Effect of age-based left-digit bias on stroke diagnosis: Regression discontinuity design.

BACKGROUND: Little is known about how left-digit bias- where humans tend to discretely categorize their decisions based on the left-most digit of the continuous variables-based on patients' age affects the initial diagnosis of stroke patients. The aim of this study is to examine whether there is a discontinuous change in the ordering of imaging tests for stroke at the age threshold of 40 years old, which is indicative of left-digit bias, and whether the effect varies by patient sex. METHODS: We conducted a cohort study by regression discontinuity design (RDD). We analyzed the claims database from a nationwide working-age health insurance plan in Japan. Patients who had after-hours hospital visits from January 2014 through December 2019 were included in our analysis. The exposure is patients' age, and the primary outcome was physicians' ordering imaging tests (CT or MRI) to diagnose stroke during the index visit. RESULTS: Of 293,390 total visits, 48,598 visits within data-driven optimal bandwidths of 6.0 years from the cut-off of 40 years were included for the RDD analysis (mean age 40.8 years [standard deviation 3.4], female 50.5%). The baseline probability of receiving imaging tests for stroke diagnosis was 0.9%. Physicians had a higher likelihood of ordering imaging tests when patients' age was above 40 years compared with when patients' age was just below 40 years (adjusted difference, +0.51 percentage points [pp], 95%CI, +0.13 to +1.07 pp; P = 0.01). We found a significant discontinuous change in the ordering of imaging tests for stroke at 40 years for male patients (+0.84 pp, 95%CI, +0.24 to +1.69 pp; P = 0.009) but not for female patients. CONCLUSIONS: Physicians have a cognitive bias in estimating stroke risk and, consistent with a left-digit bias, treat male patients aged 40 and just below differently. This pattern was observed only among male patients.

Impact of the national health guidance intervention for obesity and cardiovascular risks on healthcare utilisation and healthcare spending in working-age Japanese cohort: regression discontinuity design.

OBJECTIVES: Increases in obesity and cardiovascular diseases contribute to rapidly growing healthcare expenditures in many countries. However, little is known about whether the population-level health guidance intervention for obesity and cardiovascular risk factors is associated with reduced healthcare utilisation and spending. The aim of this study was to investigate the effect of population-level health guidance intervention introduced nationally in Japan on healthcare utilisation and spending. DESIGN: Retrospective cohort study, using a quasiexperimental regression discontinuity design. SETTING: Japan's nationwide employment-based health insurers. PARTICIPANTS: Participants in the national health screening programme (from January 2014 to December 2014) aged 40-74 years. PREDICTORS: Assignment to health guidance intervention (counselling on healthy lifestyles, and referral to physicians as needed) determined primarily on whether the individual's waist circumference was above or below the cut-off value in addition to having at least one cardiovascular risk factor. PRIMARY AND SECONDARY OUTCOME MEASURES: Healthcare utilisation (the number of outpatient visits days, any medication use and any hospitalisation use) and spending (total medical expenditure, outpatient medical expenditure and inpatient medical expenditure) within 3 years of the intervention. RESULTS: A total of 51 213 individuals within the bandwidth (±6 cm of waist circumference from the cut-off) out of 113 302 screening participants (median age 50.0 years, 11.9% woman) were analysed. We found that the assignment to the national health guidance intervention was associated with fewer outpatient visit days (-1.3 days; 95% CI, -11.4 to -0.5 days; p=0.03). We found no evidence that the assignment to the health guidance intervention was associated with changes in medication or hospitalisation use, or healthcare spending. CONCLUSION: Among working-age, male-focused Japanese from a health insurer of companies of civil engineering and construction, the national health guidance intervention might be associated with a decline in outpatient visits, with no change in medication/hospitalisation use or healthcare spending.

Association of the National Health Guidance Intervention for Obesity and Cardiovascular Risks With Health Outcomes Among Japanese Men.

Importance: Obesity and cardiovascular risks have become major public health problems. However, evidence is limited as to whether population-level lifestyle interventions for obesity and cardiovascular risk factors are associated with improved population health outcomes. Objective: To investigate the association of the national health guidance intervention in Japan with population health outcomes. Design, Setting, and Participants: This cohort study used a regression discontinuity design that included men aged 40 to 74 years who participated in the national health screening program in Japan from April 2013 to March 2018. Exposures: Assignment to the national health guidance intervention (counseling on healthy lifestyle and appropriate clinical follow-up for individuals found to have waist circumference of 85 cm or greater with 1 or more cardiovascular risk factors during annual national health screening program). Main Outcomes and Measures: Changes in obesity status (body weight, body mass index, waist circumference), and cardiovascular risk factors (blood pressure, hemoglobin A1c level, and low-density lipoprotein cholesterol level) 1 to 4 years after screening. Results: Of 74 693 men (mean [SD] age, 52.1 [7.8] years; mean [SD] baseline waist circumference, 86.3 [9.0] cm), the assignment to the health guidance intervention was associated with lower weight (adjusted difference, -0.29 kg; 95% CI, -0.50 to -0.08; P = .005), body mass index (-0.10; 95% CI, -0.17 to -0.03; P = .008), and waist circumference (-0.34 cm; 95% CI, -0.59 to -0.04; P = .02) 1 year after screening. The observed association of the guidance assignment attenuated over time and was no longer significant by years 3 to 4. No evidence was found that the health guidance intervention was associated with changes in participants' systolic blood pressure, diastolic blood pressure, hemoglobin A1c level, or low-density lipoprotein cholesterol level in years 1 to 4. Conclusions and Relevance: Among working-age men in Japan, the national health guidance intervention was not associated with clinically meaningful weight loss or other cardiovascular risk factor reduction. Further research is warranted to understand the specific design of lifestyle interventions that are effective in improving obesity and cardiovascular risk factors.

Are quality-adjusted medical prices declining for chronic disease? Evidence from diabetes care in four health systems.

Improvements in medical treatment have contributed to rising health spending. Yet there is relatively little evidence on whether the spending increase is "worth it" in the sense of producing better health outcomes of commensurate value-a critical question for understanding productivity in the health sector and, as that sector grows, for deriving an accurate quality-adjusted price index for an entire economy. We analyze individual-level panel data on medical spending and health outcomes for 123,548 patients with type 2 diabetes in four health systems: Japan, The Netherlands, Hong Kong and Taiwan. Using a "cost-of-living" method that measures value based on improved survival, we find a positive net value of diabetes care: the value of improved survival outweighs the added costs of care in each of the four health systems. This finding is robust to accounting for selective survival, end-of-life spending, and a range of values for a life-year or fraction of benefits attributable to medical care. Since the estimates do not include the value from improved quality of life, they are conservative. We, therefore, conclude that the increase in medical spending for management of diabetes is offset by an increase in quality.

Avoidable Hospital Admissions From Diabetes Complications In Japan, Singapore, Hong Kong, And Communities Outside Beijing.

Improving the quality of primary care may reduce avoidable hospital admissions. Avoidable admissions for conditions such as diabetes are used as a quality metric in the Health Care Quality Indicators of the Organization for Economic Cooperation and Development (OECD). Using the OECD indicators, we compared avoidable admission rates and spending for diabetes-related complications in Japan, Singapore, Hong Kong, and rural and peri-urban Beijing, China, in the period 2008-14. We found that spending on diabetes-related avoidable hospital admissions was substantial and increased from 2006 to 2014. Annual medical expenditures for people with an avoidable admission were six to twenty times those for people without an avoidable admission. In all of our study sites, when we controlled for severity, we found that people with more outpatient visits in a given year were less likely to experience an avoidable admission in the following year, which implies that primary care management of diabetes has the potential to improve quality and achieve cost savings. Effective policies to reduce avoidable admissions merit investigation.

Promoting innovation in small markets: Evidence from the market for rare and intractable diseases.

In many medical care markets with limited profit potential, firms often have little incentive to innovate. These include the market for rare diseases, "neglected" tropical diseases, and personalized medicine. Governments and not-for-profit organizations promote innovation in such markets but empirical evidence on the policy effect is limited. We study this issue by analyzing the impact of a demand-side policy in Japan, which reduces the cost sharing of patients with some rare and intractable diseases and attempts to establish and promote the treatment of those diseases. Using clinical trials data taken from public registries, we identify the effect of the policy using a difference-in-difference approach. We find that the demand-side policy increased firms' incentive to innovate: firm-sponsored clinical trials increased 181% (0.16 per disease per year) when covered by the policy. This result indicates that the demand-side policy can be an important part of innovation policies in markets with limited profit potential.

Patient cost sharing and medical expenditures for the Elderly.

Despite the rapidly aging population, relatively little is known about how cost sharing affects the elderly's medical spending. Exploiting longitudinal claims data and the drastic reduction of coinsurance from 30% to 10% at age 70 in Japan, we find that the elderly's demand responses are heterogeneous in ways that have not been previously reported. Outpatient services by orthopedic and eye specialties, which will continue to increase in an aging society, are particularly price responsive and account for a large share of the spending increase. Lower cost sharing increases demand for brand-name drugs but not for generics. These high price elasticities may call for different cost-sharing rules for these services. Patient health status also matters: receiving medical services appears more discretionary for the healthy than the sick in the outpatient setting. Finally, we found no evidence that additional medical spending improved short-term health outcomes.

The Impact of Physician Supply on the Healthcare System: Evidence from Japan's New Residency Program.

Using a 2004 Japanese natural experiment affecting physician supply, we study the physician labor market and its effects on hospital exits and health outcomes. Although physicians play a central role in determining the performance of a healthcare system, identifying their impacts are difficult because physician supply is endogenously determined. We circumvent the problem by exploiting an exogenous shock to physician supply created by the introduction of a new residency program - our natural experiment. Based on panel data covering all physicians in Japan, we find that the introduction of a new residency program substantially decreased the supply of physicians in some rural markets where local hospitals had relied on university hospitals for filling physician positions. We also find that physician market wages increased in the affected markets relative to less affected markets. Finally, we find that this change in physician market wages forced hospitals to exit affected markets and negatively affected patient health outcomes in those markets. These effects may be exacerbated by the fact that the healthcare market was rigidly price-regulated. Copyright © 2015 John Wiley & Sons, Ltd.

Physician Agency and Adoption of Generic Pharmaceuticals.

I examine physician agency in health care services in the context of the choice between brand-name and generic pharmaceuticals. I examine micro-panel data from Japan, where physicians can legally make profits by prescribing and dispensing drugs. The results indicate that physicians often fail to internalize patient costs, explaining why cheaper generics are infrequently adopted. Doctors respond to markup differentials between the two versions, indicating another agency problem. However, generics' markup advantages are short-lived, which limits their impact on increasing generic adoption. Additionally, state dependence and heterogeneous doctor preferences affected generics' adoption. Policy makers can target these factors to improve static efficiency.

The generic drug market in Japan: will it finally take off?

Historically, brand-name pharmaceuticals have enjoyed long periods of market exclusivity in Japan, given the limited use of generics after patent expiration. To improve the efficiency of the health-care system, however, the government has recently implemented various policies aimed at increasing generic substitution. Although this has created expectations that the Japanese generic drug market may finally take off, to date, generic usage has increased only modestly. After reviewing the incentives of key market participants to choose generics, we argue that previous government policies did not provide proper incentives for pharmacies to boost generic substitution. We offer some recommendations that may help to increase generic usage.

Experts' agency problems: evidence from the prescription drug market in Japan.

This article examined the physician-patient agency relationship in the context of the prescription drug market in Japan. In this market, physicians often both prescribe and dispense drugs and can pocket profits in so doing. A concern is that, due to the incentive created by the mark-up, physicians' prescription decisions may be distorted. Empirical results using anti-hypertensive drugs suggest that physicians' prescription choices are influenced by the mark-up. However, physicians are also sensitive to the patient's out-of-pocket costs. Overall, although the mark-up affects prescription choices, physicians appear more responsive to the patient's out-of-pocket costs than their own profits from mark-up.