Medical Absenteeism and Premature Death in Spinal Muscular Atrophy in Sweden: A Population-Based Matched Register Study of People of Working Age

Spinal muscular atrophy (SMA) is a rare, progressive, neuromuscular disorder that leads to loss of motor and respiratory function, affecting the individual’s ability to work and life expectancy. The magnitude of productivity losses due to medical absenteeism and premature death associated with SMA is unknown. We estimated the productivity losses attributable to SMA in a working age population compared with the general working age population in Sweden. This was a population-based, 1:4 matched cohort study of patients with SMA aged ≥ 18 years identified in the Swedish National Patient Registry from 2007 to 2019. Amongst those of working age (18–65 years), morbidity-induced productivity losses compared with a matched-reference cohort were estimated as the difference in the number of workdays lost attributable to SMA, monetised using mean income. Mortality-induced productivity losses were estimated as foregone lifetime earnings due to premature deaths for individuals with SMA compared with matched references, after adjusting for sex, age, and background unemployment. Overall, 172 adult patients with SMA were identified. Amongst those of working age, their average annual medical absenteeism was 100 days (95% confidence interval 61.5–138.1) higher than that of their references, leading to morbidity-induced productivity losses of €31,638 per patient per year alive whilst of productive age, of which €25,650 was directly attributable to SMA. Average mortality-induced productivity losses due to premature death were €108,253 for men and €87,160 for women with SMA. Productivity losses due to medical absenteeism and premature mortality place a significant burden on adult patients with SMA of working age and Swedish society.