Research and special interests: the Johnson and Daviss BMJ 2005 study

If I find that a study is funded by special interest money, I immediately become concerned that the results are biased. For example, when I hear about a study that claims that the Arctic wilderness will be "improved" by oil drilling, I am naturally suspicious. If I find out that the study was conducted by scientists known to be associated with the oil industry, and that the study was funded by an oil company, I discount the results. The study was designed from the outset to produce a pre-determined conclusion, one that meshed with the interests of the researchers and the oil company.

Therefore, I was distressed to find that Johnson and Daviss, authors of the 2005 BMJ study that was the largest study of homebirth to date, are NOT independent researchers. In the paper, Johnson describes his professional position as "senior epidemiologist, Surveillance and Risk Assessment Division, Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada", but he neglected to mention that he holds another position: head of the MANA Statistics and Research Committee. In fact, Johnson and Daviss have been passionate homebirth advocates for many years, long before they embarked on the study. Daviss, who is Johnson's wife, is a homebirth midwife. Furthermore, the study was not funded by an academic institution or a government agency. Rather, it was funded by Foundation for the Advancement of Midwifery, a homebirth advocacy group.

So using money from a homebirth advocacy group, NARM, a homebirth advocacy group, hired homebirth advocates Johnson and Daviss to produce a study on homebirth. The conclusion appears to be predetermined. When an industry hires known allies to do a study about that industry, the results are going to be favorable.

That explains why a study done by an epidemiologist failed to follow the standards of epidemiologists. Johnson and Daviss sliced and diced the data in every possible way. They went beyond that by selecting comparison groups that were not matched for risk, since they almost certainly knew that low risk women have a lower neonatal mortality rate than the homebirth group.

Their own comments are quite illuminating. In a NARM bulletin from summer 2005, Johnson and Davis actually advise midwives how to generate publicity for the paper, and how to spin the data. This is not what you would expect from researchers who were independent.

For example:

We invite you, if you have not already done so, to contact your local radio stations and newspapers this week about the study,..

When contacting the media take the time to educate them on the CPM credential and make sure they know that NARM, MEAC, CfM, MANA, and NACPM have information on these maternity care providers.

On spinning the data:

We purposely reported transfers as: “over 87% of mothers and neonates did not require transfer to hospital,” and most of the transfers were for lack of progress, because the mother was tired or wanted pain relief. This kind of detail is especially important when communicating with the media. For example “over 87% of the mothers…” conveys a sense of confidence, while “thirteen per cent of women still had to be transferred,” which one television broadcast did (even though it was overall a positive study) focuses on the negative end of the curve.

And:

Policy Implications: The study suggests that legislators and policy makers should pay attention to the fact that this study supports the American Public Health Association’s resolution to increase out of hospital births attended by direct entry midwives. The American College of Obstetricians and Gynecologists still opposes home birth, but has no valid evidence to support this position. The Society of Obstetricians and Gynecologists of Canada and several provinces have written statements either acknowledging that women have the right to choose their place of birth or supporting it.

For continuing information on creative and effective ways to highlight this study in the policy arena, consider joining the BirthPolicy listserve. It is a great resource for midwifery policy discussion. Plus list moderators Katie Prown and Steve Cochran have their own personal tips on how to become more media savvy.

Needless to say, "policy implications" which dovetail with the author's pre-existing advocacy, are not the typical purview of a truly independent researcher. Furthermore, it is my understanding from reading the bulletin, that this letter was unsolicited. It was the authors' idea to offer tips on how to publicize the article, how to spin the data, and how to exploit the paper for policy purposes.

I always said that this paper was poor, since it actually shows multiple preventable neonatal deaths at homebirth, and a neonatal death rate that is approximately double the neonatal death rate for low risk groups in the hospital. Now I know why the paper is poor. This paper was produced at the request of a special interest group, by special interest advocates, using special interest money. Not only is the conclusion of homebirth safety unjustified by the data in the actual paper, but the involvement of a special interest group and special interest money renders the paper ethically suspect.

At a minimum, the authors should have been required to disclose their ongoing association with homebirth advocacy organizations and the funding from a homebirth special interest group. Readers of the paper deserve to have this information.


This piece first appeared on Homebirth Debate in August 2006.