The frequency of respiratory diagnoses was significantly higher for cases than for controls before the pandemic, a case-control study of all adults in Region Stockholm with a registered PASC diagnosis.

<bold>Background:</bold> Numerous surveys have been employed in studies to characterize the Post-Acute Sequelae of COVID-19 (PASC). However, there is insufficient information regarding primary care utilization and diagnoses both before and after the onset of PASC. Our aim was to examine the prevalence of pre-pandemic symptom diagnoses, with focus on respiratory codes, in patients who developed PASC compared to controls. <bold>Method:</bold> A case-control study was designed to investigate the prevalence of registered diagnoses related to respiratory health in PASC patients (cases), aged >18, non-hospitalized, compared to controls matched for age, gender, and socioeconomic area at a 1:10 ratio. Data was from Stockholm Region's data warehouse (VAL), covering all healthcare data. <bold>Objectives:</bold> We investigated the prevalence of recorded pre-pandemic diagnoses (2019) between individuals who later received a PASC diagnosis and their matched controls. <bold>Result:</bold> The results indicate that patients with PASC, to a greater extent than their controls, have sought healthcare and been diagnosed with respiratory diagnoses before the pandemic, with a minor gender difference (Table 1). Acute upper respiratory tract infection, ICD J069, showed the highest difference in OR for both men and women (OR 2.47 and 2.22, respectively CI: 99%). <bold>Conclusion:</bold> Patients diagnosed with PASC exhibited a higher prevalence of the symptom diagnoses examined in this case-control study compared to their controls prior to the initial COVID-19 infection. It is however unclear whether these diagnoses, or any comorbidities, are related to the onset of PASC.