Distance-Metric Learning for Personalized Survival Analysis.

Personalized time-to-event or survival prediction with right-censored outcomes is a pervasive challenge in healthcare research. Although various supervised machine learning methods, such as random survival forests or neural networks, have been adapted to handle such outcomes effectively, they do not provide explanations for their predictions, lacking interpretability. In this paper, an alternative method for survival prediction by weighted nearest neighbors is proposed. Fitting this model to data entails optimizing the weights by learning a metric. An individual prediction of this method can be explained by providing the user with the most influential data points for this prediction, i.e., the closest data points and their weights. The strengths and weaknesses in terms of predictive performance are highlighted on simulated data and an application of the method on two different real-world datasets of breast cancer patients shows its competitiveness with established methods.

Clinical and economic burden of pneumococcal disease among individuals aged 16 years and older in Germany.

This study assessed the incidence rate of all-cause pneumonia (ACP) and invasive pneumococcal disease (IPD) and associated medical costs among individuals aged ≥16 in the German InGef database from 2016 to 2019. Incidence rate was expressed as the number of episodes per 100 000 person-years (PY). Healthcare resource utilisation was investigated by age group and by risk group (healthy, at-risk, high-risk). Direct medical costs per ACP/IPD episode were estimated as the total costs of all inpatient and outpatient visits. The overall incidence rate of ACP was 1345 (95% CI 1339-1352) and 8.25 (95% CI 7.76-8.77) per 100 000 PY for IPD. For both ACP and IPD, incidence rates increased with age and were higher in the high-risk and at-risk groups, in comparison to the healthy group. ACP inpatient admission rate increased with age but remained steady across age-groups for IPD. The mean direct medical costs per episode were €8075 (95% CI 7121-9028) for IPD and €1454 (95% CI 1426-1482) for ACP. The aggregate direct medical costs for IPD and ACP episodes were estimated to be €8.5 million and €248.9 million respectively. The clinical and economic burden of IPD and ACP among German adults is substantial regardless of age.

Pneumococcal vaccination coverage in individuals (16-59 years) with a newly diagnosed risk condition in Germany.

BACKGROUND: Despite recommendations from the German Standing Committee on Vaccination (STIKO), pneumococcal vaccination coverage remains low in vulnerable populations. This study estimated the pneumococcal vaccination coverage rate (VCR) and timing among individuals aged 16-59 years in Germany who were recommended to receive pneumococcal vaccination, according to STIKO. METHODS: A retrospective cohort analysis was conducted using the German InGef database. Individuals aged 16 to 59 years diagnosed with at least one "at-risk" (chronic disease) or "high-risk" (e.g., immunocompromising) condition considered to be at-risk of pneumococcal infection were identified at the time of first diagnosis, between January 1, 2016 and December 31, 2018, and followed up until December 31, 2019. The percentage of cumulative pneumococcal VCR with 95% confidence interval (CI) was reported for each calendar year of follow-up. RESULTS: There were 334,292 individuals followed for a median of 2.38 (interquartile range (IQR) 1.63-3.13) person years. For individuals aged 16-59 years diagnosed with an incident risk condition in 2016, pneumococcal VCR increased from 0.44% (95% CI 0.41-0.48) in 2016 to 1.24% (95% CI 1.18-1.30) in 2019. In 2019, VCRs were higher in individuals with high-risk conditions compared with at-risk conditions (2.24% (95% CI 2.09-2.40) vs. 0.90% (95% CI 0.85-0.96)). In 2019, VCRs were higher in individuals aged 50 to 59 years compared with individuals aged 16 to 49 years (2.25% (95% CI 2.10-2.41) vs. 0.90% (95% CI 0.84-0.96)). Similar trends were observed in individuals with newly diagnosed risk conditions identified in 2017 and in 2018. Older age, influenza vaccination and increasing number of risk conditions increased the likelihood of pneumococcal vaccination. Median time to vaccination from diagnosis of the risk condition was shorter for high-risk conditions (369.5 days (IQR 155.8-702.0)) compared to at-risk conditions (435.5 days (IQR 196.3-758.8)). CONCLUSION: Despite recommendations from STIKO, pneumococcal vaccination coverage remains very low and with long delays in vulnerable individuals aged 16-59 in Germany. Further efforts are required to increase immunization levels and shorten time to vaccination among individuals 16-59 years of age developing conditions with higher susceptibility to pneumococcal infection.

Incidence of acute otitis media in children < 16 years old in Germany during 2014-2019.

BACKGROUND: Acute otitis media (AOM) remains a common infection in children despite the introduction of pneumococcal conjugate vaccines. This study estimated AOM incidence rates (IRs) over time in children < 16 years old in Germany following PCV13 introduction. METHODS: AOM episodes were identified in the InGef healthcare claims database from 2014-2019 in children aged < 16 years. Each AOM episode was classified as either simple or recurrent. Recurrent AOM was defined as 3 or more episodes identified within a 6-month period; or 4 or more episodes within a 12-month period with at least one episode in the prior 6 months. AOM-related surgical procedures within 12 months and complications within 21 days of an AOM episode were also identified. Annual IRs were calculated as number of episodes/child-years (CY) at risk. 95% Confidence intervals (95%CI) were calculated using the Wilson method. The Mann-Kendall test was used to assess trends over time. RESULTS: Between 2014 and 2019, the study population comprised 916,805 children with 327,726 AOM episodes, of which 15% (49,011) of all episodes were identified as recurrent AOM and 85% (278,715) as simple AOM. There were significant declines in AOM (p = 0.003) in the study population overall and in all age groups over the study period; from 101 (95%CI 101-102)/1000 CY to 79 (95%CI 78-80)/1000 CY in the total study population, from 209 (95%CI 206-212)/1000 CY to 147 (95%CI 145-150)/1000 CY in < 2-year-olds, from 239 (95%CI 237-242) to 179 (95%CI 177-182)/1000 CY in 2-4-year-olds, and from 50 (95%CI 49-50) to 38 (95%CI 37-39)/1000 CY in 5-15-year-olds. No significant trends were identified for AOM-related surgical procedures over the study period; however, AOM-related complications overall increased (p = 0.003). CONCLUSION: Between 2014 and 2019, AOM incidence overall declined in children aged 0-15 years in Germany. Over the study period, the incidence of complicated AOM cases increased, however the incidence of AOM-related surgical procedures remained constant. Despite the impact of PCV13, the burden associated with AOM in Germany remains substantial.

Comparison of Approaches to Select a Propensity Score Matched Control Group in the Absence of an Obvious Start of Follow Up for this Group: An Example Study on the Economic Impact of the DMP Bronchial Asthma.

BACKGROUND: Claims data are a valuable data source to investigate the economic impact of new health care services. While the date of enrollment into the new service is an obvious start of follow-up for participants, the strategy to select potential controls is not straightforward due to a missing start of follow-up to ascertain possible confounders. The aim of this study was to compare different approaches to select controls via Propensity Score Matching (PSM) using the disease management program (DMP) bronchial asthma (BA) as an example. METHODS: We conducted a retrospective cohort study of BA patients between 2013 and 2016 to examine total one-year health care costs and all-cause mortality. We implemented different scenarios regarding the selection of potential controls: I) allotment of a random index date with subsequent PSM, II) calendar year-based PSM (landmark analysis) and III) calendar quarter-based PSM. In scenario I, we applied 2 approaches to assign a random index date: a) assign random index date among all quarters with a BA diagnosis and b) assign random index date and thereafter examine if a BA diagnosis was documented in that quarter. RESULTS: No significant differences in total one-year health care costs between DMP BA participants and non-participants were observed in any of the scenarios. This could to some extent be explained by the higher mortality in the control groups in all scenarios. CONCLUSION: If the loss of potential controls can be compensated, scenario Ib is a pragmatic option to select a control group. If that is not the case, scenario III is the more sophisticated approach, with the limitation that baseline characteristics prior PSM cannot be depicted and computational time or memory size needed to conduct the analysis need to be sufficient.

Epidemiology and health care utilization of patients suffering from Huntington's disease in Germany: real world evidence based on German claims data.

BACKGROUND: Huntington's disease (HD) is a rare, genetic, neurodegenerative and ultimately fatal disease with no cure or progression-delaying treatment currently available. HD is characterized by a triad of cognitive, behavioural and motor symptoms. Evidence on epidemiology and management of HD is limited, especially for Germany. This study aims to estimate the incidence and prevalence of HD and analyze the current routine care based on German claims data. METHODS: The source of data was a sample of the Institute for Applied Health Research Berlin (InGef) Research Database, comprising data of approximately four million insured persons from approximately 70 German statutory health insurances. The study was conducted in a retrospective cross-sectional design using 2015 and 2016 as a two-year observation period. At least two outpatient or inpatient ICD-10 codes for HD (ICD-10: G10) during the study period were required for case identification. Patients were considered incident if no HD diagnoses in the 4 years prior to the year of case identification were documented. Information on outpatient drug dispensations, medical aids and remedies were considered to describe the current treatment situation of HD patients. RESULTS: A 2-year incidence of 1.8 per 100,000 persons (95%-Confidence interval (CI): 1.4-2.4) and a 2-year period prevalence of 9.3 per 100,000 persons (95%-CI: 8.3-10.4) was observed. The prevalence of HD increased with advancing age, peaking at 60-69 years (16.8 per 100,000 persons; 95%-CI: 13.4-21.0) and decreasing afterwards. The most frequently observed comorbidities and disease-associated symptoms in HD patients were depression (42.9%), dementia (37.7%), urinary incontinence (32.5%), extrapyramidal and movement disorders (30.5%), dysphagia (28.6%) and disorders of the lipoprotein metabolism (28.2%). The most common medications in HD patients were antipsychotics (66.9%), followed by antidepressants (45.1%). Anticonvulsants (16.6%), opioids (14.6%) and hypnotics (9.7%) were observed less frequently. Physical therapy was the most often used medical aid in HD patients (46.4%). Nursing services and speech therapy were used by 27.9 and 22.7% of HD patients, respectively, whereas use of psychotherapy was rare (3.2%). CONCLUSIONS: Based on a representative sample, this study provides new insights into the epidemiology and routine care of HD patients in Germany, and thus, may serve as a starting point for further research.

One Question, Many Results­Why Epidemiological Studies Yield Heterogeneous Findings. Part 34 of a Series on Evaluation of Scientific Publications.

BACKGROUND: Observational epidemiologic studies often yield different results on the same question. In this article, we explain how this comes about. METHODS: In this review, which is based on publications retrieved by a selective search in PubMed and the Web of Science, we use information from international publications, simulation studies on sampling error, and a quantitative bias analysis on fictitious data to demonstrate why the results of epidemiologic studies are often uncertain, and why it is, therefore, generally necessary to perform more than one study on any particular question. RESULTS: Sampling errors, imprecise measurements, alternative but equally appropriate methods of data analysis, and features of the populations being studied are common reasons why studies on the same question can yield different results. Simulation studies are used to illustrate the fact that effect estimates such as relative risks or odds ratios can deviate markedly from the true value because of sampling error, i.e., by chance alone. Quantitative bias analysis is used to show how strongly effect estimates can be distorted by misclassification of exposures or outcomes. Finally, it is shown through illustrative examples that different but equally appropriate methods of data analysis can lead to divergent study results. CONCLUSION: The above reasons why epidemiologic study results can be heterogeneous are explained in this review. Quantitative bias analyses and sensitivity analyses with alternative data evaluation strategies can help explain divergent results on one and the same question.

Shortened progression free and overall survival to immune-checkpoint inhibitors in BRAF-, RAS- and NF1- ("Triple") wild type melanomas.

BACKGROUND: Melanomas lacking mutations in BRAF, NRAS and NF1 are frequently referred to as "triple wild-type" (tWT) melanomas. They constitute 5-10 % of all melanomas and remain poorly characterized regarding clinical characteristics and response to therapy. This study investigates the largest multicenter collection of tWT-melanomas to date. METHODS: Targeted next-generation sequencing of the TERT promoter and 29 melanoma-associated genes were performed on 3109 melanoma tissue samples of the prospective multicenter study ADOREG/TRIM of the DeCOG revealing 292 patients suffering from tWT-melanomas. Clinical characteristics and mutational patterns were analyzed. As subgroup analysis, we analyzed 141 tWT-melanoma patients receiving either anti-CTLA4 plus anti-PD1 or anti PD1 monotherapy as first line therapy in AJCC stage IV. RESULTS: 184 patients with cutaneous melanomas, 56 patients with mucosal melanomas, 34 patients with acral melanomas and 18 patients with melanomas of unknown origin (MUP) were included. A TERT promoter mutation could be identified in 33.2 % of all melanomas and 70.5 % of all tWT-melanomas harbored less than three mutations per sample. For the 141 patients with stage IV disease, mPFS independent of melanoma type was 6.2 months (95 % CI: 4-9) and mOS was 24.8 months (95 % CI: 14.2-53.4) after first line anti-CTLA4 plus anti-PD1 therapy. After first-line anti-PD1 monotherapy, mPFS was 4 months (95 %CI: 2.9-8.5) and mOS was 29.18 months (95 % CI: 17.5-46.2). CONCLUSIONS: While known prognostic factors such as TERT promoter mutations and TMB were equally distributed among patients who received either anti-CTLA4 plus anti-PD1 combination therapy or anti-PD1 monotherapy as first line therapy, we did not find a prolonged mPFS or mOS in either of those. For both therapy concepts, mPFS and mOS were considerably shorter than reported for melanomas with known oncogene mutations.

Early versus late response to PD-1-based immunotherapy in metastatic melanoma.

BACKGROUND: Immune checkpoint inhibition (ICI) currently is the most effective treatment to induce durable responses in metastatic melanoma. The aims of this study are the characterization of patients with early, late and non-response to ICI and analysis of survival outcomes in a real-world patient cohort. METHODS: Patients who received PD-1-based immunotherapy for non-resectable stage-IV melanoma in any therapy line were selected from the prospective multicenter real-world DeCOG study ADOREG-TRIM (NCT05750511). Patients showing complete (CR) or partial (PR) response already during the first 3 months of treatment (Early Responders, EarlyR) were compared to patients showing CR/PR at a later time (Late Responders, LateR), a stable disease (SD) and to patients showing progressive disease (Non-Responders, NonR). RESULTS: Of 522 patients, 8.2 % were EarlyR (n = 43), 19.0 % were LateR (n = 99), 37.0 % had a SD (n = 193) and 35.8 % were NonR (n = 187). EarlyR, LateR and SD patients had comparable baseline characteristics. Multivariate logbinomial regression analyses adjusted for age and sex revealed positive tumor PD-L1 (RR=1.99, 95 %-CI=1.14-3.46, p = 0.015), and normal serum CRP (RR=1.59, 95 %-CI=0.93-2.70, p = 0.036) as independently associated with the achievement of an early response compared to NonR. The median progression-free and overall survival was 46.0 months (95 % CI 19.1; NR) and 47.8 months (95 %-CI 36.9; NR) for EarlyR, NR (95 %-CI NR; NR) for LateR, 8.1 months (7.0; 10.4) and 35.4 months (29.2; NR) for SD, and 2.0 months (95 %-CI 1.9; 2.1) and 6.1 months (95 %-CI 4.6; 8.8) for NonR patients. CONCLUSION: Less than 10 % of metastatic melanoma patients achieved an early response during the first 3 months of PD-1-based immunotherapy. Early responders were not superior to late responders in terms of response durability and survival.

Accuracy of a Smartphone-Based Artificial Intelligence Application for Classification of Melanomas, Melanocytic Nevi, and Seborrheic Keratoses.

Current artificial intelligence algorithms can classify melanomas at a level equivalent to that of experienced dermatologists. The objective of this study was to assess the accuracy of a smartphone-based "You Only Look Once" neural network model for the classification of melanomas, melanocytic nevi, and seborrheic keratoses. The algorithm was trained using 59,090 dermatoscopic images. Testing was performed on histologically confirmed lesions: 32 melanomas, 35 melanocytic nevi, and 33 seborrheic keratoses. The results of the algorithm's decisions were compared with those of two skilled dermatologists and five beginners in dermatoscopy. The algorithm's sensitivity and specificity for melanomas were 0.88 (0.71-0.96) and 0.87 (0.76-0.94), respectively. The algorithm surpassed the beginner dermatologists, who achieved a sensitivity of 0.83 (0.77-0.87). For melanocytic nevi, the algorithm outclassed each group of dermatologists, attaining a sensitivity of 0.77 (0.60-0.90). The algorithm's sensitivity for seborrheic keratoses was 0.52 (0.34-0.69). The smartphone-based "You Only Look Once" neural network model achieved a high sensitivity and specificity in the classification of melanomas and melanocytic nevi with an accuracy similar to that of skilled dermatologists. However, a bigger dataset is required in order to increase the algorithm's sensitivity for seborrheic keratoses.

Healthcare resource utilization and cost of pneumococcal disease in children in Germany, 2014-2019: a retrospective cohort study.

BACKGROUND: Since the introduction of higher valency pneumococcal conjugate vaccines in 2009, recent estimates on the economic burden of pediatric pneumococcal disease (PD) in Germany have been lacking. This study estimates healthcare resource utilization (HCRU) and medical cost associated with PDs in children < 16 years old in Germany from 2014-2019. METHODS: A nationally representative sample from the Institute for Applied Health Research (InGef) German claims database was used, covering approximately 5% of the total German population. Episodes of pneumococcal pneumonia (PP), all-cause pneumonia (ACP), invasive pneumococcal disease (IPD), and acute otitis media (AOM) in children aged < 16 years were identified using ICD-10-GM codes. HCRU was estimated from annual rates of outpatient visits, outpatient antibiotic prescriptions and inpatient admissions, divided by person-years (PY) at-risk. Average direct medical costs per episode were estimated as the total cost of all HCRU, divided by the total number of episodes. The Mann-Kendall test was used to assess monotonic time trends from 2014-2019. RESULTS:  During 2014-2019, 916,805 children aged < 16 years were followed up for a total of 3,608,716 PY. The average costs per episode for out-versus inpatient care associated with PP and ACP were €67 (95% CI 58-76) versus €2,606 (95% CI 1,338-3,873), and €63 (95% CI 62-63) versus €620 (95% CI 598-641), respectively. For IPD, the average medical cost per episode for out-versus inpatients were €30 (95% CI 19-42) versus €6,051 (95% CI 3,323-8,779), respectively. There were no significant trends in HCRU or costs for IPD or pneumonia over the study period, except for a significant reduction in ACP outpatient visits. A significant decrease in rate of outpatient visits and antibiotic prescribing for recurrent AOM was observed, in addition to an increase in rates of hospital admissions for simple AOM. This was paralleled by a significant increase in inpatient costs per episode for treating AOM overall, and simple AOM, over the study period. CONCLUSIONS:  The HCRU and cost per episode of pneumonia and IPD did not vary significantly from 2014-2019, but increased for AOM. The economic burden of pneumonia, IPD, and AOM remains substantial in Germany.

Characterisation and outcome of RAC1 mutated melanoma.

BACKGROUND: Activating hot spot R29S mutations in RAC1, a small GTPase influencing several cellular processes including cell proliferation and cytoskeleton rearrangement, have been reported in up to 9% of sun-exposed melanomas. Clinical characteristics and treatment implications of RAC1 mutations in melanoma remain unclear. METHODS: We investigated the largest set (n = 64) of RAC1 mutated melanoma patients reported to date, including a retrospective single institution cohort (n = 34) from the University Hospital Essen and a prospective multicentre cohort (n = 30) from the translational study Tissue Registry in Melanoma (TRIM; CA209-578), for patient and tumour characteristics as well as therapy outcomes. RESULTS: From 3037 sequenced melanoma samples screened RAC1 mutations occurred in ∼2% of samples (64/3037). The most common RAC1 mutation was P29S (95%, 61/64). The majority of tumours had co-occuring MAP kinase mutations (88%, 56/64); mostly activating NRAS (47%, 30/64) mutations, followed by activating BRAF (28%, 18/64) and NF1 (25%, 16/64) mutations. RAC1 mutated melanomas were almost exclusively of cutaneous origin (84%, 54/64) or of unknown primary (MUP, 14%, 9/64). C > T alterations were the most frequent mutation type identified demonstrating a UV-signature for RAC1 mutated melanoma. Most patients with unresectable disease (39) received immune checkpoint inhibitors (ICI) (77%, 30/39). Objective response rate of first-line treatment in patients with stage III/IV disease was 21%; median overall survival was 47.8 months. CONCLUSIONS: RAC1 mutated melanomas are rare, mostly of cutaneous origin and frequently harbour concomitant MAP kinase mutations, particularly in NRAS. Patients with advanced disease benefit from systemic treatment with ICI.

Adjuvant treatment and outcome of stage III melanoma patients: Results of a multicenter real-world German Dermatologic Cooperative Oncology Group (DeCOG) study.

PURPOSE: Clinical trials demonstrated significantly improved recurrence-free survival (RFS) of melanoma patients receiving adjuvant treatment. As data from controlled trials are based on selected populations, we investigated adjuvantly treated stage III melanoma patients under real-world conditions. PATIENTS AND METHODS: In a prior multicenter cohort study, stage III-IV melanoma patients were analysed for their choice of adjuvant therapy. In this follow-up study, we examined RFS, overall and melanoma-specific survival (MSS) and response to the subsequent treatment of 589 stage III patients (232 BRAF-mutated) receiving adjuvant PD-1 inhibitors (PD1; n = 479) or targeted therapy (TT; n = 110). RESULTS: The median follow-up of the total cohort was 25.7 months. The main reason for premature discontinuation of adjuvant therapy was disease progression in PD1- (28.8%, n = 138/479) and adverse events in TT-treated patients (28.2%, n = 31/110). Among BRAF-mutated patients, RFS at 24 months was 49% (95% CI 40.6-59.0%) for PD1- and 67% (95% CI 58-77%) for TT-treated patients. The risk of recurrence was higher for BRAF-mutated PD1 than TT (hazard ratio 1.99; 95% CI 1.34-2.96; hazard ratio adjusted for age, sex and tumour stage, 2.21; 95% CI 1.48-3.30). Twenty-four months MSS was 87% (95% CI 81.0-94.1) for PD1 and 92% (95% CI 86.6-97.0) for TT. Response to subsequent systemic treatment for unresectable disease was 22% for all PD1- and 16% for TT-treated patients. CONCLUSIONS: PD1-treated patients had more and earlier recurrences than TT patients. In BRAF-mutated patients, adjuvant TT might prevent early recurrences more effectively than PD1 treatment. Management of recurrence despite adjuvant treatment is challenging, with low response to current therapeutic options.

Treatment Patterns and Healthcare Resource Utilization Among Patients with Atopic Dermatitis: A Retrospective Cohort Study Using German Health Claims Data.

INTRODUCTION: Atopic dermatitis (AD) is a common inflammatory skin disease. Many patients are initiating a systemic therapy, if the disease is not adequately controlled with topical treatment only. Currently, there is little real-world evidence on the AD-related medical care situation in Germany. This study analyzed patient characteristics, treatment patterns, healthcare resource utilization and costs associated with systemically treated AD for the German healthcare system. METHODS: In this descriptive, retrospective cohort study, aggregated anonymized German health claims data from the InGef research database were used. Within a representative sample of four million insured individuals, patients with AD and systemic drug therapy initiation (SDTI) in the index year 2017 were identified and included into the study cohort. Systemic drug therapy included dupilumab, systemic corticosteroids (SCS) and systemic immunosuppressants (SIS). Patients were observed for one year starting from the date of SDTI in 2017. RESULTS: 9975 patients were included (57.8% female, mean age 39.6 years [SD 25.5]). In the one-year observation period, the most common systemic drug therapy was SCS (> 99.0%). Administrations of dupilumab (0.3%) or dispensations of SIS were rare (cyclosporine: 0.5%, azathioprine: 0.6%, methotrexate: 0.1%). Median treatment duration of SCS, cyclosporine and azathioprine was 27 days, 102 days, and 109 days, respectively. 2.8% of the patients received phototherapy; 41.6% used topical corticosteroids and/or topical calcineurin inhibitor. Average annual costs for medications amounted to € 1237 per patient. Outpatient services were used by 99.6% with associated mean annual costs of € 943; 25.4% had at least one hospitalization (mean annual costs: € 5836). 5.3% of adult patients received sickness benefits with associated mean annual costs of € 5026. CONCLUSIONS: Despite unfavorable risk-benefit profile, this study demonstrated a common treatment with SCS, whereas other systemic drug therapy options were rarely used. Furthermore, the results suggest a substantial economic burden for patients with AD and SDTI.

Epidemiology, characteristics and treatment of patients with relapsing remitting multiple sclerosis and incidence of high disease activity: Real world evidence based on German claims data.

BACKGROUND: Multiple Sclerosis (MS) is a chronic inflammatory, immune mediated disease of the central nervous system, with Relapsing Remitting MS (RRMS) being the most common type. Within the last years, the status of high disease activity (HDA) has become increasingly important for clinical decisions. Nevertheless, little is known about the incidence, the characteristics, and the current treatment of patients with RRMS and HDA in Germany. Therefore, this study aims to estimate the incidence of HDA in a German RRMS patient population, to characterize this population and to describe current drug treatment routines and further healthcare utilization of these patients. METHODS: A claims data analyses has been conducted, using a sample of the InGef Research Database that comprises data of approximately four million insured persons from around 70 German statutory health insurances (SHI). The study was conducted in a retrospective cohort design, including the years 2012-2016. Identification of RRMS population based on ICD-10 code (ICD-10-GM: G35.1). For identification of HDA, criteria from other studies as well as expert opinions have been used. Information on incidence, characteristics and current treatment of patients with RRMS and HDA was considered. RESULTS: The overall HDA incidence within the RRMS population was 8.5% for 2016. It was highest for the age group of 0-19 years (29.4% women, 33.3% men) and lowest for the age group of ≥ 50 years (4.3% women, 5.6% men). Mean age of patients with RRMS and incident HDA was 38.4 years (SD: 11.8) and women accounted for 67.8%. Analyses of drug utilization showed that 82.4% received at least one disease-modifying drug (DMD) in 2016. A percentage of 49.8% of patients received drugs for relapse therapy. A share of 55% of RRMS patients with HDA had at least one hospitalization with a mean length of stay of 13.9 days (SD: 18.3 days) in 2016. The average number of outpatient physician contacts was 28.1 (SD: 14.0). CONCLUSIONS: This study based on representative Germany-wide claims data from the SHI showed a high incidence of HDA especially within the young RRMS population. Future research should consider HDA as an important criterion for the quality of care for MS patients.