Fig. 1

Flowchart of the treatment intervention provided to control the blood pressure in the oldest old; comparison with the HYVET study. The age of the oldest old in the present study corresponded with that of the oldest old in the HYVET study. However, the treatment intervention in the HYVET study mainly focused on the oldest old with robust hypertension. Using the data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS; 2008–2018), the present study classified the oldest-old population into the robust group and the frail group and investigated the risks for prognosis. Among the robust group, patients with a sBp of 150 mmHg or higher had an increased risk of mortality and were eligible for active antihypertensive treatment in the HYVET study. In the frail group of CLHLS, a decrease in blood pressure and a diastolic blood pressure of 90 mmHg or higher were reported to increase the risk of mortality; hence, the treatment intervention for the frail oldest-old population should be administered with caution while assessing their condition