September 15, 2002
Blood pressure that doesn't drop at night is an ominous indication that juvenile diabetes patients might develop kidney disease, a new study concluded.
The study looked at "type 1" diabetics, whose bodies make no insulin and who make up 5 percent to 10 percent of the nation's 17-million diabetics.
The lead author, Dr. Daniel Batlle of Northwestern University, said it is likely the results could apply to "type 2" diabetes, a form that used to be called adult-onset diabetes but which is becoming increasingly common in children.
"There are enough similarities in the two conditions, in terms of kidney involvement, that it is very likely it will apply to type 2 diabetes as well," said Batlle, whose article appeared in Thursday's edition of the New England Journal of Medicine.
Dr. Nathaniel Clark, vice president for clinical affairs of the American Diabetes Association, agreed.
"The study is very exciting. I think it has a lot of potential areas of importance," though more studies are needed to confirm the results, Clark said.
Diabetes is the underlying cause of about 40 percent of all kidney failure, which affects about 380,000 Americans. Most are on dialysis, with about 80,000 living with transplanted kidneys.
High levels of the protein albumin are an early sign of kidney disease. It shows up years before any symptom the patient would notice.
Type 2 diabetics usually have high blood pressure when their diabetes is diagnosed, but type 1 diabetics often have normal blood pressure. While most people's blood pressure drops during sleep, it often stays near daytime levels in those type 1 diabetics who have high albumin levels in their urine.
But do both symptoms develop at the same time?
To answer that question, Batlle and doctors at the University of Valencia and the Hospital de Sagunto in Spain looked at 75 adolescents and young adults. All had type 1 diabetes but normal urine and daytime blood pressure -- 32 of them did not show the normal nighttime drop in blood pressure.
After about five years, 14 of the patients had high urinary albumin. Only four of those patients were among 43 with normal nighttime blood pressure.
Clark said the findings support the idea that higher than normal blood pressure over any period of time is significant, and 24-hour checks can give vital information.
Dr. Julie Ingelfinger, editor of the journal, said that if the findings are confirmed, it might be worth treating type 1 diabetes patients with nighttime hypertension with a drug to reduce blood pressure.