Assessments (revisited)

Today I'd like to focus on Assessments in clinical medicine, including clinical research, with an emphasis on how to represent Assessment information optimally for data exchange. I've written about Assessments before. I'd like to revisit this topic again because, as standards continue to evolve and improve, we as an industry continue to fumble how we handle assessment information. I think this creates unnecessary challenges and limitations in how we document and exchange assessment information. I continue to see widespread confusion between what is an assessment vs. what is an observation. It remains common to see a 'schedule of assessments' in a study protocol when we really mean a schedule of observations. True assessments are not observations and yet they are critically important in understanding and analyzing adverse event reports or clinical trials. Standardizing assessment information remains a critical need in data standardization efforts to support automation.

First some working definitions. I use Aristotelian definitions whenever possible.

• A (Clinical) Observation is an Intervention whose intent is to measure the physical, physiological, or psychological state of a Person. 

• An Assessment is an Analysis of one or more Observations to identify and/or characterize (e.g, severity assessment) of a Medical Condition. 

• A Medical Condition is an Event that is a Disease, Injury, Disorder, or transient physiologic state (e.g. Pregnancy) that interferes or may interfere with well-being. 

These definitions lead to various corollaries.

• An Observation is a finding (as defined by CDISC) but it is also an intervention, since the observer must intervene in a person's normal routine to make and record the observation. Sometimes the details of the intervention (device used, method, etc) can affect the observation results, so are therefore worth recording. 
• An Adverse Event is not an Observation (as defined by CDISC). It is instead a Medical Condition that is temporally related to a therapeutic intervention, such as a drug administration. The relationship between an AE and an Observation is as follows. One or more observations may support the presence of an AE after a proper assessment. I note that the U.S. regulations used the words "occurrence," which is my opinion is synonymous with an event. 

Getting back to Assessments, physician's are trained from the earliest days in medical school that first one observes, then one assesses (i.e. interprets the observations) before deciding whether to treat. This makes up the familiar template of a patient encounter known as SOAP (Subjective observations, Objective observations, Assessments, Plan).

Often times Assessments are not formally conducted or documented in clinical trials, so there are no assessment data to standardize. A temperature reading of 39C (an observation) is almost always assumed to be a fever (assessment result-->medical condition), unless there are additional data to suggest something else (faulty digital thermometer, or evidence of the bizarre Munchausen Syndrome). Sometimes Assessment information is critical to ensure proper diagnosis and treatment, and in the case of clinical trials, treatment with the appropriate investigational drug. The Assessment, when formalized and standardized in the protocol, is called an Adjudication. (note: this is not to be confused with the process of ensuring an accurate observation by having, say, an independent blinded reader looking at an imaging study or pathological specimen to determine the accuracy of the observation result. The latter is simply a feature of an observation method to ensure quality measurements).

Speaking of independent observers and assessors, often times third party assessors (e.g. radiologists, pathologists) provide an independent assessment of certain observations (e.g. x-ray, lab results) when the investigator is not qualified to make his or her own assessment of the findings. These reports typically contain two sections. The first one describe the findings/observations (e.g. brain histology showing cortical atrophy, neurofibrillary tangles, amyloid plaques) followed by the assessment: findings are consistent with Alzheimer's Disease.

Because we currently confuse observations and assessments, we have no standard way to report assessment information. Currently sponsors use three possible approaches:

1. Include assessment information in findings domains
2. Include assessment information in supplemental findings domain
3. Include assessment information in custom domains

As one can imagine, the variability in reporting Assessment information currently is a significant problem. At the very least, we need an Assessment domain where one can find at a minimum:

• an Assessment ID
• what observations were used in the assessment
• who is/are the assessor(s) with a link to their qualifications
• date/time of assessment
• outcome of the assessment: i.e. cause of the observations, usually a Medical Condition, with a link to a medical conditions domain. 
• severity of the medical condition at the time of the assessment
• what method was used for the assessment (e.g. diagnostic criteria)
• what method/scale was used to document severity

It is important to note that one can have multiple assessments for the same set of observations. In health care this is known as a second opinion. Sometimes that second assessment uses different assessment criteria that the assessor believes is more relevant. A clearer picture now emerges of a Person/Subject having one or more medical conditions that are identified via an assessment of observations (some assessments are well documented, others not so much or at all), and changes in those medical conditions are documented via multiple observations and assessments at different points in time. This paradigm applies equally to the indication (i.e. the disease/condition being treated in the clinical trial) but also to new Medical Conditions (e.g. adverse events) that arise during the trial itself.

And let's remember, Death is not an adverse event, rather one of various possible outcomes for an  adverse event as the medical condition evolves over time. 

As an immediate short-term solution, SDTM should add an Assessment domain which links Assessment information to the observations that were used in the assessment. This would be a big step forward.