Impact of the COVID-19 pandemic on the care of adult PKU patients in Germany: a retrospective analysis of 115 patient data over a four years period.

Phenylketonuria (PKU) is one of the most common inborn errors of metabolism and is caused by a monogenetic mutation in the PAH-gene. To achieve good metabolic control regular serum phenylalanine (PHE) determinations and outpatient presentations are required. The COVID19 pandemic, which started in Germany 2020, has changed the lives of many people through various state measures such as lockdowns, no-contact orders, etc. It has also significantly altered the care of patients with chronic diseases. The impact of the COVID19 pandemic on the care and metabolic control of adult PKU patients in Germany is demonstrated in this abstract.

The records of 190 PKU patients who presented to our outpatient clinic from 02/2018 to 02/2022 were reviewed for the following exclusion criteria: Pregnancy during the period (22), new drug therapy (6), lost to follow-up (26) or first presentation after pandemic outbreak (33). Records of 115 patients were included (median age 32.75 years, age range 19-66 years, W:M 66:49). Retrospective statistical analysis was conducted on metabolic control, number of outpatient presentations (OP), submission of dry blood cards (DBCs) and concentration of other vitamins and micronutrients before and after the COVID outbreak.

The pandemic resulted in a significant deterioration in metabolic control ([PHE] 726 vs. 810 µmol/l; p<0.0001) although the number of OP (654 vs. 668; p=0.653) remained the same and the number of DBCs (2.6 vs. 4.1; p=0.049) increased. Matching the metabolic deterioration were a significant increase in the concentration of vit. B12 (574 vs. 656nmol/l; p=0,0002) and transferrin saturation (16,2 vs. 19,8%; p=0,001) as a sign of poorer adherence with low-protein dietary therapy.

Since the number of OP remained the same and the number of DBC submission increased, other social factors appear to be causative for the poorer metabolic control after the covid outbreak. Further research, especially with patient-related surveys, is needed.