The usual way that GERD is diagnosed-or at least suspected-is by its characteristic symptom, heartburn. Heartburn is most frequently described as a sub-sternal (under the middle of the chest) burning that occurs after meals and often worsens when lying down. To confirm the diagnosis, physicians often treat patients with medications to suppress the production of acid by the stomach. If the heartburn then is diminished to a large extent, the diagnosis of GERD is considered confirmed. This approach of making a diagnosis on the basis of a response of the symptoms to treatment is commonly called a therapeutic trial.
There are problems with this approach, however, primarily because it does not include diagnostic tests. For instance, patients who have conditions that can mimic GERD, specifically duodenal or gastric (stomach) ulcers, also can actually respond to such treatment. In this situation, if the physician assumes that the problem is GERD, he or she will not look for the cause of the ulcer disease. For example, a type of infection called Helicobacter pylori, or non-steroidal anti-inflammatory drugs (e.g., ibuprofen), can also cause ulcers and these conditions would be treated differently from GERD.
Moreover, as with any treatment, there is perhaps a 20% placebo effect, which means that 20% of patients will respond to a placebo (inactive) pill or, indeed, to any treatment. This means that 20% of patients who have causes of their symptoms other than GERD (or ulcers) will have a decrease in their symptoms after receiving the treatment for GERD. Thus, on the basis of their response to treatment (the therapeutic trial), these patients then will continue to be treated for GERD, even though they do not have GERD. What's more, the true cause of their symptoms will not be pursued further.