Physical activity, CAC scores improve risk prediction in older patients
Incorporating a question about physical activity with coronary artery calcium scoring improved prediction of clinical and mortality risk in older patients, researchers reported.
“Our findings should incentivize physicians to incorporate self-reported physicial activity questionnaire data, which is so easy to collect, into their standard assessment of patient risk at the time of coronary artery calcium scanning,” Alan Rozanski, MD, professor of medicine (cardiology) at Icahn School of Medicine at Mount Sinai and director of nuclear cardiology and cardiac stress testing and chief academic officer for the department of cardiology at Mount Sinai Morningside, told Healio. “There is also an implied suggestion from our work that older adults with significant atherosclerosis might benefit from exercise training, as is seen with cardiac rehabilitation patients. However, this would require prospective demonstration.”
CAC scanning in older patients
In a study published in Mayo Clinic Proceedings: Innovations, Quality and Outcomes, researchers analyzed data from 2,318 patients (mean age, 70 years; 55% men) aged 65 to 84 years who were free from known CAD and were referred for CAC scanning between Aug. 31, 1998, and Nov. 16, 2016.
At the time of CAC testing, patients completed a questionnaire focused on demographic and clinical information. It also focused on cardiac risk factors, chest pain symptoms medication use and physical activity, which was assessed with one question on frequency. Patients were then categorized by physical activity: low (n = 402; mean age, 71 years; 47% men), moderate (n = 1,365; mean age, 71 years; 55% men) and high (n = 551; mean age, 70 years; 64% men).
Follow-up was conducted for a mean of 10.6 years to assess for all-cause mortality. During follow-up, 23% of patients died, with an annualized mortality rate of 2.3% per year. Patients with the highest mortality rate reported low physical activity (2.9% per year), whereas those with the lowest mortality rate reported high physical activity (1.7% per year; P < .001).
The HR for all-cause mortality increased with decreased physical activity and an increased CAC score after adjusting for age, patient and CAD risk factors. Combing CAC scores and physical activity level resulted in similar multivariable-adjusted HRs for mortality, particularly in those with CAC scores between 0 and 99. This progressively increased by 2.07-fold in patients with scores between 100 and 399 and low physical activity levels compared with those with high physical activity levels. The HR also increased by 2.35-fold in patients with CAC scores of 400 or greater and low physical activity vs. high physical activity.
Patients with high physical activity and a CAC score of 400 or greater had a similar mortality rate per 1,000 person-years to the rate in patients with low physical activity and a CAC score between 0 and 99 (19.9 per 1,000 person-years vs. 16.3 per 1,000 person-years; P = .6).
The strongest predictor of mortality was age, then CAC score. The next potent predictor of all-cause mortality was patient-reported physical activity level out of the other clinical variables.
“Being a single-centered study, further studies are indicated to assess the generalizability of our findings,” Rozanski said in an interview. “Moreover, we used a single-item exercise questionnaire which simply asked patients to report their subjective assessment of physical activity volume, ranging from none to very high. However, there are other questionnaires which assess intensity, duration and even type of exercise activity, and potentially these might combine even better with CAC scores to predict patient risk. There is a need for prospective study to determine the right balance between simplicity and comprehensiveness in applying physical activity questionnaires in clinical practice.”
For more information:
Alan Rozanski, MD, can be reached at email@example.com.