or renal disease secondary to diabetic microvascu-lar changes in the kidney, is
a common complication of diabetes. People with diabetes account for nearly half
of new cases of end-stage renal disease (ESRD) each year and about a quarter of
those requiring dialysis or transplantation each year in the United States.
About 20% to 30% of people with type 1 or type 2 diabetes de-velop nephropathy,
but fewer of those with type 2 diabetes progress to ESRD. Native American,
Hispanic, and African-American persons with type 2 diabetes are at greater risk
for ESRD than non-Hispanic whites (ADA, Diabetic Nephropathy, 2003).
with type 1 diabetes frequently show initial signs of renal disease after 10 to
15 years, whereas patients with type 2 diabetes develop renal disease within 10
years of the diagnosis of diabetes. Many patients with type 2 diabetes have had
diabetes for many years before it was diagnosed and treated. Therefore, they
have evidence of nephropathy at the time of diagnosis.
is no reliable method to predict whether a person will develop renal disease.
The DCCT results showed that intensive treatment of diabetes with a goal of
achieving a hemoglobin A1C level as close to the nondiabetic range as
possible reduced the oc-currence of early signs of nephropathy, such as
microalbuminuria by 39%, and albuminuria by 54%. Similarly, the UKPDS study
demonstrated a reduced incidence of overt nephropathy in type 2 diabetes with
control of blood glucose levels (ADA, Diabetic Nephropathy, 2003).
after the onset of diabetes, and especially if the blood glucose levels are
elevated, the kidney’s filtration mechanism is stressed, allowing blood
proteins to leak into the urine. As a re-sult, the pressure in the blood
vessels of the kidney increases. It is thought that the elevated pressure
serves as the stimulus for the development of nephropathy. Various medications
and diets are being tested to prevent these complications.
of the signs and symptoms of renal dysfunction in the pa-tient with diabetes
are similar to those seen in patients without diabetes. Also, as renal failure
progresses, the catabolism (breakdown) of both exogenous and endogenous insulin
de-creases, and frequent hypoglycemic episodes may result. Insulin needs change
as a result of changes in the catabolism of insulin, and also as a result of
changes in diet related to the treatment of nephropathy. The stress of renal
disease affects self-esteem, fam-ily relationships, marital relations, and
virtually all aspects of daily life. As renal function decreases, the patient
commonly has multiple-system failure (eg, declining visual acuity, impotence,
foot ulcerations, heart failure, and nocturnal diarrhea).
the most important blood proteins that leaks into the urine is albumin. Small
amounts may leak undetected for years. Of patients with microalbuminuria,
clinical nephropathy even-tually develops in more than 85%. However, if
microalbumin-uria is not present, nephropathy develops in fewer than 5%. Early
microalbuminuria may also be discovered in a 24-hour urine sample. The urine
should be checked annually for microalbu-minuria. If the microalbuminuria level
exceeds 30 mg/24 hours on two consecutive tests, treatment is indicated.
urine dipstick test reads consistently positive for sig-nificant amounts of
albumin, serum creatinine and BUN levels are obtained. At this point in the
development of renal disease, diagnostic testing for cardiac or other systemic
problems may also be required. Some of the tests involve injection of special
dyes that are not easily cleared by the damaged kidney, so the value of the
diagnostic test must be weighed against the potential risks.
often develops in patients (both diabetic and nondiabetic) who are in the early
stages of renal disease. How-ever, essential hypertension occurs in up to 50%
of all individu-als with diabetes (for unknown reasons). Thus, it should not be
assumed that someone with diabetes who has hypertension also has renal disease;
other diagnostic criteria must also be present.
addition to achieving and maintaining near-normal blood glu-cose levels,
management for all patients with diabetes should in-clude careful attention to
· Control of hypertension
(the use of angiotensin-converting enzyme [ACE] inhibitors, such as captopril,
because control of hypertension may also decrease or delay the onset of early
· Prevention or vigorous
treatment of urinary tract infections
· Avoidance of nephrotoxic
· Adjustment of
medications as renal function changes
· Low-sodium diet
· Low-protein diet
patient has already developed microalbuminuria and its level exceeds 30 mg/24
hours on two consecutive tests, an ACEinhibitor should be prescribed. ACE
inhibitors lower blood pres-sure and reduce microalbuminuria and therefore
protect the kid-ney. Alternatively, angiotensin-receptor blocking (ARB) agents
may be prescribed. This preventive strategy should be part of the standard of
care for the person with diabetes. Carefully designed low-protein diets also
appear to reverse early leakage of small amounts of protein from the kidney
(ADA, Clinical Practice Recommendations, 2003; ADA, Diabetic Nephropathy,
chronic or end-stage renal failure, two types of treatment are available:
dialysis (hemodialysis or peritoneal dialysis) and transplantation from a
relative or a cadaver. Hemodialysis for the patient with diabetes is similar to
that for patients without the disease. Because hemodialysis creates additional
stress on patients with cardiovascular disease, it may not be ap-propriate for
certain patients. In addition, it is extremely intru-sive into a patient’s
ambulatory peritoneal dialysis is being used by an increasing number of
patients with diabetes, mainly because of the independence it allows patients.
In addition, insulin can be mixed into the dialysate, which may result in
better blood glucose control and end the need for insulin injections. However, these
patients may require more insulin because the dialysate contains glucose. Major
risks of peritoneal dialysis are infection and peri-tonitis. The mortality rate
for diabetic patients undergoing dial-ysis is higher than that in patients
without diabetes undergoing dialysis and is closely related to the severity of
disease is frequently accompanied by advancing reti-nopathy that may require
laser treatments and surgery. Severe hypertension also worsens eye disease
because of the additional stress it places on the blood vessels. Patients being
treated with hemodialysis who require eye surgery may be changed to peri-toneal
dialysis and have their hypertension aggressively controlled for several weeks
before surgery. The rationale for this change is that hemodialysis requires
anticoagulants that can increase the risk of bleeding after the surgery, and
peritoneal dialysis mini-mizes pressure changes in the eyes.
success rate for kidney transplantation in patients with diabetes has improved.
In medical centers performing large num-bers of transplants, the chances are
75% to 80% that the trans-planted kidney will continue to function in the
patient with diabetes for at least 5 years. Like the original kidneys,
transplanted kidneys in patients with diabetes can eventually be damaged if
blood glucose levels are consistently high after the transplanta-tion.
Therefore, monitoring blood glucose levels frequently and adjusting insulin
levels in diabetic patients with transplanted kidneys are essential for
long-term success. Pancreas transplants are sometimes attempted when a kidney
transplant is performed. Pancreatic transplants have not been successful enough
to be performed alone because of the risks associated with immuno-suppression.