SARS2-CoV-2 virus utilizes ACE2 to invade host cells; down-regulation of ACE2 can potentially increase Angiotensin II, promote vasoconstriction and inflammation, and promote organ damage in patients COVID-19 infection. Therefore, an RCT was conducted to determine whether losartan administration to patients hospitalized with COVID-19 infection could improve mortality compared to usual care [1].

The RCT included use of Angiotensin II receptor blockers (ARBs) or Angiotensin-converting enzyme inhibitors (ACEIs) within 7 days as one of the exclusion criteria. Of the 341 patients, 51 (15.0%) were on baseline antihypertensive medication, with mean systolic and diastolic blood pressures (BP) of 118.6 mmHg and 69.2 mmHg, respectively. When these patients were assigned to the losartan group, the RCT protocol was to start losartan at 25 mg/day and increase the dose to 50 mg/day and 100 mg/day unless serious adverse events occurred. The incidence of hypotension was 30.4% in the losartan group and 15.3% in the usual care group. Therefore, it is important to keep in mind the risk of hypotension when administering ARBs to patients with COVID-19 infection to prevent the development of organ damage due to increased Angiotensin II levels.

In our multicenter observational study, we found no significant difference in the risk of hypotension, defined as systolic BP ≤ 90 mmHg, in patients with COVID-19 infection who were already prescribed ARBs, including losartan, compared with those who were not prescribed ARBs [2]. When comparing losartan, candesartan, and valsartan as 1st-generation ARBs and telmisartan, olmesartan, irbesartan, and azilsartan as 2nd-generation ARBs, the risk of Hypotension was found to be 1.75 times greater with 2nd-generation ARBs compared to 1st-generation ARBs.

Of the 213 patients in our study who received ARBs, 182 (85.4%) had a diagnosis of hypertension, with mean systolic and diastolic BP of 133 mmHg and 76.9 mmHg, respectively. This alone suggests that the patient background is different from that of the aforementioned RCT, and therefore, we believe that the association between ARBs administration and the risk of hypotension should be noted in the patient background.

Regarding the conclusions of our paper, we describe the results of an observational study in our specific patient population; based on the results of RCTs on the efficacy and safety of losartan, Kow-CS et al. suggest the need to minimize risk through careful observation while maximizing therapeutic efficacy regardless of generation with ARBs administration. There is no disagreement that the need for ARBs should be considered according to the diagnosis and severity of the patient in front of us, and whether to continue or not and the optimal dose should be considered after careful observation, including hypotension.