Dear Diana,
Greetings from sunny East Anglia, UK. Please find below my thoughts on your
posting on the low protein trial.
The Study in question:
Hansen HP, Tauber-Lassen E, Jensen BR, Parving HH.Effect of dietary protein
restriction on prognosis in patients with diabetic nephropathy.Kidney Int
2002 Jul;62(1):220-8
I have briefly summarised the design and findings.
Aim: The purpose of this study was to determine the effect of dietary
protein restriction on survival and progression to ESRD in diabetic
nephropathy.
Design: Randomised controlled trial
Intervention: Low-protein diet (0.6 g/kg/day) compared with a usual-protein
diet.
Main outcome: The main outcome measures were decline in GFR and development
of ESRD or death.
Main results: The mean declines in GFR were 3.9 mL/min/year (2.7 to 5.2) in
the usual-protein diet group and 3.8 (2.8 to 4.8) in the low-protein diet
group. (As you can see the CI overlaps) ESRD or death occurred in 27% of
patients on a usual-protein diet as compared with 10% on a low-protein diet.
Conclusion: Moderate dietary protein restriction improves prognosis in type
1 diabetic patients with progressive diabetic nephropathy.
We can calculate the NNT to prevent the development of ESRD or death, but
the abstract does not provide the number of patients in the two arms.
As this is a classical randomised trial comparing two modalities of
treatment I sggest that you use the treatment worksheet for critical
appraisal. This will help you (to some extent) to decide whether the results
of this study are valid.
You might find most of the questions for a therapy article will be
appropriate to this study. Please see
http://www.med.ualberta.ca/ebm/ebm.htm (see under therapy/prevention)
http://servers.medlib.hscbklyn.edu/ebm/5600.htm
These are my impressions. Others might have differing views and you might
hear from them. I hope you find the above of some use/help in your
discussions in the unit. Good luck with the critical appraisal.
Cheers & regards,
Badri
Dr.P.Badrinath M.D,M.Phil,(Epid)PhD(Cantab)DFPHM(UK),MPH(Distinc)
Specialist Registrar in PHM & Honorary Clinical Lecturer,
Suffolk Public Health Network & University of Cambridge,
PO Box 170, St.Clement's Hospital,
Ipswich IP1 4LA, UK.
Tel: 00 44 1473 329 570
Fax: 00 44 1473 329 090
http://myprofile.cos.com/badrishanthi
"For an excellent review of the current medical literature, go to Journals
Scan www.uaeu.ac.ae/jscan/" - BMJ 3rd June 2000, Netlines
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