Julia Blaurock

Background: Evidence on the economic burden of post-COVID syndrome in Germany remains limited. This study quantifies post-COVID-associated healthcare resource utilization (HCRU), sick leave, and costs. Objectives: To compare HCRU, sick leave, and costs borne by the statutory health insurance (SHI) among incident pediatric and adult post-COVID patients with matched post-COVID-free controls. Methods: This retrospective cohort study analyzed an anonymized German SHI claims database provided by GWQ ServicePlus AG. The observation period spanned October 2021 to June 2025 and included all individuals with incident COVID-19 diagnosis until September 2024. Incident post-COVID was defined as the first ICD-10-GM code (U07.4!; U09.9!) recorded ≥90 days after first COVID-19 diagnosis. Post-COVID cases were exactly matched 1:2 to post-COVID–free COVID-19 controls by calendar quarter of incident COVID-19 diagnosis, acute severity, cohort entry quarter, 5-year birth interval, sex, and Elixhauser Comorbidity Index. We estimated mean differences in HCRU, sick leave, and direct SHI-borne costs per case. Rate ratios of HCRU, sick leave, and costs per person-year were estimated using Poisson (HCRU/sick leave) and linear (costs) regression. Analyses covered 365-day, 730-day, and any follow-up period. Results: We matched 25 485 identified post-COVID cases with 49 671 controls. Matched cases and controls were comparable in age, sex, and comorbidities. Overall, during 365 days of follow-up, post-COVID patients showed higher HCRU and sick leave rates across all sectors, especially sick leave days. Mean differences per case were greatest for sick leave days (365 days: +27 days) and outpatient physician contacts (365 days: 6.9 contacts). HCRU and sick leave rates remained significantly increased over extended follow-up periods. Total SHI-borne costs per person-year were higher among post-COVID patients across all follow-up periods (all P < .001). Sector-specific costs per person-year were increased primarily in the outpatient sector and for sickness benefits (all P < .001). Mean total cost differences per case were +€1806 per case (365 days) and mean excess sickness benefits per case were +€1077. Conclusions: Documented post-COVID was associated with a substantial and sustained economic burden on the German healthcare system and society. Targeted strategies are needed to mitigate potential long-term impacts on HCRU and labor productivity.

Background: Food frequency questionnaires (FFQs) are important tools for dietary assessment in large epidemiological studies, playing a crucial role in evaluating the relationship between diet and health. However, adapting the food lists in FFQs to align with specific study objectives or target populations presents a considerable challenge. Methods: The present study develops a framework using mixed-integer linear programming (MILP) to minimize the food list of an FFQ using a vegetarian population in Germany as a proof of concept. Constraints of the optimization ensured that the selected food items have a certain nutrient coverage and variance coverage, as well as an appropriate aggregation level. Nutrient intake for three scenarios for FFQs was compared with 24 h recalls (24HR) using R², calculated through linear regression. The three scenarios were: 1. FFQ reflecting the effect of categorizing portion sizes, 2. FFQ reflecting the effect of selecting food items, 3. FFQ reflecting the effect of categorizing portion sizes and selecting food items. Results: Length of minimized FFQs increased with a higher proportion of nutrient coverage and variance coverage. Including aggregation of food items produced shorter FFQs than FFQs that only contain food items at a lower aggregation level. R² values across the three scenarios showed that the FFQ captured most of the between-person variation in nutrient intake that was observed in the 24HR. Conclusions: MILP offers a reliable and data-driven framework for compiling optimized FFQs.

Food Frequency Questionnaires (FFQs) are important instruments to assess dietary intake in large epidemiological studies. To determine dietary intake correctly, food lists need to be adapted depending on the study aim and the target population. The present work compiles food lists for an FFQ with Mixed Integer Linear Programming (MILP) to minimize the number of foods in the food list. The optimized food lists were compared with the validated eNutri FFQ. The constraints of the MILP aimed to identify food items with a high nutrient coverage in a population and with a high interindividual variability. The optimization was based on data from the second German National Nutrition Survey. The resulting food lists were shorter than the one used in the validated eNutri FFQ.

Vegetarian diets have gained in popularity, especially among highly educated women, and are considered beneficial to health. Comparative studies assessing the diet of vegetarians against omnivores are rather limited and often provide ambivalent results. Therefore, this study examined the nutrient intake and nutritional quality of vegetarian and omnivorous diets in a group of 61 female students in Germany. Habitual dietary intake was evaluated using a validated graphical online food frequency questionnaire (FFQ). Differences in nutrient intakes were analyzed by Mann–Whitney-U-Tests. Odds Ratios (OR) were calculated for vegetarians exceeding dietary reference values (DRV) compared to omnivores. The overall nutritional quality was assessed using the Healthy-Eating-Index-2015 (HEI-2015). In omnivores, intakes of total energy from saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), long-chain omega-3 polyunsaturated fatty acids (LC-n3-PUFA), cholesterol, sucrose, lactose, retinol, and cobalamin were significantly higher than in vegetarians. Significantly lower intakes were observed for fiber, magnesium, and beta-carotene. Significant OR were detected for total fat (OR = 0.29), SFA (OR = 0.04), beta-carotene (OR = 4.55), and cobalamin (OR = 0.32). HEI-2015 scores were higher for vegetarians than for omnivores (79 points versus 74 points) and significant differences were recorded for the HEI-2015 components dairy, seafood & plant proteins, fatty acids, added sugars, and saturated fatty acids.