Browsing by Author "Blom, D J"

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    Cardiovascular risk assessment
    (South African Academy of Family Physicians, 2011) Blom, D J
    Cardiovascular disease remains the leading cause of mortality in the Westernised world. Lifestyle changes and drug therapy can reduce cardiovascular risk. Many interventions such as lipid-lowering therapy reduce relative risk to the same extent irrespective of baseline risk, but the absolute benefit is still highest in those with the highest absolute risk. Cardiovascular risk assessment is a tool to determine absolute cardiovascular risk in asymptomatic patients and to select those most likely to benefit from intervention. Conventional risk assessment (Framingham) requires age, gender, blood pressure, smoking status, total cholesterol and high-density lipoprotein cholesterol (HDLC) to determine risk. This is usually expressed as the 10-year risk of coronary heart disease. The accuracy and predictive ability of conventional risk assessment have limitations. Many biomarkers, genetic tests and vascular imaging procedures correlate statistically with vascular risk. Adding these tests to conventional risk assessment (expanded risk assessment) may therefore improve our ability to predict risk. It has, however, been difficult to conclusively demonstrate that expanded risk assessment outperforms conventional risk assessment. Many tests and procedures require further validation before they become part of routine clinical practice. Additional testing may be useful in patients with intermediate risk or where risk is difficult to determine for other reasons.
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    Familial hypercholesterolaemia
    (South African Academy of Family Physicians, 2011) Blom, D J
    amilial hypercholesterolaemia (FH) is a monogenic disorder of low-density lipoprotein (LDL) metabolism. It is characterised by markedly elevated LDL cholesterol, autosomal dominant inheritance, premature cardiovascular disease and tendon xanthomata. FH is a genetically heterogeneous disorder, but the most common underlying molecular cause is mutation of the LDL receptor gene. The worldwide prevalence of FH is 1:500. South Africa has three founder populations in which the prevalence of FH may be as high as 1:70. FH is diagnosed clinically, but the diagnosis can be confirmed by DNA analysis. DNA testing cannot always identify the causative mutation because there are several genes to examine and more than 1 500 different mutations have been identified in the LDL receptor alone. Statins are the treatment of choice for patients with FH. Ezetimibe or cholestyramine can be added if additional LDL lowering is required, or if patients are unable to tolerate high statin doses.
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    Statin therapy for the octogenarian?
    (2012) Blom, D J
    Cardiovascular risk increases progressively with age. Statins in octogenarians may therefore potentially bring about large reductions in absolute risk. Epidemiological studies, however, show that statin prescription declines with age and is lowest in the oldest patients with the highest cardiovascular risk. Reasons for low statin utilisation in the elderly include safety concerns, doubts about the utility of statin therapy in those of advanced age and a paucity of definite trial evidence supporting statin prescription in octogenarians. Some of the more recently completed statin outcome trials have randomised patients as old as 82 years. A meta-analysis of secondary prevention, with patients aged 65–82 years at randomisation, supported statin prescription in this age group, as statin therapy was associated with relative risk reduction similar to that observed in younger patients. A Swedish registry study showed improved survival in octogenarians prescribed a statin following hospitalisation with an acute myocardial infarction. Currently there is no definite evidence that statin therapy prevents or ameliorates cognitive impairment or dementia. Statin therapy should be considered in octogenarians at high cardiovascular risk, taking into account factors such as biological vs. chronological age, life expectancy, quality of life, risk of interaction with medications taken for co-morbidities and the ability of the patient to take the statin safely.
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    Statins: Adherence and side-effects
    (South African Academy of Family Physicians, 2011) Blom, D J
    Many patients either do not adhere to, or fail to persist with, long-term lipid-lowering therapy. This unfavourable medication utilisation behaviour compromises potential treatment benefit. In retrospective studies, patients aged 50-65 had the highest adherence rates, while both younger and older patients had lower rates. Patients with pre-existing cardiovascular disease adhere better than those in primary prevention. Financial barriers may impair adherence. At the individual patient level, health beliefs, perceptions of own cardiovascular risk and need for medication, concerns about side-effects and inconvenience of treatment may influence adherence. In clinical trials, regular reminders to patients have been shown to improve adherence, but each patient will require an individually tailored treatment strategy. Myopathy is the most common clinically relevant adverse effect of statins. The clinical severity of statin myopathy is highly variable, ranging from mild muscle ache to rare instances of rhabdomyolysis. Risk factors for statin myopathy include age, statin dose, hypothyroidism, medications that inhibit statin metabolism, combined statin and fibrate therapy, and renal impairment. Alternative causes of myopathy should be excluded before muscular symptoms are ascribed to statins. The management of statin myopathy is guided by the severity of symptoms and the creatine kinase level. Potential management strategies include statin dechallenge and rechallenge, statin dose reduction, statin switching, non-daily dosing and use of alternative lipid-lowering agents, such as ezetimibe. Statins rarely cause severe liver disease. Mild liver enzyme elevations are seen relatively frequently in patients starting statins, but are usually not clinically important. Patients with persistently elevated liver enzymes should be investigated to determine the cause of liver disease. Patients with stable, well-compensated liver disease can be prescribed statins, provided they are closely monitored.