Incidence of sick sinus syndrome projected to double within 50 years

The incidence of sick sinus syndrome in the United States is projected to double in the next 50 years, with increased risk specifically in older and white adults.

In a prospective cohort study, researchers evaluated 20,572 participants in the Atherosclerosis Risk in Communities (ARIC) study and the Cardiovascular Health Study (CHS). Participants from ARIC were from four US communities and were enrolled between 1987 and 1989. Participants from CHS were from four US communities and were enrolled between 1989 and 1993. At baseline, the participants’ mean age was 59 years, 44% were men, and all were black or white. Patients with evidence of sick sinus syndrome, atrial fibrillation, pacemaker use or heart rate <50 beats/min at baseline were excluded from the study.

Mean follow-up was 17 years, during which researchers monitored cases of sick sinus syndrome as indicated by hospitalization records.

During follow-up, 291 incident cases of sick sinus syndrome occurred (246 cases in white participants, 45 in black participants). Unadjusted incidence rates of sick sinus syndrome were 0.8 per 1,000 person-years overall (0.9 per 1,000 person-years in white patients, 0.7 per 1,000 person-years in black patients). The age-and race-standardized rate of sick sinus syndrome was 0.8 per 1,000 person-years in women and 0.9 per 1,000 person-years in men.

After adjustment for confounders, researchers observed associations between incident sick sinus syndrome and higher baseline BMI, greater height, N-terminal pro-B-type natriuretic peptide and cystatin C. Incident sick sinus syndrome was also associated with longer QRS interval, lower heart rate, hypertension, right bundle branch block and CVD. Older individuals were at increased risk for sick sinus syndrome (HR=1.73; 95% CI, 1.47-2.05 per 5-year increment), while risk was 41% lower among black participants vs. white participants (HR=0.59; 95% CI, 0.37-0.98). The researchers observed no significant difference in sick sinus syndrome risk based on sex (HR=1.25; 95% CI, 0.73-2.5 for men vs. women).

According to calculations incorporating age-specific sick sinus syndrome rates from the two cohorts and population projections from the US Census Bureau, the number of new cases sick sinus syndrome is projected to increase from an estimated 78,000 in 2012 to 172,000 in 2060, according to the researchers.

“With the aging of the population, the number of Americans with [sick sinus syndrome] will increase dramatically over the next 50 years,” the researchers concluded. They noted, however, that these findings are exploratory in nature. “… Further study is needed to confirm these findings and to further explore the difference in incidence by race.”

Source: www.healio.com