Treated and untreated hypertension, hospitalization, and medical expenditure: an epidemiological study in 314622 beneficiaries of the medical insurance system in Japan.

OBJECTIVE

This study investigated the effect of hypertension on hospitalization risk and medical expenditure according to treatment status in a Japanese population.

METHODS

A total of 314 622 beneficiaries of the medical insurance system in Japan, aged 40-69 years, without a history of cardiovascular, cerebrovascular, or end-stage renal disease were classified into seven blood pressure categories. These categories were used to compare the risk of undergoing hospitalization in the 1 year after the baseline survey and to examine the percentage of inpatient medical expenditure attributable to overall hypertension relative to total medical expenditure in the study population.

RESULTS

During the follow-up period, 6.6% of men and 5.1% of women were hospitalized. In men and women aged 40-54 years, cases of hypertension, especially grade 3 untreated hypertension, led to more frequent hospitalization, compared with optimal blood pressure. Individuals who were hospitalized, especially long-term, incurred considerably higher medical expenditure compared with those who were not hospitalized, regardless of their hypertension status. In women aged 55-69 years, there was little variation in hospitalization risk across blood pressure categories. The inpatient medical expenditure attributable to overall hypertension represented 7.2 and 6.9% of the total medical expenditure for men aged 40-54 and 55-69 years, whereas it represented 2.8 and 3.8% for women, respectively.

CONCLUSION

Although cases of hypertension were an economic burden especially in men, grade 3 untreated hypertension was more likely to incur extremely high medical expenditure as a result of hospitalization, compared with other cases.