According to the municipal Department of Health, an analysis of the city's mass health screening programme identified 339,371 people with high blood pressure among 663,306 residents aged 60 and above, equivalent to 51.16 per cent.
The findings were based on four sources: medical histories, blood pressure readings during examinations, preliminary diagnoses and confirmed diagnoses.
Data were consolidated by individual to avoid double-counting patients who underwent multiple examinations or had high blood pressure recorded in more than one source.
Among residents aged 18-59, 440,342 of the 2,348,295 people analysed, or 18.75 per cent, were recorded as having high blood pressure.
Across all adults aged 18 and above, the figure stood at 25.89 per cent, representing 779,713 people out of 3,011,601 with analysable data.
The department stressed that not all those recorded as having high blood pressure had received a confirmed diagnosis of hypertension. Some had elevated readings during screening and would require further monitoring and medical assessment.
It also cautioned that the 51.16 per cent figure applied only to older residents with analysable screening data and should not be regarded as representative of the entire elderly population in HCM City.
An earlier analysis had found that hypertension accounted for 16.17 per cent of 812,377 recorded disease occurrences among people aged 60 and above, followed by type 2 diabetes at 5.51 per cent and age-related cataracts at 5.45 per cent.
Officials said the figures used different measures: 16.17 per cent was the share of hypertension among recorded disease cases, while 51.16 per cent was the proportion of people with high blood pressure in the analysed group.
The department said the findings highlighted the need to prioritise early detection and community-based management of hypertension among older residents.
Further analysis will distinguish patients already diagnosed and receiving treatment from those with elevated blood pressure who have not yet been diagnosed.
Local health stations will monitor blood pressure, support treatment and detect complications, with specialist hospital support.