title: Forecasting the number of human immunodeficiency virus infections in the korean population using the autoregressive integrated moving average model.
abstract: OBJECTIVE
  From the introduction of HIV into the Republic of Korea in 1985 through 2012, 9,410 HIV-infected Koreans have been identified. Since 2000, there has been a sharp increase in newly diagnosed HIV-infected Koreans. It is necessary to estimate the changes in HIV infection to plan budgets and to modify HIV/AIDS prevention policy. We constructed autoregressive integrated moving average (ARIMA) models to forecast the number of HIV infections from 2013 to 2017.
  
  
  METHODS
  HIV infection data from 1985 to 2012 were used to fit ARIMA models. Akaike Information Criterion and Schwartz Bayesian Criterion statistics were used to evaluate the constructed models. Estimation was via the maximum likelihood method. To assess the validity of the proposed models, the mean absolute percentage error (MAPE) between the number of observed and fitted HIV infections from 1985 to 2012 was calculated. Finally, the fitted ARIMA models were used to forecast the number of HIV infections from 2013 to 2017.
  
  
  RESULTS
  The fitted number of HIV infections was calculated by optimum ARIMA (2,2,1) model from 1985-2012. The fitted number was similar to the observed number of HIV infections, with a MAPE of 13.7%. The forecasted number of new HIV infections in 2013 was 962 (95% confidence interval (CI): 889-1,036) and in 2017 was 1,111 (95% CI: 805-1,418). The forecasted cumulative number of HIV infections in 2013 was 10,372 (95% CI: 10,308-10,437) and in 2017 was14,724 (95% CI: 13,893-15,555) by ARIMA (1,2,3).
  
  
  CONCLUSIONS
  Based on the forecast of the number of newly diagnosed HIV infections and the current cumulative number of HIV infections, the cumulative number of HIV-infected Koreans in 2017 would reach about 15,000.
authors: Division of AIDS, Korea National Institute of Health, Osong, Korea.
authors: Hye-Kyung
authors: HK
authors: Yu
authors: Division of AIDS, Korea National Institute of Health, Osong, Korea.
authors: Na-Young
authors: NY
authors: Kim
authors: Division of AIDS, Korea National Institute of Health, Osong, Korea.
authors: Sung Soon
authors: SS
authors: Kim
authors: Division of Epidemic Intelligence Service, Korea Centers for Disease Control and Prevention, Osong, Korea.
authors: Chaeshin
authors: C
authors: Chu
authors: Division of AIDS, Korea National Institute of Health, Osong, Korea.
authors: Mee-Kyung
authors: MK
authors: Kee
keywords: HIV infection; autoregressive integrated moving average model (ARIMA); forecasting; time series analysis