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.