Decrease in blood donation rates in Japan: a time series analysis

ABSTRACT: Objective: To clarify that one of the causes for the decrease in blood donation (BD) rates was the introduction of the 400 ml BD program in 1986. Method: BP rates were monitored over 48 years (1965-2012) and were divided into pre- and post-intervention periods prior to analysis. An interrupted time series analysis was performed using annual data on BD rates, and the impact of the 400 ml BD program was investigated. Results: In a raw series, autoregressive integrated moving average analysis revealed a significant change in slope between the pre- and post-intervention periods in which the intervention factor was the 400 ml BD program. The parameters were as follows: intercept (initial value) = 0.315, confidence interval (CI) = (0.029, 0.601); slope (pre-intervention) = 0.316, CI = (0.293, 0.340); slope difference = -0.435, CI = (-0.462, -0.408); slope (post-intervention) = -0.119, CI = (-0.135, -0.103); all, p = 0.000; goodness-of-fit, R2 = 0.963. After adjusting for stationarity and autocorrelation, the parameters were as follows: intercept (initial value) = -0.699, CI = (-0.838, -0.560); slope (pre-intervention) = 0.136, CI = (0.085, 0.187); slope difference = -0.165, CI = (-0.247, -0.083); slope (post-intervention) = -0.029, CI = (-0.070, 0.012); all, p = 0.000 (except for slope (post-intervention), p = 0.170); goodness-of-fit, R2 = 0.930. Conclusion: One of the causes for decrease in BD rates may be due to the introduction of the 400 ml BD program in Japan.

摘要：
研究目的：明确献血率（Blood Donation, BD）下降的原因之一，为1986年推行的400毫升献血方案。
研究方法：对1965年至2012年共48年的献血率进行监测，将其划分为干预前与干预后两个阶段并开展分析。采用间断时间序列分析方法，基于年度献血率数据探究400毫升献血方案的影响。
研究结果：在原始序列中，自回归积分滑动平均（Autoregressive Integrated Moving Average, ARIMA）分析显示，以400毫升献血方案为干预因素的干预前后两个阶段，斜率存在显著变化。具体参数如下：截距（初始值）=0.315，置信区间（Confidence Interval, CI）=(0.029, 0.601)；干预前斜率=0.316，CI=(0.293, 0.340)；斜率变化量=-0.435，CI=(-0.462, -0.408)；干预后斜率=-0.119，CI=(-0.135, -0.103)；所有指标p值均为0.000；拟合优度R²=0.963。在对平稳性与自相关性进行校正后，参数如下：截距（初始值）=-0.699，CI=(-0.838, -0.560)；干预前斜率=0.136，CI=(0.085, 0.187)；斜率变化量=-0.165，CI=(-0.247, -0.083)；干预后斜率=-0.029，CI=(-0.070, 0.012)；所有指标p值均为0.000（干预后斜率除外，p=0.170）；拟合优度R²=0.930。
研究结论：日本献血率下降的原因之一，或与1986年推行的400毫升献血方案有关。