Evaluating the effects of tubal sterilization on menstrual function: selected issues in data analysis.
We examined selected issues in data analysis in the Collaborative Review of Sterilization (CREST). CREST is a multicentre, prospective, observational study of women undergoing tubal sterilization. We analysed menstrual function after sterilization in over 5000 women who were enrolled in the period 1978-1983 and followed for 5 years with yearly follow-up interviews. To take into account the dependency among repeated responses from the same individuals, we used the generalized estimating equations (GEE) approach to longitudinal data analysis. Marginal modelling resulted in a statistically significant increase in the odds of menstrual dysfunction at 5 years after tubal sterilization. Transitional modelling produced rates of menstrual dysfunction given a woman's menstrual function at baseline, after adjusting for other baseline characteristics such as method of contraception before sterilization. To examine the direction of the bias that could result from non-random missing data, we refitted our models using imputed values. The models with imputed values showed the same trends as the original models.
Martinez-Schnell
B
B
Division of Reproductive Health, Centers for Disease Control, Atlanta, Georgia 30333.
Wilcox
L S
LS
Peterson
H B
HB
Jamison
P M
PM
Hughes
J M
JM
D015982:Bias; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008599:Menstruation Disturbances / Q000453:epidemiology* / Q000209:etiology; D016017:Odds Ratio; D012107:Research Design / Q000592:standards; D012307:Risk Factors; D013246:Sterilization, Tubal / Q000009:adverse effects* / Q000379:methods; D013997:Time Factors