The study, published in July 2019 in the journal Nature, is now under criticism. An Austrian study provides evidence that gastric mucosal protective agents and proton pump inhibitors (PPIs) cause allergies. Scientists at the University of Vienna came to this conclusion after evaluating data from Austrian health insurance companies. Their conclusion: The use of antihistamines or the use of specific immunotherapy is two or even three times more likely in patients who have already received PPI than in other patients. According to scientists, women would be most affected by this.
The German Society for Gastroenterology, Digestive and Metabolic Diseases (DGVS) denies this association and also criticizes the design of the study. This could not make an obvious statement about the link between allergies and PPI regulations.
Justification of DGVS
The DGVS justifies its criticism of the Austrian study by the fact that scientists have not included almost any diagnosis in their evaluation. The conclusions of the study staff relate solely to the data of the Austrian health insurance companies. This alone cannot answer the question of whether the risk of allergy increases the risk – says DGVS. In addition, they see another danger: "Patients with a confirmed indication of acid inhibition therapy become unnecessarily insecure."
Weaknesses of the study
In the August 2019 press release of DGVS, nature is explored in greater detail. Professor Herbert Koop, MD, MD, and former Chief Physician at the Department of General Internal Medicine and Gastroenterology, Helios-Clinic Berlin-Buch, criticizes several points in the DGVS statement.
Compared to different drugs
The study compared different drugs, including sucralfate. Aluminum salt has virtually no effect on the pH of the stomach. Nevertheless, sucralfate was correlated with moderately effective gastric acid-inhibiting H2 and PPI blockers. According to the study, all the drugs studied increase the risk of developing an allergy. "So there is no association with the degree of acid inhibition. It is therefore questionable whether acid inhibition is ever seen in connection with the Allergieentstehung," Koop suspects.
Allergy risk is not called into question
The analysis assesses the risk of allergy only by prescribing medications that should indicate the presence of an allergy. No medical information on allergy diagnosis is available. The study includes, for example, agents such as phenothiazine, which are used today primarily as neuroleptics in neurological and psychiatric diseases. According to allergy, DGVS is an allergy quite individual cases. In principle, the fact that it is a prescribed drug cannot be used to determine the cause of other new diseases, such as allergies in this case.
Allergies are not differentiated
Moreover, DGVS complains that it was not sufficiently differentiated, what are the allergies at all. The extent of known allergies is significant. Thus, there is an over-immune response to the myriad of allergens that cause different symptoms.
No patient information
In addition, Koop criticizes another important aspect of database analysis: Additional patient information, also called "confounding factors," was not considered in the study. "It is scientifically proven that patients who, for example, take PPIs are significantly different from other patients: they are usually older, have more comorbidities, take more medication. This impact could not be assessed in a study currently published because investigators clearly did not have access to such important medication data – or better yet diagnostic data – "explains Professor Koop.
The conclusion of the DGVS is clear: Due to its design and data state, the study cannot make clear statements about whether drug-induced gastric acid inhibition is conducive to allergy development. The effectiveness of PPI has been proven repeatedly by studies. This results in clear indications and recommendations for action, listed in German and international guidelines, specialist information and instruction leaflets. Like any other drug, prescribing a proton pump inhibitor must be preceded by a well-diagnosed medical diagnosis and a confirmed indication. For this reason, DGVS reiterates its urgent reference to existing recommendations for implementation. Accordingly, over-the-counter medicines should not be taken for more than 14 days without consulting your family doctor.