In response to the letter of Pace and Multani, in general, we cannot disagree with their considerations about the use of odds ratios, risk ratios, and rate ratios. [...]

E. Ricci

F. Chiaffarino

F. Parazzini

I. La Vecchia

L. Fedele

M. Reschini

P.A. Mauri

S. Cipriani

S. Ferrari

S. Noli

Nutrients

In response to the letter of Pace and Multani, in general, we cannot disagree with their considerations about the use of odds ratios, risk ratios, and rate ratios. [...

Elena Ricci

Stefania Noli

Sonia Cipriani

Irene La Vecchia

Francesca Chiaffarino

Stefania Ferrari

Paola Mauri

Marco Reschini

Luigi Fedele

Fabio Parazzini

Multidisciplinary Digital Publishing Institute

Reply: On the Reporting of Odds Ratios and Risk Ratios, Nutrients 2018, 10, 10

Ricci, Elena

Noli, Stefania

Cipriani, Sonia

La Vecchia, Irene

Chiaffarino, Francesca

Ferrari, Stefania

Mauri, Paola Agnese

Reschini, Marco

Fedele, Luigi

Parazzini, Fabio

AIR Universita degli studi di Milano

nutrientsReplyReply: On the Reporting of Odds Ratios and RiskRatios, Nutrients 2018, 10, 10Elena Ricci 1,* , Stefania Noli 2, Sonia Cipriani 1, Irene La Vecchia 2, Francesca Chiaffarino 1,Stefania Ferrari 1, Paola Agnese Mauri 1,2 , Marco Reschini 3 , Luigi Fedele 1,2 andFabio Parazzini 1,21 Dipartimento Donna-Bambino-Neonato, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico,20122 Milan, Italy; son.cipriani@gmail.com (S.C.); francesca.chiaffarino@gmail.com (F.C.);stefania.ferrari@policlinico.mi.it (S.F.); paola.mauri@unimi.it (P.A.M.); luigi.fedele@unimi.it (L.F.);fabio.parazzini@unimi.it (F.P.)2 Department of Clinical Sciences and Community Health, Università di Milano, Fondazione IRCCS Ca’Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; stefi.noli@gmail.com (S.N.);irene.lavecchia@unimi.it (I.L.V.)3 Infertility Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy;m.reschini@gmail.com* Correspondence: ed.ricci@libero.it; Tel.: +39-02-55032318; Fax: +39-02-550320252Received: 20 October 2018; Accepted: 25 October 2018; Published: 26 October 2018Dear Editor,In response to the letter of Pace and Multani, in general, we cannot disagree with theirconsiderations about the use of odds ratios, risk ratios, and rate ratios.In the first version of the paper, our results were reported as odds ratios. Dr. Pace, one of the tworeviewers, requested a new analysis more adequate to the prospective design of the study. Although allestimates were not far from unit and odds ratios were good estimates of both risk ratios and rate ratios,we agreed to that request and reported our results as rate ratios.It was not the first time that, in the framework of assisted reproduction techniques, rate ratioshave been calculated instead of risk ratios. Such a use is due to the fact that, implicitly, a cycle of ARTis considered a unit of time, thus leading to the consideration of the proportion of failure or success asa rate [1,2]. In such a situation, rate ratios and risk ratios are equal.The conclusions of our study did not change when we changed the analysis: Odds ratios andrate ratios for the three outcomes are reported in the Table 1. What we forgot to modify was thestatistical methods, where “logistic regression” was left instead of “Cox regression”. For this reason,we apologize both to the Journal and to the readers.We should have been more explicit about these aspects of the statistical methodology, but, as therevised version was approved and published, we thought that it was clear enough. Presumably,Dr. Pace did not even see the second version, or he would have asked a further revision.Nutrients 2018, 10, 1581; doi:10.3390/nu10111581 www.mdpi.com/journal/nutrientsNutrients 2018, 10, 1581 2 of 2Table 1. Odds ratios and rate ratios for the three outcomes.Implantation Clinical Pregnancy Live BirthWomen AOR (95% CI) ARR (95% CI) AOR (95% CI) ARR (95% CI) AOR (95% CI) ARR (95% CI)Caffeine intake1st tertile 1 1 1 1 1 12nd tertile 1.42 (0.62–3.23) 1.34 (0.64–2.79) 1.23 (0.66–2.29) 1.07 (0.76–1.50) 1.50 (0.74–3.02) 1.09 (0.79–1.50)3rd tertile 0.86 (0.34–2.19) 0.90 (0.38–2.10) 0.97 (0.52–1.84) 1.00 (0.70–1.43) 0.94 (0.47–1.88) 0.99 (0.71–1.40)>90◦ percentile § 0.49 (0.12–2.05) 0.58 (0.16–2.04) 0.80 (0.25–2.59) 0.96 (0.51–1.80) 0.90 (0.27–3.06) 0.99 (0.54–1.84)MenCaffeine intake1st tertile 1 1 1 1 1 12nd tertile 1.86 (0.82–4.23) 1.64 (0.78–3.44) 1.02 (0.56–1.87) 1.01 (0.72–1.42) 1.11 (0.56–2.19) 1.02 (0.75–1.41)3rd tertile 0.74 (0.29–1.92) 0.78 (0.32–1.87) 1.28 (0.68–2.43) 1.07 (0.76–1.52) 1.02 (0.51–2.05) 1.00 (0.72–1.40)>90◦ percentile § 0.68 (0.14–3.39) 0.73 (0.17–3.16) 1.48 (0.47–4.61) 1.12 (0.59–2.14) 1.00 (0.29–3.46) 0.98 (0.54–1.83)Combined intake (W-M)Low-low 1 1 1 1 1 1Low-high 0.75 (0.29–1.91) 0.79 (0.34–1.85) 1.12 (0.54–2.32) 1.03 (0.71–1.50) 1.51 (0.67–3.40) 1.09 (0.76–1.55)High-low 1.28 (0.51–3.22) 1.22 (0.53–2.78) 0.85 (0.41–1.74) 0.95 (0.64–1.42) 1.24 (0.55–2.80) 1.06 (0.73–1.54)High-high 0.54 (0.20–1.44) 0.60 (0.24–1.48) 0.70 (0.36–1.36) 0.89 (0.61–1.30) 0.74 (0.36–1.52) 0.93 (0.65–1.33)AOR: adjusted odds ratio; ARR: adjusted rate ratio; CI: confidence interval; W-M: women-men; § as compared to10th percentile.References1. Razaz, N.; Avitan, T.; Ting, J.; Pressey, T.; Joseph, K.S. Perinatal outcomes in multifetal pregnancy followingfetal reduction. CMAJ 2017, 189, E652–E658. [CrossRef] [PubMed]2. Chen, Z.J.; Shi, Y.; Sun, Y.; Zhang, B.; Liang, X.; Cao, Y.; Yang, J.; Liu, J.; Wei, D.; Weng, N.; et al. Freshversus Frozen Embryos for Infertility in the Polycystic Ovary Syndrome. N. Engl. J. Med. 2016, 375, 523–533.[CrossRef] [PubMed]© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open accessarticle distributed under the terms and conditions of the Creative Commons Attribution(CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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Reply: On the Reporting of Odds Ratios and Risk Ratios, Nutrients 2018, 10, 10

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