Excess and reduced work absence during COVID-19 in Poland: insights from cause-specific time-series models.

Background: The COVID-19 pandemic profoundly disrupted workplace attendance, yet its impact on cause-specific work absence remains largely unexplored.

Aim: To estimate the cause-specific excess/reduced work absence associated with COVID-19 in Poland.

Methods: Following the concept of excess mortality, we define excess work absence as the difference between observed and expected absence, where the latter reflects the level anticipated in the absence of the pandemic. Using time-series analysis (Seasonal Autoregressive Integrated Moving Average) on pre-pandemic (2012-2019) quarterly (Q) social insurance data, we forecasted absence rates for disease groups (classified by ICD-10 chapters) and caregiving-related absenteeism. Forecasted absence rates were then compared to observed values during 2020-2024, allowing for the identification of excess or reduced work absence.

Results: We observed notable deviations in work absence rates during the pandemic period (until the end of Q1-2022). The highest excess absence was identified in caregiving-related absenteeism at the pandemic's onset, exceeding expected levels by over fivefold. A mental health crisis that began with the pandemic resulted in four consecutive quarters of excess absence, reaching a 54% excess in Q2-2020. We identified a notable excess absence in three ICD-10 chapters that reflect the indirect effects of the pandemic, such as increased diagnostic uncertainty, modified coding practices during early COVID-19 waves, and widespread implementation of public health interventions. Absence rates were lower than expected in neoplasms, endocrine and digestive diseases until the end of the pandemic period, likely reflecting reduced healthcare accessibility. Similarly, absence related to injuries and poisoning was below the expected level until mid-2022, indicating decreased social mobility.

Conclusions: COVID-19 substantially reshaped work absence patterns in Poland, particularly during the early pandemic phase. Pronounced increases and decreases were identified across disease categories. These diverging trends plausibly reflect both the COVID-19's effects on the development of other conditions and disruptions in healthcare access. These findings highlight the need for disease-specific policy responses to mitigate future health crises and ensure continuity of care during pandemics.