Impact of cardiovascular risk factors on medical expenditure: evidence from epidemiological studies analysing data on health checkups and medical insurance

Abstract

Concerns have increasingly been raised about the medical economic burden in Japan, of which approximately 20% is attributable to cardiovascular disease, including coronary heart disease and stroke. Because the management of risk factors is essential for the prevention of cardiovascular disease, it is important to understand the relationship between cardiovascular risk factors and medical expenditure in the Japanese population. However, only a few Japanese epidemiological studies analysing data on health checkups and medical insurance have provided evidence on this topic. Patients with cardiovascular risk factors, including obesity, hypertension, and diabetes, may incur medical expenditures through treatment of the risk factors themselves and through procedures for associated diseases that usually require hospitalization and sometimes result in death. Untreated risk factors may cause medical expenditure surges, mainly due to long-term hospitalization, more often than risk factors preventively treated by medication. On an individual patient level, medical expenditures increase with the number of concomitant cardiovascular risk factors. For single risk factors, personal medical expenditure may increase with the severity of that factor. However, on a population level, the medical economic burden attributable to cardiovascular risk factors results largely from a single, particularly prevalent risk factor, especially from mildly-to-moderately abnormal levels of the factor. Therefore, cardiovascular risk factors require management on the basis of both a cost-effective strategy of treating high-risk patients and a population strategy for reducing both the ill health and medical economic burdens that result from cardiovascular disease.

Figure 1.. The crude arithmetic mean medical expenditure per month over 10 years of follow-up in Japanese medical insurance beneficiaries 40–69 years of age, grouped according to their body mass index. Numbers in parentheses represent the geometric means after adjustment for age, sex, and smoking and drinking habits (analysis of covariance, P < 0.01). Note: data edited for currency translation.

Figure 2.. The crude arithmetic mean medical expenditure per month over 10 years of follow-up in male and female Japanese medical insurance beneficiaries 40–69 years of age, grouped according to their sex and hypertension status. Numbers in parentheses represent the geometric means after adjustment for age, body mass index, smoking and drinking habits, serum total cholesterol levels, and a history of diabetes (analysis of covariance, P < 0.01 for men and P = 0.18 for women).

Figure 3.. The crude arithmetic mean medical expenditure per month over 10 years of follow-up in Japanese medical insurance beneficiaries 40–69 years of age, grouped according to their hypertension and diabetes statuses. Numbers in parentheses represent geometric mean after adjustment for age, sex, body mass index, smoking drinking habits, and serum total cholesterol levels (analysis of covariance, P < 0.01).

Figure 4.. The percentage of medical expenditures attributable to pre-, stage 1, and stage 2 hypertension for the entire population of Japanese medical insurance beneficiaries 40–69 years of age (19 090 468 Japanese yen/month/1000 persons, 100%).

Figure 5.. The adjusted odds ratios for being in the top 1% medical expenditure group over 1 year of follow-up in male and female Japanese medical insurance beneficiaries 40–54 years of age, grouped according to their hypertension status. Adjustments were made for age, body mass index, smoking habits, serum low-density lipoprotein cholesterol levels, log-transformed fasting plasma glucose levels, and medications for hypercholesterolemia and diabetes (a logistic regression model, *P < 0.05 vs. optimal blood pressure).