Tamim Hani M, Tagalakis Vicky
Research Center/College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia.
Pharmacoepidemiol Drug Saf. 2009 Feb;18(2):140-6. doi: 10.1002/pds.1692.
An important limitation of Saskatchewan Drug Plan is the incomplete prescription data during an 18-month period (1987-1988), referred to here as the "black-hole".
To assess the impact of assuming drug non-exposure during the "black-hole" on measures of effect.
We used data from a matched case-control study carried out to assess the association between warfarin use and risk of prostate cancer. All subjects diagnosed with prostate cancer between 1981 and 2002 were matched to six controls. In order to avoid the "black-hole", we included subjects whose cancer was diagnosed after 1994. Conditional logistic regression was used to calculate adjusted incidence rates and 95% confidence intervals (CIs) of prostate cancer in relation to warfarin. Two analyses were carried out: (a) without a "black-hole" and (b) with a random "black-hole" of 18 months imposed in the drug history, during which time subjects were assumed to be unexposed.
Compared to non-use, the OR of prostate cancer for ever-use of warfarin in the preceding 5 years was 0.91 (95%CI: 0.81-1.02) (without "black-hole") and 0.89 (95%CI: 0.79-1.01) (with "black-hole"). Compared to non-use, cumulative use of 1, 2, 3, and 4 years were associated with ORs of 1.02, 0.94, 0.77, and 0.76, respectively in the analyses without a "black-hole", and 1.02, 0.88, 0.75, and 0.76, respectively in the analyses with a "black-hole" imposed.
When using Saskatchewan Drug Plan data, assuming non-exposure to warfarin during the "black-hole" has a minor effect on the measures of association.
萨斯喀彻温省药物计划的一个重要局限是1987年至1988年这18个月期间不完整的处方数据，在此称为“黑洞期”。
评估假设在“黑洞期”未使用药物对效应测量的影响。
我们使用了一项配对病例对照研究的数据，该研究旨在评估华法林使用与前列腺癌风险之间的关联。1981年至2002年间所有被诊断为前列腺癌的受试者与六名对照进行配对。为了避免“黑洞期”的影响，我们纳入了1994年后被诊断出癌症的受试者。使用条件逻辑回归计算与华法林相关的前列腺癌调整发病率和95%置信区间（CI）。进行了两项分析：（a）不考虑“黑洞期”；（b）在用药史中设置一个18个月的随机“黑洞期”，在此期间假设受试者未用药。
与未使用华法林相比，过去5年曾使用华法林的前列腺癌比值比（OR）在不考虑“黑洞期”时为0.91（95%CI：0.81 - 1.02），在设置“黑洞期”时为0.89（95%CI：0.79 - 1.01）。与未使用相比，在不考虑“黑洞期”的分析中，累积使用1、2、3和4年的OR分别为1.02、0.94、0.77和0.76，在设置“黑洞期”的分析中分别为1.02、0.88、0.75和0.76。
在使用萨斯喀彻温省药物计划数据时，假设在“黑洞期”未使用华法林对关联测量的影响较小。
