ANALYSING SURVIVAL TIME OF BILATERAL CORNEAL GRAFT FOR KERATOCONUS USING COX FRAILTY MODEL

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KHEYRI S.; FAGHIHZADEH S.; JAVADI M.A.; JAFARINASAB M.R.; HOSSEINI S.M.B.; ANISIAN A.

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Journal: BINA Year:2003 | Volume:9 | Issue:1 (33) Page(s): 40-45

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Title

ANALYSING SURVIVAL TIME OF BILATERAL CORNEAL GRAFT FOR KERATOCONUS USING COX FRAILTY MODEL

Author(s)

Keywords

SURVIVAL TIMEQ3

BILATERAL CORNEAL GRAFTQ3

KERATOCONUSQ3

COX FRAILTY MODELQ3

Abstract

Purpose: To determine the SURVIVAL TIME and risk factors for BILATERAL CORNEAL GRAFT rejection for keratoconus. Methods: Records of 119 patients who underwent BILATERAL CORNEAL GRAFT due to KERATOCONUS between 1981-2002 were reviewed. For bilateral grafts, many recipient-related and environmental factors are common for both grafts, so we expect SURVIVAL TIMEs for each subject’s graft to be correlated. For considering correlation, COX FRAILTY MODEL was used for analysis and SURVIVAL TIME was calculated by Kaplan-Meier survival curve. Results: We studied 119 patients (238 eyes), including 72 men (60.5%) and 47 women (39.5). Mean age at first transplantation was 25.5 years and at the second was 28.8 years. The period between the first and second graft was from 3.8 to 204 months with a mean of 44.6 months. During the study period, there were 54 rejections (22.7%). The SURVIVAL TIME (time lapsed between surgery and rejection) ranged from 1.1 months to 95 months with a mean of 12.5 months and median of 6.9 months. There were 4.2% vernal keratoconjunctivitis (VKC) and 4.6% corneal vascularization. The recipient age at surgery, VKC, and corneal vascularization were significant rejection risk factors. But sex, donor size, recipient size, freshness of donor cornea, and regraft were not significant risk factors. There was no significant difference between the first and second SURVIVAL TIMEs of corneal graft, but a shorter interval between two grafts resulted in increase of rejection risk for the second one. R square was 33% by fitting the COX FRAILTY MODEL and 7.5% by fitting the Cox model. Conclusion: Increasing the time between two transplantations improves the survival for the second graft. The COX FRAILTY MODEL considers correlation between the SURVIVAL TIMEs of BILATERAL CORNEAL GRAFTs, obtains more correct parameter estimates and improves the model to fit the data and is preferred for analysing such data.

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تحلیل بیزی مدل شکنندگی همبسته وایبول با استفاده از روش های مونت کارلوی زنجیر مارکوفی و کاربرد آن در شناسایی عوامل موثر بر دفع پیوند قرنیه دو طرفه

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APA: Copy

KHEYRI, S., FAGHIHZADEH, S., JAVADI, M.A., JAFARINASAB, M.R., HOSSEINI, S.M.B., & ANISIAN, A.. (2003). ANALYSING SURVIVAL TIME OF BILATERAL CORNEAL GRAFT FOR KERATOCONUS USING COX FRAILTY MODEL. BINA, 9(1 (33)), 40-45. SID. https://sid.ir/paper/42284/en

Vancouver: Copy

KHEYRI S., FAGHIHZADEH S., JAVADI M.A., JAFARINASAB M.R., HOSSEINI S.M.B., ANISIAN A.. ANALYSING SURVIVAL TIME OF BILATERAL CORNEAL GRAFT FOR KERATOCONUS USING COX FRAILTY MODEL. BINA[Internet]. 2003;9(1 (33)):40-45. Available from: https://sid.ir/paper/42284/en

IEEE: Copy

S. KHEYRI, S. FAGHIHZADEH, M.A. JAVADI, M.R. JAFARINASAB, S.M.B. HOSSEINI, and A. ANISIAN, “ANALYSING SURVIVAL TIME OF BILATERAL CORNEAL GRAFT FOR KERATOCONUS USING COX FRAILTY MODEL,” BINA, vol. 9, no. 1 (33), pp. 40–45, 2003, [Online]. Available: https://sid.ir/paper/42284/en

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