Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study
Background Epidemiological surveillance of HIV infection in Japan involves two technical problems for directly applying a classical backcalculation method, i.e., (i) all AIDS cases are not counted over time and (ii) people diagnosed with HIV have received antiretroviral therapy, extending the incuba...
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PeerJ Inc.
2019-01-01
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| Online Access: | https://peerj.com/articles/6275.pdf |
| _version_ | 1797418466061320192 |
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| author | Hiroshi Nishiura |
| author_facet | Hiroshi Nishiura |
| author_sort | Hiroshi Nishiura |
| collection | DOAJ |
| description | Background Epidemiological surveillance of HIV infection in Japan involves two technical problems for directly applying a classical backcalculation method, i.e., (i) all AIDS cases are not counted over time and (ii) people diagnosed with HIV have received antiretroviral therapy, extending the incubation period. The present study aimed to address these issues and estimate the HIV incidence and the proportion of diagnosed HIV infections, using a simple statistical model. Methods From among Japanese nationals, yearly incidence data of HIV diagnoses and patients with AIDS who had not previously been diagnosed as HIV positive, from 1985 to 2017, were analyzed. Using the McKendrick partial differential equation, general convolution-like equations were derived, allowing estimation of the HIV incidence and the time-dependent rate of diagnosis. A likelihood-based approach was used to obtain parameter estimates. Results Assuming that the median incubation period was 10.0 years, the cumulative number of HIV infections was estimated to be 29,613 (95% confidence interval (CI): 29,059, 30,167) by the end of 2017, and the proportion of diagnosed HIV infections was estimated at 80.3% (95% CI [78.7%–82.0%]). Allowing the median incubation period to range from 7.5 to 12.3 years, the estimate of the proportion diagnosed can vary from 77% to 84%. Discussion The proportion of diagnosed HIV infections appears to have not yet reached 90% among Japanese nationals. Compared with the peak incidence from 2005–2008, new HIV infections have clearly been in a declining trend; however, there are still more than 1,000 new HIV infections per year in Japan. To increase the diagnosed proportion of HIV infections, it is critical to identify people who have difficulty accessing consultation, testing, and care, and to explore heterogeneous patterns of infection. |
| first_indexed | 2024-03-09T06:33:02Z |
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| id | doaj.art-77f5d1ef0cd541398c5d2d2cc9ddf22d |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:33:02Z |
| publishDate | 2019-01-01 |
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| spelling | doaj.art-77f5d1ef0cd541398c5d2d2cc9ddf22d2023-12-03T11:02:48ZengPeerJ Inc.PeerJ2167-83592019-01-017e627510.7717/peerj.6275Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling studyHiroshi Nishiura0Graduate School of Medicine, Hokkaido University, Sapporo, JapanBackground Epidemiological surveillance of HIV infection in Japan involves two technical problems for directly applying a classical backcalculation method, i.e., (i) all AIDS cases are not counted over time and (ii) people diagnosed with HIV have received antiretroviral therapy, extending the incubation period. The present study aimed to address these issues and estimate the HIV incidence and the proportion of diagnosed HIV infections, using a simple statistical model. Methods From among Japanese nationals, yearly incidence data of HIV diagnoses and patients with AIDS who had not previously been diagnosed as HIV positive, from 1985 to 2017, were analyzed. Using the McKendrick partial differential equation, general convolution-like equations were derived, allowing estimation of the HIV incidence and the time-dependent rate of diagnosis. A likelihood-based approach was used to obtain parameter estimates. Results Assuming that the median incubation period was 10.0 years, the cumulative number of HIV infections was estimated to be 29,613 (95% confidence interval (CI): 29,059, 30,167) by the end of 2017, and the proportion of diagnosed HIV infections was estimated at 80.3% (95% CI [78.7%–82.0%]). Allowing the median incubation period to range from 7.5 to 12.3 years, the estimate of the proportion diagnosed can vary from 77% to 84%. Discussion The proportion of diagnosed HIV infections appears to have not yet reached 90% among Japanese nationals. Compared with the peak incidence from 2005–2008, new HIV infections have clearly been in a declining trend; however, there are still more than 1,000 new HIV infections per year in Japan. To increase the diagnosed proportion of HIV infections, it is critical to identify people who have difficulty accessing consultation, testing, and care, and to explore heterogeneous patterns of infection.https://peerj.com/articles/6275.pdfEpidemicStatistical modelStatistical estimationForecastingOutbreakOpportunistic infection |
| spellingShingle | Hiroshi Nishiura Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study PeerJ Epidemic Statistical model Statistical estimation Forecasting Outbreak Opportunistic infection |
| title | Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study |
| title_full | Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study |
| title_fullStr | Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study |
| title_full_unstemmed | Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study |
| title_short | Estimating the incidence and diagnosed proportion of HIV infections in Japan: a statistical modeling study |
| title_sort | estimating the incidence and diagnosed proportion of hiv infections in japan a statistical modeling study |
| topic | Epidemic Statistical model Statistical estimation Forecasting Outbreak Opportunistic infection |
| url | https://peerj.com/articles/6275.pdf |
| work_keys_str_mv | AT hiroshinishiura estimatingtheincidenceanddiagnosedproportionofhivinfectionsinjapanastatisticalmodelingstudy |