William Miedema (2526808) & Lieke Touwen (s2447827), WG 22
Why a potassium restricted diet and a co-morbid CKD 4 patient aren’t a suitable
match
Medical dilemmas are part of every doctor’s career. Opinions about the optimal care for a
patient can vary, bringing about discussions as to what the course of a patient's treatment
ought to be. The same debate applies to the following patient case. A patient with chronic
kidney disease stage 4 and a potassium concentration of 5.0 mmol/liter is at risk of
hyperkalemia and progressing kidney damage. Moreover, the patient suffers from diabetes
and hypertension. He had a blood pressure of 140/90 while using 12,5 mg
hydrochlorothiazide at the last check up. The question arises whether the patient should
follow a potassium restricted diet. At the moment, there are no clear guidelines about diet
instructions for patients with complex morbidity, nor is there a guideline for potassium
concentrations in CKD 4 patients. Currently, a potassium-restricted diet is often prescribed to
patients with an impaired renal function.
Clearly we are dealing with a patient that has multi-factoral complaints. Firstly, the kidney
dysfunction, which is seen as a considerable problem. This patient has chronic kidney
disease stage four, meaning the eGFR is between 15 and 19 ml/min. Obviously, this is a
severe disorder of the kidney, taking into account that this is the last stage before kidney
failure. On top of this, the patient also has diabetes. This increases the likelihood of further
kidney damage due to the high plasma glucose concentrations being able to damage the
vessel walls. Additionally, the potassium concentration of this patient is on the verge of being
too high, since 3.5-5.0 mmol/liter is being used as the cut off value for a ‘normal’ potassium
concentration. Lastly, the patient has hypertension. This is currently being treated with
hydrochlorothiazide, a diuretic, to lower the blood pressure.
Hypertension leads to microvascular damage in the kidneys. Consequently, the kidney
function will begin to deteriorate, leading to excessive fluid retention and accumulation of
waste-products. As a result of this, the blood pressure will increase, meaning that this is a
vicious circle of elevating blood pressures and progressive kidney damage. Because of this,
, William Miedema (2526808) & Lieke Touwen (s2447827), WG 22
it is essential to lower the blood pressure and to retain the renal function as much as
possible. Otherwise, the CKD4 might progress to kidney failure. This must obviously be
prevented. At the moment, the patient uses hydrochlorothiazide in order to counter the
hypertension. Judging from the blood pressure of the patient, this will probably not suffice in
lowering the blood pressure towards normal values. The treatment of hypertension and
controlling it is the most important concern in this case, since there is no treatment for
chronic kidney failure. There is a narrow relationship between hypertension, CKD and
potassium. As mentioned before, a potassium-restricted diet is the current treatment of
choice for patients with impaired renal function. However, to correct hypertension and
increase the mortality of the comorbid patient, the doctor should implement a diet with
standard potassium intake in the patient’s treatment, with a normal to high serum potassium
as a result.
To elucidate this statement, a number of publications will be discussed. First of all, a
research called: ‘Effect of increased potassium intake on cardiovascular risk factors and
disease: systematic review and meta-analyses’. As the name suggests, this is a systematic
meta analysis to fill in the gaps regarding potassium intake and the consequences on one’s
health. In totality, 22 RCT’s, consisting of 1606 participants, and eleven cohort studies,
consisting of 127,038 participants, were analysed. This big aggregation of studies suggests
that a high potassium intake lowers the blood pressure in people with hypertension. Thereby
causing no negative effects on blood lipid concentrations, catecholamine concentrations and
renal function in adults (1). On top of this, another study called ‘The importance of potassium
in managing hypertension’ further supports this claim. This meta-analysis of many more
observational studies, clinical trials and meta analyses suggests that a high potassium intake
reduces blood pressure in a dose-dependent manner (2). When applying a potassium-
restricted diet these positive effects on blood pressure, induced by potassium, could be
missed. Besides, the reduction of potassium might even increase the blood pressure, which
is extremely undesirable since the patient already suffers from hypertension. Keeping in
Why a potassium restricted diet and a co-morbid CKD 4 patient aren’t a suitable
match
Medical dilemmas are part of every doctor’s career. Opinions about the optimal care for a
patient can vary, bringing about discussions as to what the course of a patient's treatment
ought to be. The same debate applies to the following patient case. A patient with chronic
kidney disease stage 4 and a potassium concentration of 5.0 mmol/liter is at risk of
hyperkalemia and progressing kidney damage. Moreover, the patient suffers from diabetes
and hypertension. He had a blood pressure of 140/90 while using 12,5 mg
hydrochlorothiazide at the last check up. The question arises whether the patient should
follow a potassium restricted diet. At the moment, there are no clear guidelines about diet
instructions for patients with complex morbidity, nor is there a guideline for potassium
concentrations in CKD 4 patients. Currently, a potassium-restricted diet is often prescribed to
patients with an impaired renal function.
Clearly we are dealing with a patient that has multi-factoral complaints. Firstly, the kidney
dysfunction, which is seen as a considerable problem. This patient has chronic kidney
disease stage four, meaning the eGFR is between 15 and 19 ml/min. Obviously, this is a
severe disorder of the kidney, taking into account that this is the last stage before kidney
failure. On top of this, the patient also has diabetes. This increases the likelihood of further
kidney damage due to the high plasma glucose concentrations being able to damage the
vessel walls. Additionally, the potassium concentration of this patient is on the verge of being
too high, since 3.5-5.0 mmol/liter is being used as the cut off value for a ‘normal’ potassium
concentration. Lastly, the patient has hypertension. This is currently being treated with
hydrochlorothiazide, a diuretic, to lower the blood pressure.
Hypertension leads to microvascular damage in the kidneys. Consequently, the kidney
function will begin to deteriorate, leading to excessive fluid retention and accumulation of
waste-products. As a result of this, the blood pressure will increase, meaning that this is a
vicious circle of elevating blood pressures and progressive kidney damage. Because of this,
, William Miedema (2526808) & Lieke Touwen (s2447827), WG 22
it is essential to lower the blood pressure and to retain the renal function as much as
possible. Otherwise, the CKD4 might progress to kidney failure. This must obviously be
prevented. At the moment, the patient uses hydrochlorothiazide in order to counter the
hypertension. Judging from the blood pressure of the patient, this will probably not suffice in
lowering the blood pressure towards normal values. The treatment of hypertension and
controlling it is the most important concern in this case, since there is no treatment for
chronic kidney failure. There is a narrow relationship between hypertension, CKD and
potassium. As mentioned before, a potassium-restricted diet is the current treatment of
choice for patients with impaired renal function. However, to correct hypertension and
increase the mortality of the comorbid patient, the doctor should implement a diet with
standard potassium intake in the patient’s treatment, with a normal to high serum potassium
as a result.
To elucidate this statement, a number of publications will be discussed. First of all, a
research called: ‘Effect of increased potassium intake on cardiovascular risk factors and
disease: systematic review and meta-analyses’. As the name suggests, this is a systematic
meta analysis to fill in the gaps regarding potassium intake and the consequences on one’s
health. In totality, 22 RCT’s, consisting of 1606 participants, and eleven cohort studies,
consisting of 127,038 participants, were analysed. This big aggregation of studies suggests
that a high potassium intake lowers the blood pressure in people with hypertension. Thereby
causing no negative effects on blood lipid concentrations, catecholamine concentrations and
renal function in adults (1). On top of this, another study called ‘The importance of potassium
in managing hypertension’ further supports this claim. This meta-analysis of many more
observational studies, clinical trials and meta analyses suggests that a high potassium intake
reduces blood pressure in a dose-dependent manner (2). When applying a potassium-
restricted diet these positive effects on blood pressure, induced by potassium, could be
missed. Besides, the reduction of potassium might even increase the blood pressure, which
is extremely undesirable since the patient already suffers from hypertension. Keeping in
