D D Gladman1, D R Koh, M B Urowitz, V T Farewell. 1. The Centre for Prognosis Studies in The Rheumatic Diseases, Toronto Western Hospital, University Health Network, Ontario, Canada.
Abstract
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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
OBJECTIVE: To determine the extent of and reasons for lost-to-follow-up, as well as its impact on outcome studies in a cohort of lupuspatients. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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
Authors: Claire Barber; Andrew Herzenberg; Ellie Aghdassi; Jiandong Su; Wendy Lou; Gan Qian; Jonathan Yip; Samih H Nasr; David Thomas; James W Scholey; Joan Wither; Murray Urowitz; Dafna Gladman; Heather Reich; Paul R Fortin Journal: Clin J Am Soc Nephrol Date: 2012-03-22 Impact factor: 8.237
Authors: J G Hanly; M B Urowitz; L Su; S C Bae; C Gordon; D J Wallace; A Clarke; S Bernatsky; D Isenberg; A Rahman; G S Alarcón; D D Gladman; P R Fortin; J Sanchez-Guerrero; J Romero-Diaz; J T Merrill; E Ginzler; I N Bruce; K Steinsson; M Khamashta; M Petri; S Manzi; M A Dooley; R Ramsey-Goldman; R Van Vollenhoven; O Nived; G Sturfelt; C Aranow; K Kalunian; M Ramos-Casals; A Zoma; J Douglas; K Thompson; V Farewell Journal: Ann Rheum Dis Date: 2009-04-08 Impact factor: 19.103
Authors: Edith M Williams; Kate Lorig; Saundra Glover; Diane Kamen; Sudie Back; Anwar Merchant; Jiajia Zhang; James C Oates Journal: BMC Health Serv Res Date: 2016-08-02 Impact factor: 2.655