MORGAM Manual

Data Transfer Format: Stroke Events Form: 23 Version: 4 Date: 12.12.2000

© National Institute for Health and Welfare and the MORGAM Project investigators Last updated: 14 June 2005 For more information, please contact Kari Kuulasmaa (firstname.lastname@thl.fi)

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

Format specification

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 stroke events to the MONICA Data Centre (MDC). Data in the format specified here should be submitted to the MDC for as many stroke events as specified in Item STROKES of the Data Transfer Format: stroke events inventory for each member of the MORGAM cohort (see specific instructions for item STROKES of the "Data transfer format: stroke 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 83 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 needs not 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: 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.

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 23 indicates the "Data transfer format: stroke events".

Enter the version number from the heading of the "Data transfer format: stroke 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: stroke events" of URL: http://www.thl.fi/morgam/internal/manual/contents.htm that you are using the valid version of the format.

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".

This is a key item, which identifies the person's different stroke events. 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 stroke 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.

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.

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.

If the event was registered in the MONICA Project, enter here the MONICA stroke 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.

Enter the exact date of onset of the stroke. Enter 01-31 in the first two columns and 01-12 in the third and fourth columns for day and month of onset, and the year (19--) in the fifth and sixth columns.

Onset is the onset of acute symptoms, whatever they were, that continued up to the appearance of the stroke (or, in their absence, the fatal collapse of the person). Where the patient has vague or intermittent symptoms with complete recovery (such as a transient ischaemic attack) followed by prolonged more severe symptoms, the time of onset will be the time of onset of the prolonged symptoms. Where several attacks of symptoms occur and each of these attacks could qualify as a possible onset, the onset could be timed from the onset of the first stroke. Where there is a vague onset and a slow increase in severity of symptoms over several days (but without complete recovery), that is a crescendo onset, then the onset should be dated to the beginning of the episode.

(Note: This means the rules are slightly different from those for a crescendo onset for coronary events).

In cases of sudden death presenting with a fatal collapse, the time and the date of onset will be the same as that for death. Where a person is found dead, use circumstantial evidence to estimate the most likely time (and therefore date as this may be overnight) of onset and death. If the 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 onset (and of death) as the intermediate between the time the person was last seen and the time the body was found. (MPCs should establish quality assurance procedures for standardizing the coding of similar problems to this, such as keeping a file of problem cases and how they were coded, and having a review committee.)

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

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

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.

Enter the code for 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.

This item assesses the fatality of the event at 7 days. The 7-day period starts on the date specified in item EVDATE. Two dates are defined to belong to the same 7-day period, if the difference between the dates is less than 7 days. In cases where one or more acute stroke events occur during the 7 days' period, the events should be considered as the same event, and the counting of the 7 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 SURV7 = 2 if EXDATE - EVDATE < 7 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 at 7 days will be derived from their difference.

In the rare cases where EXDATE - EVDATE < 7 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 SURV7 according to the survival status at 7 days after EVDATE even if it is later than EXDATE.

This item is needed to assess the fatality of the event at 28 days 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 stroke 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 SURV28 = 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 SURV28 according to the survival status at 28 days after EVDATE even if it is later than EXDATE. The death information of the "Data transfer format - follow-up data" will not be collected for such events.

Items SESOUR1...SESOUR6: Source of notification of acute stroke event

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

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

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

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

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

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

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

Items DGSOUR1...DGSOUR5: Source of validation of the diagnosis of acute stroke event

The purpose of these items is to indicate sources of data for validation of the diagnosis of acute stroke event.

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

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

Code 1 (yes) if hospital notes and/or necropsy report were seen but systematic review was not done. Also code 1 when the patient was not hospitalized but the outpatient records were seen.

To the top of the form

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

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.

Items MANAGE ... INVEST8: Management and examinations

Code 1 (in hospital) if a medical consultation occurred after the onset of the event and a decision was made to refer or admit the patient as an inpatient and the patient reached hospital alive. Include also patients whose onset of symptoms occurred when they were already in hospital.

Code 2 (nursing home) if there was a medical decision to manage the patient in a nursing home and the patient arrived there alive, or alternatively if he or she was already a patient there. Local definitions should be used in each MPC to decide what is a nursing home and what is a hospital.

Code 3 (at home by a doctor) if there was a medical consultation in the event and a decision by the doctor to manage the patient resting at home.

Code 4 (medically unattended) where no decision on management could be taken because the patient was already dead when first seen by a doctor.

Code 5 (other medical consultation without bed rest, in hospital or at home) where the patient was seen in the event by a doctor but, because death occurred too rapidly or because the event was not diagnosed at the time or because recognition occurred some time after onset, no decision was made to admit the patient for bed rest or to order rest at home, or the patient died in transit.

Code 9 (insufficient data) if information is inadequate to allocate another code.

Code 1 (yes) if the relevant examination was made between the onset of acute symptoms and 28 days and there are records to prove it.

Code 2 (no) if the relevant examination was not made between the onset of acute symptoms and 28 days. Evidence for this would be that: there are records stating that the examination was not done, or there are records of examinations that were done and no record of the examination concerned, or the patient died too rapidly for any of them to be done, or was managed at home or in an institution where it would not be possible to do the examination.

Code 9 (insufficient data) if no records of the examination done are available and it is therefore not possible to state whether the examination was done or not.

Items DGNCAT ... ASSMI: Diagnosis

Code 1 (definite stroke) if there were rapidly developed clinical signs of focal* (or, in selected instances, global**) disturbance of cerebral function lasting more than 24 hours (unless interrupted by surgery or death) with no apparent cause other than a vascular origin. This includes patients presenting clinical signs and symptoms suggestive of subarachnoid haemorrhage, intracerebral haemorrhage, or cerebral infarction. It does not include transient cerebral ischaemia or stroke events in cases of blood disease (e.g. leukaemia, polycythaemia vera), brain tumour or brain metastases. Secondary stroke caused by trauma should also be excluded.

* The following are accepted in MORGAM as focal neurological symptoms and signs:

• Unilateral or bilateral motor impairment (including dyscoordination)
• Unilateral or bilateral sensory impairment
• Aphasia/dysphasia (non-fluent speech)
• Hemianopia (half-sided impairment of visual fields)
• Diplopia
• Forced gaze (conjugate deviation)
• Dysphagia of acute onset
• Apraxia of acute onset
• Ataxia of acute onset
• Perception deficit of acute onset.

Not accepted as sole evidence of focal dysfunction

• Dizziness, vertigo
• Localised headache
• Blurred vision of both eyes
• Dysarthria (slurred speech)
• Impaired cognitive function (including confusion)
• Impaired consciousness
• Seizures

(although stroke may present in this way, these signs are not specific and cannot therefore be accepted as definite evidence for stroke if they occur without concomitant focal signs)

**"Global" applies to patients with subarachnoid haemorrhage or deep coma caused by a stroke. Coma of systemic vascular origin such as shock, Stokes-Adams syndrome, or hypertensive encephalopathy is excluded.

Do not code 1 for transient cerebral ischaemia (that is, focal neurological signs or symptoms that recede completely within 24 hours) or if the duration of neurological deficit is insufficiently specified.

Note: A brain lesion visualised by any imaging technique and NOT accompanied by acute clinical symptoms and signs is not included as a stroke in MORGAM.

Code 4 (not stroke) if the registered event does not satisfy the study criteria of definite stroke (code 1) given above. There is no need to transfer such events to the MDC, but there is no problem if they are transferred.

Code 9 (unclassifiable) if the data concerning origin or duration of symptoms is insufficient to code 1 or 4. These will include cases in which there is no diagnosis other than stroke to explain the illness but the information is inadequate to make it a definite stroke, or the duration is insufficiently defined to determine whether it was more or less than 24 hours.

Code 1 (yes) if a stroke event occurred within 28 days after a definite or possible myocardial infarction.
Code 2 (no) if the event was not preceded by a definite or possible myocardial infarction within 28 days.
Code 8 (irrelevant) if DGNCAT = 4.
Code 9 (insufficient data) if there is no information available to choose another code.

Items SAH...OTYPE : Type of stroke

Stroke subtyping is essential for phenotypic characterization in MORGAM. The three main subtypes are subarachnoid haemorrhage (SAH), intracerebral haemorrhage (ICH) and cerebral infarction (CI). To facilitate coding of less common subtypes a fourth item OTYPE has been added. In cases of SAH and CI, the underlying causes should be given in the items SOURSAH, CAREM and DISSART.

Code 1 (yes): To be accepted as a case of subarachnoid haemorrhage in MORGAM, at least one of the following must be present:

1. Necropsy - recent subarachnoid haemorrhage
2. CT - signs of blood in the subarachnoid cisterns or in cerebral ventricles
3. Magnetic resonance imaging - signs of blood in the subarachnoid cisterns or in cerebral ventricles
4. Cerebrospinal fluid (liquor) bloody and/or xanthochromic and the possibility of intracerebral haemorrhage excluded by necropsy or CT examination

Typical symptoms of SAH (abrupt onset of severe headache or unconsciousness in the absence of focal neurological symptoms) may support the diagnosis but cannot be used alone to establish or refute the diagnosis of SAH.

Code 2 (no) if any of the diagnostic procedures above have been performed and the criteria for code 1 are not fulfilled.

Code 8 (irrelevant) if DGNCAT has been coded 4.

Code 9 (insufficient data) if no laboratory diagnostic procedures (or necropsy) have been performed. This code may also be used if the laboratory procedures provide ambiguous diagnostic information.

Code 1 (yes): To be accepted as a case of intracerebral haemorrhage in MORGAM, at least one of the following must be present:

1. Necropsy - recent intracerebral haemorrhage
2. CT - hyperdensity changes in the brain parenchyma. Note that small haematomas or diffuse bleedings occurring within a hypodense lesion (so-called haemorrhagic transformation) are not coded as intracerebral haemorrhage but as cerebral infarction (item CI below)
3. Magnetic resonance imaging - typical signs of bleeding in the brain parenchyma
4. Cerebrospinal fluid (liquor) bloody in the presence of focal neurological signs at onset.

Clinical symptoms and signs cannot be used alone to establish a diagnosis of ICH.

Code 2 (no) if any of the diagnostic procedures above have been performed and the criteria for code 1 are not fulfilled.

Code 8 (irrelevant) if DGNCAT has been coded 4.

Code 9 (insufficient data) if no laboratory diagnostic procedures (or necropsy) have been performed. This code may also be used if the laboratory procedures provide ambiguous diagnostic information.

Code 1 (yes): To be accepted as a case of brain infarction (ischaemic stroke) in MORGAM, at least one of the following must be present:

1. Necropsy - recent brain infarction
2. CT - circumscribed hypodensity changes of recent origin in the brain parenchyma or absence of localised changes of recent origin although the criteria for definite stroke are fulfilled (see item DGNCAT above). Cases with small haematomas or diffuse bleedings occurring within a hypodense lesion (so-called haemorrhagic transformation) are coded as having cerebral infarction.
3. Magnetic resonance imaging - typical signs of infarct in the brain parenchyma

Code 2 (no) if any of the diagnostic procedures above have been performed and the criteria for code 1 are not fulfilled.

Code 8 (irrelevant) if DGNCAT has been coded 4.

Code 9 (insufficient data) if no laboratory diagnostic procedures (or necropsy) have been performed. This code may also be used if the laboratory procedures provide ambiguous diagnostic information.

Code 1 (yes) if any other type of stroke has been confirmed by an imaging technique or necropsy. This would usually apply to rare disorders (Moyamoya syndrome, antiphospholipid syndrome, Sneddon's syndrome, etc.).

Code 2 (no) if an imaging technique has been applied or a necropsy was done , and the criteria for code 1 are not fulfilled.

Code 8 (irrelevant) if DGNCAT has been coded 4.

Code 9 (insufficient data) if no laboratory diagnostic procedures (or necropsy) have been performed. This code may also be used if the diagnostic procedures provide ambiguous diagnostic information.

Items SOURSAH...DISSART: Further specification of type of stroke

These items are not critical in MORGAM, but they are useful if the data are available.

Code 1 (aneurysm) if SAH has been coded 1 and a ruptured aneurysm has been confirmed by necropsy or by an imaging technique (various angiographic modalities, CT scan, MRI or other)

Code 2 (arteriovenous malformation) if SAH has been coded 1 and an arteriovenous malformation has been confirmed by necropsy or by an imaging technique (various angiographic modalities, CT scan, MRI or other)

Code 3 (undetermined) if any of the diagnostic procedures above have been performed and the criteria for code 1 or 2 are not fulfilled.

Code 8 (irrelevant) if SAH has been coded 2, 8 or 9.

Code 9 (insufficient data) if SAH has been coded 1 and no laboratory diagnostic procedures (or necropsy) have been performed. This code may also be used if the imaging procedures provide ambiguous diagnostic information.

Code 1 yes if CI has been coded 1 and any of the following cardiac sources of embolism is present (this includes conditions that are both well documented sources of embolism and confer a markedly elevated risk for stroke):

• Chronic atrial fibrillation
• Rheumatic valve disease
• Prosthetic mitral or aortic valves
• Recent myocardial infarction (last 4 weeks)
• Infective endocarditis
• Dilated myocardiopathy
• Left ventricular aneurysm
• Infective endocarditis
• Myxoma, other tumors
• Ischaemic stroke occurring during cardiac manipulation (heart surgery, valvuloplasty, angioplasty, angiography)

Other potential sources of embolism that are either less well documented or confer only slightly increased risk are not accepted as cardiac sources of embolism in MORGAM. This includes for instance atrial flutter, intermittent atrial fibrillation, sick sinus syndrome, patent foramen ovale, mitral valve prolapse, mitral annulus or aortic valve calcifications.

Code 2 (no) if none of the above cardiac sources of embolism has been confirmed.

Code 8 (irrelevant) if CI has been coded 2, 8 or 9.

Code 1 if a dissection of a precerebral artery has been confirmed by an imaging procedure (different modalities of angiography, CT scan, MRI, sonography or other).

Code 2 (no) if none of the above cardiac sources of embolism has been confirmed.

Code 8 (irrelevant) if CI has been coded 2, 8 or 9.

Items CONSC...COURSE: Severity of the stroke

Code 1 (fully conscious) if the person was at the first examination fully alert.
Code 2 (somnolent or stuporous) if the person at the first examination was not fully rousable or drowsy responding as best to speech.
Code 3 (comatose) if the person at the first examination was unconscious responding as best to pain only.
Code 4 (dead) if the person was dead at the first examination.
Code 8 (irrelevant) if DGNCAT = 4.
Code 9 (insufficient data) if information on the level of consciousness at the first examination is inadequate to allocate another code.

Code 1 (improving) if the person's clinical condition improved (e.g. level of consciousness improved, degree of limb weaknesses or other neurological deficits decreased etc.).
Code 2 (unchanged) if the person's clinical condition was unchanged during the first 72 hours.
Code 3 (worsening, including death) if the person's condition worsened (e.g. level of consciousness fell, degree of limb weaknesses or other neurological deficits increased etc.) or person died of stroke (or of stroke related complication) during the first 72 hours.
Code 4 (other) if the clinical course in the first 72 hours was other than described by codes 1-3, for example fluctuating with both improvement(s) and deterioration(s).
Code 8 (irrelevant) if DGNCAT = 4.
Code 9 (insufficient data) if information on the course of stroke in the first 72 hours is inadequate to allocate another code.

Item DIAB: diabetes

Code 1 (yes, type I) if insulin dependent diabetes mellitus has been diagnosed before or during the stroke event.
Code 2 (yes, type II) if non-insulin dependent diabetes mellitus has been diagnosed before or during the stroke event.
Code 3 (yes, type unspecified) if diabetes has diagnosed before or during the stroke event, but the type of diabetes is unknown.
Code 4 (no) if the person is not a diabetic.
Code 9 (insufficient data) if there is no information available to choose another code.

Updates