Associations between diagnoses linked with adverse COVID-19-related outcomes and sickness absence due to COVID-19 or COVID-19 like diagnoses: a prospective Swedish cohort study of 292 274 blue-collar workers in the retail and wholesale industry

Several diagnoses have been associated with increased risk for adverse health outcomes following COVID-19 infection. Whether these diagnoses also predispose individuals to long-term sickness absence (SA) due to COVID-19 is unclear. The aim was to examine associations between risk diagnoses and long-term SA due to COVID-19/COVID-19-like diagnoses among blue-collar workers in the retail and wholesale industry. We conducted a two-year prospective cohort study of all blue-collar workers aged 18-67 in 2019, employed in retail and wholesale industry in Sweden (N = 292 274), using linked microdata from several nationwide registers. We estimated odds ratios (OR) through logistic regression models to determine the association between diagnoses linked with adverse health outcomes following COVID-19 infection and SA spells due to COVID-19/COVID-19-like diagnoses in 2020-2021. We included COVID-19-like diagnoses because of diagnostic uncertainty early in the pandemic. Of all the workers, 34 594 (11.8%) had least one COVID-19 risk diagnosis. Only 7812 (2.7%) workers had SA due to COVID-19/COVID-19-like diagnoses in the two-year follow-up (2020-2021). Most risk diagnoses were associated with elevated likelihoods of SA due to COVID-19, particularly immunodeficiency (OR 2.58; 95% CI 1.68-3.27) and respiratory disease (2.00; 1.89-2.12). The associations for these diagnoses and diabetes and hypertension persisted after we stratified by prior SA, but no other risk diagnosis was significantly associated with SA due to COVID-19/COVID-19-like diagnoses among those with prior SA in 2019. Stratifying on all-cause SA thus removed the association between most COVID-19 risk diagnoses and SA due to COVID-19/COVID-19-like diagnoses.