Monthly Archives: June 2015

Send them home

New Zealand is the home of Home Haemodialysis and Christchurch the hub. Sending people home to dialyse is not only more convenient for them and more cost effective, but also has been shown to reduce mortality.  However, is this reduction in mortality sustained across changes in dialysis medicine over time?  This is an important question as Home Haemodialysis is now being considered seriously in many jurisdictions across the world.  The question was recently addressed by Dr Mark Marshall and colleagues across New Zealand and Australia in an article which appeared online ahead of print a couple of weeks back in the American Journal of Kidney Disease (see here, sadly behind a paywall).

What they did

Step 1 was to extract data from 1998 to 2012 from the Australia New Zealand Dialysis & Transplant Registry which prospectively collects information for all long term renal replacement therapy patients. This is a very important registry and the study highlights the importance of keeping data in this way.

Step 2 Placed patients into one of three time periods according to when they started their dialysis: 1998-2002, 2003-2007, 2008-2012.

Step 3: Identified the exposure of the patients to one of: Facility lead haemodialysis (facility HD), Home haemodialysis (home HD), or Peritoneal dialysis (PD).

Step 4: Compared rates of death for patients starting in each time period for each of the dialysis modalities after accounting for age, sex, ethnicity, primary kidney disease, and glomerular filtration rate at the start of therapy (ie how well the kidney was functioning).

What they found (with my commentary)

there is demonstrable survival benefit associated with recent era irrespective of the landmark initiation time.

Indeed, it was a 25% lower (adjusted) mortality for those starting dialysis in  2008-2012 compared to the 1998-2002.

Well done kidney docs – they are getting better and keeping people alive.

There is significant effect modification by modality [type of dialysis] (P <0.001), and separate models were developed in each subgroup: there is a 23% corresponding reduction for those on facility HD therapy, a 29% reduction for those on PD therapy, and a 46% reduction for those on home HD therapy

In other words, all things being equal, survival was improved more on home haemodialysis than either of the other types.

Hazard ratios for death according to era and mode of dialysis.  Lower numbers are better!  From: Marshall, M. R., Polkinghorne, K. R., Kerr, P. G., Agar, J. W. M., Hawley, C. M., & McDonald, S. P. (2015). Temporal Changes in Mortality Risk by Dialysis Modality in the Australian and New Zealand Dialysis Population. American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation. doi:10.1053/j.ajkd.2015.03.014

Hazard ratios for death according to era and mode of dialysis. Lower numbers are better! From: Marshall, M. R., Polkinghorne, K. R., Kerr, P. G., Agar, J. W. M., Hawley, C. M., & McDonald, S. P. (2015). Temporal Changes in Mortality Risk by Dialysis Modality in the Australian and New Zealand Dialysis Population. American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation. doi:10.1053/j.ajkd.2015.03.014

I note patients were only around 60 years old on average when they first initiated dialysis, yet 37% died before the end of the study period or could receive a transplant.  Folks – do your damnedest to avoid kidney disease – starting with avoiding diabetes.

Conclusions

  1. Survival has increased during the past 15 years
  2. Survival of peritoneal dialysis patients has increased more than facility haemodialysis patients
  3. The relative survival of home haemodialysis patients has improved the most

Has home haemodialysis caused people to survive longer?  This study can’t say, because it is an association study not one set out to demonstrate causation. However, it is evidence that supports the continued use and possibly even expansion of home dialysis in New Zealand and Australia.

For further reading, refer to the paper itself:

Marshall, M. R., Polkinghorne, K. R., Kerr, P. G., Agar, J. W. M., Hawley, C. M., & McDonald, S. P. (2015). Temporal Changes in Mortality Risk by Dialysis Modality in the Australian and New Zealand Dialysis Population. American Journal of Kidney Diseases : the Official Journal of the National Kidney Foundation. doi:10.1053/j.ajkd.2015.03.014

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Christchurch has breast cancer research hub

Guest post by: Kim Thomas, Communications Manager at the University of Otago, Christchurch

Research Radar UOC

A team of specialist cancer researchers have joined forces to focus on the impact of obesity on breast cancer.

The researchers all work at the University of Otago, Christchurch’s Mackenzie Cancer Research Group. The Group is headed by Canterbury District Health Board oncologist Professor Bridget Robinson, a breast cancer expert.

Researchers Associate Professor Gabi Dachs, Dr Margaret Currie and Dr Logan Walker have previously investigated various aspects of cancer but decided to team up and focus on the significant health issue of obesity.

Associate Professor Dachs says that international studies have shown breast cancer patients who were obese before or after diagnosis are less likely to survive than patients with normal BMI. Risk of dying from breast cancer increases by a third for every increment of 5kg/m2 in BMI.

autumn15obesity

From left to right: A/Prof Gabi Dachs, Dr Margaret Currie, Dr Logan Walker

The three researchers are investigating different aspects of obesity and breast cancer:

  • Associate Professor Dachs is looking at molecular factors associated with obesity in cancer, particularly how fat cells communicate with cancer cells and negatively affect them.
  • Dr Margaret Currie is putting fat and breast cancer cells together to see how the fat cells make tumours more resistant to treatment. She suspects the fat cells provide ‘an extra energy hit’ to cancer cells by providing lipids, or fats, in addition to glucose.
  • Geneticist Dr Logan Walker will investigate whether the obesity-related gene responsible for the amylase enzyme in saliva (AMY1) contributes to breast cancer development. He will also explore the role of key genes that behave differently in breast tumours from obese women.

The researchers’ work is funded by the NZ Breast Cancer Foundation, the Cancer Society of New Zealand, the Canterbury and West Coast Division of the Cancer Society NZ, the Mackenzie Charitable Foundation and the University of Otago.

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