[Direct medical costs of Parkinson's disease by Hoehn and Yahr severity in Japan: An analysis of administrative claims data].

To estimate the medical costs related to Parkinson's disease (PD) by Hoehn and Yahr (HY) scale, we conducted a descriptive study by using a large-scale hospital based administrative claims database in Japan. Approximately 20,000 PD patients who had a diagnosis of PD with HY severity between April 2008 and December 2018 were included in the analysis. Estimated PD related outpatient costs, frequency of hospitalization, length of stay, and inpatient costs were increased with HY severity. Our estimates of the PD related medical costs are based on the large-scale claims database, despite limitations such as the reliability of HY severity in the claims data, could be used in future cost-effectiveness studies for treatment of PD.

The number needed to treat needs an associated odds estimation.

BACKGROUND: The number needed to treat (NNT) is a practically useful indicator that represents how many patients must be treated to prevent one adverse event when provided with a new intervention instead of the standard one. The NNT associates the net-benefit of an experimental treatment with the number of patients, or the size of trials, expecting one outcome of success. The NNT, however, also suggests that we assume an implicit execution of independent Bernouilli trials--as it were, the hypothetical NNT trials--independently repeated the same number of times as the value of NNT and with the same occurrence-probability of success as the value of absolute risk reduction. These independent Bernouilli trials, of course, have some probabilities of failure. Most decision-makers in practice would be more interested in how much the hypothetical NNT trials can achieve 'success/failure' with 'how many' patients, or the 'odds' of success versus failure, rather than 'one' outcome of success as the mean value. METHODS: We investigated the properties of hypothetical NNT trials. A binomial distribution was employed to develop formulae for estimating the odds of success versus failure to gain net-benefit in the NNT-associated trials. RESULTS: Most of the estimates of odds expected by the new intervention are between three and 1.72, converging to e-1 as the NNT increases. CONCLUSION: When basing decisions on an NNT, clinicians and public health specialists should take account of the odds of achieving the theoretical NNT.

[The analysis of the sensitivity and the specificity of the mass screening system of BSE].

Since the first infected case of BSE(Bovine Spongiform Encephalopathy) was identified in September, 2001 in Japan, Japanese people have been deeply concerned about safety of meat despite a mass screening system established by Japanese government. In the system all the cows for food must be examined with ELISA as screening and additionally with more accurate tests such as western blot etc. if the screened result is positive. To investigate the accuracy of the system, we calculated the number of false negatives and positives using computer simulation. Consequently, the sensitivity analysis towards ELISA showed that even if Japanese cattle were in a low risk group, a few of them are likely to be misdiagnosed as "negative" in spite of true BSE under the current screening system. Also we indicated how to improve the current system to get less false negatives. We believe the analysis of this study can contribute to risk communication with people to minimize the fear or irrationality caused by BSE epidemic.