Medical documentation typically distinguishes between the person, the patient and the case. The person-related basic module of the core data set is intended to allow reference to be made to other modules. This module can contain site-specific identifiers from local identity management systems or existing unique keys from other modules of the core data set. Where required, the module may include personal attributes for cross-institutional or cross-sector integration. The goal is not just to monitor basic data for a single hospitalisation for a specific person, but to make it possible to track the course of treatment across multiple hospitalisations. The current specification explicitly models the person module for patients and clinical study participants.
Case-related data form the backbone of the data model. They are required, in particular, for correlation to a particular sector, time or geographical location, and for data provenance. A “case” commences with hospitalisation on a specific admission date and ends when the patient is released on a specific discharge date. Case data include the type of patient discharge (including “deceased” as a possible form of discharge). Valuable demographic attributes include age, sex, and place of residence (post code). The person’s health insurance policy (member) number and the name of the health insurer are also included.
A diagnosis is the reason for treatment in a given health care system. With in-patient care, the primary and any secondary diagnoses are entered into hospital information systems (HIS) for a variety of purposes. With out-patient care, the attending physician generally only records a diagnosis for each case on a quarterly basis within the scope of invoicing/cost settlement. In many research projects, the diagnosis is the most important (generally) independent variable.
A further central element of medical documentation is the standardised description of any treatment. The procedure module contains data elements related to the documentation of operations, interventions, other medical procedures and selected therapies with medication. A procedure is any activity within the scope of health care performed with or for a patient. This includes diagnostics and treatment/therapy. The procedure module records the details of current and historical interventions.
Laboratory test results module
Laboratory tests are performed for almost all hospital in-patients. The test results are usually stored centrally. The following items of information for each patient and case should be transferred to the corresponding data integration centre (DIC) each time a laboratory test is conducted:
- The test/analysis designation, with unique test identifier (using the LOINC standard coding system)
- The date the test was conducted
- The result (measured value) with standardised unit of measurement
- Interpretation: indication whether result represents a pathological value (recommended)
- Type of scale (optional)
- Reference range (recommended)
- Source laboratory (optional)
It is also possible to model other clinical tests, microbiological tests and vital signs that go beyond the scope of conventional clinical/chemical and haematological laboratory data.
The medication module contains data elements that document the prescription and administration of medication. The prescription of medication is a core aspect of routine health care and takes place at all MII hospitals. However, the proportion of prescriptions documented in digital form varies greatly from site to site with regard to the degree to which it is structured, and the populations and medications included. Data on medication is central to a wide range of questions, e.g. on pharmacovigilance (drug safety), and as inclusion/exclusion criteria for specific studies.
It is possible to distinguish between the following types of administered medication to be documented:
- Medication in hospital (primarily/partially in-patient care)
- Medication upon discharge from hospital
- Medication for out-patients
- Self-medication (OTC)
- Medication administered within the scope of clinical studies
Data can range from the basic documentation of the administration of a particular pharmaceutical product in a case of treatment, to the detailed, structured capture of individual doses with encoding of the active ingredient, dosage form, route of administration, and dosage in line with international standards.
At a minimum, accessible data should include the active ingredient. As a next step, it is proposed to make the following data elements available:
- Commercial names of administered pharmaceuticals
- The dose with unit of measurement
- Dosage form
- Location and route of administration
Where the data are available, a third step could extend the scope of documentation to include the following elements:
- Dosage regimen
- Composition of infusions / flow rate of infusion pumps
- Indication (i.e. reference to the related diagnosis)