Methods of competing risks analysis of time to occurrence of reflux among children with antenatal hydronephrosis
-
Maryam Nazemipour
,
Abdol-Mohammad Kajbafzadeh
,
Kazem Mohammad
,
Abbas Rahimi Foroushani
,
Maryam SeyedTabib
,
Ali Nazemipour
,
Mahmood Mahmoudi
Abstract
Background & Aim: We aimed to describe a standard survival analysis, so that we can analyze some factors related to the time of occurrence of different types of reflux (unilateral-left, unilateralright, and bilateral) in children with antenatal hydronephrosis (ANH) and to provide an approach taking competing risks into account.
Methods & Materials: We used data of 193 children that was collected from Pediatric Urology Research Center of Children’s Hospital Medical Center, affiliated to Tehran University of Medical Sciences, Iran. The cause-specific and subdistribution hazard were computed. P < 0.05 was considered as statistically significant. R packages were used for analyzing the data.
Results: Among these infants (36 girls, 157 boys), 117 (68%) cases had bilateral reflux as the event of interest. The variables “Sex” and “Direction of ANH (in bilateral level)” were significantly different (P<0.05), while “Severity of ANH (in moderate level)” and “Number of other kidney diseases beside ANH and vesicoureteral reflux (VUR)” were borderline. The cumulative incidence derived from the competing risks approach was at a lower level of estimate in comparison with the Kaplan-Meier method. The cumulative incidence curve depicted for the bilateral reflux in subgroups of the sex variable, confirmed the effect of sex.
Conclusion: In the competing risks framework, it is inappropriate to use the Cox and Kaplan-Meier methods, which do not take competing risks into account. Multivariate regression model like the subdistribution hazard model besides the cumulative incidence curve are recommended.
Putter H, Fiocco M, Geskus RB. Tutorial in biostatistics: competing risks and multi-state models. Stat Med 2007; 26(11): 2389-430.
Southern DA, Faris PD, Brant R, Galbraith PD, Norris CM, Knudtson ML, et al. Kaplan- Meier methods yielded misleading results in competing risk scenarios. J Clin Epidemiol 2006; 59(10): 1110-4.
Gelman R, Gelber R, Henderson IC, Coleman CN, Harris JR. Improved methodology for analyzing local and distant recurrence. J Clin Oncol 1990; 8(3): 548-55.
Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc 1958; 53(282): 457-81.
Gooley TA, Leisenring W, Crowley J, Storer BE. Estimation of failure probabilities in the presence of competing risks: new representations of old estimators. Stat Med 1999; 18(6): 695-706.
Pintilie M. Competing risks: a practical perspective. New York, NY: John Wiley & Sons; 2006.
Rushton HG. Vesicouretral reflux and scaring. In: Avner ED, Harmon W, Niaudet P, Niaudet P, Editors. Pediatric nephrology. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004. p. 1027-48.
Ransley PG, Risdon RA. Reflux nephropathy: effects of antimicrobial therapy on the evolution of the early pyelonephritic scar. Kidney Int 1981; 20(6): 733-42.
Vesicoureteric reflux: all in the genes? Report of a meeting of physicians at the Hospital for sick children, Great Ormond street, London. Lancet 1996; 348(9029): 725-8.
Kramer S. Vesico-Ureteral reflux. In: Barry Belman A, King LR, Kramer SA, Editors. Clinical pediatric urology. 4th ed. Boca Raton, FL: CRC Press; 2001. p. 749.
Williams G, Fletcher JT, Alexander SI, Craig JC. Vesicoureteral reflux. J Am Soc Nephrol 2008; 19(5): 847-62.
Mathews R, Carpenter M, Chesney R, Hoberman A, Keren R, Mattoo T, et al. Controversies in the management of vesicoureteral reflux: the rationale for the RIVUR study. J Pediatr Urol 2009; 5(5): 336-41.
Sharbaf FG, Fallahzadeh MH, Modarresi AR, Esmaeili M. Primary vesicoureteral reflux in Iranian children. Indian Pediatr 2007; 44(2): 128-30.
Nakai H, Kakizaki H, Konda R, Hayashi Y, Hosokawa S, Kawaguchi S, et al. Clinical characteristics of primary vesicoureteral reflux in infants: multicenter retrospective study in Japan. J Urol 2003; 169(1): 309-12.
Berry SD, Ngo L, Samelson EJ, Kiel DP. Competing risk of death: an important consideration in studies of older adults. J Am Geriatr Soc 2010; 58(4): 783-7.
Kim HT. Cumulative incidence in competing risks data and competing risks regression analysis. Clin Cancer Res 2007; 13(2 Pt 1): 559-65.
Fine JP, Gray RJ. A proportional hazards model for the subdistribution of a competing risk. J Am Stat Assoc 1999; 94(446): 496-506.
Gray RJ. A class of K-sample tests for comparing the cumulative incidence of a competing risk. Ann Stat 1988; 16(3): 1141-54.
Kalbfleisch JD, Prentice RL. The statistical analysis of failure time data. New York, NY: Wiley; 2002.
Lim HJ, Zhang X, Dyck R, Osgood N. Methods of competing risks analysis of end- stage renal disease and mortality among people with diabetes. BMC Med Res Methodol 2010; 10: 97.
Teixeira L, Rodrigues A, Carvalho MJ, Cabrita A, Mendonca D. Modelling competing risks in nephrology research: an example in peritoneal dialysis. BMC Nephrol 2013; 14: 110.
Gichangi A, Vach W. The analysis of competing risks data: A guided tour. [Odense, Denmark: Department of Statistics, University of Southern Denmark. 2005.
Pintilie M. Analysing and interpreting competing risk data. Stat Med 2007; 26(6): 1360-7.
Andersen PK, Geskus RB, de Witte T, Putter H. Competing risks in epidemiology: possibilities and pitfalls. Int J Epidemiol 2012; 41(3): 861-70.
| Files | ||
| Issue | Vol 2 No 2 (2016) | |
| Section | Original Article(s) | |
| Keywords | ||
| Competing risks Cause-specific hazard Cumulative incidence function Antenatal hydronephrosis Reflux | ||
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