Epidemiology and control of hypertension in Japan: a comparison with Western countries

Home blood pressure measurement days and changes in urinary sodium-to-potassium ratio, estimated salt and potassium intakes and blood pressure: 1-year prospective study

OBJECTIVE

Current international guidelines recommend home blood pressure (BP) measurement and low sodium and high potassium intakes for the management of hypertension. We hypothesized that increased home BP measurement may result in more effective management of sodium and potassium intakes and BP.

METHODS

We examined associations of home BP measurement days with changes in the urinary sodium-to-potassium (Na/K) ratio, estimated salt and potassium intakes and BP. We included 209 healthy participants (mean age, 55.9 years; 56.5% women) from a prospective cohort study. We examined 1-year data on self-measured home BP and spot urine samples.

RESULTS

Median (interquartile range) days of home BP measurement was 324 (225-358) over 1-year. Baseline mean (SD) Na/K ratio, salt and potassium intakes, morning and evening SBP, and morning and evening DBP were 3.8 (2.3), 8.5 (1.9) g/day, 1833.5 (416.5) mg/day, 120.4 (14.0) mmHg, 118.2 (14.2) mmHg, 79.2 (10.1) mmHg, and 76.2 (10.1) mmHg, respectively. In multivariable-adjusted linear regression , β (standard error) per 10 days increase in number of home BP measurement were -0.031 (0.017) for Na/K ratio, -0.036 (0.015) for salt intake, -1.357 (2.797) for potassium intake, -0.178 (0.064) for morning SBP, -0.079 (0.041) for morning DBP, -0.109 (0.067) for evening SBP and -0.099 (0.045) for evening DBP. Additionally, relationships persisted for men and women, but changes in salt intake were more pronounced among participants taking antihypertensive medication (interaction P = 0.002).

CONCLUSION

Continuous measurement of home BP may lead not only to self-monitoring of BP, but also to declines in salt intakes and some BP indices.

The trends of antihypertensive drug prescription based on the Japanese national data throughout the COVID-19 pandemic period

In 2020, concerns arose about the potential adverse effects of angiotensin II type 1 receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) on patients with the Coronavirus Disease 2019 (COVID-19). However, there is no national data on antihypertensive prescriptions during the COVID-19 pandemic in Japan. This study aimed to explore the trends in antihypertensive drug prescriptions in Japan throughout COVID-19 pandemic period. This study used data from the National Database (NDB) Open Data in Japan, an annual publication by the Ministry of Health, Labour and Welfare. To capture changes before and after social activity restrictions, the present study focused on extracting the number of prescribed oral medicine tablets for outpatients from the NDB Open Data from 2018 to 2021. The fiscal year 2020 exhibited the lowest for both outpatient claims and prescribed drugs. In contrast, all categories of antihypertensive drug prescription showed annual increases, and no specific changes in the prescription patterns of ARBs and ACEIs around fiscal year 2020 were observed. This study implies that antihypertensive drug prescriptions were adequately maintained throughout the COVID-19 pandemic in Japan.

Risk and Population Attributable Fraction of Stroke Subtypes in Japan

BACKGROUND

Associations of major risk factors for stroke with total and each type of stroke, as well as subtypes of ischemic stroke, and their population attributable fractions had not been examined comprehensively.

METHODS

Participants of the Japan Public Health Center-based prospective (JPHC) Study Cohort II without histories of cardiovascular disease and cancer (n = 14,797) were followed from 1993 through 2012. Associations of current smoking, hypertension, diabetes, overweight (body mass index ≥25 kg/m2), non-high-density lipoprotein cholesterol (non-HDLC) categories, low HDLC (<40 mg/dL), urine protein, and history of arrhythmia were examined in a mutually-adjusted Cox regression model that included age and sex. Population attributable fractions (PAFs) were estimated using the hazard ratios and the prevalence of risk factors among cases.

RESULTS

Subjects with hypertension were 1.63 to 1.84 times more likely to develop any type of stroke. Diabetes, low HDLC, current smoking, overweight, urine protein, and arrhythmia were associated with risk of overall and ischemic stroke. Hypertension and urine protein were associated with risk of intracerebral hemorrhage, while current smoking, hypertension, and low non-HDLC were associated with subarachnoid hemorrhage. Hypertension alone accounted for more than a quarter of stroke incidence, followed by current smoking and diabetes. High non-HDLC, current smoking, low HDLC, and overweight contributed mostly to large-artery occlusive stroke. Arrhythmia explained 13.2% of embolic stroke. Combined PAFs of all the modifiable risk factors for total, ischemic, and large-artery occlusive strokes were 36.7%, 44.5%, and 61.5%, respectively.

CONCLUSION

Although there are differences according to subtypes, hypertension could be regarded as the most crucial target for preventing strokes in Japan.

High blood pressure and colorectal cancer mortality in a 29-year follow-up of the Japanese general population: NIPPON DATA80

Onco-hypertension has been proposed, although associations of high blood pressure (BP) with cancer risk remain inconsistent. We examined associations of high BP with risk of mortality from stomach, lung, colorectal, liver, and pancreatic cancers independent of possible confounders in an analysis that excluded deaths within the first 5 years of follow-up to consider the reverse causality. In a prospective cohort representative of the general Japanese population (1980-2009), we studied 8088 participants (mean age, 48.2 years; 56.0% women) without clinical cardiovascular disease or antihypertensive medication at baseline. Fine-Gray competing risks regression was used to estimate hazard ratios for 10 mmHg higher BP adjusted for confounders including smoking, alcohol-drinking, obesity, and diabetes mellitus. During 29-year follow-up, 159 (2.0%), 159 (2.0%), 89 (1.1%), 86 (1.1%), and 68 (0.8%) participants died from stomach, lung, colorectal, liver, and pancreatic cancers, respectively. We observed a positive association of high BP with risk of colorectal cancer mortality but not with mortality risks from any other cancers. The association with colorectal cancer mortality for systolic and diastolic BP was evident in those aged 30-49 years (hazard ratios 1.43 [95% confidence interval, 1.22-1.67] and 1.86 [1.32-2.62], respectively) but not in those aged 50-59 years and ≥60 years (P for age interaction <0.01 for systolic and diastolic BP). The associations with colorectal cancer mortality were similar in the analyses stratified by smoking, alcohol-drinking, obesity, and diabetic status. In conclusion, high BP among young to middle-aged adults was independently associated with risk of colorectal cancer mortality later in life.

Epidemiology of Acute Aortic Dissection in a General Population of 1.4 Million People in Japan - Shiga Stroke and Heart Attack Registry

BACKGROUND

Acute aortic dissection (AAD) is a life-threatening cardiovascular disease, with a reported incidence rate ranging from 2.5 to 7.2 per 100,000 person-years in several population-based registries in Western countries, but epidemiological data are lacking in Japan.Methods and Results: The Shiga Stroke and Heart Attack Registry is an ongoing multicenter population-based registry of cerebro-cardiovascular diseases. We enrolled patients who developed AAD, defined by any imaging examination method from 2014 to 2015 in Shiga Prefecture. Death certificates were used to identify cases that were not registered at acute care hospitals. The incidence rates of AAD were calculated by age categories and adjusted using standard populations for comparison. We evaluated differences in patient characteristics between Stanford type A-AAD and type B-AAD subtypes. A total of 402 incident cases with AAD were analyzed. The age-adjusted incidence rates using the 2015 Japanese population and the 2013 European Standard Population were 15.8 and 12.2 per 100,000 person-years, respectively. Compared with cases of type B-AAD, those with type A-AAD were older (75.0 vs. 69.9 years, P=0.001) and more likely to be women (62.3% vs. 28.6%, P<0.001).

CONCLUSIONS

Population-based incidence rates of AAD in Japan appear to be higher than in previous reports from Western countries. Incident cases with type A-AAD were older and female predominance.

Risk factors for unfavourable outcomes after shunt surgery in patients with idiopathic normal-pressure hydrocephalus

A number of vascular risk factors (VRFs) have been reported to be associated with idiopathic normal-pressure hydrocephalus (iNPH), but it remains unclear whether these VRFs are related to patient outcomes after shunt surgery. Therefore, we investigated the risk factors for unfavourable outcomes after shunt surgery in iNPH patients using two samples from Tohoku University Hospital and from a multicentre prospective trial of lumboperitoneal (LP) shunt surgery for patients with iNPH (SINPHONI-2). We enrolled 158 iNPH patients. We compared the prevalence of VRFs and clinical measures between patients with favourable and unfavourable outcomes and identified predictors of unfavourable outcomes using multivariate logistic regression analyses. The presence of hypertension, longer disease duration, more severe urinary dysfunction, and a lower Evans' index were predictors of unfavourable outcomes after shunt surgery. In addition, hypertension and longer disease duration were also predictors in patients with independent walking, and a lower Evans' index was the only predictor in patients who needed assistance to walk or could not walk. Our findings indicate that hypertension is the only VRF related to unfavourable outcomes after shunt surgery in iNPH patients. Larger-scale studies are needed to elucidate the reason why hypertension can affect the irreversibility of symptoms after shunt placement.