- Email: [email protected]
How up-to-date are Cochrane reviews?
Correspondence
For the Cochrane Collaboration website see http://www. cochrane.org
ectomy is associated with an increased risk of stress urinary incontinence. Elisabetta Costantini and colleagues raise the interesting question of whether uterine preservation instead of hysterectomy in women with uterine prolapse might decrease the risk of subsequent stress urinary incontinence. Unfortunately our cohort study is unsuitable to answer that question, since we did not include a cohort of women with pelvic organ prolapse undergoing uterus-preserving surgery. Setting aside differences in appraisal of the data, we agree with Costantini and colleagues that the important question is whether it is good clinical practice to submit millions of women to major surgery on benign indications each year without adequate knowledge, or informing them, of possible adverse consequences. Our results should serve as an alarm bell for all those who still believe that pelvic surgery and hysterectomy are trivial matters. We declare that we have no conflict of interest.
*Daniel Altman, Sven Cnattingius [email protected] Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, SE-182 88 Stockholm, Sweden 1
2 3
4
5
Gasquet I, Tcherny-Lessenot S, Gaudebout P, Bosio Le Goux B, Klein P, Haab F. Influence of the severity of stress urinary incontinence on quality of life, health care seeking, and treatment: a national cross-sectional survey. Eur Urol 2006; 50: 818–25. Magos A. Does hysterectomy cause urinary incontinence? Lancet 2007; 370: 1462–63. Prior A, Stanley K, Smith AR, Read NW. Effect of hysterectomy on anorectal and urethrovesical physiology. Gut 1992; 33: 264–67. Morgan JL, O’Connell HE, McGuire EJ. Is intrinsic sphincter deficiency a complication of simple hysterectomy? J Urol 2000; 164: 767–69. Brown JS, Sawaya G, Thom DH, Grady D. Hysterectomy and urinary incontinence: a systematic review. Lancet 2000; 356: 535–39.
How up-to-date are Cochrane reviews? The Cochrane Collaboration has proudly announced that it now offers all Indian residents “complementary access to reliable, up-to-date health research evidence” from the Cochrane Library.1 The 384
offer is supposed to be “helping shape the future of medicine in India”. The reality might be less spectacular. In November, 2007, the number of published Cochrane reviews was about 3200 according to a graph available on the collaboration’s website. The annual number of updates, however, has been in the order of 100–200 per year. This means that, on average, a Cochrane review will not be updated until it is at least 10 years old. This survival time should be judged against the findings of a study which suggested that 23% of reviews are outdated after 2 years and about 70% are outdated after 10 years.2 Although the Cochrane Library contains more than the Cochrane reviews, these have been widely seen as the ultimate quality evidence. There is widespread concern about misleading marketing of pharmaceuticals. Surprisingly, the Cochrane Collaboration seems to do little better. The case is particularly sad in the context of India, a subcontinent in desperate need of improving the health of its people. I declare that I have no conflict of interest.
Ivar Sønbø Kristiansen [email protected] University of Oslo, 0317 Oslo, Norway 1 2
Reynolds F. The Cochrane Library now available across India. Cochrane News 2007; 39: 2. Shojania KG, Sampson M, Ansari MT, Ji J, Doucette S, Moher D. How quickly do systematic reviews go out of date? A survival analysis. Ann Intern Med 2007; 147: 224–33.
Response from the Cochrane Collaboration Ivar Sønbø Kristiansen highlights a major challenge for health-care decision making—the need for up-todate systematic reviews of relevant research. The updating of these reviews is perhaps the major challenge in their production. The Cochrane Collaboration is funding projects to tackle this challenge,1 recognising that there is room for improvement. However, we disagree with Kristiansen’s criticism of the Cochrane Library and his estimate of the pro-
portion of Cochrane reviews that are out of date. We believe that national provisions to the Cochrane Library such as that in India make a valuable contribution to equity in access to knowledge, which is vital to improving health around the world.2,3 In 12 years, Cochrane reviews have increased from a few dozen to more than 3000. This is thanks to the work of teams of volunteers who prepare and update reviews, often outside working hours and without dedicated funding. People from India are increasingly involved in this work, in determining what reviews get done and updated, and in using the findings to improve health care. By virtue of their electronic publication, Cochrane reviews can be revised and updated at any time, with republication in the next quarterly issue of the Cochrane Library. Each review should be updated every 2 years but the difficulties of doing this for all reviews have led to the projects noted above. However, in certain areas of health care, some reviews can be valid even if they have not been updated for several years.4 The collaboration is seeking ways to identify these reviews. When an updated review is sufficiently different to highlight this in the Cochrane Library, it is marked as updated. These are the 100–200 reviews per year mentioned by Kristiansen. Many other Cochrane reviews are also brought up to date each year but this is not marked so prominently. To illustrate: in 2006, 24 Cochrane Review Groups based in England and Scotland published 234 new reviews and updated 341, but only 127 of these warrant being labelled as updated. From later this year, the most recent date on which a review was assessed as up-to-date will be added. Finally, as an example of how Cochrane reviews are indeed “shaping the future of medicine in India”, a review of primaquine for preventing relapses in Plasmodium vivax malaria showed that the recommended regimen in India and Sri Lanka is www.thelancet.com Vol 371 February 2, 2008
For the Cochrane Collaboration website see http://www. cochrane.org
ectomy is associated with an increased risk of stress urinary incontinence. Elisabetta Costantini and colleagues raise the interesting question of whether uterine preservation instead of hysterectomy in women with uterine prolapse might decrease the risk of subsequent stress urinary incontinence. Unfortunately our cohort study is unsuitable to answer that question, since we did not include a cohort of women with pelvic organ prolapse undergoing uterus-preserving surgery. Setting aside differences in appraisal of the data, we agree with Costantini and colleagues that the important question is whether it is good clinical practice to submit millions of women to major surgery on benign indications each year without adequate knowledge, or informing them, of possible adverse consequences. Our results should serve as an alarm bell for all those who still believe that pelvic surgery and hysterectomy are trivial matters. We declare that we have no conflict of interest.
*Daniel Altman, Sven Cnattingius [email protected] Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, SE-182 88 Stockholm, Sweden 1
2 3
4
5
Gasquet I, Tcherny-Lessenot S, Gaudebout P, Bosio Le Goux B, Klein P, Haab F. Influence of the severity of stress urinary incontinence on quality of life, health care seeking, and treatment: a national cross-sectional survey. Eur Urol 2006; 50: 818–25. Magos A. Does hysterectomy cause urinary incontinence? Lancet 2007; 370: 1462–63. Prior A, Stanley K, Smith AR, Read NW. Effect of hysterectomy on anorectal and urethrovesical physiology. Gut 1992; 33: 264–67. Morgan JL, O’Connell HE, McGuire EJ. Is intrinsic sphincter deficiency a complication of simple hysterectomy? J Urol 2000; 164: 767–69. Brown JS, Sawaya G, Thom DH, Grady D. Hysterectomy and urinary incontinence: a systematic review. Lancet 2000; 356: 535–39.
How up-to-date are Cochrane reviews? The Cochrane Collaboration has proudly announced that it now offers all Indian residents “complementary access to reliable, up-to-date health research evidence” from the Cochrane Library.1 The 384
offer is supposed to be “helping shape the future of medicine in India”. The reality might be less spectacular. In November, 2007, the number of published Cochrane reviews was about 3200 according to a graph available on the collaboration’s website. The annual number of updates, however, has been in the order of 100–200 per year. This means that, on average, a Cochrane review will not be updated until it is at least 10 years old. This survival time should be judged against the findings of a study which suggested that 23% of reviews are outdated after 2 years and about 70% are outdated after 10 years.2 Although the Cochrane Library contains more than the Cochrane reviews, these have been widely seen as the ultimate quality evidence. There is widespread concern about misleading marketing of pharmaceuticals. Surprisingly, the Cochrane Collaboration seems to do little better. The case is particularly sad in the context of India, a subcontinent in desperate need of improving the health of its people. I declare that I have no conflict of interest.
Ivar Sønbø Kristiansen [email protected] University of Oslo, 0317 Oslo, Norway 1 2
Reynolds F. The Cochrane Library now available across India. Cochrane News 2007; 39: 2. Shojania KG, Sampson M, Ansari MT, Ji J, Doucette S, Moher D. How quickly do systematic reviews go out of date? A survival analysis. Ann Intern Med 2007; 147: 224–33.
Response from the Cochrane Collaboration Ivar Sønbø Kristiansen highlights a major challenge for health-care decision making—the need for up-todate systematic reviews of relevant research. The updating of these reviews is perhaps the major challenge in their production. The Cochrane Collaboration is funding projects to tackle this challenge,1 recognising that there is room for improvement. However, we disagree with Kristiansen’s criticism of the Cochrane Library and his estimate of the pro-
portion of Cochrane reviews that are out of date. We believe that national provisions to the Cochrane Library such as that in India make a valuable contribution to equity in access to knowledge, which is vital to improving health around the world.2,3 In 12 years, Cochrane reviews have increased from a few dozen to more than 3000. This is thanks to the work of teams of volunteers who prepare and update reviews, often outside working hours and without dedicated funding. People from India are increasingly involved in this work, in determining what reviews get done and updated, and in using the findings to improve health care. By virtue of their electronic publication, Cochrane reviews can be revised and updated at any time, with republication in the next quarterly issue of the Cochrane Library. Each review should be updated every 2 years but the difficulties of doing this for all reviews have led to the projects noted above. However, in certain areas of health care, some reviews can be valid even if they have not been updated for several years.4 The collaboration is seeking ways to identify these reviews. When an updated review is sufficiently different to highlight this in the Cochrane Library, it is marked as updated. These are the 100–200 reviews per year mentioned by Kristiansen. Many other Cochrane reviews are also brought up to date each year but this is not marked so prominently. To illustrate: in 2006, 24 Cochrane Review Groups based in England and Scotland published 234 new reviews and updated 341, but only 127 of these warrant being labelled as updated. From later this year, the most recent date on which a review was assessed as up-to-date will be added. Finally, as an example of how Cochrane reviews are indeed “shaping the future of medicine in India”, a review of primaquine for preventing relapses in Plasmodium vivax malaria showed that the recommended regimen in India and Sri Lanka is www.thelancet.com Vol 371 February 2, 2008