- Email: [email protected]
Dr. Shaw Replies
, , ,
LETTERS
THE
TO
EDITOR
First, we cannot know if the three groups (neosalpingostomy via laparoscopy, neosalpingostomy via laparotomy and IVF-ET) are comparable; they may in fact be quite different. As stated by the authors, "There was selection bias as the neosalpingostomies were performed on women with bilateral tubal obstruction while the IVF-ET procedures were performed on women with bilateral tubal obstruction of any kind." We do not know the indications or the reasons for a woman to receive a given treatment. For example, what percentage of patients included in the IVF-ET group actually failed to conceive with a previous neosalpingostomy? Furthermore, we do not clearly know the comparability between groups for other important confounding factors such as woman's age, type of infertility, duration of infertility and combined causes of infertility (e.g. presence or absence of male factor). We know that there was 32.4 percent of primary infertility in the laparoscopy group, but what about the other groups? Even if the authors said that the age distributions were similar among groups, the IVF-ET group was on average three to four years older. The authors also said that the length of infertility was similar among groups by referring to Table 1, but there were no such data in Table 1. We do not know the tubal damage scores for the IVF-ET group. Thus, for all these reasons we have serious questions concerning the groups' comparability. Second, the live birth rates are computed differently among groups and then have different meanings. Indeed, the live birth rate for IVF-ET was a single cycle rate. However, for the neosalpingostomy groups, the live birth rates were one year cumulative rates. It is not surprising then to get with neosalpingostomies live birth rates (19%,22%) similar to the one obtained with IVF-ET (19%). Here is a suggestion for the authors: why not compute the rates of the two neosalpingostomy groups over a two-year period (or more) ... the results would have been a lot better and the cost per live birth would have been cut in half (or more)! Why not compare the groups for monthly live birth rates with their adjusted costs? It could have given the following results.
To THE EDITOR:
rai lu avec beaucoup d'interet l'article du [)f Dorothy Shaw, intitule : «Contraception: Special Considerations in the Mature Woman» et publie dans Ie journal SOGC en fevrier 1998. rai note que Ie docteur Shaw indique en page 135 que Ie FDA a approuve Ie Gyne-T 380 S pour 6 a8 ans. La reference qui appuie cette observation fut publiee en 1991. Cependant en 1994, Ie FDA a modifie sa position et a homologue Ie TCU-380 A pour une periode de 10 ans. Vous trouverez en annexe une publication du Population Reports (1995) et un extrait du Clinical Guide for Contraception ( 1996) qui corrobore cette information. Je vous prie d'agreer l'expression de mes sentiments les plus distingues. Jocelyn Berube, MD-MSc Clinique de plannification des naissances, Centre hospitalier regional de Rimouski, 150, ave Rouleau, Rimouski, Quebec. DR. SHAW REPLIES. To THE EDITOR:
Dr. Berube's interest in my article, "Contraception: Special Considerations in the Mature Woman," is gratifying. The more current information regarding FDA ten-year approval for the TCu-380A is not only appreciated but serves to emphasize further the discrepancy between the Canadian and US regulations to which I was alluding. Clearly, for most women using this or other IUDs inserted after the age of 40, removal prior to menopause is unnecessary. Yours sincerely, Dorothy Shaw, MBChB, FRCSC, Clinical Professor, Department of Obstetrics and Gynaecology and Medical Genetics, University of British Columbia. RE: VILOS GA, VERHOEST CR, MARTIN JS, BOTZ C. ECONOMIC EVALUATION OF IN VITRO FERTILIZATIONEMBRYO TRANSFER (IVF-ET) AND NEOSALPlNGOSTOMY FOR BILATERAL TUBAL OBSTRUCTION. J SOC OBSTET GYNAECOL CAN
IVF-ET
1998;20(2):139-47.
To THE EDITOR:
19%
We recently read this article and would like to express our serious doubts concerning the validity of the results due to the following major weaknesses.
JOURNAL SOGe
, , ,
$128,150
927
SEPTEMBER 1998
LETTERS
THE
TO
EDITOR
First, we cannot know if the three groups (neosalpingostomy via laparoscopy, neosalpingostomy via laparotomy and IVF-ET) are comparable; they may in fact be quite different. As stated by the authors, "There was selection bias as the neosalpingostomies were performed on women with bilateral tubal obstruction while the IVF-ET procedures were performed on women with bilateral tubal obstruction of any kind." We do not know the indications or the reasons for a woman to receive a given treatment. For example, what percentage of patients included in the IVF-ET group actually failed to conceive with a previous neosalpingostomy? Furthermore, we do not clearly know the comparability between groups for other important confounding factors such as woman's age, type of infertility, duration of infertility and combined causes of infertility (e.g. presence or absence of male factor). We know that there was 32.4 percent of primary infertility in the laparoscopy group, but what about the other groups? Even if the authors said that the age distributions were similar among groups, the IVF-ET group was on average three to four years older. The authors also said that the length of infertility was similar among groups by referring to Table 1, but there were no such data in Table 1. We do not know the tubal damage scores for the IVF-ET group. Thus, for all these reasons we have serious questions concerning the groups' comparability. Second, the live birth rates are computed differently among groups and then have different meanings. Indeed, the live birth rate for IVF-ET was a single cycle rate. However, for the neosalpingostomy groups, the live birth rates were one year cumulative rates. It is not surprising then to get with neosalpingostomies live birth rates (19%,22%) similar to the one obtained with IVF-ET (19%). Here is a suggestion for the authors: why not compute the rates of the two neosalpingostomy groups over a two-year period (or more) ... the results would have been a lot better and the cost per live birth would have been cut in half (or more)! Why not compare the groups for monthly live birth rates with their adjusted costs? It could have given the following results.
To THE EDITOR:
rai lu avec beaucoup d'interet l'article du [)f Dorothy Shaw, intitule : «Contraception: Special Considerations in the Mature Woman» et publie dans Ie journal SOGC en fevrier 1998. rai note que Ie docteur Shaw indique en page 135 que Ie FDA a approuve Ie Gyne-T 380 S pour 6 a8 ans. La reference qui appuie cette observation fut publiee en 1991. Cependant en 1994, Ie FDA a modifie sa position et a homologue Ie TCU-380 A pour une periode de 10 ans. Vous trouverez en annexe une publication du Population Reports (1995) et un extrait du Clinical Guide for Contraception ( 1996) qui corrobore cette information. Je vous prie d'agreer l'expression de mes sentiments les plus distingues. Jocelyn Berube, MD-MSc Clinique de plannification des naissances, Centre hospitalier regional de Rimouski, 150, ave Rouleau, Rimouski, Quebec. DR. SHAW REPLIES. To THE EDITOR:
Dr. Berube's interest in my article, "Contraception: Special Considerations in the Mature Woman," is gratifying. The more current information regarding FDA ten-year approval for the TCu-380A is not only appreciated but serves to emphasize further the discrepancy between the Canadian and US regulations to which I was alluding. Clearly, for most women using this or other IUDs inserted after the age of 40, removal prior to menopause is unnecessary. Yours sincerely, Dorothy Shaw, MBChB, FRCSC, Clinical Professor, Department of Obstetrics and Gynaecology and Medical Genetics, University of British Columbia. RE: VILOS GA, VERHOEST CR, MARTIN JS, BOTZ C. ECONOMIC EVALUATION OF IN VITRO FERTILIZATIONEMBRYO TRANSFER (IVF-ET) AND NEOSALPlNGOSTOMY FOR BILATERAL TUBAL OBSTRUCTION. J SOC OBSTET GYNAECOL CAN
IVF-ET
1998;20(2):139-47.
To THE EDITOR:
19%
We recently read this article and would like to express our serious doubts concerning the validity of the results due to the following major weaknesses.
JOURNAL SOGe
, , ,
$128,150
927
SEPTEMBER 1998