Gladman D D, Koh D R, Urowitz M B, Farewell V T
The Centre for Prognosis Studies in The Rheumatic Diseases, Toronto Western Hospital, University Health Network, Ontario, Canada.
Lupus. 2000;9(5):363-7. doi: 10.1191/096120300678828325.
To determine the extent of and reasons for lost-to-follow-up, as well as its impact on outcome studies in a cohort of lupus patients.
As of September 1991, 247 patients, in a cohort of 621 patients with SLE, being followed in a long-term prognosis study, had not been seen since 1 March, 1990 and were considered lost-to-follow-up. Patients were contacted and encouraged to return for an evaluation or to answer a questionnaire by telephone. Descriptive statistics were used to compare the lost-to-follow-up and non-lost-to-follow-up patients and the survival experience during the lost-to-follow-up period was compared with that when patients were not considered lost-to-follow-up. Estimated survival curves with and without the information gained through contacts with lost-to-follow-up patients were compared.
Of the 247 patients, 29 have died, 66 returned for a full assessment, 84 completed a questionnaire and 68 (11%) were true lost-to-follow-up. The lost-to-follow-up patient group had 10% more Caucasians and 6% more males than the patients under regular follow-up. The estimated survival curves of the entire cohort with and without the new lost-to-follow-up data, calculated as of July 1992, were very similar. There was no evidence of a differential mortality rate during the period in which patients were lost-to-follow-up. Some suggestive evidence that the relative mortality rate comparing the rate during a period of lost-to-follow-up and during a period of active follow-up may depend on disease duration at the time of lost-to-follow-up was found.
While it would be prudent to limit lost-to-follow-up as much as possible, especially for outcomes such as mortality which do not necessarily require a clinic visit, it does not appear that significant bias will be present in prospective studies based on our single clinic database. Since the retrieved 179 lost-to-follow-up patients did not affect survival studies it is likely that the 68 true lost-to-follow-up patients will also not have an impact on prognostic studies. Lupus (2000) 9, 363-367
确定狼疮患者队列中失访的程度和原因，以及其对结局研究的影响。
截至1991年9月，在一项长期预后研究中随访的621例系统性红斑狼疮（SLE）患者队列中，自1990年3月1日起未再就诊的247例患者被视为失访。与这些患者取得联系，并鼓励他们回来接受评估或通过电话回答问卷。使用描述性统计方法比较失访患者和未失访患者，并将失访期间的生存经历与患者未被视为失访时的生存经历进行比较。比较了包含和不包含通过与失访患者联系获得信息的估计生存曲线。
在这247例患者中，29例死亡，66例回来接受了全面评估，84例完成了问卷，68例（11%）为真正失访。失访患者组中的白种人比定期随访患者多10%，男性多6%。截至1992年7月计算的整个队列包含和不包含新失访数据的估计生存曲线非常相似。在患者失访期间没有证据表明死亡率存在差异。发现了一些提示性证据，即比较失访期和积极随访期的相对死亡率可能取决于失访时的疾病持续时间。
虽然尽可能限制失访是谨慎的做法，特别是对于不一定需要门诊就诊的结局，如死亡率，但基于我们单一临床数据库的前瞻性研究似乎不会出现显著偏差。由于找回的179例失访患者未影响生存研究，68例真正失访患者可能也不会对预后研究产生影响。《狼疮》（2000年）9卷，第363 - 367页
