MORGAM Manual

Data Transfer Format: Venous Thromboembolic Events Form: 26 Version: 4 Date: 10.10.2000

© National Institute for Health and Welfare and the MORGAM Project investigators Last updated: 31 October 2007 For more information, please contact Veikko Salomaa (firstname.lastname@thl.fi)

This data transfer format is no longer in use. It has been replaced by Data Transfer Format: Follow-up for Venous Thromboembolism (Form 86).

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

Contents

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

Format specification

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General Instructions

The record format is ASCII fixed length and record size is 58 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 to extracting these data items from the local data set.

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.

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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.

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Number 26 indicates the "Data transfer format: venous thromboembolic events".

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Enter the version number from the heading of the "Data transfer format - venous thromboembolic 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 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 VTEs 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 VTE 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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Enter the date of onset of the acute symptoms of VTE (or, in their absence, the fatal collapse of the person). 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. If detailed medical history is unavailable or if events are extracted from computerized data base the date of onset of the event is estimated as the date of death or as the date of hospital admission.

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

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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.

Note: The 3-character code does not always fully specify the VTE but can be used for comparison with the type of VTE.

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Enter the code for the the ICD version which was used for coding items CLIND1 ... CLIND3 and subsequent item CLINDU.

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 VTEs 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.

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Items TESOUR1...TESOUR5: Source of notification of venous thromboembolic event

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

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 records 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 notification was obtained from some other source e.g. from the person's relative.

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Items VDSOUR1...VDSOUR4: Source of validation of the diagnosis of venous thromboembolic event

The purpose of these items is to indicate sources of data for validation of the diagnosis of VTE.

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

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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.

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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 VTETYPE... CLINDU: Type and predisposing factors

Each VTE is defined as lasting for 28 days (unless interrupted by death) so that any recurrence or exacerbation of the condition within that period is counted as part of the original episode whereas beyond that time it counts as a new (recurrent) episode.

Code 1 (pulmonary embolism) if the event was classified as pulmonary embolism with or without the diagnosis of deep vein thrombosis.
Code 2 (deep vein thrombosis) if the diagnosis of deep vein thrombosis was done without the diagnosis of pulmonary embolism.

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Code 1 if the VTE was associated with other disease or condition known to predispose to the VTE. For example obstetric or puerperal VTE should be always coded as 1.
Code 2 if there was no such disease or condition which could predispose to the VTE.
Code 9 if there is no information available to choose another code.

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This item intends to gather information on likely predisposing factors to VTE [1]. If several diseases or conditions are valid, code the one with the lowest code number.

Code 1 if VTE was associated with previous surgery of any cause.
Code 2 if recent trauma without surgery was an obvious predisposing factor for the VTE.
Code 3 if VTE was secondary to active malignant neoplasm (excluding nonmelanoma skin cancer) without recent surgery.
Code 4 if patient had a neurologic disease and extremity paresis or plegia.
Code 5 for an obstetric or puerperal VTE.
Code 6 if another disease or condition known to predispose to the venous thromboembolism underlied the VTE.
Code 8 if VTESEC = 2 or 9.
Code 9 if there is no information available to choose another code.

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Record  here the ICD code of the underlying disease or condition according to the International Classification of Diseases, Injuries and Causes of Death (ICD) 8th, 9th or 10th Revision. Code the 3-character code.

If VTE was associated with recent surgery do not record the code of procedure or operation but the ICD code of the disease or condition which was the cause of surgery. Accordingly if VTE was associated with previous trauma do not record the code of the cause of trauma but the ICD code of the trauma (i.e for example ICD code of bone fracture).

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References

1. John A. Heit, Marc D. Silverstein, David N. Mohr, et al. Risk Factors for Deep Vein Thrombosis and Pulmonary Embolism. A Population-Based Case-Control Study. Arch Intern Med 2000;160:809-815.

Updates