Hypertension and kidney disease

Hypertension is a serious condition where the blood pressure is persistently higher than normal. If left untreated, people with hypertension are at risk for heart attack, stroke or Kidney failure. Hypertension often causes no symptoms even if severe. It is also known as silent killer. The only way to determine whether you have high blood pressure or not is consistent monitoring of your blood pressure. In Pakistan only 3% of hypertensive population seems to have effective blood pressure control.
WHAT IS HYPERTENSION?
According to most recent JNC-7 hypertension guidelines: Normal blood pressure is less than 120/80 mmHg.
The risk of heart disease begins at 115/75. For example, in individuals aged 40-70 years, each 20/10 mmHg increase in blood pressure doubles the risk of cardiovascular disease, including heart attack, stroke or kidney disease. Being a diabetic, the risk of all of these complications is even higher.
-- High Risk Population for Hypertension;
-- People with family history of Hypertension;
-- Men over the age of 55;
-- Women over the age of 65/Post menopausal women;
-- Women who take birth control pills;
-- Overweight people;
-- People with high cholesterol and /or diabetes;
Chronic kidney disease (CKD) is one of the world's major public health problems, and the prevalence of kidney failure is rising steadily. CKD is defined in the Seventh report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure [1] as either (1) and estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 or (2) the presence of clinical proteinuria (>300 mg/d or 200 mg/g creatinine).
The prevalence of HTN continues to increase due to a combination of unhealthy diet, obesity, diabetes mellitus, and sedentary lifestyle. Over the past several decades, it has become clear that HTN is a cause and a consequence of kidney disease.
HOW DO WE RECOGNIZE CKD?
There are two ways to detect this disease.
1. Measure for proteinuria (macroalbuminuria), which can be detected on initial urinalysis. Patients with hypertension should have a routine urinalysis. Increased urinary protein excretion is usually a marker of kidney damage and a predictor of disease progression.
Testing for microalbuminuria is optional if no protein is detected on the initial dipstick, except for patients with diabetes where this should be a routine procedure. Micoralbuminuria (>30 mg/d and <300 mg/d) is a risk factor for progressive kidney disease and a strong risk factor for cardiovascular (CV) disease, even in nondiabetic and nonhypertensive individuals.
2. Determine the glomerular filtration rate (GFR). This step remains the most sensitive and specific means of assessing renal function in health and disease. While the GFR is most accurately determined by measurement of inulin clearance, this test is rarely done today because of its inherent complexity and cost.
Serum creatinine concentration is often used as a means of estimating GFR and the presence of CKD (define as a serum creatinine of >1.5 mg/dL in men or >1.3 mg/dL in women).[1] Creatinine is, however, affected by many factors such as muscle mass, diet, and the use of certain medications that can lead to errors in the assessment of rnal function.[9] Kindney disease is often present in people with normal serum creatinine levels.
The Modification of Diet in Renal Disease (MDRD)[9] equation is an accurate estimate of GFR. While the MDRD equation tends to underestimate GFR in people with near normal renal function, it is now considered to be the gold standard in early as well as late manifestations of impaired kidney function.
CKD AS A CORONARY RISK EQUIVALENT: The burden of CV disease among patients with CKD is substantial. As noted, CV disease remains the most common cause of death in individuals with CKD, and CKD remains an independent risk factor for CV disease. Individuals with stage 3 CKD (eGFR <60 cc/min) have a 16% increase in CV disease mortality while those with stage 4 or 5 CKD (eGFR<30 cc/min) have a 30% increase.
The increased risk of CV disease with CKD is partly the result of some of the same risk factors for CV disease seen in the general population. Although risk factors such as age, hypertension, hyperlipidemia, diabetes, and physical inactivity are found in patients with CKD, these risk factors are compounded by additional factors, such as proteinuria.
SELF MONITORING: Vital for Controlling Blood Pressure
Taking your blood pressure measurements regularly allows you and your doctor to gauge how well you're controlling your hypertension, and is essential for any hypertension treatment program. Due to the lack of visible hypertension symptoms, blood pressure measurements are the only way to determine how well you are responding to treatment.
HYPERTENSION IN ELDERLY: There are special concerns regarding BP measurement in the elderly. Systolic BP is often quite variable, and the phenomenon of white-coat hypertension may be common in the elderly, especially in older women. Orthostatic hypotension and postprandial hypotension are more common in the elderly, in most cases because of dysautonomia of aging.
Modification of adverse lifestyle factors is beneficial in the elderly and should be encouraged.[75] Salt sensitivity increases with age and with the reduction in renal function that is common in the elderly.[76] In patients who require drugs, lower initial doses should be considered, especially in the presence of orthostatism or comorbid vascular diseases.
Diabetic Patients. Patients who have both hypertension and diabetes have twice the risk of CV disease as nondiabetic hypertensive patients. In addition, hypertension increases the risk of diabetic retinopathy and nephropathy. All patients with diabetes should be encouraged to adopt lifestyle modifications.
Weight loss (if the patient is overweight or obese) and moderate exercise are especially beneficial in diabetic patients because in addition to lowering BP, these interventions improve insulin sensitivity and blood lipid levels. Many patients will require lifestyle modifications and three or more drugs to achieve the BP goals.
Numerous studies have shown the effectiveness of ACE inhibitors and ARBs in retarding progression of diabetic nephropathy. [84, 85]. For diabetic patients with nephropathy, the American Diabetes Association guidelines recommend ACE inhibitors as initial drugs of choice in type 1 diabetes but ARBs in type 2 diabetesquire lifestyle modifications and three or more drugs to achieve the BP goals. For asymptomatic patients with known coronary artery disease, an ACE inhibitor should be considered initially.
An ACE inhibitor would also be the initial drug of choice for patients with concomitant reduced systolic function or concomitant diabetes with renal involvement. [81,84,90] If there is a history of myocardial infarction, the first drug should be a beta blocker.
For hypertensive patients with previous myocardial infarction and reduced left ventricular function, combination therapy with a beta blocker and a ACE inhibitor should be considered.[92] In addition, the aldosterone antagonist eplerenone has been shown to be effective.
Patients with Heart Disease. Ischemic heart disease is the most common cause of death in patients with hypertension. Poorly controlled hypertension also results in the development of LVH. Both LVH and ischemic injury lead to the development of heart failure from either systolic or diastolic dysfunction.
CONCLUSION:
1. The early detection of CKD in patients with hypertension is the sine qua non for an early multi-pronged intervention. Patients with CKD are more likely to die of CV disease than to develop ESRD. Physicians continue to miss opportunities to recognise the early stages of CKD and to intervene to reduce other CV risk factors. By reporting eGFR, especially in people with hypertension, these individuals will be identified. Early, aggressive, and effective control of BP to a level<130/80 mm Hg substantially slows the progression of kidney failure.
2. In conclusion, management and control of BP is fundamental to and essential for decreasing cardiovascular disease and renal morbidity. The agent of choice depends on the degree of pre-existing cardiovascular and renal morbidity. The benefit of calcium channel blockers and beta-blockers is BP reduction; ACEIs and ARBs offer more effective protection against cardiovascular morbidity and mortality in patients with pre-existing cardiovascular and renal diseases.