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Sodium sensitivity and cardiovascular events in patients with essential hypertension
1Division of Nephrology, National Cardiovascular Centre, Osaka, Japan.
Insights
Sodium sensitivity is an independent cardiovascular risk factor in patients with essential hypertension. Individuals with sodium-sensitive hypertension experience more cardiovascular events, highlighting its clinical significance.
Area of Science:
- Cardiology
- Nephrology
- Hypertension Research
Background:
- Sodium-sensitive hypertension is linked to increased glomerular pressure and microalbuminuria, both predictors of cardiovascular events.
- A lack of nocturnal blood pressure decrease in these patients also correlates with heightened cardiovascular risk.
- This study investigated sodium sensitivity as a potential common factor underlying these risks.
Purpose of the Study:
- To determine if sodium sensitivity is an independent cardiovascular risk factor in patients with essential hypertension.
- To assess the association between sodium sensitivity and the occurrence of cardiovascular events.
- To explore the relationship between sodium sensitivity and other known cardiovascular risk factors.
Main Methods:
- A retrospective study was conducted on 156 patients with essential hypertension.
- Sodium sensitivity was defined as a ≥10% difference in blood pressure between low- and high-sodium diets.
- Cardiovascular events and patient data were reviewed, with sodium sensitivity status blinded during analysis.
Main Results:
- Sodium sensitivity was identified in 62 patients; 94 were non-sodium sensitive.
- Left-ventricular hypertrophy was more prevalent in the sodium-sensitive group (38% vs. 16%).
- Cardiovascular events occurred at a higher rate in the sodium-sensitive group (4.3 per 100 patient-years vs. 2.0 per 100 patient-years).
- Cox's model identified sodium sensitivity, mean arterial pressure, and smoking as independent cardiovascular risk factors.
Conclusions:
- Cardiovascular events are more frequent in patients with sodium-sensitive hypertension.
- Sodium sensitivity is confirmed as an independent cardiovascular risk factor in Japanese patients with essential hypertension.
- These findings underscore the importance of assessing sodium sensitivity in hypertension management.
Background:
In patients with sodium-sensitive hypertension, glomerular pressure is increased and microalbuminuria, a marker of glomerular hypertension, is a predictor of cardiovascular events. Similarly, the lack of a nocturnal decrease in blood pressure in these patients is also associated with an increased risk of cardiovascular events. We hypothesised that sodium sensitivity may be the common factor and carried out a retrospective study of cardiovascular events in patients with essential hypertension who had had sodium sensitivity measured in our clinic.
Methods:
Sodium sensitivity was assessed in about 350 patients with essential hypertension during the initial investigation of their disorder. The definition of sodium sensitivity was a 10% or greater difference in blood pressure on low-sodium or high-sodium diets. By alphabetical order, the records of 201 patients were obtained and 156 patients without pre-existing disorders were followed up. The records of patients who had a cardiovascular event or died were reviewed without knowledge of the patient's sodium-sensitivity status.
Findings:
62 patients were deemed sodium sensitive and 94 non-sodium sensitive. Left-ventricular hypertrophy was found more frequently in the sodium-sensitive group than in the non-sodium-sensitive group (38 vs 16%; p < 0.01), whereas significantly fewer patients in this group smoked (23 vs 42%; p < 0.05). There were 17 cardiovascular events in the sodium-sensitive group and 14 in the non-sodium-sensitive group. The rate of total, non-fatal and fatal cardiovascular events, was 2.0 per 100 patient-years in the non-sodium-sensitive group and 4.3 per 100 patient-years in the sodium-sensitive group. Cox's proportional-hazards model identified sodium sensitivity (p < 0.01), mean arterial pressure (p < 0.01), and smoking (p < 0.01) as independent cardiovascular risk factors.
Interpretation:
Cardiovascular events occurred more frequently in patients with sodium-sensitive hypertension. Sodium sensitivity is an independent cardiovascular risk factor in Japanese patients with essential hypertension.