“同伴交换”的针具年覆盖人数估计模型研究

A study on estimation model for annual coverage number of IDUs based on needle exchange program among peer educators

目的探寻适用于"同伴交换"的针具年覆盖人数估计方法。方法结合专题小组讨论、深入访谈、德尔菲法确定估计针具年覆盖人数的参数(包括针具交换、美沙酮、地区特征);采用典型抽样选择四川省4个同伴针具交换点,收集发放记录和参数数据,共获得9组合格数据;运用偏最小二乘回归建立模型。结果建立了同伴交换的针具年覆盖人数估计模型,模型中标准偏回归系数绝对值大于0.2的参数有:"静脉吸毒者(IDUs)的HIV感染率"、"累计在册人数"、"月均新到访人数"、"最近一月共针率";模型的决定系数R2为0.89。数据质量较高时,模型估计针具覆盖人数的误差能达到5%以下。结论该模型能有效估计同伴交换的针具年覆盖人数,具有一定的应用价值。数据质量是影响估计准确性的主要因素。

Objective To explore a method to estimate the annual coverage number of IDUs who got clean nee dles from their peer educators. Methods Focus group discussion, in-depth interview, and Delphi were adopted to identify model parameters. Four needle exchange sites in Sichuan were selected and a total of 9 set of qualified data were collected from these sites. Partial Least-squares Regression was used to establish the model. Results The estimation model was set up and the important parameters（β〉0.2） included the prevalence of HIV in IDUs, the rate of sharing needles in the latest month, cumulative number of IDUs registered in the needle exchange site, monthly average number of new users of exchange program. The determination coefficient of the model was 0.89. The error rates of the estimate were below 5~ with the supporting of high-quality data. Conclusion This model can accept ably estimate the annual coverage number of IDUs in needle exchange program among peer educators. The estimation accuracy relies on the quality of data.