About Coding in MedDRA

I am coding a study conducted in patients with Diabetes Mellitus. One of the adverse events is "hypoglycemia" or "decreased blood sugar". However they are treated as two different adverse events and coded to two different MedDRA codes. I do not quite understand why that is so.

The fact is that PT - LLT Hypoglycaemia and PT - LLT Blood glucose decreased both exist; further, they reside in different and distinct SOCs in MedDRA. If you look at the MedDRA structure, you will see that almost all the "decreased/increased" terms are in the Investigations SOC, whereas all the "hypo/hyper" terms are placed under their respective body system disorders SOC. The reason behind this is that the "hypo/hyper" terms represent a diagnosis whereas the "increased/decreased" terms represent laboratory results. (A known exception to this rule is with the LLT Blood pressure high, which is placed under the PT Hypertension, and LLT Low blood pressure, placed under PT Hypotension. This was done intentionally because a common expression for hypertension is 'high blood pressure.' The above-mentioned exception was created within MedDRA to enable most conservative capture of the stated verbatim.)

"Decreased blood sugar" is an indication of an occurrence of a decrease in blood sugar noted in a lab test. However, "Hypoglycemia" is a diagnosis. In your example, an event is reported as both 'hypoglycemia' and a 'decreased blood sugar.' This is a diagnosis with supporting lab data, and in such a case, according to the ICH coding guidelines, it is sufficient to capture just the diagnosis. However, when retrieving data on 'hypoglycemia', it is important to be comprehensive and search for all the records coded to PT Hypoglycaemia as well as PT Blood glucose decreased.

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I was faced with two recent problems in MedDRA concerning terms "VERTIGO" and "DIPLOPIA". "Vertigo" is classified as belonging to the Ear and Labyrinth Disorders SOC. In my particular situation, the vertigo was a so-called "central vertigo" in accordance with Harrisson's and therefore, in my opinion, should fall in the Nervous disorders SOC. Because the associated SOC for the term "Vertigo" was not appropriate, I chose the term "Balance impaired" instead. The same occurred with the term "Diplopia" which is classified in Eye disorders SOC, which is not adequate in our case since the diplopia had a central origin. What do you think?

From what I can tell, it looks like one of three things could have happened: (1) your browser or coding tool may not be "MedDRA compliant" (2) the coding tool is just user unfriendly, or (3) MedDRA was downloaded improperly. The reason I say this is because both terms, PT Vertigo and PT Diplopia, have what are known as "secondary SOCs" which allows one term to be located under multiple SOCs - this is what is meant when people say MedDRA is "multi-axial". Thus, PT Vertigo appears not only in the Ear and Labyrinth SOC but also in the Nervous System SOC. In a similar manner, PT Diplopia appears in both the Eye disorders SOC and Nervous system SOC. Both of these PTs are multi-axial. However, PT Vertigo is not the most specific PT available for the condition you have conveyed - there is LLT Vertigo of central origin – PT Vertigo CNS origin that is classified exclusively under the Nervous system disorders SOC (it is not multiaxial.)

The first question is - why were you as a coder not able to see that PT Vertigo and PT Diplopia had secondary SOCs? The second question is - what if the situation you had presented was true i.e. that there was only a PT Vertigo and that it was only located under the Ear & Labyrinth SOC? What could you do as an organization that would enable you to use this term appropriately?

The answer to the first issue is simply to identify the problem as I have stated above. In loading and implementing MedDRA, had validation taken place? Did someone validate that the structure of MedDRA had been preserved in the loading process? Even before loading MedDRA, did someone check and verify that the coding tool or browser could even handle MedDRA's structure? Is the tool user friendly making it easy for the user to learn a new and fairly complex dictionary that is ever changing?

The second issue is a little more difficult. Your choice of another term may pose a future problem for your organization in data retrieval. If you decide that there are times when "vertigo" has to be coded as PT Balance impaired, and at other times vertigo is to be appropriately coded as PT Vertigo, in performing a search for all reports which may have stated "vertigo" as an adverse event, your data managers would have to perform 2 queries for these 2 PTs- one under the Ear Disorders SOC and the other under the Nervous system disorders SOC. This is assuming that the data manager or anyone performing this type of search is even aware of the 2 ways in which one adverse event, vertigo, has been coded! If they are unaware of this, they may just outright miss all the reports coded as "balance impaired" and their search results would be incomplete. The impacts of this can be very serious.

Rather than choosing another term because of what you deem is a deficiency in MedDRA, bring it to the attention of the MSSO. It is their job to maintain the dictionary to meet the user's needs. As the user, it is your responsibility to validate MedDRA. If you have a valid argument, and you submit the change request appropriately, it is the MSSO's responsibility to make the changes and deliver them in the next version update. This way, your coding stays uniform and consistent throughout the database, which will make it easier to retrieve a complete data set.

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What is the MedDRA code for the suspicion of a disease (for example "suspicion of heart infarction")?

MedDRA, like COSTART and WHO-ART, is not capable of capturing such concepts as "suspicion of, maybe, possibility, to be ruled out". However, when the only information stated is a provisional diagnosis, it is coded as a confirmed diagnosis. ICH Coding guidelines provide options for data capture when the verbatim conveys sign(s)/symptom(s) and provisional diagnosis. Depending on your organization's objectives, your internal coding guidelines need to specify what to code in such an example It is important to stress that no matter how an organization chooses to address this coding issue, it needs to be addressed so as to promote coding uniformity and consistency, thus enabling complete data retrieval.

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What is the distinction between the MedDRA terms PT MELAENA and PT FEACES DISCOLOURED?

* Melena is a tarry stool resulting from the presence of blood passing through the intestine. In this process, the hemoglobin in the red blood cells is altered (the extent of alteration depends on where in the digestive tract the blood is introduced), resulting in a classic tarry, black stool. Clinically, melena is a result of a gastrointestinal hemorrhage and in MedDRA the PT Melaena is grouped in the Gastrointestinal disorders SOC as well as Vascular disorders SOC.

* Discoloration of feces can be caused by a wide variety of metabolic and endocrine disorders, resulting in everything from light-colored stools (due to fat malabsorption or disorder of pancreatic enzymes) to dark-colored stools. The PT Faeces discoloured in MedDRA appears in the Gastrointestinal disorders SOC.

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What is the MedDRA term "CONDITION AGGRAVATED" and how should it be used?

* The MedDRA PT CONDITION AGGRAVATED is best defined by looking at the LLT's, which are subsumed under the PT. This PT, in turn, is found under a single HLT, "General symptoms and signs NEC".

There are additional conditions that have a "worsened" or "exacerbated" term associated with the baseline condition. In coding adverse events, if a disease, condition or event is known prior to the start of suspect drug therapy, it is not processed as an AE, since it represents a pre-existing condition. If, however the disease, condition, or event becomes worse during the course of the suspect medication, the underlying disease, condition, or event is best coded with an LLT conveying both concepts, the specific event and its aggravation. If such an LLT is not available, the choice is usually just the LLT for the event.

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Many MedDRA terms use the abbreviations NOS or NEC. What do they mean and how do they differ?

* "NOS" is the abbreviation for "not otherwise specified" and "NEC" is the abbreviation for "not elsewhere classified". "NOS" (for example, in the MedDRA LLT PAIN NOS) indicates that the reported event of PAIN is not further specified (such as "CHEST PAIN" or "FLANK PAIN"). This term is often a general term for a condition that has specific instances listed as separate PT's. The other PT's may be in multiple SOC's as the example of different pains indicates. In MedDRA "NOS" now appears only at the LLT level.

"NEC" (for example, MedDRA HLGT "EYE DISORDERS NEC") indicates that the condition is not classified in any other grouping or within any other SOC under the multi-axial classification schema. "NEC" is seen at the HLT or HLGT level, to gather PT's which represent conditions not classified under other HLT's or HLGT's.

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