Polymyalgia rheumatica and giant cell arteritis following COVID-19 vaccination: Results from a nationwide survey.

We conducted a national in-depth analysis including pharmacovigilance reports and clinical study to assess the reporting rate (RR) and to determine the clinical profile of polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) in COVID-19-vaccinated individuals. First, based on the French pharmacovigilance database, we estimated the RR of PMR and GCA cases in individuals aged over 50 who developed their initial symptoms within one month of receiving the BNT162b2 mRNA, mRNA-1273, ChAdOx1 nCoV-19, and Ad26.COV2.S vaccines. We then conducted a nationwide survey to gather clinical profiles, therapeutic management, and follow-up data from individuals registered in the pharmacovigilance study. A total of 70 854 684 COVID-19 vaccine doses were administered to 25 260 485 adults, among which, 179 cases of PMR (RR 7. 1 cases/1 000 000 persons) and 54 cases of GCA (RR 2. 1 cases/1 000 000 persons) have been reported. The nationwide survey allowed the characterization of 60 PMR and 35 GCA cases. Median time to the onset of first symptoms was 10 (range 2-30) and 7 (range 2-25) days for PMR and GCA, respectively. Phenotype, GCA-related ischemic complications and -large vessel vasculitis as well as therapeutic management and follow-up seemed similar according to the number of vaccine shots received and when compared to the literature data of unvaccinated population. Although rare, the short time between immunization and the onset of first symptoms of PMR and GCA suggests a temporal association. Physician should be aware of this potential vaccine-related phenomenon.

A Movement Classification of Polymyalgia Rheumatica Patients Using Myoelectric Sensors.

Gait disorder is common among people with neurological disease and musculoskeletal disorders. The detection of gait disorders plays an integral role in designing appropriate rehabilitation protocols. This study presents a clinical gait analysis of patients with polymyalgia rheumatica to determine impaired gait patterns using machine learning models. A clinical gait assessment was conducted at KATH hospital between August and September 2022, and the 25 recruited participants comprised 18 patients and 7 control subjects. The demographics of the participants follow: age 56 years ± 7, height 175 cm ± 8, and weight 82 kg ± 10. Electromyography data were collected from four strained hip muscles of patients, which were the rectus femoris, vastus lateralis, biceps femoris, and semitendinosus. Four classification models were used-namely, support vector machine (SVM), rotation forest (RF), k-nearest neighbors (KNN), and decision tree (DT)-to distinguish the gait patterns for the two groups. SVM recorded the highest accuracy of 85% among the classifiers, while KNN had 75%, RF had 80%, and DT had the lowest accuracy of 70%. Furthermore, the SVM classifier had the highest sensitivity of 92%, while RF had 86%, DT had 90%, and KNN had the lowest sensitivity of 84%. The classifiers achieved significant results in discriminating between the impaired gait pattern of patients with polymyalgia rheumatica and control subjects. This information could be useful for clinicians designing therapeutic exercises and may be used for developing a decision support system for diagnostic purposes.

Concordance and agreement between different activity scores in polymyalgia rheumatica.

OBJECTIVE: The C reactive protein polymyalgia rheumatica activity score (CRP-PMR-AS) is a composite index that includes CRP levels and was developed specifically for PMR. As treatments such as interleukin-6 antagonists can normalise CRP levels, the erythrocyte sedimentation rate (ESR) of PMR-AS, the clinical (clin)-PMR-AS and the imputed-CRP (imp-CRP)-PMR-AS have been developed to avoid such bias. Our primary objective was to measure the correlation of these activity scores. Our secondary objective was to evaluate the concordance between different cutoffs of the PMR-ASs. METHOD: Data from the Safety and Efficacy of tocilizumab versus Placebo in Polymyalgia rHeumatica With glucocORticoid dEpendence (SEMAPHORE) trial, a superiority randomised double-blind placebo-controlled trial, were subjected to post hoc analysis to compare the efficacy of tocilizumab versus placebo in patients with active PMR. The CRP-PMR-AS, ESR-PMR-AS, clin-PMR-AS and imp-CRP-PMR-AS were measured at every visit. The concordance and correlation between these scores were evaluated using kappa correlation coefficients, Bland-Altman correlations, intraclass correlation coefficients (ICCs) and scatter plots. RESULTS: A total of 101 patients were included in the SEMAPHORE trial, and 100 were analysed in this study. The correlation between the PMR-ASs was excellent, as the ICC and kappa were >0.85 from week 4 until week 24 (CRP-PMR-AS ≤10 or >10). Bland-Altman plots revealed that the differences between the CRP-PMR-AS and the other threescores were low. The cut-off values for the clin-PMR-AS were similar to those for the CRP-PMR-AS 86% of the time. CONCLUSION: The correlation between all the PMR-ASs was excellent, reflecting the low weight of CRP. In clinical trials using drugs that have an impact on CRP, the derived activity scores can be used. TRIAL REGISTRATION NUMBER: NTC02908217.

Anti-interleukin-6 receptor antibody for the treatment of remitting seronegative symmetrical synovitis with pitting oedema: a new outlook?

We present the case of an elderly man with a small-joint polyarthritis, accompanied by pitting oedema, involving hands and feet, raising clinical suspicion of remitting seronegative symmetrical synovitis with pitting oedema (RS3PE). Treatment with corticosteroids was initiated with significant improvement, but unacceptable iatrogeny ensued, and tapering was not possible without disease flare-up. A trial of tocilizumab allowed disease activity control, slow weaning of corticosteroids and, ultimately, its suspension. RS3PE is a rare rheumatological entity, initially thought to be a variant of rheumatoid arthritis (RA), with shared traits with polymyalgia rheumatica (PMR), and other seronegative spondyloarthropathies, thereby implying a shared pathophysiological background. Elevated levels of interleukin 6 (IL-6) are found in patients with RA, have shown to mirror disease activity in PMR and have also been described in the serum and synovial fluid of patients with RS3PE. Tocilizumab, an anti-IL-6 receptor antibody, shows auspicious results in several other rare rheumatic diseases other than RA.

Did the first description of patients with polymyalgia rheumatica take place in Scotland or in Denmark?

The first description of polymyalgia rheumatica (PMR) is generally attributed to Dr. Bruce. In an 1888 article entitled Senile rheumatic gout, he described five male patients aged from 60 to 74 years whom he had visited at the Strathpeffer spa in Scotland. In 1945, Dr. Holst and Dr. Johansen reported on five female patients examined over several months at the Medical Department of Roskilde County Hospital in Denmark. These patients suffered from hip, upper arms, and neck pain associated with elevated ESR and constitutional manifestations such as low-grade fever or loss of weight. In the same year, Meulengracht, another Danish physician, reported on two patients with shoulder pain and stiffness associated with fever, weight loss, and an increased erythrocyte sedimentation rate. As in the five patients reported by Dr. Holst and Dr. Johansen, a prolonged recovery time was recorded. On reading and comparing these three accounts, we question whether it is correct to attribute the first description of PMR to Dr. Bruce and put forward shifting this accolade to the three Danish physicians.

[Polymyalgia rheumatica-A challenge in geriatrics : Interdisciplinary presentation of diagnostics and treatment]. / Polymyalgia rheumatica ­ eine Herausforderung in der Altersmedizin : Diagnostik und Therapie interdisziplinär dargestellt.

Polymyalgia rheumatica is the second most frequent inflammatory rheumatic disease in people aged over 50 years, after rheumatoid arthritis. It is characterized by pain and morning stiffness in the region of the shoulders, hip girdle and neck. It can be associated with giant cell arteritis (CGA). Treatment with glucocorticoids is indispensable. The duration of treatment varies and often exceeds 1 year. The additive administration of methotrexate is an option for saving glucocorticoids. The biologicals tocilizumab or secukinumab are very promising alternatives. The course of treatment should be closely monitored for inflammation parameters, glucocorticoid side effects, pain, visual acuity, depression, activities of daily living and especially related to functions of the upper extremities. The geriatric assessment plays an important role in the management of this condition.

Human leucocyte antigens and Japanese patients with polymyalgia rheumatica: the protective effect of DRB1*09:01.

OBJECTIVE: The hallmarks of the chronic inflammatory disease polymyalgia rheumatica (PMR) include pain, and morning stiffness in areas of the neck, shoulder and pelvic girdle. The human leucocyte antigen (HLA) gene was reported to be an important risk factor for PMR, but it has not been analysed precisely, especially in populations other than Europeans. METHODS: Genotyping of DRB1 and DQB1 was performed in Japanese PMR patients (n=270) and controls (n=413). Associations between allele carrier and genotype frequencies were determined for PMR. RESULTS: DRB1*04:05 was associated with a predisposition to PMR (p=0.0006, Pc=0.0193, OR 1.85, 95% CI 1.31 to 2.62). DRB1*09:01 was associated with protection against PMR (p=1.46×10-5, Pc=0.0004, OR 0.40, 95% CI 0.26 to 0.61). A shared epitope (SE) associated with PMR (p=3.07×10-6, OR 2.11, 95% CI 1.54 to 2.88). DQB1*03:03 (p=0.0010, Pc=0.0140, OR 0.52, 95% CI 0.35 to 0.77) was associated with protection against PMR and DQB1*04:01 (p=0.0009, Pc=0.0140, OR 1.82, 95% CI 1.28 to 2.58) was associated with predisposition to PMR. A gene dosage effect was observed for DRB1*09:01 and DQB1*03:03, but not for DRB1*04:05, SE or DQB1*04:01. Haplotype and logistic regression analyses suggested a protective effect for DRB1*09:01. CONCLUSION: This study is the first to demonstrate predisposing associations of DRB1*04:05, SE, and DQB1*04:01, and protective associations of DRB1*09:01 and DQB1*03:03 with PMR in Japanese patients. Our data indicate HLA has predisposing and protective effects on the pathogenesis of PMR.

Review of phase 2/3 trials in polymyalgia rheumatica and giant cell arteritis.

INTRODUCTION: GCA (giant cell arteritis) and PMR (polymyalgia rheumatica) are two overlapping inflammatory rheumatic conditions that are seen exclusively in older adults, sharing some common features. GCA is a clinical syndrome characterized by inflammation of the medium and large arteries, with both cranial and extracranial symptoms. PMR is a clinical syndrome characterized by stiffness in the neck, shoulder, and pelvic girdle muscles. Both are associated with constitutional symptoms. AREAS COVERED: In this review, we assess the established and upcoming treatments for GCA and PMR. We review the current treatment landscape, completed trials, and upcoming trials in these conditions, to identify new and promising therapies. EXPERT OPINION: Early use of glucocorticoids (GC) remains integral to the immediate management of PMR and GCA but being aware of patient co-morbidities that may influence treatment toxicity is paramount. As such GC sparing agents are required in the treatment of PMR. Currently there are limited treatment options available for PMR and GCA, and significant unmet needs remain. Newer mechanisms of action, and hence therapeutic options being studied include CD4 T cell co-stimulation blockade, IL-17 inhibition, IL-12/23 inhibition, GM-CSF inhibition, IL-1ß inhibition, TNF-α antagonist and Jak inhibition, among others, which will be discussed in this review.

The contributions of deleterious rare alleles in NLRP12 and inflammasome-related genes to polymyalgia rheumatica.

Polymyalgia rheumatica (PMR) is a chronic inflammatory disease characterized by arthralgia and myalgia of the shoulder and hip girdles, and fever. PMR is linked to autoimmune diseases and autoinflammatory disorders. Exome sequencing has revealed the roles of rare variants in some diseases. Causative genes for monogenic autoinflammatory disorders might be candidate genes for the selective exome analysis of PMR. We investigated rare variants in the coding and boundary regions of candidate genes for PMR. Exome sequencing was performed to analyze deleterious rare variants in candidate genes, and the frequencies of the deleterious rare alleles in PMR were compared with those of Japanese population controls. Deleterious rare alleles in the NLRL12 gene were associated with PMR (P = 0.0069, Pc = 0.0415, odds ratio [OR] 4.49, 95% confidence interval [CI] 1.79-11.27). A multigene analysis demonstrated the deleterious rare allele frequency of the candidate genes for autoinflammatory disorders was also increased in PMR (P = 0.0016, OR 3.69, 95%CI 1.81-7.54). The deleterious rare allele frequencies of the candidate genes including NLRP12 were increased in PMR patients, showing links to autoinflammatory disorders in the pathogenesis of PMR.

Prevalence and characteristics of subclinical giant cell arteritis in polymyalgia rheumatica.

OBJECTIVE: The main objective of this study was to analyse the prevalence and characteristics of subclinical GCA in patients with PMR. METHODS: This was a cross-sectional multicentre international study of consecutive patients with newly diagnosed PMR without symptoms or signs suggestive of GCA. All patients underwent US of the temporal superficial, common carotid, subclavian and axillary arteries. Patients with halo signs in at least one examined artery were considered to have subclinical GCA. The clinical, demographic and laboratory characteristics of the PMR group without subclinical vasculitis were compared with subclinical GCA, and the pattern of vessel involvement was compared with that of a classical single-centre GCA cohort. RESULTS: We included 346 PMR patients, 267 (77.2%) without subclinical GCA and 79 (22.8%) with subclinical GCA. The PMR patients with subclinical GCA were significantly older, had a longer duration of morning stiffness and more frequently reported hip pain than PMR without subclinical GCA. PMR with subclinical GCA showed a predominant extracranial large vessel pattern of vasculitic involvement compared with classical GCA, where the cranial phenotype predominated. The patients with PMR in the classical GCA group showed a pattern of vessel involvement similar to classical GCA without PMR but different from PMR with subclinical involvement. CONCLUSION: More than a fifth of the pure PMR patients had US findings consistent with subclinical GCA. This specific subset of patients showed a predilection for extracranial artery involvement. The optimal screening strategy to assess the presence of vasculitis in PMR remains to be determined.

Risk Factors for Relapse and/or Prolonged Glucocorticoid Therapy in Polymyalgia Rheumatica: Multicenter Study in 185 Patients.

BACKGROUND: In polymyalgia rheumatica (PMR) relapses and long-term GC dependency are common. We assessed risk factors for higher relapse rate and/or prolonged glucocorticoid therapy in PMR patients. METHODS: A multicenter and observational study (chart review) of PMR patients seen between 2006 and 2021 who had at least a 3-month follow-up period after starting GCs was performed. Results were expressed as median and interquartile range 25th-75th or mean ± standard deviation for numerical variables and percentage for categorical ones. Relapse versus nonrelapse groups were compared using Cox proportional analysis. Hazards ratios (HRs) with 95% confidence intervals (CIs) are reported. In all cases, a p value <0.05 was considered to indicate statistical significance. RESULTS: We included 185 patients (69.1% female). The median follow-up time was 17.1 months (interquartile range, 6.8-34.7). Incidence of relapses was 1.2 per 100 persons/month. In univariate analysis, PMR patients with a previous history of dyslipidemia had a lower risk of relapse (HR, 0.55; 95% CI, 0.33-0.94; p = 0.03); high-dose GC (HR, 2.35; 95% CI, 1.42-3.87; p = 0.001) and faster GC dose reduction had higher risk of relapse (HR, 3.04; 95% CI, 1.77-5.21; p = 0.001). In multivariate analysis, a previous history of dyslipidemia had a lower risk of relapse (HR, 0.54; 95% CI, 0.32-0.92; p = 0.023), and high dose of GC (HR, 2.46; 95% CI, 1.49-4.08; p = 0.001) remained the only risk factors for relapse. CONCLUSIONS: Lower doses of corticosteroids and a slow rate of reduction are critical to avoid relapse in PMR. Risk factors for higher relapse rate rely on therapy more than clinical characteristics of the patients at the time of diagnosis of PMR.

Humoral SARS-CoV-2 Vaccine Responses in Patients With Giant Cell Arteritis and Polymyalgia Rheumatica: Decay After Primary Vaccination and Effects of the Booster.

OBJECTIVE: Vaccination remains essential in preventing morbidity of SARS-CoV-2 infections. We previously showed that >10 mg/day of prednisolone and methotrexate was associated with reduced antibody concentrations after primary vaccination in patients with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR). This follow-up study was undertaken to measure the decay of antibody concentrations and the immunogenicity of SARS-CoV-2 booster vaccination. METHODS: Patients with GCA/PMR included in the primary vaccination (BNT162b2 [Pfizer-BioNTech] or ChAdOx1 [Oxford/AstraZeneca]) study were asked again to donate blood samples 6 months after primary vaccination (n = 24) and 1 month after booster vaccination (n = 46, BNT162b2 or mRNA1273). Data were compared to those of age-, sex-, and vaccine-matched controls (n = 58 and n = 42, respectively). Multiple linear regression was performed with post-booster antibody concentrations as dependent variable and post-primary vaccination antibodies, prednisolone >10mg/day, and methotrexate use as predicting variables. RESULTS: Antibody concentrations decreased faster over time in GCA/PMR patients than in controls, which was associated with prednisolone treatment during primary vaccination. Post-booster antibody concentrations were comparable between patients and controls. Antibody concentrations post primary vaccination, but not treatment during booster vaccination, were predictive for antibody concentrations post booster vaccination. CONCLUSION: These results indicate that the decay of humoral immunity after primary vaccination is associated with prednisolone treatment, whereas the subsequent increase after booster vaccination, was not. Patients with low antibody concentrations following primary vaccination remained at an immunogenic disadvantage after a single booster vaccination. This longitudinal study in GCA/PMR patients stresses the importance of repeated booster vaccination for patients with poor responses to primary vaccination.

Combining immune-checkpoint inhibitors with tocilizumab to treat a lung adenocarcinoma patient with pre-existing polymyalgia rheumatica: A case report.

Immune-checkpoint inhibitors (ICIs) have changed the management of advanced cancers. However, patients with pre-existing autoimmune diseases (ADs) have usually been excluded from clinical trials of ICIs due to concerns about exacerbation of AD. Here, we combined ICIs with selective immunosuppressant treatment in a metastatic lung adenocarcinoma patient with active pre-existing polymyalgia rheumatica (PMR). Remarkably, the strategy led to durable response and no exacerbation of PMR. Thus, we provide the first clinical evidence of treating metastatic cancer with ICIs and concomitant use of tocilizumab and hydroxychloroquine for active pre-existing PMR.

Accuracy of self-reported diagnoses of polymyalgia rheumatica and giant cell arteritis in the French prospective E3N- EPIC cohort: A validation study.

OBJECTIVES: To assess the accuracy of self-reported giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) diagnoses in a large French population-based prospective cohort, and to devise algorithms to improve their accuracy. METHODS: The E3N-EPIC cohort study (Etude Epidémiologique auprès des femmes de la Mutuelle Générale de l'Education Nationale) includes 98,995 French women born between 1925 and 1950, recruited in 1990 to study risk factors of cancer and chronic diseases. They completed biennially mailed questionnaires to update their health-related information and lifestyle characteristics. In three questionnaires, women could self-report a diagnosis of GCA/PMR. Those women were additionally sent a specific questionnaire, designed to ascertain self-reported diagnoses of GCA/PMR. Four algorithms were then devised to improve their identification. Accuracies of self-reported diagnoses and of each algorithm were calculated by comparing the diagnoses with a blinded medical chart review. RESULTS: Among 98,995 participants, 1,392 women self-reported GCA/PMR. 830 women sent back the specific questionnaire, and 202 women provided medical charts. After independent review of the 202 medical charts, 87.6 % of the self-reported diagnoses of GCA/PMR were accurate. Using additional data from a specific questionnaire (diagnosis confirmation by a physician, and self-report of >3-month of glucocorticoids), and from a reimbursement database (at least two deliveries of glucocorticoids in less than 3 consecutive months) improved their accuracy (91.8 % to 92.8 %). CONCLUSION: The accuracy of self-reported diagnosis of GCA/PMR was high in the E3N-cohort but using additional data as a specific GCA/PMR questionnaire and/or corticosteroid reimbursement database further improved this accuracy. With nearly 600 detected cases of GCA/PMR, we will be able to investigate risk factors for GCA/PMR in women.

Subclinical giant cell arteritis increases the risk of relapse in polymyalgia rheumatica.

OBJECTIVE: The aim of the present study was to determine the clinical significance of subclinical giant cell arteritis (GCA) in polymyalgia rheumatica (PMR) and ascertain its optimal treatment approach. METHODS: Patients with PMR who fulfilled the 2012 European Alliance of Associations for Rheumatology/American College of Rheumatology Provisional Classification Criteria for PMR, did not have GCA symptoms and were routinely followed up for 2 years and were stratified into two groups, according to their ultrasound results: isolated PMR and PMR with subclinical GCA. The outcomes (relapses, glucocorticoid use and disease-modifying antirheumatic drug treatments) between groups were compared. RESULTS: We included 150 patients with PMR (50 with subclinical GCA) with a median (IQR) follow-up of 22 (20-24) months. Overall, 47 patients (31.3 %) had a relapse, 31 (62%) in the subclinical GCA group and 16 (16%) in the isolated PMR group (p<0.001). Among patients with subclinical GCA, no differences were found in the mean (SD) prednisone starting dosage between relapsed and non-relapsed patients (32.4±15.6 vs 35.5±12.1 mg, respectively, p=0.722). Patients with subclinical GCA who relapsed had a faster prednisone dose tapering in the first 3 months compared with the non-relapsed patients, with a mean dose at the third month of 10.0±5.2 versus 15.2±7.9 mg daily (p<0.001). No differences were found between relapsing and non-relapsed patients with subclinical GCA regarding age, sex, C reactive protein and erythrocyte sedimentation rate. CONCLUSIONS: Patients with PMR and subclinical GCA had a significantly higher number of relapses during a 2-year follow-up than patients with isolated PMR. Lower starting doses and rapid glucocorticoid tapering in the first 3 months emerged as risk factors for relapse.

Evidence on treat to target strategies in polymyalgia rheumatica and giant cell arteritis: a systematic literature review.

OBJECTIVES: To inform an international task force about current evidence on Treat to Target (T2T) strategies in PMR and GCA. METHODS: A systematic literature research (SLR) was conducted in Medline, EMBASE, Cochrane Library, clinicaltrials.gov from their inception date to May 2022, and in the EULAR/ACR abstract database (2019-2021). Randomised clinical trials (RCTs) and non-randomised interventional studies published in English and answering at least one of the eleven PICO questions on T2T strategies, treatment targets and outcomes, framed by the taskforce, were identified. Study selection process, data extraction and risk of bias assessment were conducted independently by two investigators. RESULTS: Of 7809 screened abstracts, 397 were selected for detailed review and 76 manuscripts were finally included (31 RCTs, eight subgroup/exploratory analyses of RCTs and 37 non-randomised interventional studies). No study comparing a T2T strategy against standard of care was identified. In PMR RCTs, the most frequently applied outcomes concerned treatment (90.9% of RCTs), particularly the cumulative glucocorticoids (GC) dose and GC tapering, followed by clinical, laboratory and safety outcomes (63.3% each). Conversely, the most commonly reported outcomes in RCTs in GCA were prevention of relapses (72.2%), remission as well as treatment-related and safety outcomes (67.0% each). CONCLUSIONS: This SLR provides evidence and highlights the knowledge gaps on T2T strategies in PMR and GCA, informing the task force developing T2T recommendations for these diseases.

Systematic review to estimate the prevalence of inflammatory rheumatic diseases in Germany.

OBJECTIVE: This study aimed to update the prevalence estimates of inflammatory rheumatic diseases (IRD) in Germany. METHODS: A systematic literature search in PubMed and Web of Science (last search 08 November 2022) identified original articles (regional and nationwide surveys and claims data analyses for arthritides, connective tissue diseases, and vasculitides) on prevalences for the period 2014-2022. Data sources, collection period, case definition, and risk of bias are reported. Prevalences were estimated from available national data, with consideration of international data. RESULTS: Screening by two authors yielded 263 hits, of which 18 claims data analyses and 2 surveys met the inclusion criteria. Prevalences ranged from 0.42 to 1.85% (rheumatoid arthritis), 0.32-0.5% (ankylosing spondylitis), 0.11-0.32% (psoriatic arthritis), 0.037-0.14% (systemic lupus erythematosus), 0.07-0.77% (Sjögren's disease/sicca syndrome), 0.14-0.15% (polymyalgia rheumatica, ≥ 40 years), 0.04-0.05% (giant cell arteritis, ≥ 50 years), and 0.015-0.026% (ANCA-associated vasculitis). The risk of bias was moderate in 13 and high in 7 studies. Based on the results, we estimate the prevalence of IRD in Germany to be 2.2-3.0%, which corresponds to approximately 1.5-2.1 million affected individuals. The prevalence of juvenile idiopathic arthritis was reported to be around 0.10% (0.07-0.10%) of 0-18-year-olds, corresponding to about 14,000 children and adolescents in Germany. CONCLUSION: This systematic review shows an increase in the prevalence of IRD in Germany, which is almost exclusively based on claims data analyses. In the absence of multistage population studies, the available data are, overall, uncertain sources for prevalence estimates, with a moderate to high risk of bias.