The aim of this cross-sectional study was to identify post-COVID-19 condition (PCC) phenotypes and to investigate the health-related quality of life (HRQoL) and healthcare use per phenotype. We administered a questionnaire to a cohort of PCC patients that included items on socio-demographics, medical characteristics, health symptoms, healthcare use, and the EQ-5D-5L. A principal component analysis (PCA) of PCC symptoms was performed to identify symptom patterns. K-means clustering was used to identify phenotypes. In total, 8630 participants completed the survey. The median number of symptoms was 18, with the top 3 being fatigue, concentration problems, and decreased physical condition. Eight symptom patterns and three phenotypes were identified. Phenotype 1 comprised participants with a lower-than-average number of symptoms, phenotype 2 with an average number of symptoms, and phenotype 3 with a higher-than-average number of symptoms. Compared to participants in phenotypes 1 and 2, those in phenotype 3 consulted significantly more healthcare providers (median 4, 6, and 7, respectively, p < 0.001) and had a significantly worse HRQoL (p < 0.001). In conclusion, number of symptoms rather than type of symptom was the driver in the identification of PCC phenotypes. Experiencing a higher number of symptoms is associated with a lower HRQoL and more healthcare use.

Scant research has examined health-related quality of life (HRQoL) in family members of patients with severe brain injury, even less has been done in Scandinavian countries, and none has examined this construct longitudinally. The current study therefore used multilevel modelling to investigate the trajectories of HRQoL in 94 Danish family members of patients with severe brain injury at five time points, beginning at the patient's stay in a neuro intensive care unit through one year after injury. The family members’ HRQoL scores significantly and strongly increased over time, and Role Limitations – Emotional scores were higher when patients had high Rancho Los Amigos Scale scores at admission to early intensive rehabilitation in hospital. These results suggest that the acute and sub-acute periods after brain injury are an extremely difficult time psychologically for many families, and family-based mental health interventions during the acute and sub-acute phases are critical, especially for families who have a patient with severe deficits.