A landmark for popperian epidemiology: refutation of the randomised Aldactone evaluation study

Koch, Elard; Otárola, Álvaro; Kirschbaum, A

doi:10.1136/jech.2004.031633

Cited by 12 publications

(6 citation statements)

References 51 publications

(53 reference statements)

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“…On the other hand, no epidemiological study should be expected to contribute more than what is contained in its design 79. Therefore many of our conjectures are speculative and require further investigation using prospective designs in different populations.…”

Section: Discussionmentioning

confidence: 94%

Impact of parity on anthropometric measures of obesity controlling by multiple confounders: a cross-sectional study in Chilean women

Koch

Bogado

Araya

et al. 2008

Journal of Epidemiology & Community Health

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Section: Discussionmentioning

confidence: 94%

Impact of parity on anthropometric measures of obesity controlling by multiple confounders: a cross-sectional study in Chilean women

Koch

Bogado

Araya

et al. 2008

Journal of Epidemiology & Community Health

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“…In this context, the examination of current abortion laws in 32 Mexican states provided an interesting natural experiment to assess whether more or less permissive legislation was associated with lower or higher incidences of maternal and abortion-related deaths, simultaneously controlling for multiple confounders at the population level. However, this study—based on aggregated data—cannot conclusively rule out the influence of different factors impacting maternal health to an individual level of analysis, and therefore an ecological fallacy112 113 should be avoided. In contrast, an individualistic fallacy,113 114 based on the ‘high-risk’111 approach, should also be avoided in the interpretation of these results.…”

Section: Discussionmentioning

confidence: 92%

“…However, this study—based on aggregated data—cannot conclusively rule out the influence of different factors impacting maternal health to an individual level of analysis, and therefore an ecological fallacy112 113 should be avoided. In contrast, an individualistic fallacy,113 114 based on the ‘high-risk’111 approach, should also be avoided in the interpretation of these results.…”

Section: Discussionmentioning

confidence: 92%

Abortion legislation, maternal healthcare, fertility, female literacy, sanitation, violence against women and maternal deaths: a natural experiment in 32 Mexican states

Koch¹,

Chireau

Pliego

et al. 2015

BMJ Open

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ObjectiveTo test whether there is an association between abortion legislation and maternal mortality outcomes after controlling for other factors thought to influence maternal health.DesignPopulation-based natural experiment.Setting and data sourcesOfficial maternal mortality data from 32 federal states of Mexico between 2002 and 2011.Main outcomesMaternal mortality ratio (MMR), MMR with any abortive outcome (MMRAO) and induced abortion mortality ratio (iAMR).Independent variablesAbortion legislation grouped as less (n=18) or more permissive (n=14); constitutional amendment protecting the unborn (n=17); skilled attendance at birth; all-abortion hospitalisation ratio; low birth weight rate; contraceptive use; total fertility rates (TFR); clean water; sanitation; female literacy rate and intimate-partner violence.Main resultsOver the 10-year period, states with less permissive abortion legislation exhibited lower MMR (38.3 vs 49.6; p<0.001), MMRAO (2.7 vs 3.7; p<0.001) and iAMR (0.9 vs 1.7; p<0.001) than more permissive states. Multivariate regression models estimating effect sizes (β-coefficients) for mortality outcomes showed independent associations (p values between 0.001 and 0.055) with female literacy (β=−0.061 to −1.100), skilled attendance at birth (β=−0.032 to −0.427), low birth weight (β=0.149 to 2.166), all-abortion hospitalisation ratio (β=−0.566 to −0.962), clean water (β=−0.048 to −0.730), sanitation (β=−0.052 to −0.758) and intimate-partner violence (β=0.085 to 0.755). TFR showed an inverse association with MMR (β=−14.329) and MMRAO (β=−1.750) and a direct association with iAMR (β=1.383). Altogether, these factors accounted for (R2) 51–88% of the variance among states in overall mortality rates. No statistically independent effect was observed for abortion legislation, constitutional amendment or other covariates.ConclusionsAlthough less permissive states exhibited consistently lower maternal mortality rates, this finding was not explained by abortion legislation itself. Rather, these differences were explained by other independent factors, which appeared to have a more favourable distribution in these states.

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“…We must again emphasize that the aim of our study was not to argue for or against abortion legislation, but to examine its association with the MMR in Mexico, regardless of our personal opinions or biases. Confirmation or disconfirmation bias often tends to immunize research articles against conflicting evidence or errors and is difficult to detect even during peer review [42]. For instance, we may infer that Dr. Darney was speaking of one or more of our studies when she used the term "anti-abortion junk science" in the Accordingly, our previous article [1] was subjected to open peer review [44,45] and the complete process is publically available at BMJ Open.…”

Section: Discussionmentioning

confidence: 99%

Review, replication, and re-analysis of a recent study on the impact of abortion law on maternal mortality in Mexico – Maintaining rigor and research integrity

Koch¹,

Chireau²,

Stanford³

et al. 2018

Preprint

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This report provides a review, replication, and re-analysis of an study by Darney et al (Contraception. 2017;95(1):105-111) on the association between maternal mortality ratio (MMR, number of maternal deaths per 100,000 live births) and abortion legislation in Mexico City compared with 31 other states. In their study, Darney et al disputed evidence from our study (Koch et al, BMJ Open 2015;5(2):e006013), which found a null association between abortion laws and MMR, and reported their own conclusion of a negative association between abortion availability and MMR. After replicating their dataset and statistical analysis, we found that the beta coefficient (effect size) for abortion legislation was apparently misinterpreted by Darney et al to support the conclusion that legislation allowing abortion on request in Mexico City was associated with a 22.49-unit decrease in MMR. In fact, their analysis showed the opposite result: after multivariable adjustments, Mexico City was associated with a 22.49-unit increase in MMR compared with the 31 states with restricted access to abortion. Moreover, Darney et al did not report the initial time-adjusted effect size, where the 95% CI supports the hypothesis of null association (beta = 4.17; 95%CI -7.19 to 15.54; p=0.470). In our re-analysis of their data, estimates were highly unstable in multiple regression models, and the initial effect size (4.17) for the association between abortion legislation and the MMR was inflated up to 5-fold (22.49) as a result of a ‘tipping effect’ on coefficients and multicollinearity among covariates. In conclusion, our reanalysis of Darney et al’s study provides evidence of serious methodological flaws, faulty statistical analysis and misinterpretation of regression coefficients, ultimately resulting in an invalid conclusion.

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A landmark for popperian epidemiology: refutation of the randomised Aldactone evaluation study

Cited by 12 publications

References 51 publications

Impact of parity on anthropometric measures of obesity controlling by multiple confounders: a cross-sectional study in Chilean women

Impact of parity on anthropometric measures of obesity controlling by multiple confounders: a cross-sectional study in Chilean women

Abortion legislation, maternal healthcare, fertility, female literacy, sanitation, violence against women and maternal deaths: a natural experiment in 32 Mexican states

Review, replication, and re-analysis of a recent study on the impact of abortion law on maternal mortality in Mexico – Maintaining rigor and research integrity

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