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A comparison of disease-specific medical expenditures in Japan using the principal diagnosis method and the
Shinichi Tanihara1, Etsuji Okamoto, Hiroshi Une
1Department of Hygiene and Preventive Medicine, School of Medicine, Fukuoka University, Jonan-ku, Fukuoka, Japan. taniyan@cis.fukuoka-u.ac.jp
Insights
Conventional health insurance claims analysis overestimates medical spending for principal diagnoses. A new proportional distribution method (PDM) using all diagnoses provides more accurate disease-specific medical expenditure estimates.
Area of Science:
- Health economics
- Medical informatics
- Public health
Background:
- Technical limitations in Japanese health insurance claims (HICs) hinder comprehensive data analysis.
- Current methods for disease-specific medical expenditure estimation often rely on a single principal diagnosis per HIC, even with multiple diagnoses present.
Purpose of the Study:
- To develop and evaluate a method for estimating disease-specific medical expenditures that accounts for all diagnoses within a health insurance claim.
Main Methods:
- Utilized 169,622 outpatient HICs from employer-provided health insurance in May 2006.
- Compared the conventional single-principal-diagnosis method with a proportional distribution method (PDM) that incorporates all diagnoses.
Main Results:
- The PDM revealed that principal diagnoses accounted for 52.4% of diabetes mellitus and 19.6% of digestive system diseases.
- Estimated medical expenditures for diabetes mellitus were 1.49 times higher with the conventional method compared to PDM.
- Estimated expenditures for other digestive system diseases were 0.64 times with the conventional method compared to PDM, indicating potential over- and underestimation by the conventional approach.
Conclusions:
- The conventional method for estimating disease-specific medical expenditures requires improvement.
- Incorporating all diagnostic information from HICs using methods like PDM is crucial for accurate expenditure analysis.
Background:
There are technical limitations to handling all the information mentioned in health insurance claims (HICs) in Japan. Therefore, conventional methods for estimating disease-specific medical expenditures assume that all medical care expenditures in a given HIC are spent on only one principal diagnosis even when the HIC contains multiple diagnoses.
Objectives:
To estimate the disease-specific medical expenditures that consider all diagnosis on a given HIC.
Methods:
Data were obtained from 169 622 outpatient HICs in May 2006 from health insurance provided by the employer. We compared the estimated disease-specific medical expenditures of the conventional method with a proportional distribution method (PDM), which considers all diagnoses on the HICs.
Results:
For diabetes mellitus and other diseases of the digestive system, the proportion of principal diagnoses among total diagnoses was 52.4% (4849/9251) and 19.6% (2614/13331), respectively. In addition, the ratio of the estimated disease-specific medical expenditures between the conventional method and the PDM method was 1.49 for diabetes mellitus and 0.64 for other diseases of the digestive system. The estimation of disease-specific medical expenditures using the conventional method may therefore have overestimated the expenditures on the disease category typically selected as the principal diagnosis and underestimated the expenditures on the disease category less likely to be selected as the principal diagnosis.
Conclusions:
The conventional method for estimation of disease-specific medical expenditures should be improved by utilizing all the diagnoses information on HICs.
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