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Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study

BMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g4731 (Published 30 July 2014) Cite this as: BMJ 2014;349:g4731

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I read with interest the study by Mehrabadi and colleagues (authors), but have reservations about their study methodology.1 The authors observed that the rates of obstetric acute renal failure rose from 1.66 to 2.68 per 10,000 deliveries, when deliveries that occurred during 2003-04 were compared to those from 2009-10.1 This temporal increase was particularly related to gestational (pregnancy related) hypertension with significant proteinuria (preeclampsia); but the prevalence of preeclampsia remained stable (1.1%) during the study period.1 Women diagnosed with a severe form of preeclampsia (uncontrolled blood pressure despite appropriate doses of anti hypertensive) are usually offered delivery with the view to minimise maternal morbidity and case fatality. The authors’ observations about temporal increase in obstetric acute renal failure may be related to increase in the proportion of women diagnosed with this severe form of preeclampsia before delivery was considered.

HELLP (Haemolysis, Elevated Liver enzymes, and Low Platelets) syndrome is a recognised risk factor for acute renal failure in women diagnosed with preeclampsia.2 The authors, however, did not report whether the prevalence of HELLP syndrome was different between the study periods (2003-4 versus 2009-10). I am of the opinion that further studies are needed in this area before firm conclusions are drawn.

REFERENCES:
1.Mehrabadi A, Liu S, Bartholomew S, Hutcheon JA, Magee MA, Kramer MS et al. Hypertensive disorders of pregnancy and the recent increase in obstetric acute renal failure in Canada: population based retrospective cohort study. BMJ 2014; 349:g4731.
2.Drakeley AJ, Le Roux PA, Anthony J, Penny J. Acute renal failure complicating severe preeclampsia requiring admission to an obstetric intensive care unit. Am J Obstet Gynecol 2002; 186: 253-6.

Competing interests: No competing interests

02 August 2014
olaleye sanu
obstetrician
Watford