TEST YOUR KNOWLEDGE
A MAN WITH DYSLIPIDEMIA: TO TREAT OR NOT TO TREAT?
Ong Hean Teik FACC FRCP(Glas, Edin), HT Ong Heart Clinic
Ong HT. Test your knowledge. A man with dyslipidemia: to treat or not to treat? Malaysian Family Physician. 2006;1(1):40-41
Mr R is a 43 year-old Indian man. He has hypertension for the past one year, and was started on an angiotensin II receptor blocker recently (his latest BP is 130/80 mm Hg). He is a non-smoker and is not known to have diabetes. His BMI is 25.4 kg/m2. His latest fasting glucose is 5.1 mmol/L. Mr R. does not consume alcohol and does not exercise regularly. His father died of a heart attack at the age of 55. His grandfather had hypertension and diabetes. His fasting lipid results are as follow:
| Normal Range | Desirable Level | ||
| Total cholesterol | 3.7 mmol/L | 3.0-6.4 | <5.2 |
| HDL-cholesterol | 0.41 mmol/L | 0.90-1.55 | >1.0 |
| LDL-cholesterol | 1.90 mmol/L | 2.3-4.4 | <3.4 |
| Triglyceride | 3.03 mmol/L | 0.70-1.55 | <2.3 |
| TC/HDL-C (risk) | 9.0 | 3.0-5.9 | |
Question: Does he need antilipidemic agent? If so, what is the drug of choice?
The principle
The main point to remember in the management of dyslipidemia is that lipid
abnormalities by itself is not a clinical disease. It produces no symptoms
and has no immediate morbidity and mortality. However, dyslipidemia is
a risk factor that over time increases the likelihood of clinical atheromatous
disease. In considering whether to pharmacologically treat the patient
with dyslipidemia, the actual likelihood of cardiovascular disease development
must be quantified, taking into account dyslipidemia and other risk factors
for clinical disease.1
The guidelines
The NCEP guidelines [Link] on management of dyslipidemias, updated in
2004, give clear instructions on what to do in the face of the presenting
patient.2 As shown in Table 2 of the guidelines, our patient, Mr R, has
3 major risk factors for coronary disease, namely hypertension, low HDL
cholesterol and a family history of coronary disease. Next, the 10-year
absolute risk of developing coronary disease must be calculated, and the
Framingham point scores are a simple way to do this, with the charts being
reproduced in the appendix of the NCEP guidelines of 2001. Points are
given for age, total cholesterol levels, smoking status, HDL levels and
systolic blood pressure.
The importance of HDL can be seen that it is used twice in the NCEP guidelines, once as a major risk factor, and again in the calculation of absolute 10-year risk of disease development. Note also that triglycerides are not involved in these calculations. Mr R has a Framingham score of 4 and so his absolute 10-year coronary risk is only 1%. Patients with 2 or more major coronary risks, and an absolute 10-year risk of <10% should have an LDL cholesterol of less than 3.3 mmol/l. Since his LDL is only 1.9 mmol/l, no antilipidemic treatment is required for Mr R.
Additional discussion
It used to be argued that patients with low HDL and high triglycerides
may benefit more from the fibrates. However, a recent review of different
anti-hyperlipidemic agents involving 97 trials recruiting over 250,000
patients showed that only the statins and n-3 fatty acids have been shown
to reduce the incidence of overall and cardiovascular mortality.3 This
is further supported by a report in the Lancet of a 5-year trial on 9795
diabetic patients.4 The primary outcome of coronary events was similar
in the placebo and fibrate groups, with both total and cardiovascular
mortality being non-significantly higher in the fenofibrate treated patients.
The objective of treatment should not be to improve the lipid profile
per se but to reduce cardiovascular morbidity and mortality, and the large
numbers studied in the trials means that we can confidently say that the
statins do reduce cardiovascular events and mortality when used in the
appropriately high risk patients.
Patients similar to Mr R have in fact been studied in the AFCAPAS/TEXCAPS trial. Lovastatin, at 20mg to 40mg a day, when used in over 6,000 patients with low HDL-cholesterol was found to produce a highly significant reduction in incidence of first coronary event after a mean follow-up of 5.2 years.5 However, there was no difference in the overall mortality between the treated and placebo group, as these patients are not at high risk of developing coronary deaths. Thus it is useful to provide this bit of data to Mr R, that we can reduce his incidence of cardiac disease, but the cost and inconvenience of therapy will not actually prolong his live, since overall, his risk of dying of heart disease is not high.
Low HDL-cholesterol levels may occur secondarily to physical inactivity, very high carbohydrate intake, obesity and certain drugs such as beta-blockers. Mr R is not a smoker or diabetic, the other common causes of low HDL levels. It may be important to encourage Mr R to lose weight and increase physical activity, as well as to consider using a more lipid neutral antihypertensive agent. There is increasing evidence that exercise and physical activity do reduce clinical cardiovascular disease.
REFERENCES
- Ong HT. The statin studies: from targeting hypercholesterolemia to
targeting the high-risk patient. QJM. 2005 Aug;98(8):599-614 [PubMed]
- Grundy SM, Cleeman JI, Merz CNB, et al, for the Coordinating Committee
of the National Cholesterol Education Program. Implications of recent
clinical trials for the National Cholesterol education Program Adult
Treatment Panel III Guidelines. Circulation. 2004 Jul 13;110(2):227-39 [PubMed] [Full text]
- Studer M, Briel M, Leimenstoll B, Glass TR, Bucher HC. Effect of different
antilipidemic agents and diets on mortality. A systematic review. Arch
Intern Med. 2005 Apr 11;165(7):725-30 [PubMed]
- Keech A, Simes RJ, Barter P, for the FIELD study investigators. Effects
of long-term fenofibrate therapy on cardiovascular events in 9795 people
with type 2 diabetes mellitus (the FIELD study): randomised controlled
trial. Lancet. 2005 Nov 26;366(9500):1849-61 [PubMed]
- Downs JR, Clearfield M, Weis S, et al. Primary prevention of acute coronary events with lovastatin in men and women with average cholesterol levels: results of AFCAPS/TexCAPS. Air Force/Texas Coronary Atherosclerosis Prevention Study. JAMA. 1998 May 27;279(20):1615-22 [PubMed]