question: OBJECTIVE: To explore the self-reported impact of the COVID-19 pandemic on changes to care and behaviour in UK patients with systemic autoimmune rheumatic diseases, to help ensure that patient experiences are considered in future pandemic planning. METHODS: This was a longitudinal mixed methods study, with a cohort completing baseline surveys in March 2020 and follow-up surveys in June 2020 (N = 111), combined with thematic analysis of the LUPUS UK forum and participant interviews (N = 28). RESULTS: Cancellations of routine care and difficulties accessing medical support contributed to some participants deteriorating physically, including reports of hospitalisations. The majority of participants reported that fear of COVID-19 and disruptions to their medical care had also adversely impacted their mental health. Feeling medically supported during the pandemic correlated with multiple measures of mental health and perceptions of care, including the Warwick-Edinburgh Mental Wellbeing Score (r = 0.44, p = 0.01). Five themes were identified: 1. Detrimental reduction in care; 2. Disparities in contact and communication, (medical security vs abandonment sub-theme); 3. Perceived and actual endangerment; 4. The ‘perfect storm’ of reduced clinician ability to help, and increased patient reticence to seek help; and 5. Identifying the patients most vulnerable to reduced medical care. CONCLUSION: The diversion of resources away from chronic disease care was perceived by many participants to have caused adverse outcomes. Fear about increased vulnerability to COVID-19 was high, contributing to healthcare-avoidant behaviours. This study also highlights the influence of clinician accessibility and patients feeling medically supported on multiple measures of physical and mental health.