The mRNA Vaccination Rate Is Negatively and the Proportion of Elderly Individuals Is Positively Associated With the Excess Mortality Rate After 2020 in Japan.

BACKGROUND: The impact of mRNA vaccines on excess mortality during the COVID-19 pandemic in Japan is not clear. This study aimed to verify the explanatory factors of excess mortality rate using officially published data by government and research institutions. METHODS: Multiple regression analysis was performed using the excess mortality rate in Japanese prefectures as the objective variable and the mRNA vaccination rate, proportion of elderly individuals in the population, number of physicians per population, and medical expenditure per person as explanatory variables. RESULTS: From July 2021 to April 2023, the independent determinants of the excess mortality rate were as follows: proportion of elderly individuals (regression coefficient (B) = 0.0097, p < 0.001), partial vaccination rate (B = -0.0034, p = 0.048), proportion of elderly individuals (B = 0.010, p < 0.001), and third-shot vaccination rate (B = -0.0025, p < 0.046). The stepwise method did not essentially change the results. However, the p-values were smaller. The other two indicators were not associated with the excess mortality rate. CONCLUSIONS: mRNA vaccination was associated with a lower excess mortality in Japan during the period, whereas the proportion of elderly individuals was associated with an increase in excess mortality. Thus, a policy of aggressive recommendations for mRNA vaccination is justified.

Evaluation of the calculation formulas of the cardio-ankle vascular index used in the Japanese apparatus.

Background: Recently, coefficients in the equation of cardio-ankle vascular index (CAVI) used in VaSera® device were disclosed. This study aimed to simulate the influence of adjusting the coefficients in the equation of CAVI and also aimed to validate the equation. Methods: The CAVI displayed by VaSera (CAVIvs) and the CAVI estimated (CAVIes) with fixing the coefficients of the middle range of the heart-ankle stiffness parameter ß (haß) in the equation were compared. Moreover, the heart-ankle pulse wave velocity (haPWV) which corresponds to the low cutoff haß of 7.348 was estimated in various blood pressure patterns to validate the formula. Results: The CAVIvs was clearly lower than CAVIes in the low and the high range of CAVIvs. Moreover, it was virtually impossible to obtain the low cutoff haß of 7.348 by using typical values of haPWV. Conclusion: The CAVIvs in the high-range of VaSera underestimates the original property of stiffness parameter ß. Moreover, there will be also a missing information in the equations introduced in the corresponding article, especially in the calculation formula of CAVIvs from haß. Therefore, in order to make the best use of the nature of the stiffness parameter ß to be used in VaSera, fixing the coefficients or termination of its use should be considered.

Brachial-ankle pulse wave velocity, cardio-ankle vascular index, and prognosis.

BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) and cardio-ankle vascular index (CAVI) are indices of arterial stiffness, and several studies have used these indices. However, there is no comprehensive review of these parameters in the prognostic significance. METHODS: The aim of this study was to review the articles exploring the prognostic significance of these parameters. Articles demonstrating independent significance after multivariate analysis on the Cox proportional hazards model were defined as "successful." The success rate was compared using Fisher's exact test. In addition, multivariate logistic regression analysis was performed to explore the independent determinants of the success of prognostic prediction. RESULTS: The success rate of the baPWV articles (65.7% [46/70]) tended to be higher than that of the CAVI articles (40.0% [6/15]; P=0.083). Multivariate analysis demonstrated that log (number of patients) (OR 11.20, 95% CI 2.45-51.70, P=0.002) and dialysis population (OR 0.28, 95% CI 0.08-0.94, P=0.039) were positive and negative independent determinants of the success of prognostic prediction, respectively. In addition, after redefining two studies as the absence of arteriosclerosis obliterans (ASO) exclusion, baPWV (OR 3.36, 95% CI 0.86-13.20, P=0.083) and the existence of exclusion criteria of ASO (OR 3.08, 95% CI 0.96-9.93, P=0.060) exhibited statistical tendency in the multivariate analysis. CONCLUSION: This study demonstrated that the number of study participants and dialysis population were the independent determinants of the success of prognostic prediction. This study also showed the importance of exclusion criteria of ASO when using these indices. In addition, a prospective large-scale study to confirm the superiority in the prognostic prediction of these indices is warranted.

Pitfalls in the ankle-brachial index and brachial-ankle pulse wave velocity.

BACKGROUND: The ankle-brachial index (ABI) and pulse wave velocity (PWV) are indices of atherosclerosis and arterial stiffness. The Japan-made measuring devices of those indices have spread widely because of their convenience and the significance of the parameters. However, studies that comprehensively discuss the various pitfalls in using these indices are not available. METHODS: This study presents several representative pitfalls in using the ABI and brachial-ankle PWV (baPWV) by showing the result sheets of the device, "the Vascular Profiler". Furthermore, some considerations when utilizing these indices in the future are also discussed. RESULTS: Several diseases such as arteriosclerosis obliterans (ASO), arterial calcification in the lower limb, arterial stenosis in the right upper-limb, aortic valve diseases, arterial stenosis in the upper-limb of the contralateral side of the hemodialysis access, are the representative pitfalls when evaluating ABI and baPWV. Moreover, a measurement error is found to actually exist. Furthermore, same phenomena are considered most likely to occur when using other similar indices and devices. CONCLUSION: The ABI and baPWV are the useful and significant biomarkers. Nevertheless, caution is sometimes necessary when interpreting them. Moreover, rigorous patient exclusion criteria should be considered when using those indices in the severely conditioned patient population. And the results of this study can be applied to enhance the literacy using other indices, such as the cardio-ankle vascular index and other similar devices.

Factors associated with high brachial-ankle pulse wave velocity in non-hypertensive and appropriately treated hypertensive patients with atherosclerotic risk factors.

While pulse wave velocity (PWV) correlates with blood pressure (BP), its extent differs between patients, and some cases of high PWV in normotensives are present. Moreover, PWV frequently remains high in hypertensive patients despite adequate BP control. The factors associated with such phenomena are yet to be elucidated. Here, we investigated the factors associated with brachial-ankle PWV (baPWV) in 107 patients whose systolic BP was under 140 mmHg at their latest baPWV measurement. There were 64 controlled hypertensives and 43 normotensives. Multivariate regression analysis identified age, hypertension, body mass index (BMI), systolic BP, and heart rate (HR) as independent factors for baPWV. Next, we divided the subjects into groups according to their age (in 5-year increments) and calculated the mean and standard deviation (SD) of the baPWV for each group. For each age group, we defined patients with a baPWV above the mean + SD baPWV for the group as the high-baPWV cohort. Multivariate logistic regression analysis revealed that BMI, hypertension, and smoking were independent determinants of a high-baPWV subject. This represents the first study to report the existence of the hypertensive state itself as one of the independent predictors of high baPWV in normotensive and well-treated hypertensive patients. This finding implies that the hypertensive state itself possibly worsens arterial stiffness independently from aging in spite of adequate BP maintenance. To prevent the early progression of arterial stiffness, the application of an appropriate intervention during the early stages of hypertension is important and the continuation of an appropriate BP treatment is suggested.