LETTER
Total Cholesterol and Death from Coronary Heart Disease in Older Persons
Charles M. Grossman, MD
1 February 1998 | Volume 128 Issue 3 | Page 242
TO THE EDITOR:
There are several problems with Corti and colleagues' attempt to correlate death from coronary heart disease and cholesterol levels in older persons [1]. First, calculations from crude mortality rates, requiring adjustments to achieve results that are the opposite of the raw data, can hardly be called observational evidence (as is done twice in the Discussion section). Second, statistical significance occurs only when the 44 deaths that occurred in the first year were excluded from the analysis. The authors collected these data in accordance with their own experimental design. The authors then argue that persons in the last year of life may have had several terminal illnesses. This argument applies to persons who died in the other 4 years of the study.
Third, the final paragraph contains misstatements of fact. Shepherd and colleagues (the West of Scotland study) [2] did not find a significant decrease in the rate of death from coronary heart disease in their pravastatin group. Neither did Sacks and associates in the CARE (Cholesterol and Recurrent Events) study [3]. The Scandinavian Simvastatin Survival Study (4S) did report a significant decrease in coronary heart disease mortality [4], but criticism of that report has been published [5]. To quote the 4S study as saying that it showed the efficacy of cholesterol-lowering treatment in the "secondary prevention of death from coronary heart disease among men and women" fails to point out that equal numbers of deaths occurred in women receiving simvastatin and those receiving placebo.
Corti and colleagues recognize the weaknesses of a single cholesterol measure and of information obtained from death certificates. The latter include a line for comorbid conditions: Did the authors determine whether such conditions were listed for the 44 deaths excluded from the analysis and for the other 208 deaths?
When the authors adjust for serum iron and albumin levels and then exclude the 44 deaths that occurred in the first year, are they not adjusting twice for comorbid conditions? Is this acceptable?
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Author and Article Information
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Portland, OR 97205
1. Corti MC, Guralnik JM, Salive ME, Harris T, Ferrucci L, Glynn RJ, et al. Clarifying the direct relation between total cholesterol levels and death from coronary heart disease in older persons. Ann Intern Med. 1997; 126:753-60.
2. Shepherd J, Cobbe SM, Ford I, Isles CG, Lorimer AR, McFariane PW, et al. Prevention of coronary heart disease with pravastatin in men with hypercholesterolemia. West of Scotland Coronary Prevention Study. N Engl J Med. 1995; 333:1301-7.
3. Sacks FM, Pfeffer MA, Moye LA, Rouleau JL, Rutherford JD, Cole TG, et al. Effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med. 1996; 335:1001-9.
4. Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease. The Scandinavian Simvastatin Survival Study (4S). Lancet. 1994; 344:1383-9.
5. Grossman CM. Cholesterol reduction, heart disease, and mortality [Letter]. Ann Intern Med. 1997; 126:661.
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