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In this issue of The Journal of Clinical Hypertension, a message for World Kidney Day, entitled “Hypertension and Kidney Disease: A Marriage That Should Be Prevented,” by Drs Bakris and Ritz on behalf of the World Kidney Steering Committee, highlights the fact that chronic kidney disease (CKD) is increasing worldwide and that physicians should be paying more attention to the problem.1 The paper urges physicians to make the diagnosis as early as possible and to aggressively treat the 2 pathogenic factors, diabetes and hypertension, that account for the majority of cases. In general, this call to action is well-crafted and we agree with its conclusions.

Prevalence of CKD

  1. Top of page
  2. Prevalence of CKD
  3. End-Stage Renal Disease
  4. What to Do About the Diagnosis of CKD?
  5. CKD and Hypertension
  6. References

There are, however, certain features of the report that deserve comment. The commentary highlights the fact that the prevalence of CKD is rising, but this may require some clarification. Is this the result of the fact that laboratories are now reporting glomerular filtration rates (GFRs) as part of standard medical screening? If CKD is defined as a GFR <60 mL/min, are these numbers a reflection of an aging population? Many people in their 70s and 80s have declining GFRs, which may be lower than the critical level of the definition. The numbers may, therefore, not reflect an increase in a disease but depend on other factors.

End-Stage Renal Disease

  1. Top of page
  2. Prevalence of CKD
  3. End-Stage Renal Disease
  4. What to Do About the Diagnosis of CKD?
  5. CKD and Hypertension
  6. References

The paper also notes that end-stage renal disease (ESRD) is increasing rapidly and that nearly a half million people in the United States were treated for ESRD in 2004. Next year this number may increase by about 40%. The budget in the United States for ESRD is now >$35 billion per year. Although several reasons are suggested for this increase, it might be useful to comment further. Numbers for ESRD are taken from dialysis statistics. Thirty to 40 years ago, a 75- or 80-year-old man or woman with diabetes or hypertension with renal failure would probably not have undergone dialysis. Today there are literally thousands of people in their 70s and 80s with ESRD, diabetes, heart disease, or other chronic illness who make up the ESRD statistics. Not unexpectedly, the number will increase as more and more people live to older ages. An additional factor mentioned briefly in the report is that patients who used to die prematurely of coronary disease, complications of diabetes, or the cardiovascular sequelae of hypertension (ie, stroke, coronary heart disease, or heart failure), are no longer dying at early ages. They live to experience vascular disease progression, and many progress to ESRD. Thus, it may be statistically true that the numbers are increasing rapidly but there may be specific reasons for this increase other than an increase in the occurrence and severity of renal disease.

What to Do About the Diagnosis of CKD?

  1. Top of page
  2. Prevalence of CKD
  3. End-Stage Renal Disease
  4. What to Do About the Diagnosis of CKD?
  5. CKD and Hypertension
  6. References

Is it important that physicians make the diagnosis of CKD based on the new definition of a GFR <60 mL/min? Is it important that a 75- or 80-year-old man or woman with a GFR of 50 to 55 mL/min be told that they have chronic renal disease? Yes, if they have hypertension or diabetes, are reluctant to undergo treatment, and cannot be motivated; but perhaps not, if they are already being treated successfully for these comorbidities. I do not believe that it is useful to label elderly people because of a laboratory finding that may not change the approach to treatment.

It may be important, however, for physicians who are presented with these numbers to take them into consideration when choosing therapy. For example, an elderly, thin woman with a creatinine of 1.2 mg/dL or 1.3 mg/dL might appear to have normal renal function but have a decreased GFR. In deciding on therapy for hypertension, this patient may require a loop diuretic instead of the thiazide. In some other instances, the diagnosis of CKD based on a GFR or the presence of albuminuria may require the use of a renin-angiotensin inhibitor such as an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in addition to other therapy.

CKD and Hypertension

  1. Top of page
  2. Prevalence of CKD
  3. End-Stage Renal Disease
  4. What to Do About the Diagnosis of CKD?
  5. CKD and Hypertension
  6. References

This paper appropriately discusses the most important treatment for prevention of CKD, ie, control of hypertension. It overemphasizes, however, the poor results of hypertension treatment in patients with diabetes and renal disease. Considering the fact that the new definition of goal blood pressure (BP) levels of <130/80 mm Hg in this group of patients has been widely publicized only within the past few years, it is not surprising that control rates at this BP level are still lower than with goal rates of <140/90 mm Hg.

Control rates in the general population have been improving dramatically over the past few years. Recent studies from the Behavioral Risk Modification Survey2 and from a Harris Poll3 have reported that patients with hypertension are now generally aware of the presence of elevated BP, that >75% to 80% of them are being treated, and that approximately 50% are now being controlled at goal levels. There is obviously still room for improvement, but it may be more appropriate to highlight the success rates in preventing cardiovascular disease that have been achieved than to continuously highlight the negatives.4 Although several experts believe that bad news may result in more attention being paid to solutions to a problem, this may not always be the best approach.

It is certainly true that the control of diabetes and hypertension in patients with CKD can be improved. Whether it is important, as the paper suggests, that more patients be made aware that they have CKD is debatable. They should be made aware that they have elevated BP since something can be done about this to help prevent further kidney disease.

References

  1. Top of page
  2. Prevalence of CKD
  3. End-Stage Renal Disease
  4. What to Do About the Diagnosis of CKD?
  5. CKD and Hypertension
  6. References