Canadian patients who received in center nocturnal dialysis saw a significant reduction in left ventricular mass after one year, compared to patients on conventional dialysis, according to a new study published in the Canadian Journal of Cardiology

A team led by Drs. Ron Wald and Andrew Yan of St. Michael’s Hospital compared the thickness of the heart wall in patients who converted to in-hospital nocturnal dialysis and those who remained on conventional dialysis.

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In the prospective cohort study, researchers enrolled 67 prevalent conventional hemodialysis recipients at two medical centers in Canada and converted 37  to in-center nocturnal hemodialysis, and 30 remained on conventional hemodialysis. The primary outcome was the change in left ventricular mass (LVM) after one year as assessed by cardiac magnetic resonance imaging. Secondary outcomes included changes in serum phosphate concentration, phosphate binder burden, haemoglobin, erythropoiesis stimulating agent usage, and blood pressure.

Patients who received conventional dialysis got 12 hours of dialysis a week, given as four hours a session, three days per week. In-hospital nocturnal dialysis patients received eight-hour sessions, three nights a week.

The size of the left ventricle is an important risk factor in cardiovascular disease, with a larger mass being associated with more cardiovascular disease and more deaths from cardiovascular disease. Reduction in left ventricular mass has also been linked to a lower risk of cardiovascular diseases such as heart failure, heart attack and stroke.

Benefits of nocturnal dialysis

The nocturnal dialysis patients also tended to have lower blood pressure and lower blood phosphate levels, compared to the conventional dialysis patients.

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“This study is good news in several ways,” said Wald, a nephrologist. “It suggests there is a cardiovascular benefit for people who are receiving in-hospital nocturnal dialysis and it may encourage other kidney patients to switch to this more intense form of dialysis. In addition to the potential health benefits, nighttime dialysis may free up patients’ daytime hours to do the things that hemodialysis treatments typically disrupt such as employment, child care and household chores.”

Yan, a cardiologist, noted this study was not a randomized clinical trial, so the conclusions that can be drawn are that in-hospital nocturnal dialysis is associated with reduced left ventricular mass, not that it necessarily caused the reduction. Nevertheless, their findings are consistent with other randomized trials of intensified dialysis, and provide support for the use of in-hospital nocturnal dialysis among eligible patients.