Relative efficacy of angiotensin converting enzyme inhibitors on mortality of patients with congestive heart failure: implications of randomized trials and role of the aetiology (ischaemic or non-ischaemic) of heart failure

We examined the influence of angiotensin converting enzyme inhibitors (ACE inhibitors) on mortality in patients with heart failure of both ischaemic or non-ischaemic origin. Eleven, randomized, placebo-controlled trials of ACE inhibitors involving 1266 patients were selected. The follow-up period varied from 3 to 6 months. Four different ACE inhibitors were used in the 11 clinical trials. A total of 679 patients presented with an ischaemic heart failure and 587 with a non-ischaemic heart failure. Meta-analysis, performed for both subgroups, showed that mortality was significantly decreased in the ischaemic subgroup only (ischaemic group: odds ratio 0.45; 95% confidence interval 0.28 to 0.71; non-ischaemic subgroup: odds ratio 0.7; 95% confidence interval 0.4 to 1.5). Although the two odds ratio are not significantly different, further randomized, placebo-controlled trials with ACE inhibitors are required in order to determine more precisely the benefit/risk ratio in patients with non-ischaemic heart failure.

Quality of life assessment in therapeutic trials: rationale for and presentation of a more appropriate instrument

In therapeutic trials, quality of life studies are usually based on a health model which results in a restrictive view. Therefore, it is important to clearly define the concept of the quality of life, since ambiguous concepts can alter the results. The key to this problem is the clear distinction between the two components of the quality of life, ie subjective and objective. This latter component is the only one considered in the current medical approach. The use of the subjective quality of life introduces a number of methodological problems not found when the objective quality of life is assessed, and thus requires a specific model which can be derived from the model of life goals used by sociologists. This model is presented here and illustrated with some results obtained with a new questionnaire, the Subjective Quality of Life Profile (SQLP) questionnaire. We suggest that both subjective and objective quality of life studies should be considered in order to emphasize the humanistic approach to therapeutic indications.

Controlled low protein diets in chronic renal insufficiency: meta-analysis

OBJECTIVE

To determine whether low protein diets retard the development of end stage renal disease.

DESIGN

Meta-analysis of 46 trials since 1975, from which six randomised controlled trials were selected.

SETTING

Five trials in Europe and one in Australia between 1982 and 1991.

SUBJECTS

890 patients with mild to severe chronic renal failure who were followed up for at least one year. 450 patients received a low protein diet and 440 a control diet.

INTERVENTION

Difference in protein intake between control and treated groups of at least 0.2 g protein/kg/day.

MAIN OUTCOME MEASURE

Number of renal deaths (the necessity to start dialysis or death of patient during study).

RESULTS

156 renal deaths were recorded, 61 in the low protein diet group and 95 in the control group, leading to an odds ratio of low protein to control of 0.54 with a 95% confidence interval of 0.37 to 0.79.

CONCLUSIONS

This result, obtained on a large population of patients suffering from chronic renal insufficiency, strongly supports the effectiveness of low protein diets in delaying the onset of end stage renal disease.