Interactive Effects of Fitness and Statin Treatment on Mortality Risk in Veterans With Dyslipidaemia: A Cohort Study
What are the combined effects of fitness and statin treatment on all-cause mortality in individuals with dyslipidemia?
In this prospective cohort study, the investigators included dyslipidemic veterans from Veterans Affairs Medical Centers in Palo Alto, CA, and Washington, DC, who had an exercise tolerance test between 1986 and 2011. They assigned participants to one of four fitness categories based on peak metabolic equivalents (MET) achieved during exercise test, and eight categories based on fitness status and statin treatment. The primary endpoint was all-cause mortality adjusted for age, body mass index, ethnic origin, sex, history of cardiovascular disease, cardiovascular drugs, and cardiovascular risk factors. The authors assessed mortality from Veterans Affairs’ records on December 31, 2011, and compared groups with the Cox proportional hazard model.
The authors assessed 10,043 participants (mean age 58.8 years, standard deviation 10.9 years). During a median follow-up of 10.0 years (interquartile range 6.0-14.2), 2,318 patients died, with an average yearly mortality rate of 22 deaths per 1,000 person-years. Mortality risk was 18.5% (935/5,046) in people taking statins versus 27.7% (1,386/4,997) in those not taking statins (p < 0.0001). In patients who took statins, mortality risk decreased as fitness increased; for highly fit individuals (>9 MET; n = 694), the hazard ratio (HR) was 0.30 (95% confidence interval [CI], 0.21-0.41; p < 0.0001) compared with least fit (≤5 MET) patients (HR, 1; n = 1,060). For those not treated with statins, the HR for least fit participants (n = 1,024) was 1.35 (95% CI, 1.17-1.54; p < 0.0001) and progressively decreased to 0.53 (95% CI, 0.44-0.65; p < 0.0001) for those in the highest fitness category (n = 1,498).
The authors concluded that statin treatment and increased fitness are independently associated with low mortality among dyslipidemic individuals.
This study supports the notion that both statin treatment and increased fitness lower mortality significantly and independently from other clinical characteristics. Regular exercise and improved fitness appear to be an attractive adjunct treatment to statins or possibly an alternative when statins cannot be prescribed. Furthermore, the low exercise capacity (roughly 7 MET) associated with the health benefits is clinically significant, and highlights the importance of physical activity for individuals with dyslipidemia. Overall, the study findings provide clinically relevant information with significant implications for public health.
Keywords: Exercise Tolerance, Washington, Incidence, Blood Coagulation, Cardiovascular Agents, Follow-Up Studies, Body Mass Index, Exercise, Cardiovascular Diseases, Risk Factors
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