OBJECTIVES: The study aimed to quantify the productivity losses due to medical absenteeism and premature death of adult-SMA patients.

METHODS: This population-based matched-reference cohort study included adult-SMA patients aged 18-65 years, identified in the Swedish National Patient Registry (NPR) from 1-01-2007 to 31-12-2018, matched 1:4 to a reference cohort without a diagnosis of SMA on sex, age, and county of residence. The index date was 1 January 2007 for prevalent patients and their matches or the date of the first diagnosis for incident cases and their matches. NPR data was linked to MiDAS (Mikrodata för analys av socialförsäkringen) to identify medical absenteeism.

Morbidity induced productivity losses were estimated as the number of workdays lost attributable to SMA (difference in annual mean number between cohorts estimated using generalised estimating equations), monetized using national mean income. Mortality induced productivity losses were estimated as foregone lifetime earnings due to premature deaths in the SMA cohort compared to the reference cohort, after adjusting for age and sex specific background unemployment.

RESULTS: 172 adult-SMA patients were identified. At index, 67.6% SMA patients participated in the labor force, which was significantly lower than the reference cohort 86.5% (p<0.0001). Annual productivity losses due to medical absenteeism were 100 (95%CI: 61.5, 138.1) days higher for each adult-SMA patient than the reference. Morbidity induced productivity losses were on average SEK260,215.81 (€24,794.78) per-patient per-year, and foregone lifetime earnings due to premature mortality were on average SEK937,859.83 (€89,360.20) and SEK830,701.88 (€79,150.09) for men and women with SMA, respectively.

CONCLUSIONS: Productivity losses due to medical absenteeism and premature mortality due to SMA represents a significant burden on patients and Swedish society. Gains from improving the lives of these patients will not only be important for them but also for society as a whole.