An estimation of deviation towards the mean for serum lipid fractions in patients followed for a varied duration.

We evaluated the deviation towards the mean and attempted to quantify it among the different lipid fractions in patients. The study was done retrospectively on patients who were judged to be metabolically stable and had repeated total cholesterol (TC), high density lipoprotein cholesterol (HDL) and triglyceride (TG) measured in a single laboratory with known coefficient of variation for repeated measurements. The patients and their data were separated into 3 groups. Group A (56 patients) evaluated the difference between the first and its average obtained from an average of 4 samples per patient within a mean of 9 months. Group B, examined pairs of data taken an average of 12 months apart. Group C, evaluated 45 patients with at least 3 data points each a year apart. Linear correlations were applied for the repeats versus the first samples. Highly significant correlations were obtained for all the groups. The slopes were less than one (generally between 0.66 and 0.85) and intercepts had positive values. This was seen even for the HDL whose range of values span 25 to 85 mg per cent. These results strongly supported deviation towards the mean such that from our calculation and in this population, a person with an initial TC of 200 mg per cent would have from 37 to 61 per cent chance of obtaining a significantly higher value if the test was repeated. The magnitude of the change would average 30 mg per cent for cholesterol and as much as 30 per cent of the initial values for TG. In this evaluation, the time intervals between repeats did not appear to influence the result. Yearly follow-up also did not seem to exhibit the effect of aging. However, the latter 2 conclusions rested on a small number of observations. It is suggested that several repeated estimations of these lipid fractions be done before a decision is made towards intervening. In instances of epidemiological studies, it is imperative to obtain representative repeated measurements since this deviation towards the mean will alter the slope of the events versus the lipid-variables.

Early response of hyperlipidemic subjects to simvastatin.

Seventy eight patients with hypercholesterolemia from 4 major hospitals were studied with regard to their responses to an adjustable dose of simvastatin, a HMG-CoA reductase inhibitor. They were followed for up to 6 months with 4 sample points during the drug and 2 prior to therapy. The average dose was 10.2 mg/day (S.D. 5.5). Four were controlled on 5 mg and 4 needed 30 mg per day. Thirty seven per cent had elevated serum transaminases but none to greater than twice normal. Only a third of these showed elevation of transaminases during drug therapy alone. The mean total cholesterol (TC) was 304 mg/100 ml and low density lipoprotein (LDL) was 221 mg/100 ml. These fell 70 and 60 per cent respectively and over 90 per cent of the patients reduced their TC and LDL more than the limits defined from previous long term monitoring of patients (i.e. TC fell by more than 17% and LDL by 25%). High density lipoprotein, HDL, started off at 45 mg/100 ml and rose to an average of 115 per cent. Triglyceride, TG, started off at 207 mg/100 ml and fell to about 86 per cent during simvastatin. However, in terms of the proportion of patients who responded greater than the limit previously determined (i.e. more than a 25% change for HDL and 45% for TG), only about 20 per cent significantly responded with elevation of HDL and 13 per cent dropped their TG. The response of TG was more marked at TG greater than 300 mg/100 ml.

Observation on the short and long term response to anti-lipemic drugs in southern Thailand.

Patients with dyslipidemia were evaluated with regard to the 5 drugs regimen: simvastatin (average dose, 11.8 mg/day), gemfibrozil (dose 963 mg/day), bezafibrate (433 mg/day), fenofibrate (211 mg/day) and acipimox (667 mg/day). The responses to the drug were divided into different time periods and the magnitude of responses were presented either as average changes in per cent from baseline or as proportion of patients (also in %) whose levels changed by a predetermined percentage. These predetermined percentage took into account the variation observed among patients who had more than 3 measurements during baseline. These levels for significant changes were 16 per cent for total cholesterol (TC), 25-30 per cent for high- and low-density lipoprotein (HDL and LDL), and 44 per cent for triglyceride (TG). Our subjects responded to the drugs within the range reported by other investigators except for acipimox which produced no alteration. Sixty to 100 per cent of patients reduced their TC by 16 per cent with an average change in TC of around -16 per cent to -24 per cent. Simvastatin and fenofibrate appeared most effective in altering TC. The HDL increased 10 per cent to 29 per cent depending on the drug but in terms of proportion that responded by an increment greater than 25 per cent, this was seen in only 23 per cent to 45 per cent of the patients. Long term follow-up which was possible only on 42 patients showed 11 who lessened their response and 6 whose response became more marked.(ABSTRACT TRUNCATED AT 250 WORDS)

In-hospital and follow-up mortality of patients with acute myocardial infarction.

Patients with definite acute MI who were admitted to Songkla University Hospital between 1982 and 1990 were studied. The 195 patients and 202 admissions were nearly equally distributed between these 65 and older versus those younger than 65. Three quarters were males. The in-hospital mortality was 19.5 per cent and 76.3 per cent of the deaths were from heart failure. Neither age nor gender determined the mortality once corrected for the Killip's staging. There was no difference in mortality when comparing Q versus non-Q MI, anterior versus inferior wall MI or males versus females. One hundred and thirty-eight patients could be followed for and average of 27.1 months. First year mortality was 11 per cent and the first 2 years was 14 per cent. The in-hospital mortality, representing the prethrombolytic era, appeared to be similar to values reported from the Thai and Western literature. The predominance of death from heart failure rather than from arrhythmia may be a consequence of delayed admission whence arrhythmic death had already occurred or patients will seek hospital advice only if highly symptomatic.

Trimetazidine and stable angina a double-blind trial.

The effect of trimetazidine was evaluated in patients with stable angina by adding it to the other antianginal regimen in a double blind crossover design each of 8 week's duration. The method of evaluation made use of symptom recall, daily dairy of the intake of sublingual nitrates or of anginal discomfort and in some, symptom limited treadmill exercise stress test (EST). Thirty-six patients completed the trial. Symptom-wise, 16 patients could not differentiate the effect of the true tablet from the placebo. Eight had less and 12 had more angina while on the drug. Of the 17 evaluable EST, 9 showed no change in the degree of ischemic changes while 4 performed with less and 4 with more ischemia while on the drug. Symptom-wise and taking into account the pre and post trial periods, a placebo effect was not found to be dominant. It is concluded that trimetazidine does not improve angina among those already being treated with conventional doses of nitrates, beta and calcium blockers.