BACKGROUND: In survival analysis, a patient who is missing complete follow-up is included in the analysis as a censored observation. The analysis makes the assumption that the censoring is noninformative; that is, that a censored patient has the same risk of death as those who have complete follow-up. We tested this assumption in a large, long-term follow-up study. METHODS: From 1986 through 2003, 14,495 patients underwent isolated coronary artery bypass grafting procedures. Of 13,963 eligible patients, 2312 were lost to follow-up. We obtained National Death Index data to complete our follow-up, and then compared survival between the original data and the complete National Death Index-augmented data. RESULTS: The National Death Index data revealed 855 additional deaths and increased the total follow-up years from 86,810 to 102,157. Survival estimates and regression models did not differ between the original and National Death Index-augmented data. CONCLUSIONS: Patients lost to follow-up might not differ with regard to survival from those with complete data. The requirement for 95% completeness is somewhat arbitrary. The quality and type of follow-up is more important than the percentage in time-related analyses.
BACKGROUND: In survival analysis, a patient who is missing complete follow-up is included in the analysis as a censored observation. The analysis makes the assumption that the censoring is noninformative; that is, that a censored patient has the same risk of death as those who have complete follow-up. We tested this assumption in a large, long-term follow-up study. METHODS: From 1986 through 2003, 14,495 patients underwent isolated coronary artery bypass grafting procedures. Of 13,963 eligible patients, 2312 were lost to follow-up. We obtained National Death Index data to complete our follow-up, and then compared survival between the original data and the complete National Death Index-augmented data. RESULTS: The National Death Index data revealed 855 additional deaths and increased the total follow-up years from 86,810 to 102,157. Survival estimates and regression models did not differ between the original and National Death Index-augmented data. CONCLUSIONS:Patients lost to follow-up might not differ with regard to survival from those with complete data. The requirement for 95% completeness is somewhat arbitrary. The quality and type of follow-up is more important than the percentage in time-related analyses.
Authors: Jeannie-Marie S Leoutsakos; Sarah N Forrester; Constantine G Lyketsos; Gwenn S Smith Journal: J Alzheimers Dis Date: 2015 Impact factor: 4.472
Authors: Jeannie-Marie S Leoutsakos; Elizabeth A Wise; Constantine G Lyketsos; Gwenn S Smith Journal: Int J Geriatr Psychiatry Date: 2019-09-02 Impact factor: 3.485
Authors: Gillis Carrigan; Samuel Whipple; Michael D Taylor; Aracelis Z Torres; Anala Gossai; Brandon Arnieri; Melisa Tucker; Philip P Hofmeister; Peter Lambert; Sandra D Griffith; William B Capra Journal: Pharmacoepidemiol Drug Saf Date: 2019-03-14 Impact factor: 2.890