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Evaluating the effects of tubal sterilization on menstrual function: Selected issues in data analysis
Author(s) -
MartinezSchnell Beverly,
Wilcox Lynne S.,
Peterson Herbert B.,
Jamison Patricia M.,
Hughes Joyce M.
Publication year - 1993
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.4780120317
Subject(s) - sterilization (economics) , gee , generalized estimating equation , missing data , medicine , observational study , odds , demography , fertility , menstrual cycle , obstetrics , statistics , gynecology , population , mathematics , logistic regression , environmental health , sociology , hormone , monetary economics , economics , foreign exchange market , foreign exchange
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.