Immediate pressor response to oral salt and its assessment in the clinic: a time series clinical trial

Background High blood pressure (BP) is associated with high-salt consumption especially in sub-Saharan Africa. Although the pressor effect of salt is viewed as a chronic effect, some studies suggest that a salty meal may increase BP immediately in some individuals, and that this effect may cause endothelial dysfunction. Therefore, the aim of our research was to study the immediate pressor response to oral salt (IPROS) and its determinants, with the expectation that a simple methodology may be devised to diagnose it in the clinic or in low-resource environments. Methods We conducted a time series trial at Livingstone Central Hospital. We present data in 127 normotensive participants who ingested 2 g of sodium chloride; their BP was monitored for 120 minutes in intervals of 10 minutes. Sociodemographic and clinical data were collected. Descriptive and inferential statistics were used for analyses of data. Results Median age was 30 years (interquartile range, 22-46 years) and 52% were female patients. An increase of >= 10 mmHg in mean arterial pressure (MAP), considered a clinically significant IPROS, was present in 62% of participants. Systolic BP 30 minutes after the salt load was a significant predictor of IPROS, avoiding the need to calculate MAP in the clinic setting. Conclusions We confirm the presence of an IPROS in a high proportion (62%) of otherwise normotensive participants. The average time course for this response was 30 minutes and its duration was sustained for the 120-minutes period of study in most of the participants. Prediction of IPROS by increment SBP (change in systolic blood pressure) at 30 minutes allows for easy assessment of possible responder status in the clinic. Our data indicate that the IPROS to oral salt-loads in the range currently consumed by the Western world and African populations in single meals may increase the 24-hour BP load, which is a risk factor for hypertension and target organ damage. The relevance of our findings indicates the need to include dietary sodium assessment in the diagnosis, prevention, and management of high BP.

Automated summary

This study found that 62% of normotensive individuals experienced a clinically significant increase in mean arterial pressure after ingesting salt, with the systolic blood pressure at 30 minutes post-salt load being a significant predictor of this response. The findings suggest that salt consumed in single meals may contribute to an increased 24-hour blood pressure load, which is a risk factor for hypertension and target organ damage, emphasizing the importance of including dietary sodium assessment in the diagnosis, prevention, and management of high blood pressure.