PIM Kinases as Potential Biomarkers and Therapeutic Targets in Inflammatory Arthritides.

The Proviral Integration site for the Moloney murine leukemia virus (PIM)-1 kinase and its family members (PIM-2 and PIM-3) regulate several cellular functions including survival, proliferation, and apoptosis. Recent studies showed their involvement in the pathogenesis of rheumatoid arthritis RA, while no studies are available on psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). The main objective of this study is to assess the expression of PIM kinases in inflammatory arthritides, their correlation with proinflammatory cytokines, and their variation after treatment with biologic disease-modifying anti-rheumatic drugs or JAK inhibitors. We evaluated PIM-1, -2, and -3 expression at the gene and protein level, respectively, in the peripheral blood mononuclear cells and serum of patients with RA, PsA, axSpA, and healthy individuals (CTR). All the samples showed expression of PIM-1, -2, and -3 kinases both at the gene and protein level. PIM-1 was the most expressed protein, PIM-3 the least. PIM kinase levels differed between controls and disease groups, with reduced PIM-1 protein and increased PIM-3 protein in all disease samples compared to controls. No difference was found in the expression of these molecules between the three different pathologies. PIM levels were not modified after 6 months of therapy. In conclusion, our preliminary data suggest a deregulation of the PIM pathway in inflammatory arthritides. In-depth studies on the role of PIM kinases in this field are warranted.

Prevalence of Type 2 and Type 1 Diabetes in Psoriatic Arthritis: An Italian Study.

OBJECTIVE: Psoriatic arthritis (PsA) is burdened by an increased susceptibility to cardiovascular diseases. Comorbid diabetes may represent one of the key factors contributing to this risk. The aim of our medical records review study was to investigate the prevalence of type 2 diabetes (T2D) and type 1 diabetes (T1D) in an Italian PsA cohort. METHODS: The clinical records of all patients consecutively seen at our clinic with a diagnosis of PsA during a 12-month period were reviewed to identify comorbid T2D or T1D. For comparison, a 1:1 age- and sex-matched group of individuals with noninflammatory diseases was recruited. RESULTS: The final study cohort comprised 408 patients. The prevalence of T2D was 7.8% (95% confidence interval, 5.6-10.8) in PsA and 4.4% in controls (95% confidence interval, 2.8-6.9; p = 0.04). Two cases (0.49%) of T1D were identified in the PsA cohort, whereas no cases were observed in controls. In a multivariate logistic regression model including age, disease duration, and body mass index (BMI) as covariates, increasing age (odds ratio [OR], 1.079; p = 0.006) and BMI (OR, 1.188; p = 0.011) but not PsA duration predicted being classified as having T2D. In a similar model accounting for age and BMI, average disease activity score including 28 joints and C-reactive protein showed a trend toward significance (OR, 1.639; p = 0.066). CONCLUSIONS: In conclusion, our data provide further support to the emerging evidence of an increased risk of T2D in PsA patients. Cardiometabolic comorbidity represents a significant aspect of integrated arthritis management to improve long-term cardiovascular outcomes and to provide a comprehensive treatment.

Incidence, prevalence and mortality of systemic sclerosis in Italy: a nationwide population-based study using administrative health data.

To study incidence, prevalence and mortality of systemic sclerosis (SSc) in Italy, assessing epidemiological differences between men and women and in distinct age groups. We performed a nationwide population-based study using administrative health data from regional co-payment exemption registries. Patients entitled with SSc-specific co-payment exemption were included. Fourteen of the 20 Italian regions contributed data covering a population of over 45 million individuals. Crude annual incidence rate, annual prevalence, crude annual mortality rate and standardised mortality ratio (SMR) were calculated. In 2016, the overall crude incidence rate of SSc was 18.5 (95% CI 16.9-20.2) per million per year. Incidence rate was 31.0 (95% CI 28.1-34.1) per million in women, and 4.3 (95% CI 3.2-5.6) per million in men. Peak incidence was observed in the age range 55-69 years. Overall annual prevalence was 306.1 (95% CI 301.1-311.2) per million. Prevalence was 530.8 (95% CI 521.5-540.2) per million in women and 67.8 (95% CI 64.4-71.3) per million in men, with a female to male ratio of 7.8:1. Highest prevalence was observed in the range 70-84 years. Crude annual mortality rate was 27.9 (95% CI 24.9-31.1) per 1000 patients. Overall SMR in patients with SSc was 2.8 (95% CI 1.9-3.8). SMR was 3.8 (95% CI 2.9-5.1) in men and 2.6 (95% CI 1.8-3.6) in women. We provided updated estimates on epidemiology of SSc in Italy. Our findings on incidence, prevalence and mortality of SSc are consistent with previously published literature.

Nailfold capillaroscopy in common non-rheumatic conditions: A systematic review and applications for clinical practice.

OBJECTIVE: The role of nailfold capillaroscopy (NC) in common non-rheumatic conditions has not been systematically reported. The aim of this review is to outline NC features observed in frequent non-rheumatic conditions, providing a practical tool to support rheumatologists for the interpretation of capillaroscopic abnormalities in patients with no established connective tissue disease (CTD). METHODS: We undertook a systematic search in PubMed and Web of Science databases. Studies reporting adults or children with common non-rheumatic diseases or conditions in which quantitative and/or qualitative assessment of morphological nailbed capillary findings was obtained, were included. The presence of a control group composed by subjects not affected by the studied condition and direct comparison of findings between groups were needed. RESULTS: We included 25 articles. Diabetes mellitus (11 studies), glaucoma (7 studies) and essential hypertension (3 studies) were the most represented diseases. Reduced capillary density, tortuosity, dilated capillaries, microhaemorrhages, ramified capillaries and avascular areas can be observed in diabetic patients. Association was reported between poor glycaemic control or longer duration of diabetes, or presence of microvascular complications as retinopathy and neuropathy, and more severe capillaroscopic abnormalities. Decreased capillary density, tortuosity, microhaemorrhages, dilated capillaries, avascular areas and ramifications might also be present in glaucoma, while in essential hypertension a reduced capillary density might be expected. CONCLUSION: Abnormal capillaroscopic findings are not uncommon even in individuals with no CTD. Therefore, presence of comorbidities known to potentially affect the microvascular array should always be investigated in patients undergoing NC and the interpretation of findings might be weighted accordingly.

Efficacy, Safety, and Tolerability of a Very Low-Calorie Ketogenic Diet in Women with Obesity and Symptomatic Knee Osteoarthritis: A Pilot Interventional Study.

BACKGROUND/OBJECTIVES: Obesity is a major risk factor for knee osteoarthritis (OA), and weight loss is crucial for its management. This pilot study explores the effects of a Very Low-Calorie Ketogenic Diet (VLCKD) in women with obesity and symptomatic knee OA. METHODS: Women with symptomatic knee OA and obesity, defined as a body mass index (BMI) ≥ 30 kg/m2, were eligible for the VLCKD protocol. The intervention included a ketogenic phase from baseline (T0) to the 8th week (T8), followed by a progressive reintroduction of carbohydrates over the next 12 weeks, ending at the 20th week (T20). Body mass index (BMI), the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, the EuroQol 5D (EQ-5D), and the 36-item Short Form Health Survey (SF-36) were assessed at all time points. Generalized estimating equations were used to analyze the association between BMI and patient-reported outcomes across the study period. RESULTS: Twenty participants started the study, but four discontinued the intervention, with two of these being due to adverse effects. The mean age of the 16 patients who completed the 20-week program was 57.3 ± 5.5 years, and their mean BMI was 40.0 ± 4.8 kg/m2. The mean BMI significantly decreased to 37.5 ± 4.5 at T4, 36.3 ± 4.6 at T8, and 34.8 ± 4.8 at T20 (all p < 0.001 compared to baseline). The total WOMAC score improved from a mean of 43.6 ± 16.9 at T0 to 30.2 ± 12.8 at T4 (p = 0.005) and further to 24.7 ± 10.6 at T8 (p = 0.001) and to 24.8 ± 15.9 at T20 (p = 0.005). The reduction in BMI was significantly correlated with the improvements in WOMAC, EQ-5D, and SF-36 over time. No major adverse effects were observed. CONCLUSIONS: A 20-week VLCKD in women with obesity and knee OA significantly reduced their weight and improved their outcomes, warranting further research. This trial is registered with number NCT05848544 on ClinicalTrials.gov.

Does early arthritis clinic organisation improve outcomes? What evidence is there? A systematic review.

OBJECTIVES: To perform a systematic review aimed to identify studies addressing the effect of the establishment of a structured organisation programme, named early arthritis clinic (EAC), finalized to manage patients with early arthritis (EA) or suspected early rheumatoid arthritis (ERA). METHODS: A literature search was performed until May 2012 using electronic databases. Additional information was obtained through a hand and grey literature search. Primary and secondary outcomes and eligibility criteria have been defined. RESULTS: The search provided a total of 3367 citations and, after the selection process, 11 non randomised controlled trials were selected, including a total of 8240 participants. The efficacy of EAC did clearly emerge with regard to reduction of the referral lag time and of the time to treatment (secondary outcomes). Only two studies met the primary outcomes: one study demonstrated that the EAC contributed to reducing disease activity and radiographic progression but not functional disability, while another reported a reduction of pain after a 6-12-month period of follow-up. CONCLUSIONS: Whether the establishment of EAC would improve the prognosis of EA in terms of primary outcomes such as clinical, functional and radiologic progression compared to patients managed outside from EAC does appear a still poorly addressed issue in the literature, which should be recognised as an urgent unmet need by the rheumatology community to gain more evidence-based information on this topic.

Building a rheumatology biobank for reliable basic/translational research and precision medicine.

Research biobanks are non-profit structures that collect, manipulate, store, analyze and distribute systematically organized biological samples and data for research and development purposes. Over the recent years, we have established a biobank, the Rheumatology BioBank (RheumaBank) headed by the Medicine and Rheumatology unit of the IRCCS Istituto Ortopedico Rizzoli (IOR) in Bologna, Italy for the purpose of collecting, processing, storing, and distributing biological samples and associated data obtained from patients suffering from inflammatory joint diseases. RheumaBank is a research biobank, and its main objective is to promote large-scale, high-quality basic, translational, and clinical research studies that can help elucidate pathogenetic mechanisms and improve personalization of treatment choice in patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and other spondyloarthritides (SpA).

Post-Acute COVID-19 Joint Pain and New Onset of Rheumatic Musculoskeletal Diseases: A Systematic Review.

As the number of reports of post-acute COVID-19 musculoskeletal manifestations is rapidly rising, it is important to summarize the current available literature in order to shed light on this new and not fully understood phenomenon. Therefore, we conducted a systematic review to provide an updated picture of post-acute COVID-19 musculoskeletal manifestations of potential rheumatological interest, with a particular focus on joint pain, new onset of rheumatic musculoskeletal diseases and presence of autoantibodies related to inflammatory arthritis such as rheumatoid factor and anti-citrullinated protein antibodies. We included 54 original papers in our systematic review. The prevalence of arthralgia was found to range from 2% to 65% within a time frame varying from 4 weeks to 12 months after acute SARS-CoV-2 infection. Inflammatory arthritis was also reported with various clinical phenotypes such as symmetrical polyarthritis with RA-like pattern similar to other prototypical viral arthritis, polymyalgia-like symptoms, or acute monoarthritis and oligoarthritis of large joints resembling reactive arthritis. Moreover, high figures of post-COVID-19 patients fulfilling the classification criteria for fibromyalgia were found, ranging from 31% to 40%. Finally, the available literature about prevalence of rheumatoid factor and anti-citrullinated protein antibodies was largely inconsistent. In conclusion, manifestations of rheumatological interest such as joint pain, new-onset inflammatory arthritis and fibromyalgia are frequently reported after COVID-19, highlighting the potential role of SARS-CoV-2 as a trigger for the development of autoimmune conditions and rheumatic musculoskeletal diseases.

Efficacy, safety and tolerability of very low-calorie ketogenic diet in obese women with fibromyalgia: a pilot interventional study.

Introduction: Obesity can worsen fibromyalgia (FM) and very low-calorie ketogenic diet (VLCKD) is a potential therapeutic option for diseases that share clinical and pathophysiological features with FM. In this pilot interventional study, we investigated the effects of VLCKD in obese women with FM. Methods: Female patients with FM and a body mass index (BMI) ≥ 30 kg/m2 were eligible for VLCKD. The ketogenic phase (T0 to T8) was followed by progressive reintroduction of carbohydrates (T8 to T20). Changes in BMI, Fibromyalgia Impact Questionnaire (FIQ), Hospital Anxiety and Depression Scale (HADS), EuroQol 5D (EQ-5D) and 36-item Short Form Health Survey (SF-36) were evaluated. A change of 14% in FIQ was considered clinically relevant. The longitudinal association between BMI and patient-reported outcomes (PROs) was assessed using generalized estimating equations. Results: Twenty women were enrolled. Two discontinued the intervention. The mean age of the 18 patients who reached T20 was 51.3 years and mean BMI was 37.2 kg/m2. All patients lost weight during the first period of VLCKD and this achievement was maintained at T20. Mean BMI decreased from 37.2 kg/m2 at T0 to 34.8 kg/m2 at T4, 33.5 kg/m2 at T8 and 32.1 kg/m2 at T20 (p < 0.001). A significant reduction of mean FIQ from 61.7 at T0 to 37.0 at T4 and to 38.7 at T8 (p < 0.001) was observed and it was maintained at T20 with a mean FIQ of 39.1 (p = 0.002). Similar results were obtained for HADS, EQ-5D and SF-36. Analysing each participant, the reduction of FIQ was clinically meaningful in 16 patients (89%) at T4, in 13 (72%) at T8 and in 14 (78%) at T20. No significant association was observed between change in BMI and improvement of the PROs over time. Adverse effects were mild and transient. No major safety concerns emerged. Conclusion: These are the first data on the efficacy of VLCKD in FM. All patients achieved improvement in different domains of the disease, which was maintained also after carbohydrate reintroduction. Our results suggest that ketosis might exert beneficial effects in FM beyond the rapid weight loss. Clinical trial registration: This trial is registered on ClinicalTrials.gov, number NCT05848544.

Inflammatory rheumatic diseases with onset after SARS-CoV-2 infection or COVID-19 vaccination: a report of 267 cases from the COVID-19 and ASD group.

OBJECTIVES: To better define the spectrum of new-onset post-COVID-19 and post-COVID-19 vaccine inflammatory rheumatic diseases (IRD) from a large multicentric observational study. METHODS: Consecutive cases of IRD encountered during a 12-month period and satisfying one of the following inclusion criteria: (a) onset of the rheumatic manifestations within 4 weeks from SARS-CoV-2 infection or (b) onset of the rheumatic manifestations within 4 weeks from the administration of one of the COVID-19 vaccines ws recruited. RESULTS: The final analysis cohort comprised 267 patients, of which 122 (45.2%) in the post-COVID-19 and 145 (54.8%) in the postvaccine cohort. Distribution of IRD categories differed between the two cohorts: the post-COVID-19 cohort had a higher percentage of patients classified as having inflammatory joint diseases (IJD, 52.5% vs 37.2%, p=0.013) while the post-vaccine cohort had a higher prevalence of patients classified as polymyalgia rheumatica (PMR, 33.1% vs 21.3%, p=0.032). No differences were detected in the percentage of patients diagnosed with connective tissue diseases (CTD 19.7% vs 20.7%, p=0.837) or vasculitis (6.6% vs 9.0%, p=0.467). Despite the short follow-up period, IJD and PMR patients' response to first-line therapy was favourable, with both groups achieving a drop in baseline disease activity scores of ~30% and ~70% respectively. CONCLUSION: Our article reports the largest cohort published to date of new-onset IRD following SARS-CoV-2 infection or COVID-19 vaccines. Although causality cannot be ascertained, the spectrum of possible clinical manifestations is broad and includes IJD, PMR, CTD and vasculitis.

Osteitis condensans ilii: prevalence and characteristics of a neglected mimic of sacroiliitis.

OBJECTIVES: Osteitis condensans ilii (OCI) is a benign condition characterised by triangular sclerosis of the iliac bone which may mimic radiographic sacroiliitis. Prevalence is estimated between 0.9 and 2.5%, with female predominance, but the most recent article reporting original epidemiological data in the general population was published in 1971. The aim of our study is to contribute updated figures about prevalence of OCI in Italy. METHOD: A retrospective review of pelvic radiographs was conducted. Consecutive patients visiting the emergency department of our Institution between 1st January and 31st December 2020 were enrolled. Individuals with a past diagnosis of axial spondyloarthritis were excluded. Presence of OCI was evaluated by two musculoskeletal radiologists. Clinical and radiologic features such as osteoarthritis and insertional enthesopathy were also assessed. RESULTS: We included 1047 individuals (61% female) with a median age of 74 years. OCI was present in 10 cases, accounting for a prevalence in the general population of 1.0% (95% CI 0.5-1.7). All patients with OCI were women and, in the female sample, prevalence was 1.6% (95% CI 0.7-2.8). Clinical characteristics and associated radiographic features were not different between patients with OCI and women without OCI. CONCLUSIONS: The prevalence of OCI observed in our study is consistent with previous literature, and we confirm that it is more frequently retrieved in women. Longitudinal research is warranted to elucidate the evolution, while knowledge about the disorder is needed to raise the awareness of rheumatologists and radiologists and to properly identify and report the condition. Key Points • OCI may mimic sacroiliitis and is a major differential diagnosis of radiographic axial spondyloarthritis. • Prevalence of OCI in our sample is 1.0%, in line with previous literature. • OCI predominantly affects women, and our study suggests that the disorder can be incidentally identified even after childbearing age. • Increased awareness of the characteristics of OCI can facilitate identification and reporting of the disorder.

Ultrasonography of Inflammatory and Structural Lesions in Hand Osteoarthritis: An Outcome Measures in Rheumatology Agreement and Reliability Study.

OBJECTIVE: To standardize and assess the reliability of ultrasonographic assessment of inflammatory and structural lesions in patients with hand osteoarthritis (OA). METHODS: The Outcome Measures in Rheumatology Ultrasound Working Group selected synovial hypertrophy (SH), joint effusion (JE), and power Doppler (PD) signals as the main inflammatory lesions in hand OA, and suggested osteophytes in the scapho-trapezio-trapezoid (STT) and cartilage defects in the proximal interphalangeal (PIP) joints as novel additions to previous structural scoring systems. A complementary imaging atlas provided detailed examples of the scores. A reliability exercise of static images was performed for the inflammatory features, followed by a patient-based exercise with 6 sonographers testing inflammatory and structural features in 12 hand OA patients. We used Cohen's kappa for intrareader and Light's kappa for interreader reliability for all features except PD, in which prevalence-adjusted bias-adjusted kappa (PABAK) was applied. Percentage agreement was also assessed. RESULTS: The web-based reliability exercise demonstrated substantial intra- and interreader reliability for all inflammatory features (κ > 0.64). In the patient-based exercise, intra- and interreader reliability, respectively, varied: SH κ = 0.73 and 0.45; JE κ = 0.70 and 0.55; PD PABAK = 0.90 and 0.88; PIP joint cartilage κ = 0.56 and 0.45; and STT osteophytes κ = 0.62 and 0.36. Percentage close agreement was high for all features (>85%). CONCLUSION: With ultrasound, substantial to excellent intrareader reliability was found for inflammatory features of hand OA. Interreader reliability was moderate, but overall high close agreement between readers suggests that better reliability is achievable after further training. Assessment of osteophytes in the STT joint and cartilage in the PIP joints achieved less reliability and the latter is not endorsed.

Systemic inflammation and antibodies to citrullinated peptides in hand osteoarthritis.

OBJECTIVES: To investigate systemic inflammation and autoimmune response to citrullinated peptides in patients with erosive and non erosive 'lone' hand osteoarthritis (HOA) with no hip/knee involvement and their relationship with radiographic structural damage. METHODS: Sera were obtained from a total of 99 patients with HOA (52 patients with erosive HOA and 47 patients with non-erosive HOA) and from 50 control subjects (NC). Hand radiographs were obtained from all patients and scored for joint damage according to the Kellgren-Lawrence and the Kallman scores. Serum levels of high-sensitivity CRP (hsCRP), IL-6, pentraxin-3 (PTX-3), anti-CCP and anti-modified citrullinated vimentin (MCV) antibodies were evaluated by a sandwich ELISA. RESULTS: Circulating levels of inflammatory biomarkers hsCRP, IL-6 and PTX3 were not significantly different in the two groups of patients with erosive and non-erosive HOA compared to NC and no significant difference was seen between non-erosive and erosive HOA. Anti-CCP positivity was detected respectively in 1 patient (2.1%) with non-erosive HOA and 1 patient (1.9%) with erosive HOA. Anti-MCV antibodies were present in 4 patients (8.5%) with non-erosive HOA, and 4 patients (7.7%) with erosive HOA. In the control group, one subject (2%) was positive for anti-CCP and 2 subjects (4%) had anti-MCV antibodies. Significant correlation was obtained only between body mass index and hsCRP concentration (r=0.4071; p<0.0001). No correlation between inflammation markers/autoantibodies and disease duration and radiological scores was found. CONCLUSIONS: Our study underlines the lack of systemic inflammation and autoimmunity in 'lone' HOA and confirms the association between BMI and CRP levels.

Seasonality of Back Pain in Italy: An Infodemiology Study.

BACKGROUND: E-health tools have been used to assess the temporal variations of different health problems. The aim of our infodemiology study was to investigate the seasonal pattern of search volumes for back pain in Italy. METHODS: In Italian, back pain is indicated by the medical word "lombalgia". Using Google Trends, we selected the three search terms related to "lombalgia" with higher relative search volumes (RSV), (namely, "mal di schiena", "dolore alla schiena" and "dolore lombare"), representing the semantic preferences of users when performing web queries for back pain in Italy. Wikipedia page view statistics were used to identify the number of visits to the page "lombalgia". Strength and direction of secular trends were assessed using the Mann-Kendall test. Cosinor analysis was used to evaluate the potential seasonality of back pain-related RSV. RESULTS: We found a significant upward secular trend from 2005 to 2020 for search terms "mal di schiena" (τ = 0.734, p < 0.0001), "dolore alla schiena" (τ = 0.713, p < 0.0001) and "dolore lombare" (τ = 0.628, p < 0.0001). Cosinor analysis on Google Trends RSV showed a significant seasonality for the terms "mal di schiena" (pcos < 0.001), "dolore alla schiena" (pcos < 0.0001), "dolore lombare" (pcos < 0.0001) and "lombalgia" (pcos = 0.017). Cosinor analysis performed on views for the page "lombalgia" in Wikipedia confirmed a significant seasonality (pcos < 0.0001). Both analyses demonstrated a peak of interest in winter months and decrease in spring/summer. CONCLUSIONS: Our infodemiology approach revealed significant seasonal fluctuations in search queries for back pain in Italy, with peaking volumes during the coldest months of the year.

Fibromyalgia and obesity: A comprehensive systematic review and meta-analysis.

INTRODUCTION: Obesity has been associated with several complications, including musculoskeletal disorders. Aim of the present systematic review was to identify all available evidence on the relationship between fibromyalgia (FM) and obesity, including epidemiological association, impact of obesity on FM severity and effect of weight loss strategies on FM symptoms. METHODS: MedLine, Cochrane Central Register of Controlled Trials and Web of Science databases were searched up to September 2020 to identify eligible articles. Data from studies reporting the prevalence of obesity in FM patients were pooled using a random-effects model. RESULTS: After removal of duplicate records, 393 studies proceeded to review. A total of 41 articles were deemed eligible for inclusion in final synthesis. Quality assessment revealed that the overall risk of bias was high. The overall prevalence of obesity in FM was 35.7% (95% CI: 31.8 - 39.9%), with higher figures reported for USA. The majority of studies included demonstrated that obesity is associated with different domains of the disorder, including composite measures of activity, pain severity, tender point count, stiffness, fatigue, physical functioning/disability, sleep, cognitive dysfunction, and quality of life; the strength of correlation was weak on average. Inconsistent data were available regarding the correlation with depression and anxiety. Only few studies addressed the effect of therapeutic weight loss in FM, either by bariatric surgery, diet/exercise combination or behavioral weight loss, providing preliminary evidence for a potential benefit of weight loss in ameliorating FM symptoms. CONCLUSIONS: Available data support a potential interplay between obesity and FM-related symptoms. Weight management should be encouraged in patients with FM.

The Effect of Ketogenic Diet on Inflammatory Arthritis and Cardiovascular Health in Rheumatic Conditions: A Mini Review.

The principle of ketogenic diet (KD) is restriction of carbohydrates to a maximum of 5-10% of the total daily caloric intake, aiming at shifting body metabolism toward ketone bodies. Different studies suggested promising results of KD to help patients to lose weight, to reduce insulin requirements in diabetes, to supplement cancer protocols, to treat neurological conditions and to optimize control of metabolic and cardiovascular diseases. However, literature about the anti-inflammatory properties of KD in rheumatic diseases is still limited. The beneficial effects of weight loss in patients with inflammatory arthritis can be explained by biomechanical and biochemical factors. Obesity is associated with macrophage activation and production of pro-inflammatory cytokines including TNF-α, IL-1b, and IL-6. The clinical effect of KD may be primarily attributed to improvement of insulin sensitivity. Insulin resistance is associated with an increase of TNF-α, IL-1α, IL-1ß, IL-6, and leptin. Moreover, reduction of body's adipose tissue and weight loss account for part of the anti-inflammatory effects and for the impact of KD on cardiovascular health. In rheumatoid arthritis, fasting was shown to be effective in reducing disease symptoms, possibly through the production of ß-hydroxybutyrate (BHB), the main ketone body. BHB may exert inhibitory effects also on IL-17 and intermittent fasting improved the clinical manifestations of psoriatic arthritis. In ankylosing spondylitis, current literature doesn't allow to draw conclusion about the effects of KD. Future prospective studies will be needed to elucidate the potential beneficial effects of KD on specific domains and clinical outcomes in patients with inflammatory arthritis.