Minimizing Spatial Variability of Healthcare Spatial Accessibility-The Case of a Dengue Fever Outbreak.

Outbreaks of infectious diseases or multi-casualty incidents have the potential to generate a large number of patients. It is a challenge for the healthcare system when demand for care suddenly surges. Traditionally, valuation of heath care spatial accessibility was based on static supply and demand information. In this study, we proposed an optimal model with the three-step floating catchment area (3SFCA) to account for the supply to minimize variability in spatial accessibility. We used empirical dengue fever outbreak data in Tainan City, Taiwan in 2015 to demonstrate the dynamic change in spatial accessibility based on the epidemic trend. The x and y coordinates of dengue-infected patients with precision loss were provided publicly by the Tainan City government, and were used as our model's demand. The spatial accessibility of heath care during the dengue outbreak from August to October 2015 was analyzed spatially and temporally by producing accessibility maps, and conducting capacity change analysis. This study also utilized the particle swarm optimization (PSO) model to decrease the spatial variation in accessibility and shortage areas of healthcare resources as the epidemic went on. The proposed method in this study can help decision makers reallocate healthcare resources spatially when the ratios of demand and supply surge too quickly and form clusters in some locations.

Behavioral Risk Profile of Men Who Have Sex with Men in Beijing, China: Results from a Cross-sectional Survey with Randomized Response Techniques.

BACKGROUND: Human immunodeficiency virus (HIV) is spreading rapidly among men who have sex with men (MSM) in China. Anonymous questionnaires or direct interviews have been frequently used to study their behavior. The aim of the study was to describe the behavioral risk profile of the MSM in Beijing using the randomized response techniques (RRTs). METHODS: A cross-sectional survey of sexual behavior among a sample of MSM was conducted in two HIV counseling and testing clinics in Beijing. The survey was carried out with an anonymous questionnaire containing sensitive questions on sexual behavior. To obtain the honest responses to the sensitive questions, three distinctive RRTs were used in the questionnaire: (1) Additive randomized response model for quantitative questions, (2) randomized response model for multiple choice questions, and (3) Simmons randomized response model for binomial questions. Formulae for the point estimate, variance, and confidence interval (CI) were provided for each specific model. RESULTS: Using RRTs in a sample of 659 participants, the mean age at first homosexual encounter was estimated to be 21.7 years (95% CI: 21.2-22.2), and each had sex with about three (2.9, 95% CI: 2.4-3.4) male partners on average in the past month. The estimated rate for consistent condom use was 56.4% (95% CI: 50.1-62.8%). In addition, condom was estimated to be used among 80.0% (95% CI: 74.1-85.9%) of the population during last anal sex with a male partner. CONCLUSIONS: Our study employed RRTs in a survey containing questions on sexual behavior among MSM, and the results showed that RRT might be a useful tool to obtain truthful feedback on sensitive information such as sexual behavior from the respondents, especially in traditional Chinese cultural settings.

[Study on the incidence of HIV and associated risk factors through a prospective cohort among men who have sex with men in Beijing, China].

OBJECTIVE: To investigate the dynamic change and associated risk factors of HIV sero-conversion rate in Beijing. METHODS: 809 sero-negative men who have sex with men (MSM) were recruited in the cohort from August to December in 2009. HIV sero-antibody, medicinal examination and behavior questionnaire interview were carried out every six months. RESULTS: 962 MSM with overall baseline prevalence of HIV infection as 6.34% (61/962) together with 809 sero-negative MSM, were enrolled in the cohort. Of the 809 sero-negative participants, 95.1% (769/ 809), 85.5% (692/809) and 71.0% (574/809) of them were retained in the 6-month, 12-month and 18-month follow-up visits, with 19, 29 and 17 of them became HIV sero-conversion at 6-month, 12-month, and 18-month follow-up visits and the HIV incidence rates appeared to be 5.47, 12.37 and 6.86 per 100 person-years respectively. The HIV incidence was 7.59 per 100 person-years in the 18 months follow-up visit. Factors including: younger than 25-years old (HR = 2.32, 95%CI: 1.39 - 3.87), having more than 8 MSM partners (HR = 2.50, 95%CI: 1.49 - 4.20), less than 2000¥ every month income (HR = 1.76, 95%CI: 1.05 - 2.95), having more than 4 homosexual partners in the last six months (HR = 3.50, 95%CI: 2.11 - 5.81), showing phimosis and redundant prepuce (HR = 2.47, 95%CI: 1.50 - 4.07) as well as positive syphilis test (HR = 2.62, 95%CI: 1.53 - 4.49) etc., were significantly associated with HIV incidence. CONCLUSION: High HIV incidence was shown among MSM in Beijing and had spread fast in this population, calling for more favorable prevention measures to be taken.