Biomedical subjects

Yasushi Ohkusa

Publications and source records attributed to Yasushi Ohkusa.

11 recordsLinked to original sources

PubMed2006

When do people visit a doctor?

We examine the length of time between when an individual feels sick and when he/she visits a doctor using survival analysis to capture the dynamic aspects of this behavior. If the disease is light, actions such as OTC medicine or sick leave are alternatives to visiting a clinic or a hospital immediately. The timing of the visit depends only the person's decision, not on a doctor's, so we can limit discussion to the effect of ex-post moral hazard excluding physician induced demand. Participants were asked to keep a log of illness-related behavior such as dates of episodes, subjective symptoms, sick leaves, and medical treatment at hospitals. Neither the copayment rate nor access cost had a significant effect on the behavior of visiting a doctor, whereas available alternatives delay the timing of a visiting. Severe symptoms and fever hastened the time. The results suggest that the traditional argument about ex-post moral hazard is somewhat misleading.

Adolescent↗

PubMed2006

[Cost-effectiveness analysis of routine immunization for varicella in Japan].

OBJECTIVE: Immunization for varicella is not currently included in routine immunizations in Japan. This study was conducted to assess test its cost-effectiveness when it becomes a routine. METHODS: We surveyed and collected information for the year beginning 15th June 2004 in one area. Almost all 11 pediatric clinics or hospitals in the area cooperated in this survey. There was a questionnaire form for families and for doctors. Absent days from routine tasks, i.e., job, housekeeping or study, for family nursing and others were asked on family form. Medical costs and other costs were asked on doctor form. Neither form included the patient's name or name of the medical institution. Doctors explained this survey to patients' family on their first visiting day and asked to cooperate. If they refused the doctor form was also discarded. Since family form was written after recovery and mailed, cooperation in this survey was voluntary. Opportunity cost for family nursing is estimated as opportunity cost based on the 2002 Basic Surveillance of Wage Structure. The burden of sequel cases was estimated assuming six million yen per Quality-adjusted Life Years (QALY). Total number of patients was estimated to be 0.84 million, which includes unvaccinated people in a birth cohort. We adopted incremental benefit cost ratios form societal viewpoint as a measure. RESULTS: We collected 402 data from the doctor form and 265 from the family form. Total disease burden in all of Japan is estimated to be 52.2 billion yen, but opportunity cost accounted for 80%. The incremental benefit cost rations averaged more than 4 when vaccination cost is assumed to be five to twelve thousand yen. The lower limit of the confidence intervals is about 1.5. DISCUSSION AND CONCLUSION: The disease burden of varicella was greater than measles in 2000, when there were measles 0.2 million patients. The incremental benefit cost ratio showed that there will almost surely be an additional benefit due to routine immunization is greater than the additional cost. Therefore, we found strong evidence for routine immunization for varicella.

Chickenpox↗

PubMed2006

[Synptons of outpatients as data for syndromic surveillance].

OBJECTIVE: To review complaints (such as fever, respiratory symptoms, diarrhea, vomiting, and rashes) in the medical records of outpatients as potential sources of data for syndromic surveillance, and to examine the possibility of practical application from a statistical view point. MATERIALS AND METHODS: Using data obtained from a certain internal and pediatric clinic, we count the number of patients each day who suffered from one of the above five symptoms from January 1st, 2003 to June 30th, 2005. In order to detect outbreaks prospectively after January 1st, 2005, we at first estimate the baseline using the data from January 1st, 2003 to the day before any given day. We then predict the number of patients there ought to be in any given day and judge whether or not an outbreak has occurred. So as to evaluate the system, we check the sensitivity and specificity in its ability to detect outbreaks other than those seen in previous patterns. RESULTS: The total number of cases in which each of the above symptoms occurred were respectively: 11,896 cases of fever, 16,273 cases of respiratory symptoms, 3,672 cases of diarrhea, 3,485 cases of vomiting, and 542 cases of rash. We found prolonged outbreaks of fever and respiratory symptoms in February and March and shorter outbreaks of vomiting and diarrhea in January. The sensitivity and specificity of this system' s ability to detect outbreaks was very high and thus we can confirm that it showed satisfactory performance. DISCUSSION: We found large-scale outbreaks of influenza late in the 2004/2005 season, and small outbreaks of GI that seemed to be particularly related to the Noro virus. In both cases, these outbreaks seemed to be natural phenomena, not artificial, human induced phenomena such as outbreaks caused by bioterrorism attacks. However, since this system was able to detect these outbreaks, we would also be able to use it to detect an outbreak caused by a bioterrorism attack if the size of the outbreak was similar to these cases. CONCLUSION: In order to use this system to detect outbreaks in the community on a smaller level we would have to increase the number of medical institutions cooperating in this study. Moreover, we would need to find a way to handle the different electronic medical record systems and different writing styles used by different medical institutions in order to move toward the practical use of Syndromic Surveillance.

Child↗

PubMed2005

Experimental surveillance using data on sales of over-the-counter medications--Japan, November 2003-April 2004.

OBJECTIVES: This report describes a study to explore the possibility of using data on sales of over-the- counter (OTC) medications as part of a routine syndromic surveillance system aimed at early detection of infections of public health concern. A retrospective evaluation was conducted of sales of OTC medications used to treat the common cold. This report discusses the correlation of these data to influenza activity in Japan during the 2003-04 influenza season and evaluates the potential of using such data to predict influenza epidemics. METHODS: Data from approximately 1,100 pharmacies throughout Japan collected during November 2003-April 2004 were analyzed. OTC sales data were compared with influenza incidence data (one weekly and two daily data sets) to determine correlations and predictability. Adjusted R-square was used as an index of goodness of-fit in the estimation. Data reflecting daily influenza activity were obtained from the National Surveillance of Daily Influenza Outpatients and the Mailing List-Based Influenza Epidemic Database. National sentinel surveillance data for influenza from approximately 5,000 sites nationwide also were analyzed. RESULTS: Although a correlation was demonstrated between sales of OTC medications used to treat the common cold and concurrent influenza activity, analysis of sales data alone was not sufficient to determine influenza activity in advance even when sales promotion effects were excluded from the analysis. CONCLUSION: Because visiting a health-care provider costs more than purchasing OTC medications, the hypothesis was formed that an ill person will purchase OTC medications first and visit a physician only if the condition does not resolve or worsens. The results of this study do not provide any clear evidence to support this hypothesis. For this reason, OTC sales do not appear to be a good candidate for a national real-time detection system for influenza epidemics in Japan.

Commerce↗

PubMed2005

Policy evaluation for the subsidy for influenza vaccination in elderly.

OBJECTIVE: In Japan, the subsidy of influenza vaccination for the elderly was introduced in November 2001. This paper examines its policy evaluation from the viewpoint of cost-benefit analysis. MATERIALS: The data of copayment of influenza vaccination, population and shot rate of the elderly are surveyed by telephone interview to the correspondents in the local governments of Tokyo metropolitan and other 12 big cities in Japan. The mortality due to pneumonia or influenza is obtained from Vital Statistics of Population. METHOD: At first, I examine the impact of amount of copayment, through its effect on shot rate, on the percentage of elderly receiving influenza vaccinations. Using these estimation results, benefit-cost ratio (BCR) is calculated. RESULTS: The estimated coefficient of copayment on shot rate is -0.007 and statistically significant. Shot rate significantly reduces pneumonia and influenza mortality and its magnitude is -0.0028. The obtained net benefit (NB) is 134.9 million yen or US$1.08 billion and benefit-cost ratio is 22.9 and its 95% confidence interval is [2.2, 43.7]. DISCUSSION: If copayment would be cut by a 1000 yen (US$8), it could avoid about 400 deaths in average big city. The benefit-cost ratio is quite high compared with the other countries or other vaccinations. CONCLUSION: We found the strong evidence in a sense of cost-benefit analysis in the subsidy for influenza vaccination in the elderly.

Aged↗

PubMed2005

Prediction of smallpox outbreak and evaluation of control-measure policy in Japan, using a mathematical model.

Since the September 1 terrorist attacks and moreover, since the anthrax exposure events in 2001 in the United States, bioterrorism attacks seem to be a real threat. Of course, the public health authorities in Japan have started to prepare control measures for such events. We report here our attempts, using a mathematical model, to estimate outbreak size and to examine the most effective measures; comparing ring vaccination (contact tracing, isolation, and vaccination among contacts) and mass vaccination of the susceptible population in the area. The basic framework of the mathematical model follows a model used in previous research. The initial susceptible population is assumed to be 30 million persons. Concerning the important parameters, such as the number of initial-exposure cases, R0 (infectious power, or natural history) and, the starting day of intervention after the initial exposure, we checked the robustness of our conclusions by sensitivity analysis. We found that mass vaccination is preferable to ring vaccination when the values for the initial-exposure cases and R0 are high and when the start of intervention by public health authorities is delayed. In the base-case situation, the mass vaccination strategy needs almost 30 million vaccine doses. On the other hand, though ring vaccination needs fewer doses, it needs fewer than 50,000 doses in the worst-case scenario, that with larger first exposure, higher R0, or later start of public health authority intervention. This mathematical model can measure the prevalence of an infectious disease and can evaluate control measures for it before an outbreak. Especially, it is useful for the planning of the outbreaks of emerging diseases such as severe acute respiratory syndrome (SARS) or for bioterrorism attacks involving such diseases as smallpox. In further research, we will have to take into account the population people vaccinated of for smallpox, who account for about 70% of the total population in Japan.

Disease Outbreaks↗

PubMed2005

[Research on choices of people with mild symptoms of common cold between consulting physicians and taking OTC (over-the-counter) medicine using a hypothetical question method].

PURPOSE: This study was aimed at predicting the demand for medical services of people with mild symptoms of common cold. Three alternatives to cope with this condition were presented in questionnaires, which were: consulting physicians, taking OTC (over-the-counter) medicine, and doing nothing. Our prediction of employees' choices with these alternatives will contribute to cost-containment policies of health insurers. METHOD: We mailed questionnaires to 12,000 selected randomly employees, insured by "A" health insurance company. The questionnaires were designed a hypothetical question method, utilizing several criteria, including number of OTC medicines on hand, and socioeconomic status. A multinomial probit model was used for our estimation and analysis, with alternatives set as dependent variables. RESULTS: There were 3139 respondents, and the response rate was 26.2%. Gender, age, number of family members, and income level did not have any significant effect on the choice of any of the three alternaives. On the other hand, having a family doctor and a number of OTC medicines on hand had significant consequences. In males with a family doctor and without OTC medicine, the probabilities of choose to consult with a physicians, take on OTC medication, or doing nothing, were predicted to be 0.46, 0.32, and 0.22, respectively. People with three or more kinds of OTC medicine are more likely to choose OTC medication than physicians. CONCLUSION: The study suggests that more kinds of OTC medicine on hand of for individual with mild symptoms of common cold, the leaves the demand for medical services. To reduce medical expenses through consulting medical services, it might be effective for health insurers to provide insured employees with incentives to keep more OTC medicines on hand.

Common Cold↗

PubMed2004

Analysis of health-related quality of life (HRQL), its distribution, and its distribution by income in Japan, 1989 and 1998.

Research conducted over the past decade has increasingly focused on health inequality. The goals of improving the health of a population are now often expressed as the increase in the average level of health and the decrease in health inequality as clearly specified in the Healthy People 2010 and the World Health Report 2000. Using a nationally representative sample of the 1989 and 1998 waves of the Japanese Comprehensive Survey of Living Conditions of the People on Health and Welfare (CSLC), this research examines the average health-related quality of life (HRQL), its distribution, and its distribution by income share. This study departs from previous health inequality analyses in the following two ways: (1) construction of a measure of HRQL in the CSLC and its application to health inequality analysis, and (2) inclusion of the dead in health inequality analysis using a cross-sectional survey. This study found that between 1989 and 1998 the average HRQL in Japan slightly reduced (0.005 reduction), its inequality by income slightly reduced (0.002 reduction in the difference between the top 20% and bottom 20% income share groups), and its inequality measured by the Gini coefficient slightly increased (0.002 increase). Women's HRQL was almost always lower than men's, except in earlier ages younger than 10 years old. HRQL was more unequally distributed among women than men and in older ages. This analysis shows that the success in the improvement in the length of life in Japan did not always coincide with the improvement in HRQL and provides a basis for the future population health research.

Activities of Daily Living↗

PubMed2003

Horizontal inequity in health care utilization in Japan.

International comparisons of horizontal inequity in health has recently become one of the most pertinent issues in health economics. However, no previous studies have been undertaken on Japan. This omission is rectified in this paper. Moreover, we consider the dynamics of horizontal inequity in health over six years from 1992 to 1998. These dynamics have never been considered in this field. In a rigorous international comparison, though we cannot find any horizontal inequity in health in 1998, we find pro-rich inequity before 1995. The reason for this may be the reform of the health insurance system in 1997.

Adolescent↗

PubMed2003

[An analysis of the demand for influenza vaccination among the elderly in Japan].

PURPOSE: This paper will discuss an analysis of the demand for vaccination for the elderly as a high-risk group. Influence of the governmental endorsement and/or subsidy on these demand is, then, evaluated from the estimation results. METHODS: Original data were obtained from two surveys conducted by the author for the elderly living with and without descendents. Information was collected about the elderly themselves, the household, experience of influenza and immunization in the last season, and the hypothetical questionnaire about immunization was answered by each respondent to be applied for Conjoint Analysis. Three estimations are performed for the actual behavior, Conjoint Analysis and the joint estimation of these two methods. RESULTS: Experience of influenza and immunization in the last season, proved to be two of the most important determinants. Among the others estimated parameters, cost of immunization, the number of immunization to complete for effectiveness, availability of the immunization at night or on a weekend, and the governmental endorsement greatly affected the immunization demand. Moreover, the superiority of the statistical properties of the joint estimation was confirmed. CONCLUSIONS: The estimation results imply that about 8.9 million elderly people would demand vaccination if there was no cost and there was a governmental endorsement. This would be reduced to be 3.2 million if the cost was 6,000 yen (about 50 dollars) and there was no governmental endorsement. Governmental endorsement alone would increase the number by 2.0 million. The change from no cost to only 500 yen (about 4 dollars) would depress the demand by 1.6 million.

Aged↗

PubMed2002

[An analysis of the length and costs of respirator use with observational data based on medical records].

OBJECTIVE: This paper documents an analysis of the impact of respirator use on medical expenses with observational data based on medical records from all over Japan. METHOD: The data set included records of medical procedures during a single month, but not for procedures and information extending over plural months. Accordingly, censoring was an important problem. To overcome this, samples are classified into four groups; complete, right censoring, left censoring and both censoring ones using length of respirator use and hospital stay. Then, the Gompertz model was applied to calculate the expected length of respirator use. Simultaneously, medical expenses for respirator use were also estimated. RESULTS: The estimated expected length of respirator use was from 10 to 104 days, with expected medical expenses per case of from 30,000 to 40,000 yen and the number of respirator usages on aggregate of 5510. CONCLUSIONS: This means the impact of respirator use on medical expenses is from 18 to 250 billion yen per year.

Costs and Cost Analysis↗