Establishing correlation between genetics and nonresponse.

Sir,

This is a comment on “Correlation of rennin angiotensin system (RAS) candidate polymorphism with response to ramipril in patients with essential hypertension” published in an earlier issue of the journal.[1] The authors have not made a mention of how the diagnosis of “essential hypertension” was established and laboratory investigations for secondary causes of hypertension need to be carried out. A few examples of secondary causes include hypothyroidism/hyperthyroidism or hypercalcemia (endocrine causes of hypertension).[2] The authors also state that “Once the diagnosis of essential hypertension was made, treatment of cases was initiated with the ACE inhibitor ramipril, given at the dose of 1.25 mg once daily.” The authors further state that “Patients who failed to respond to 5 mg Ramipril once daily for four weeks were classified as non-responders and a second drug was added to their treatment regimens.”

The usual daily dose (dosing frequency/day) of ramipril is 2.5-20 mg (one to two times a day).[2] The selection of antihypertensive agents and the combination of agents need to be individualized, taking into account age, severity of hypertension, and other cardiovascular disease risk factors.[2] On average, standard doses of most antihypertensive agents reduce blood pressure by 8-10/4-7 mmHg; however, there may be subgroup differences in responsiveness. Younger patients may be more responsive to beta blockers and angiotensin-converting enzyme inhibitors (ACEIs), whereas patients aged over 50 years may be more responsive to diuretics and calcium antagonists. In continuity with this the authors have not given us any idea about the blood pressure levels of the study participants (classified as hypertensives) and classification of responders. Individualized management of hypertension becomes important in view of the existing guidelines on management of hypertension [Joint National Committee (JNC) 7/8].[3] The guidelines suggest the use of lifestyle measures as part of the management plan for hypertension as these with or without therapeutic interventions are able to reduce blood pressure. So the authors should have accounted for the use of lifestyle measures too in drawing a conclusion on nonresponders.