- 著者
- Han Eol Jeong Hyesung Lee In-Sun Oh Kristian B. Filion Ju-Young Shin
- 出版者
- Japan Epidemiological Association
- 雑誌
- Journal of Epidemiology (ISSN:09175040)
- 巻号頁・発行日
- vol.33, no.2, pp.82-90, 2023-02-05 (Released:2023-02-05)
- 参考文献数
- 25
- 被引用文献数
- 2
Background: Impact of immeasurable time bias (IMTB) is yet to be examined in self-controlled designs.Methods: We conducted case-crossover, case-time-control, and case-case-time-control analyses using Korea’s healthcare database. Two empirical examples among elderly patients were used: 1) benzodiazepines-hip fracture; 2) benzodiazepines-mortality. For cases, the date of hip fracture diagnosis or death was defined as the index date, and the inherited date of their matched cases for controls or future cases. Exposure was assessed in the 1–30 day (hazard) and 61–90 day (control) windows preceding the index date. A non-missing exposure setting included in- and outpatient prescriptions and the pseudo-outpatient setting included only the outpatients. Conditional logistic regression was done to estimate odds ratios (ORs) with 95% confidence intervals (CIs), where the relative difference in OR among the two settings was calculated to quantify the IMTB.Results: The IMTB had negligible impacts in the hip fracture example in the case-crossover (non-missing exposure setting OR 1.27; 95% CI, 1.12–1.44; pseudo-outpatient setting OR 1.21; 95% CI, 1.06–1.39; magnitude 0.05), case-time-control (OR 1.18; 95% CI, 0.98–1.44; OR 1.13; 95% CI, 0.92–1.38; 0.04, respectively), and case-case-time-control analyses (OR 0.99; 95% CI, 0.80–1.23; OR 0.94; 95% CI, 0.75–1.18; 0.05, respectively). In the mortality example, IMTB had significant impacts in the case-crossover (non-missing exposure setting OR 1.44; 95% CI, 1.36–1.52; pseudo-outpatient setting OR 0.72; 95% CI, 0.67–0.78; magnitude 1.00), case-time-control (OR 1.38; 95% CI, 1.26–1.51; OR 0.68; 95% CI, 0.61–0.76; 1.03, respectively), and case-case-time-control analyses (OR 1.27; 95% CI, 1.15–1.40; OR 0.62; 95% CI, 0.55–0.69; 1.05, respectively).Conclusion: Although IMTB had negligible impacts on the drug’s effect on acute events, as these are unlikely to be accompanied with hospitalizations, it negatively biased the drug’s effect on mortality, an outcome with prodromal phases, in the three self-controlled designs.
- 著者
- Ju-Young Shin Kyu Rang Kim Yong Hee Lee
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.18, pp.41-46, 2022 (Released:2022-03-18)
- 参考文献数
- 28
Determining the thresholds for risk assessment is critical for the successful implementation of thermal health warning systems. A risk assessment methodology with multiple thresholds must be developed to provide detailed warning information to the public and decision makers. This study developed a new methodology to identify multiple thresholds for different risk levels for heat or cold wave events by considering simultaneously impact on public health. A new objective function was designed to optimize segmented Poisson regression, which relates public health to temperature indicators. Thresholds were identified based on the values of the objective functions for all threshold candidates. A case study in identifying thresholds for cold and heat wave events in Seoul, South Korea, from 2014 to 2018, was conducted to evaluate the appropriateness of the proposed methodology. Daily minimum or maximum air temperature, mortality, and morbidity data were used for threshold identification and evaluation. The proposed methodology can successfully identify multiple thresholds to simultaneously represent different risk levels. These thresholds show comparable performance to those using the relative frequency approach.
- 著者
- Ju-Young Shin Kyu Rang Kim Yong Hee Lee
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2022-007, (Released:2022-01-26)
Determining the thresholds for risk assessment is critical for the successful implementation of thermal health warning systems. A risk assessment methodology with multiple thresholds must be developed to provide detailed warning information to the public and decision makers. This study developed a new methodology to identify multiple thresholds for different risk levels for heat or cold wave events by considering simultaneously impact on public health. A new objective function was designed to optimize segmented Poisson regression, which relates public health to temperature indicators. Thresholds were identified based on the values of the objective functions for all threshold candidates. A case study in identifying thresholds for cold and heat wave events in Seoul, South Korea, from 2014 to 2018, was conducted to evaluate the appropriateness of the proposed methodology. Daily minimum or maximum air temperature, mortality, and morbidity data were used for threshold identification and evaluation. The proposed methodology can successfully identify multiple thresholds to simultaneously represent different risk levels. These thresholds show comparable performance to those using the relative frequency approach.