen) by atheroma of one or more coronary arteries:

Code 4 (negative) when there is recorded at necropsy

1. no definite evidence as described above,

and

2. evidence of non-cardiac or cardiac non-atherosclerotic disease causing death.

Note that the findings of chronic coronary heart disease in 2(a) and (b) are compatible with code 4 if there is another pathology present that caused death. MONICA rules simplify a complex situation by assuming that whatever killed the victim in a fatal case was also responsible for the acute symptoms.

Code 8 (not relevant) if the patient is still alive at the end of the 28 days survival period or if necropsy was not done.

Code 9 (insufficient data) when the results of the necropsy were not obtained.

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If the event validation was done using the MONICA criteria (i.e. if DSOUR1 = 1) allocation of diagnostic category follows the definitions provided in MONICA Manual, Part IV, Section 1, Subsections 2.2 and 2.3. Note, however, that if troponin or other nonenzymatic marker test of cardiac injury was used, the MONICA item ENZ in the diagnostic algorithm can be replaced with the MORGAM item MARKER, with the following conversion rule: MARKER=1 corresponds to ENZ=1 and MARKER=2 corresponds to ENZ=4.

Note that there is a difference in the numbering of the resulting diagnostic categories:

If the event validation was not done using the MONICA criteria (i.e. if DSOUR1 = 2 or 9), then the coding instructions for DGNCAT are:

Code1 (definite acute myocardial infarction) if the event was classified as definite acute myocardial infarction.

Code 2 ( possible acute myocardial infarction or coronary death) if the event was classified as possible acute myocardial infarction.

Code 3 (definite or possible acute myocardial infarction or coronary death) if the event was classified as definite or possible acute myocardial infarction or coronary death, without making a difference between them (for example 3-character ICD code from hospital discharge register).

Code 4 (unstable angina pectoris) if  the patient was admitted to hospital and diagnosed as having unstable angina pectoris.

Code 5 (unclassifiable) if no decision on any other diagnostic categories could be made on the basis of the rule used for validation of the event.

Code 6 (silent myocardial infarction) if the person has had an ECG taken, with no Minnesota Q-wave code, and a later interval ECG with Minnesota code 1-1 or 1-2 except 1-2-6 and 1-2-8.

Code 7 (no acute myocardial infarction or coronary death) if the conclusion from the validation of the event was that the patient did not have an acute myocardial infarction or coronary death. There is no need to send such event records to the MDC.

Code 8 (irrelevant) if EVTYPE = 1 or 2.

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Enter here the place of death.

Code 1 (yes) if patient died (medically attended or unattended) before arrival at hospital. Unsuccessful resuscitation on emergency without other management should also be coded 1. Also, code 1 if there was a medical decision to manage the patient in a place other than hospital, e.g. in a nursing home, and the patient arrived there alive, or alternatively if he or she was already a patient there and died.

Code 2 (no)  the patient reached hospital alive. Include also patients whose onset of symptoms occurred when they were already in hospital.

Code 8 (irrelevant) if EVTYPE = 1 or 2 or SURVIV = 1.

Code 9 (insufficient data) if the patient has died but information on the place of death is missing.

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Code 1 if thrombolytic therapy was used during the event.
Code 2 if there is no evidence that thrombolytic therapy was used.
Code 9 for patients for whom there are no records available from which the use of thrombolytic therapy can be discovered, and there may have been drugs and interventions administered. If a patient was found in circumstances in which medication and procedures could not have been used, then it is reasonable to code 2 (no) rather than 9 (insufficient data).

Updates

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