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29th August 2022
The risk of developing open angle glaucoma is significantly elevated in patients with hypertension who frequently add salt to their food either from the table or through cooking according to the findings of study by an international group of researchers.
Glaucoma is a multifactorial optic neuropathy characterised by the degeneration of retinal ganglion cells. The condition is associated with intra-ocular pressure-related damage to the optic nerve. Glaucoma is a leading cause of blindness and a 2017 analysis estimated that prevalence of blindness due to glaucoma worldwide was 75.6 per 100 000 in 2017. The treatment of glaucoma is directed towards a lowering of the intra-ocular pressure in the eye through medication, laser surgery, incisional surgery or a combination of these. The two main types of glaucoma are open angle glaucoma (OAG) and closed angle glaucoma, although there at least 8 different additional types. Furthermore, some research indicates a connection between OAG and blood pressure, although the findings are equivocal. For instance, one study found that hypertension, particularly if poorly controlled, appears to be related to a modest increased risk of OAG. In contrast, another suggested that among patients with existing glaucoma, the nocturnal reduction in blood pressure might be an additional risk factor for such patients. A factor known to affect blood pressure is intake of sodium through salt and there is a good deal of evidence indicating that a reduction in dietary sodium (via salt) decreases both blood pressure and the incidence of hypertension. But whether a greater intake of salt, particularly in those with existing hypertension, would also increase the the risk of OAG is unclear. As a result, in the present study, researchers examined the relationship between glaucoma and salt intake, among patients with hypertension and who were receiving anti-hypertensive treatment.
The researchers used data from the Thessaloniki Eye Study which was designed to examine the prevalence of open angle glaucoma in adults age 60 years and older. All study participants had in-clinic examinations which included blood pressure measurement and were interviewed about co-morbidities and lifestyle factors. Participants were asked about salt intake and were categorised as ‘never users’, ‘rare/occasional’ (i.e., rare or occasional salt use at the table or during cooking) and ‘frequent users’ who normally added salt to food at the table and through cooking. For the study, researchers considered the occurrence of any OAG, primary open angle glaucoma (POAG) and pseudo-exfoliation syndrome, regardless of whether these individuals also had glaucoma. Any OAG did include POAG even though the effect of salt intake was analysed separately for this form of glaucoma.
Open angle glaucoma and salt intake among hypertensives
The study included 1076 participants with a mean age of 80.5 years (48.1% female) of whom, 51.3% did not have OAG and 8.3% had any OAG.
Among the whole cohort, there was no association between the frequency of salt intake and any form of OAG. This was apparent for occasional vs never salt users (odds ratio, OR = 1.02, 95% CI 0.59 – 1.79, p = 0.93) and between often (or frequent) users vs never users (OR = 1.38, 95% CI 0.66 – 2.89, p = 0.39).
However, when the researchers looked at those with hypertension and currently taking treatment, there was a significant association for any type of OAG but only for the comparison of often vs never salt users (OR = 2.65, 95% CI 1.12 – 6.28, p = 0.03). Using the same comparison, i.e., often vs never salt users, the relationship was also significant for POAG (OR = 3.59, 95% CI 1.16 – 11.11, p = 0.03). However, there were no significant effects from frequent salt intake among those with pseudo-exfoliation syndrome. There was also a significant relationship between frequent use of salt and any OAG in patients with a diastolic blood pressure below 90 mmHg (OR = 2.42, 95% CI 1.0 – 5.84, p = 0.05).
Based on these findings, the authors concluded that frequent dietary salt intake may be associated with an increased prevalence of OAG in those currently taking anti-hypertensive drugs. They called for future studies to examine the pathophysiological changes to optic nerves vascular supply caused by salt load.
Tseng VL et al. Association Between Dietary Salt Intake and Open Angle Glaucoma in the Thessaloniki Eye Study J Glaucoma 2022
17th August 2022
Patients with hypertension even after receipt of three COVID-19 vaccination doses, remain at an elevated risk of severe breakthrough infections with the Omicron variant according to researchers from the Department of Cardiology, Cedars-Sinai Medical Center, Los Angeles, US.
Although full vaccination against COVID-19 initially required individuals to have two doses, the fact that immunity appears to wane over time has led to a recommendation for a third dose. In fact, a third dose appears to provide greater protection with data showing how a third dose of the BNT162b2 vaccine administered a median of 10.8 months after the second dose provided 95.3% efficacy against COVID-19 compared with two doses. As more information emerged during the pandemic, it became clear that there were several important risk factors associated with the development of more severe illness and hypertensive patients were found to be more vulnerable to the development of serious complications. However, several unanswered questions remained. For example, do the same risk factors apply with COVID-19 variants and does full vaccination mitigate these risk factors? These were the questions raised in the present, retrospective analysis by the US team.
The researchers examined a cohort of adults with at least three doses of the COVID-19 vaccine but who subsequently developed a breakthrough infection with the Omicron variant (confirmed by nasopharyngeal swabs and PCR testing) and were hospitalised at their centre. The team collected demographic and co-morbidity data and used multivariable logistic regression analysis to assess the association between various factors such as age, comorbid conditions and the risk of hospitalisation and these covariates were adjusted for in the final analysis.
Hypertension and risk of severe illness
The researchers identified a total of 912 patients with a mean age of 56 years (41% male) of whom 15.9% were subsequently hospitalised with a breakthrough Omicron infection. Among the overall cohort, 27% were obese, 21% had diabetes and 54% were hypertensive and there was a mean of 72 days between vaccination and infection.
In regression analysis, the presence of hypertension was associated with a more than two-fold higher odds of being hospitalised, after adjustment for covariates (odds ratio, OR = 2.29, 95% CI 1.24 – 4.32). Other related elevated risk factors included the presence of a previous myocardial infarction (OR = 2.21, 95% CI 1.29 – 3.77).
Because hypertension is common in patients with a prior myocardial infarction, heart failure and chronic kidney disease, in a further analysis, the authors excluded patients with these three comorbidities. However, the elevated risk of hospitalisation in those with hypertension remained significant (OR = 2.54, 95% CI 1.32 – 5.37).
The authors concluded that the presence of hypertension remains an important risk factor for breakthrough COVID-19 infections even after full vaccination and that further research is required to understand the relationship between this risk factor to enable the development of mitigation strategies.
Ebinger J et al. Hypertension and Excess Risk for Severe COVID-19 Illness Despite Booster Vaccination Hypertension 2022
20th May 2022
Higher arterial stiffness (AS) rather than the presence of hypertension is a better predictor for the development of diabetes according to the findings of a prospective study by a team of Chinese researchers.
The World Health Organization estimates that there are approximately 422 million people worldwide that have diabetes. The most common form of diabetes is type 2 and in 2017, it was estimated that approximately 462 million individuals were affected by the condition, corresponding to 6.28% of the world’s population. Hypertension is common in those with type 2 diabetes and reportedly affects over two-thirds of patients and a Chinese study has suggested that a higher blood pressure is a risk factor for type 2 diabetes in both middle-aged and elderly patients.
Furthermore, the presence of arterial stiffness, especially in the aorta, has been shown to be an independent predictor of all-cause and cardiovascular mortality in patients with essential hypertension. In addition, other work has suggested that the presence of arterial stiffness is associated with an increased incidence of diabetes, independent of other risk factors and may represent an early risk marker for developing diabetes. However, whether arterial stiffness among hypertensive patients is a useful prognostic marker for the development of diabetes compared with hypertension alone is unclear.
For the present study, the Chinese researchers looked at data obtained from the Kailuan study, which is an ongoing prospective study following patients initially free of hypertension and examines factors associated with development of the condition. In a subgroup of patients, brachial-ankle pulse wave velocity measurements, which is a widely used technique to assess arterial stiffness, were taken. The researchers set the primary outcome as the development of diabetes during the follow-up period. Participants blood pressure and arterial stiffness was categorised as ideal vascular function (IVF) and normotensive, normotensive with AS, hypertensive and with normal AS and hypertensive and with elevated AS (HTAS).
Arterial stiffness and the development of type 2 diabetes
A total of 11,166 participants were enrolled in the study and followed for 6.16 years during which time 768 (6.88%) of incident cases of type 2 diabetes were identified.
After adjustment for covariates (e.g., age, gender, co-morbidities), compared to the IVF group, individuals in the HTAS group had the highest risk developing type 2 diabetes (hazard ratio, HR = 2.42, 95% CI 1.93 – 3.03). This was followed by the normotensive, elevated AS group (HR = 2.11, 95% CI 1.64 – 2.61). Interestingly, the lowest risk was associated with those who were hypertensive and with normal AS (HR = 1.48). These results did not change when further adjusted for mean arterial or diastolic pressure.
The researchers then examined whether an elevated AS or hypertension, or both, increased the predictive power of a conventional model, i.e., with age, sex, BMI, smoking status etc, for the development of diabetes The results showed that the C statistic increased from 0.690 to 0.707 (p = 0.0003), i.e., had more predictive power, after addition of AS. However, the predictive power increased to 0.709 when both hypertension and AS were added, in other words, there was little additional benefit to the model by adding hypertension alone.
The authors concluded that an elevated AS performed better than hypertension for the prediction of type 2 diabetes and suggested that future strategies for the prevention of type 2 diabetes should focus on both hypertension and AS.
Tian X et al. Hypertension, Arterial Stiffness, and Diabetes: a Prospective Cohort Study Hypertension 2022
3rd November 2021
A sustained weight loss over several years, not only delays but reduces the overall incidence of adverse cardiometabolic outcomes including type 2 diabetes, hypertension and hyperlipidaemia. This was the conclusion of a retrospective analysis of nearly 50,0000 patients by researchers from Geisinger Health, Pennsylvania, US. According to the world Health Organisation (WHO), worldwide levels of obesity have tripled since 1975 and in 2016, more than 1.9 billion adults, 18 years and older, were overweight and of these over 650 million were obese. However, obesity is not limited to adults and WHO data also suggests that in 2020, 39 million children under the age of 5 were overweight or obese. In a 2017 article, the World Obesity Federation issued a position statement, arguing that obesity should be perceived as a chronic relapsing disease process in which an abundance of food, coupled with low levels of physical activity, various environmental factors and genetic susceptibilities, all interact to create a positive energy balance. Increased weight and obesity are linked to a higher incidence of cardiovascular diseases, musculoskeletal disorders and some cancers. Nevertheless, even a 5% sustained weight loss improves metabolic function in multiple organs although longer term maintenance of weight loss is challenging, with one meta-analysis of 29 weight loss studies concluding that “weight-loss maintenance 4 or 5 y after a structured weight-loss program averages 3.0 kg or 23% of initial weight loss.”
However, what remains unclear is the impact of sustained weight loss on the development of cardiometabolic diseases and for the present study, researchers turned to in data held the Geisinger Health System, which represents one of the largest healthcare organisations in the US. The team looked at adult patients for whom there were 3 or more electronic health record entries for weight measurements within a 2-year period. Individuals were then categorised as obesity maintainers (OM), i.e., those with a history of obesity and who maintained their weight within 3% of their baseline levels; weight loss rebounders (WLRs) who had lost > 5% body weight but had regained > 20% of their 1-year loss and finally weight loss maintainers (WLMs), who again loss > 5% of their body weight but maintained > 80% of their 1-year weight loss. The outcomes of interest were the development of type 2 diabetes, hypertension and hyperlipidaemia, all of which were extracted from the electronic health records. In their analysis, researchers adjusted for several factors such as age, gender and various co-morbidities.
The sample contained 49,327 individuals with a mean age of 50.4 years (60.2% female) with the majority classed as OM (the reference group) and the whole sample were followed-up for a mean period of 6.6 years. After 5 years, 11.1% of the OM, 9.1% of the WLR and 6.5% of the WLM had developed type 2 diabetes and those in the sustained weight loss group (WLM) had a 33% lower risk of developing incident type 2 diabetes (adjusted hazard ratio, aHR = 0.68, 95% CI 0.62 – 0.74, p < 0.0001). Similarly, the WLM had a reduced risk of developing hypertension (aHR = 0.72) and hyperlipidaemia (aHR = 0.86).
Based on these findings, the authors concluded that sustained weight loss was associated with a delayed onset of cardiometabolic diseases and that these associations are enhanced in those with the greatest weight loss.
Bailey-Davis L et al. Impact of Sustained Weight Loss on Cardiometabolic Outcomes. Am J Cardiol 2021
21st October 2021
The use of mobile technology can support hypertension self-management in patients with the condition, according to the findings of a three-year study by a group from the Department of Epidemiology & Biostatistics, University of California, California, US. Hypertension is a global problem with the World Health Organisation (WHO) estimating that it affects 1.28 billion adults aged 30-79 years. However, perhaps of greater concern, is the WHO statistic that only 1 in 5 adults (21%) with hypertension have their condition under control.
Although self-monitoring can lead to reductions in blood pressure (BP) over and above usual care, a 2017 systematic review concluded that self-monitoring alone is not associated with lower BP or better control but that it requires co-interventions such as education or lifestyle counselling, to achieve clinically significant reductions which persist for at least 12 months. The use of mobile technology in the form of smartphone health apps, have been suggested a method to enable effective self-management of hypertension. Yet despite this potential role, a 2018 review of such apps concluded that although available studies do suggest a reduction in blood pressure among those using health apps, the conclusion should be interpreted with caution, since many studies were at high risk of bias.
Given the high risk of bias and the importance of co-interventions, the Californian team used a smartphone app in conjunction with BP monitoring that included digital-based coaching to help support hypertension self-management. Participants were US adults with elevated BP recruited through an employer-based health plan. Blood pressure was measured using an FDA approved Bluetooth-enabled monitor paired with the smartphone app which also allowed participants to track their weight and levels of physical activity. The app included medication reminders and coaching to drive lifestyle changes based on usage patterns to personalise the advice. At baseline, participants were categorised in terms of their systolic BP as: normal and < 120 mmHg; systolic between 120 and 129 mmHg; systolic between 130 and 139 (stage 1 hypertension) and finally a systolic > 140 mmHg (stage 2 hypertension). Blood pressure measurements (both systolic and diastolic) were evaluated in the first week (week 0) and then several times up to weeks 148 to 163.
A total of 28,189 individuals with a median age of 51 years (59.6% male) were included in the hypertension self-management study. After 3 years, median systolic blood pressure was reduced in 53.7% of those with a systolic BP between 120 and 129 mmHg, 75.3% of those with stage 1 hypertension and in 84.4% of those with stage 2 hypertension. Similarly, after 3 years, the mean reductions in diastolic BP were -4.4 mmHg, -6.8 mmHg and -11.6 mmHg respectively.
A subgroup of 3,229 participants recorded their body mass index (BMI) and for each unit reduction in BMI, there was a 0.74 mmHg decrease in systolic BP. Similarly, among 590 individuals who recorded their physical activity, for each 1000-step increase per day, there was a 0.8 mmHg lower systolic BP (P = 0.03).
The authors concluded that their hypertension self-management program supported by mobile technology, achieved long-term control of BP, suggesting that this approach may be useful for BP monitoring and control.
Gazit T et al. Assessment of Hypertension Control Among Adults Participating in a Mobile Technology Blood Pressure Self-management Program. JAMA Netw Open 2021