The findings of this study demonstrate the high burden of patients with malignant lymphomas (FL, DLBCL). Nearly one-thousand prevalent patients of both entities per year, the maximal documented annual inpatient stay of 335 days, given intensive therapy options like stem cell transplants, and maximal total costs of €620.000€ per patient in one year. These results indicating a challenging setting for all stakeholders in the care of these patients. Annually €87.4m for approx. n = 956 FL-patients and €191.8m for n = 1.361 DLBCL-patients were spent by third party payers between the years 2015–2020. This study generates valuable insights on FL & DLBCL-care in Germany. To our knowledge, this is likely to be one of the first comprehensive analyses of German claims data for malignant lymphomas such as FL and DLBCL.
On European level, annual prevalence of 37/100.000 for FL [ICD:C82.0, C82.1, C82.2, C82.3, C82.4, C82.5, C82.6, C82.7, C82.9] and 43/100.000 for DLBCL-patients [ICD-10 C83.3] were recently published. [22] In our German study cohort, the FL prevalence extrapolated for Germany was slightly lower (30,3/100.000). The extrapolated prevalence for the DLBCL cohort was 42,4/100.000 what is comparable to aforementioned European data. One reason for these lower FL-rates can be the methodologic difference by the including ICD-codes. Also, there is a trend of rising prevalence over the observation period. Between 2015 and 2020 the prevalence increased by 23% for FL and 22% for DLBCL. This trend of increasing patient numbers is comparable with German data, provided by the “Krebs in Deutschland für 2017/2018”-report published by the governmental Robert-Koch institute [4].
In terms of the age-distribution, the majority of the patients had a documented age above 60 years. Up to 75% (FL) and 76% (DLBCL) of the respective patients were in this age group. This observation must be interpreted in a broader view. The number of incident NHL-patients with an age of more than 80years are highest. Discussed in context of a higher mortality-risk for patients > 75y, the low numbers in the eldest age-groups in our prevalent cohort are plausible. [4] In terms of gender distribution, the InGef-cohort is almost in line with Dürig J et al. gender is balanced in the FL group (men: 49% men), in the DLBCL group a the proportion of men (57.7%)was slightly higher [23]. This observation is also in line with previous publications. [5, 16, 17].
No German publication on comorbidities has been found, therefore no national comparisons are possible. Yang X. et al showed in a US claims data analysis on n = 2.500 DLBCL patients a mean CCI-Index number for prevalent patients of 2.3 (SD ± 2.4) [24]. In our study cohort CCI-score for the prevalent DLBCL cohort was 4,8 (SD ± 2.7). The CCI-score is clearly higher, because of e.g. different methodological approaches (entity not excluded). For FL-patients no public available information has been found. Beside the scores, the individual underlying variables indicate a huge patient burden (Supplement Table 1). For example, about 30% of all prevalent patients in both entities had a depression in our study cohort. In a previous publication for Germany a depression-rate for NHL-pts of 22,3% within 10-years after index date was communicated [25]. Also the documented side effects indicate the high burden for these patients. Here, a clear difference between the two entities was documented. The shares of agranulocytosis and neutropenia, reaction to severe stress and anxiety, and acute renal failure are more than doubled for DLBCL patients. This observation as well as the more intense treatment regimens might be responsible for the documented longer inpatient-days in the DLBCL-cohort. In addition, the mean numbers of diagnostic procedures shown underscore the high resource use, as all patients underwent at least one procedure. However, we assume that this number is underestimated and that patients have significantly more procedures.
Other results on treatment-details, are generally consistent with the expectations of clinical experts and previous international research. Thus, a substantial percentage of chemotherapy-based treatment approaches for the DLBCL cohort (e.g. R-CHOP) is documented. [26] In contrast, in the FL-cohort 25% of the prevalent patients received Rituximab in the ambulant setting only. In addition, the increasing usage of innovative treatment after market-approval were documented. After its approval in September 2017, the Obinutuzumab-use for FL-patients continuously increased between 2018 and 2020 [27].
When discussing patient-burden, hospitalization-rates are an additional indicator of previously discussed aspects. The results identified a mean of 20,7 inpatient days in the FL cohort and 29,3 days for the DLBCL patients. The number of hospitalizations were n = 2,0 and n = 2,9 admissions, in respective. The maximum number of n = 323 (FL) and n = 336 (DLBCL) inpatient days indicate major expenditures of resources, and a huge burden of disease for individual patients. This observation of huge efforts for a small number of high risk patients, is consistent with a German DLBCL study [28]. In this retrospective analysis of relapsed and refractory DLBCL-patients, a mean number of 63 inpatient days (median 66; range 17–123; SD ± 36) and 5 admissions (3; 1–12; ±3) were documented in DLBCL patients with > 3 lines of therapy.
However, in our study the annual costs for inpatient care contributed to highest shares of total cost for both entities and over the total observation period. A high proportion of inpatient cost was also noted in several international real-world cost analysis on DLBCL and FL. [29–31] A recent German claims data analysis on DLBCL-patients documented hospitalization as the main cost driver with 71%. The time-unadjusted absolute costs sum up to €59,868 (43,331), €35,870 (37,387), and €28,832 (40,540) during first-line, second-line, and third-line treatments, respectively. [32] Due to methodological differences (e.g. results classified in lines of therapy only) no detailed comparison were performed. International publications also show comparable results: In a Canadian study of DLBCL patients, the inpatient stay for second-line treatment was the largest cost driver (62%)[30]. Tsutsué et al. showed in a Japanese claims data analysis, that the majority of the overall costs as well as per-treatment line were due to inpatient costs (n = 6,821) of 47,903.08 USD (SD, 47,497.30; range, 247.43–488,296.86) [29]. A major factor in this context is the choice of therapy. One example of a treatment approach that has a huge economic impact is the stem cell transplantation. In a Canadian study, autologous SCT and hospitalization contributed the most to direct costs for DLBCL patients in more than three lines of therapy [33]. We discussed this in context of the subgroup analysis on SCTs, in the following text.
In general, the mean and median numbers of all cost-data differ significantly because of the wide range of min and max numbers, with a maximal annual cost of €255.353 per patient in FL and €602.243 for the DLBCL. A small number of patients with very high total costs were documented. From 2018 to 2019/20 the maximal costs almost doubled in the DLBCL-cohort. This significant increase may be caused by a higher number of treatment-approaches with cost-intensive innovative / personalized medicines. In total, mean costs of €15.4m are documented per year in the FL-cohort, in comparison to €34.6m in the DLBCL patients. The mean annual costs in years 2017 to 2020 amounted to 0.3% (FL) and 0,7% (DLBCL) of the German statutory health insurance expenses in these years on antineoplastic agents (approximately €5 billion) [34].
In terms of outcomes, we focussed on mortality and survival. The mean annual mortality rate for the prevalent FL-patients was 5% and 13,4% for the DLBCL-cohort. Since these cohorts are a cross-section of all patients in the corresponding year, the outcome-results of the SCT subgroup were discussed only. Regarding the outcomes in the subgroup analysis on stem cell transplanted patients (Fig. 1), a recent Canadian study on FL-patients demonstrated also an potential long-term benefit of SCT in Canada [35]. Because of the insufficient evidence level on German data for both entities, no further comparison with national data was possible. However, when discussing on treatment and respective outcome, innovative approaches must be set into perspective e.g. CAR-T cell therapies [36].
As an addition, in the subgroup analysis, the mean 12M-total cost after autologous SCT were €46.270 for FL and €56.558 for the DLBCL patients. The mean 12M–costs for DLBCL-patients with allo-SCT were €161.662. Mayerhoff et al. reported direct costs of €230,399/patient (DLBCL/FL allogeneic) and €107,457/patient (DLBCL/FL autologous) for Germany. These reported costs are substantially higher, because they were summed up in the period of two quarters before and eight quarters after SCT. [37] Moertl et al. documented mean treatment costs per DLBCL-patient with auto-SCT of €55,468 and €131,264 for allo-SCT in the clinical setting[28]. Further research and detailed information are needed to put conventional treatments in the context of innovative treatment approaches, such as CAR T-cell therapy, which ranged between 276 086 EUR and 328 727 EUR [38].
Summarizing, in terms of rising prevalence of haematological malignancies in Germany, comprehensive care for patients can lead to high costs for health systems and places pressure on public budgets. Our results can be used as a baseline for future economic studies, in the context of innovative lymphoma therapies in Germany.
Certain factors limit our findings. The analyses were based on health claims records, which are collected for billing purposes and not primary for research reasons. Therefore, all results depend on quality of coding. Because of the high level of data protection in Germany, individual case validation was not possible and no results for a patient count of n < 5 could be displayed. Because of general limitations in health claims datasets, classification of socioeconomic status, clinical details (e.g. tumor status, lines of therapy) or quality of life (QoL) criteria is impossible. Despite this lack of data, the impact of high-dose chemotherapies on the quality of life of e.g. FL patients should not be neglected [39]. Another limitation of the health claims data is the missing of comprehensive information on specific treatments. For instance, singular medicines dispensed in the inpatient setting cannot be assessed separately as these costs are usually included in the compensation schemes for diagnosis related groups (DRG). On the other hand, this also reflects a major strength of this study as it evaluates overall costs and resource utilization based on the perspective of health insurances with a high rate of data completeness. Similarly, the large and representative sample size is a huge strength.