ATLANTA – Patients with systemic sclerosis aged 44 years and younger in the United States now have mortality comparable to that of the general population in that age group, according to recent results presented at the annual meeting of the American College of Rheumatology.
Dr. Ram R. Singh
“Mortality for scleroderma has steadily decreased in younger ages for the last 5 decades,” Ram R. Singh, MD, professor of medicine, pathology, and laboratory medicine at the University of California, Los Angeles, said in his presentation.
Using the Centers for Disease Control and Prevention’s National Vital Statistics System database, Dr. Singh and colleagues analyzed data of adults with systemic sclerosis (SSc) and identified 46,798 adults who died between 1968 and 2015. They divided the adults with and without SSc into three different age groups: 44 and younger, 45-64, and 65 and older. The researchers performed a joinpoint trend analysis, calculating the annual percent change (APC) and average APC as well as the age-standardized mortality rate (ASMR) in each age group.
In 1968, 466 deaths were attributed to SSc, compared with 1,195 deaths in 2015. Between 1968 and 2015, there was a 19% cumulative percentage increase in SSc-related deaths, compared with a 44% decrease in mortality not attributed to SSc; when the researchers analyzed the ratio of SSc-related ASMR to non-SSc-related ASMR, there was an increase of 112%, Dr. Singh said.
When analyzing the mortality of adults with SSc by age group during 1968-2015 using the CDC’s database, Dr. Singh and colleagues found 5,457 deaths in adults 44 and younger (11.7%), 18,395 deaths in adults aged 45-64 (39.3%), and 22,946 deaths in adults aged 65 and older (49.0%), compared with totals for the general population of 10.3 million deaths in adults aged 44 and younger (9.7%), 20.8 million deaths in adults 45-64 years (19.6%), and 74.8 million deaths in adults aged 65 and older (70.6%).
Over the 48-year period, there were three major trends in SSc-related ASMR, Dr. Singh noted. In the first trend period between 1968 and 1988, there was a 1.0% increase per year (95% confidence interval, 0.6%-1.4%). The second trend period, lasting until 2000, saw a 2.2% increase per year (95% CI, 1.6%-2.7%), while the SSc-related ASMR declined by 2.6% per year in the third trend period from 2001 to 2015 (95% CI, –3.1% to –2.2%).
The percentage of annual deaths for adults with SSc decreased between 1968 and 2015, from 23.4% to 5.7%, and the average APC was greater among adults aged 44 and younger with SSc (–2.2%; 95% CI, –2.4% to –2.0%) than for adults without SSc in the same age group (–1.5%; 95% CI, –1.9% to –1.1%).
There was a cumulative 60% decrease in the ASMR of adults with SSc aged 44 and younger between 1968 and 2015 from an ASMR of 1.0 per million (95% CI, 0.8%-1.2%) to an ASMR of 0.4 per million (0.3-0.5). Adults aged 45-64 years with SSc had a cumulative 20.3% decrease in ASMR over the same time period, with an ASMR of 5.9 per million in 1968 (95% CI, 5.2-6.7) and an ASMR of 4.7 per million in 2015 (95% CI, 4.2-5.2). However, adults aged 65 and older with SSc had a 187% cumulative increase in ASMR, with an ASMR of 5.4 per million in 1968 (95% CI, 4.4-6.5) and an ASMR of 15.5 per million in 2015 (95% CI, 14.3-16.6). Adults with non-SSc-related deaths between 1968 and 2015 had a 50.0% cumulative decrease in ASMR in the group aged 44 and under, a 48.0% cumulative decrease in the 45-year to 64-year-old group, and a 42.1% decrease in the 65-year-old or older group.
The ratio of SSc to non-SSc ASMRs between 1968 and 2015 in the group aged 44 and younger declined 20.0%, whereas there was a 53.1% cumulative increase in the 45- to 64-year-old group and a 395.4% cumulative increase in the 65-year-old and older group. In the oldest group, the APC increased by 3.9% each year for 33 years (95% CI, 3.7%-4.1%) before declining by 1.6% until 2015 (95% CI, –2.0 to –1.3). In contrast, the APC for adults 44 and younger never significantly increased over the 48 years, Dr. Singh noted.
“Increasing scleroderma mortality in older age could be due to improving survival and/or increasing age of onset of scleroderma,” he said.
Dr. Singh reported no conflicts of interest.
SOURCE: Yen E et al. Arthritis Rheumatol. 2019;71(suppl 10), Abstract 825.