Background: Mitochondrial disorders belong to the most prevalent inherited metabolic diseases with the m.3243A > G mutation reflecting being one of the most common mutations in mitochondrial DNA. Previous studies showed little relationship between mitochondrial genetics and disease manifestation. Relationship between genotype and disease manifestation with patient reported quality of life and other patient reported outcomes is still unexplored.
Methods: Seventy-two out of the 122 invited adult patients with m.3243A > G mutation completed online standardized questionnaires on quality of life, functional impairment, fatigue and mental health as assessed by the RAND-SF36, the Sickness Impact Profile (SIP), the Checklist Individual Strength (CIS) and the Hospital Anxiety and Depression scale (HADS). Data were related to clinical manifestation reflected by the Newcastle Mitochondrial Disease Adult Scale (NMDAS) score and heteroplasmy levels of the mutation in urine epithelial cells.
Results: Patients reported impaired quality of life. Sixty percent showed severe levels of fatigue, and 37% showed clinical relevant mental health problems, which was significantly more than healthy norms. These patient reported health outcomes showed negligible relationship with levels of heteroplasmy (r = <.30) and weak (.30 < r < .50) to moderate (.50 < r < .70) relationship with clinical manifestation.
Conclusions: Patient reported outcomes on quality of life, fatigue and mental health problems, are only partly reflected by clinical assessments. In order to support patients more effectively, integration of patient reported outcomes, alongside symptoms of their disease, in clinical practice is warranted.
Keywords: Fatigue; Mental health; Mitochondrial disease; Participation; Patient reported outcomes; Quality of life; m.3243A > G mutation.