Methods

Health insurance is compulsory in Germany and is either provided by statutory health insurance (covering around 89% of the population) or by substitutive private health insurance. Statutory health insurance is organized in over 90 sickness funds which act as third-party payers. [13] In addition to covering the cost for acute care, German residents are entitled to health insurance covering the cost for long-term care (either at home or at specialized institutions). The linked financial assistance increases with the extend of functional deficits (care level, so-called “Pflegegrad”). This creates incentives for the population to apply 1) if newly perceived functional impairments are present or 2) in case of functional status deterioration for re-assessment. Dedicated, medical assessors evaluate the autonomy and ability of each applicant in modules with different weightings. The overall score classifies the individual into five categories. This assessment results in a composite score which determines the grade of functional deficits (“Pflegegrad”) ranging from no significant impairment (grade 0), mild or moderate impairments (grades 1 and 2) to severe and very severe limitations (grades 3 and 4) with increased care requirements (grade 5). The grade is recorded by the BARMER health insurance organisation for all members in an anonymised database.

Although the Pflegegrad is a legally defined construct specific to the German long-term care system, it conceptually aligns with the WHO's internationally recognized framework of intrinsic capacity, encompassing domains such as locomotion, cognition, psychological well-being, and vitality. The care level can therefore be understood as an operationalized, legally binding proxy measure of intrinsic capacity within the German healthcare context. [14] A conceptual comparison between the Pflegegrad system and intrinsic capacity is displayed in Table 1.

Aspect | Intrinsic Capacity (WHO) | Pflegegrad (Germany)
Perspective | Capacity-oriented | Impairment-oriented†
Primary aim | Functional health and healthy aging | Assessment of long-term care dependency
Multidimensional approach | Yes | Yes
Inclusion of cognitive and psychological domains | Yes | Yes (since 2017)‡
Legally binding | No | Yes
Grading |  | Care level 0: no significant impairmentsCare level 1: mild impairmentsCare level 2: moderate impairmentsCare level 3: severe limitationsCare level 4: very severe limitationsCare level 5: very severe limitations with increased care requirements

Demographic data, data on frailty, co-morbidities and survival were drawn from the anonymized database of the second largest sickness fund in Germany (BARMER, www.barmer.de), which covers approximately 10 % of the German population. Additionally, the number of heart failure hospitalizations, doctor-patient contacts in the ambulatory setting and overall medical expenses 12 months before and after M-TEER were analysed.

Statistics: Continuous variables are presented as median with interquartile range (IQR) and categorical variables as absolute numbers and percentages. Group comparisons for continuous variables were performed using the Mann-Whitney U test, and chi-square or Fisher's exact test was applied for categorical variables, as appropriate. Long-term survival was assessed using Cox proportional hazards regression analysis, with results expressed as odds ratios (OR) with 95% confidence intervals (CI). Kaplan-Meier curves were generated to illustrate survival probabilities across subgroups. Prior to modelling, multicollinearity among all ordinal and categorical predictors with more than two levels was assessed using Spearman correlation coefficients. No strong correlations were identified between any variable pairs (all r < 0.2), confirming sufficient independence of model parameters. A two-sided p-value of <0.05 was considered statistically significant. All statistical analyses were performed using R (version 4.3.1R (version 4.3.1, www.r-project.org).

Ethics: This study is in line with the declaration of Helsinki and was approved by the local Ethics committee (No. 2024–2952).