The requirement to respect autonomy - The Royal New Zealand ...

BACK TO BACKFigure 1. Effect of statin treatment: primary prevention 2Figure 2. Primary and secondary outcomes in the PROSPER trial. 2Figure 3. Overall outcomes in the PROSPER trial. 3benefit using the primary composite endpoint ofcoronary heart disease death or non-fatal myocardialinfarction (absolute risk reduction 2.1%,numbers needed to treat 48). This is shown inFigure 2. 2This looks more promising in terms of effectiveness.However, it is helpful to consider these datain the context of the patients we see in generalpractice—overall mortality and morbidity. Despitea change in these cardiovascular compositeoutcomes, there is no change in all-cause mortality:hazard ratio (HR) 0.97 (95% CI 0.83–1.14).In contrast, rates of cancer diagnosis and deathwere increased in the treatment group comparedwith placebo. 2 The HR for cancer death was 1.28(0.97–1.68) and the HR for cancer diagnosis 1.25(1.04–1.51), with an absolute risk increase of 1.7%and numbers needed to harm of 59 (Figure 3). Sooverall there was no change in time to point ofdeath or in morbidity. If the data from morbidityand mortality were combined in the same way asfor the CVD outcomes it is likely that this effectwould be more marked.The increase in new cancer diagnoses countersany arguments of compression of morbidity. Preventingone cause of death and morbidity simplyreveals another.The clinical contextIf a patient asks a medical practitioner for helpwith symptoms or disease from which they aresuffering, the doctor does the best they can and arenot responsible for defects in medical knowledge.There are extra ethical responsibilities around bothscreening for disease and subsequently giving preventivetreatments—whether it is colorectal canceror measuring cholesterol or blood pressure. If thepractitioner initiates procedures and treatments fora disease from which a patient is not suffering theyare in a very different situation and a much greaterlevel of certainty is required.tion occurs by conflating primary and secondaryprevention by including patients with establishedcardiovascular disease.This paper then combined data for primary andsecondary prevention, which showed a modestThe evidence for statins in this age group doesnot support this level of certainty. Enthusiasticextrapolation is not enough. The half-life of scientific‘truth’ is often short in medicine. The latterpoint is reinforced by the recent evidence onaspirin for primary prevention—it now appears334 VOLUME 2 • NUMBER 4 • DECEMBER 2010 J OURNAL OF PRIMARY HEALTH CARE