Ethnic differences in risks of adverse reactions

Editor—McDowell et al conclude that ethnic group may be one determinant of harms of a given treatment in an individual patient.¹ Genomics is insufficient to explain ethnic differences. The authors did not tackle compliance with pharmacological agents prescribed to patients by doctors including the subject of the doctor-patient relationship. Most studies of adverse drug reactions and encounters between patients and doctors were carried out in Europe and North America, with fewer doctors from ethnic minority groups.

Biopsychosocial and cultural research has shown that compliance with treatment cannot be ignored if doctors are to appreciate the “effects” of the agents they prescribe to patients. A quantitative study of antihypertensive drug treatment among Caribbean hypertensive subjects found that when symptoms such as headaches and feeling hot were absent, dosages were skipped.² The drugs were not taken on these days because of the patient's lay and cultural beliefs about blood pressure, not because of adverse reactions. An earlier qualitative study reached similar conclusions.³

There is insufficient reporting and recording of adverse drug reactions even in the United Kingdom, let alone the zero reporting in many developing countries. This fact as well as the ethnic lay beliefs and cultural factors may determine whether a drug is taken. It then becomes easy to conclude and advance the hypothesis that the explanation is adverse drug reactions.