Re: “Increased Cardiometabolic Risk and Worsening Hypoxemia at High Altitude” by Miele et al.

It is with great interest that we read the publication of Miele et al. (2016) describing the relationship between cardiometabolic risks and worsening hypoxemia at high altitude. This important study that took place at Peruvian highlands takes into consideration the association between oxyhemoglobin saturation and excessive erythrocytosis at high altitude and their detrimental effects on metabolic syndrome risk, insulin resistance, hemoglobin A1c, high-sensitivity C-reactive protein, and pulmonary function. They found that “lower resting oxyhemoglobin saturation was associated with high odds of having multiple unfavorable cardiometabolic factors” (Miele et al., 2016). Although it was interesting to see how metabolic syndrome risk was approached in this study at high altitude, we believe that the characterization of therapeutic response of essential systemic arterial hypertension at high altitude must receive a different kind of attention.

Systemic arterial hypertension has been described by the World Health Organization as a global public health crisis that disproportionately affects populations that live in low- and middle-income countries (WHO, 2013). As highlanders live mainly in countries that are considered developing countries, we feel the urge to describe the behavior of this disease in these inhabitants.

In the past years, we have witnessed worldwide efforts to describe the relationship between high altitude and hypertension and its therapeutic consequences. Unfortunately, clinical studies trying to elucidate the effects of high altitude on the therapeutic response of hypertension have been done for short periods of time (Bilo et al., 2015), and have been focusing mainly on hypertensives who will be exposed to high-altitude environments for eventual occupational, military, or short-term recreational activities (Bilo et al., 2015). Also, there is a trend to study the effects of high altitude on hypertension and antihypertensive properties of different medications, but in healthy participants or subjects (Parati et al., 2014).

We have not found any study that describes the clinical features of hypertension in highlanders associated with a therapeutic approach with antihypertensive medications used in these patients compared with those in low- or middle-altitude hypertensives. To decrease the morbidity and mortality burden of hypertension, there is a growing need to describe this disease in minor populations in which cardiovascular adaptive mechanisms might have a profound impact on the basic pathophysiologic processes that affects its natural history and therapeutic response. As data are scarce for the response of antihypertensive treatment in hypertensives living at high altitude, the recommendations from different hypertension guidelines have to be extrapolated for highlanders to determine which first-line treatment to use and what other available options we have in a moment when precision medicine is on the rise.

In conclusion, further clinical studies are needed to describe the response to different antihypertensive medication in hypertensive patients living chronically at high altitude. Studies focusing on this special relationship should be emphasized and prioritized in the high-altitude cardiovascular field, so as to decrease the burden of hypertension and be able to prevent adverse events with a more detailed understanding of this phenomenon.