Systemic sclerosis mortality trends in Spain from 1980 to 2019: age-period-cohort and joinpoint analysis

Systemic sclerosis (SSc) is an autoimmune chronic rheumatic disease with a high mortality rate, which continues to be a challenge for clinicians today.

To assess changes in mortality trends in the Spanish SSc population between 1980 and 2019, taking into account the independent effects of sex, age, time period and birth cohort.

SSc death records and mid-year population data were collected from the National Statistics Institute. Age-standardized mortality rates were calculated for the overall population and for each sex (male, female) and age group (5-year groups). Significant changes in mortality trends were identified by joinpoint regressions. An age-period-cohort (APC) analysis and potential years of life lost (PYLL) analysis were performed to identify the burden of SSc.

Age-standardized mortality rates due to SSc increased from 1.87 (95% CI 1.00-3.02) per 1 000 000 inhabitants between 1980 and 1984, to 2.47 (95% CI 1.74-3.02) per 1 000 000 inhabitants between 2015 and 2019. The relative risk of mortality fell in all groups in cohorts born after 1990. The PYLL rates showed a gradual rise for both sexes.

There was an increase in overall SSc mortality in Spain during the 39 years evaluated, although there was a progressive drop for men.