Adalimumab treatment of resistant chondrocalcinosis.

In this article, we present a case of resistant chondrocalcinosis who had a good response with 40mg subcutaneous adalimumab. To our knowledge, this is the first report using adalimumab successfully in severe CPDD. Anti-TNF therapy can be a good therapeutic option for second line therapy in CPPD.

Calcium Pyrophosphate Crystal Formation and Deposition: Where Do we Stand and What Does the Future hold?

PURPOSE OF THE REVIEW: Although calcium pyrophosphate deposition (CPPD) has been known since the 1960s, our understanding of its pathogenesis remains rudimentary. This review aims to illustrate the known mechanisms underlying calcium pyrophosphate (CPP) crystal formation and deposition and explore future directions in research. By examining various perspectives, from basic research to clinical and imaging assessments, as well as new emerging methodologies, we can establish a starting point for a deeper understanding of CPPD pathogenesis. RECENT FINDINGS: Recent years have seen significant advances in CPPD research, particularly in the clinical field with the development of the 2023 ACR/EULAR classification criteria for CPPD disease, and in imaging with the introduction of the OMERACT ultrasonographic definitions and scoring system. However, progress in basic research has been slower. New laboratory approaches, such as Raman spectroscopy and omics sciences, offer promising insights that may help piece together the puzzle of CPPD. CPPD is a common yet understudied condition. As the population ages and CPPD becomes more prevalent, there is an urgent need to better understand the disease and the mechanisms involved in crystal formation and deposition, in order to improve diagnosis and therapeutic approaches.

Current Role of Conventional Radiology in Rheumatology.

The correct interpretation of the most common radiological findings in rheumatological diseases can be pivotal for an accurate diagnosis. X rays offer immediacy, worldwide availability, affordability, and the ability to detect subtle bone changes. Numerous scoring systems that have been developed to support clinical practice are based on joint damage that can be observed on X rays. Metabolic, degenerative, infective, and inflammatory processes manifest as distinct alterations in joints and their identification can be challenging. In this review, the authors will discuss the most common radiological findings in hands, hips, and the spine that can serve as valuable diagnostic tools.

A Narrative Review of Chondrocalcinosis: Clinical Presentation, Diagnosis, and Therapies.

Calcium pyrophosphate deposition disease is categorized into radiographic chondrocalcinosis, acute calcium pyrophosphate arthritis, chronic calcium pyrophosphate arthritis, and osteoarthritis with calcium pyrophosphate deposition. These entities collectively are characterized by the deposition of calcium into joints, which then may cause localized and systemic inflammation, resulting in pain and swelling in the affected joints. Patients with the ANKH gene are more susceptible to the development of CPP arthritis as are those with primary hyperparathyroidism, hypomagnesemia, and hemochromatosis. Radiographic chondrocalcinosis is asymptomatic. Acute calcium pyrophosphate arthritis results in self-limited periods of joint pain and swelling in the affected joint. Along with localized inflammation, there may also be systemic inflammation characterized by fever and elevated inflammatory markers. Chronic calcium pyrophosphate arthritis results in periods of quiescence interrupted by flares that are identical to acute periods of disease. Osteoarthritis associated calcium pyrophosphate arthritis presents with chronic pain well described in osteoarthritis with periods of acute flares. In 2023, a joint effort by the American College of Rheumatology and the European League Against Rheumatism developed guidelines meant to aid in the recognition of calcium pyrophosphate deposition diseases. The diagnosis is made if there is proof of either crowned dens syndrome or synovial fluid analysis demonstrating calcium pyrophosphate crystals or when more than 56 points are summed utilizing the criteria described in the guidelines. Radiographic chondrocalcinosis requires no therapy. Acute calcium pyrophosphate arthritis is treated with the goal of aborting the flare. Treatment options include nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, oral corticosteroids, parenteral corticosteroids, intraarticular corticosteroids, IL-1 inhibitors, or parenteral adrenocorticotropic hormone (ACTH). The goal in treatment for chronic calcium pyrophosphate arthritis is the suppression of acute flares. The drugs used for acute flare treatment may be given as maintenance therapy with the additional options of methotrexate and hydroxychloroquine.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice.

OBJECTIVE: To summarise current data regarding the use of imaging in crystal-induced arthropathies (CiAs) informing a European Alliance of Associations for Rheumatology task force. METHODS: We performed four systematic searches in Embase, Medline and Central on imaging for diagnosis, monitoring, prediction of disease severity/treatment response, guiding procedures and patient education in gout, calcium pyrophosphate dihydrate deposition (CPPD) and basic calcium phosphate deposition (BCPD). Records were screened, manuscripts reviewed and data of the included studies extracted. The risk of bias was assessed by validated instruments. RESULTS: For gout, 88 studies were included. Diagnostic studies reported good to excellent sensitivity and specificity of dual-energy CT (DECT) and ultrasound (US), high specificity and lower sensitivity for conventional radiographs (CR) and CT. Longitudinal studies demonstrated sensitivity to change with regard to crystal deposition by US and DECT and inflammation by US and structural progression by CR and CT. For CPPD, 50 studies were included. Diagnostic studies on CR and US showed high specificity and variable sensitivity. There was a single study on monitoring, while nine assessed the prediction in CPPD. For BCPD, 56 studies were included. There were two diagnostic studies, while monitoring by CR and US was assessed in 43 studies, showing a reduction in crystal deposition. A total of 12 studies with inconsistent results assessed the prediction of treatment response. The search on patient education retrieved two studies, suggesting a potential role of DECT. CONCLUSION: This SLR confirmed a relevant and increasing role of imaging in the field of CiAs.

Calcium pyrophosphate deposition disease: historical overview and potential gaps.

CPPD disease can affect patients' quality of life through its various clinical presentations. This mini-review discusses the evolution of CPPD from its discovery to current knowledge of its pathogenesis, genetic associations, diagnostics, and treatment options. Despite extensive research, the exact mechanisms of CPPD are not well understood, and there is a notable lack of knowledge about psychosocial impacts and patient experiences. This study aims to present a CPPD Disease Timeline identifying gaps in current knowledge and potential directions for future research. These findings contribute to a broader understanding of CPPD disease and emphasize the importance of continued research and innovation in this field.

Acute cervical epidural abscess with concurrent calcium pyrophosphate deposition after cervical spinal surgery: A case report.

Background: Spinal epidural abscess (SEA) is a rare condition that may result in catastrophic outcomes. On the other hand, calcium pyrophosphate (CPP) deposition disease (CPPD) causes inflammatory arthritis. Spinal involvement of a crystal-induced inflammation caused by CPPD is also common. Surgery is a common risk factor for both SEA and CPPD; however, the postoperative acute onset of SEA complicated with CPPD is extremely rare. Case Description: A man in his 70s presented to our hospital, complaining of right upper limb weakness, loss of dexterity, and gait disturbance. The diagnosis of cervical spondylotic myelopathy was made, and he performed laminectomy at C3, C4, and C5 levels. Four days after the laminectomy, he suffered from acute neck pain, weakness, and hypoesthesia in his arms and legs. Magnetic resonance imaging revealed a mass occupying the dorsal epidural space of C6 and C7, compressing the cervical spinal cord. Considering the acute symptomatology, an acute spinal epidural hematoma after surgery was suspected; therefore, emergency C6 and C7 laminectomy was performed. Surgical findings indicated that the pressure inside the spinal canal was elevated, and the mass was purulent exudate. Pathological examination showed suppurative inflammation with concomitant deposition of CPP. SEA complicated with CPPD was considered; therefore, antibiotics and non-steroidal anti-inflammatory drugs were administered. The motor weakness and hypoesthesia were improved despite a slight residual deficit in his dexterity. Conclusion: An acute onset of SEA complicated with CPPD after cervical surgery has rarely been reported. The suppurative inflammation fostered by the crystal-induced inflammation may account for the acute symptomatology.

Crystal induced arthropathies-a comparative study of 40 patients with apatite rheumatism, chondrocalcinosis and primary synovial chondromatosis.

Introduction: Apatite rheumatism (AR), chondrocalcinosis (Ch-C), and primary synovial chondromatosis (prSynCh) are regarded as distinct clinical entities. The introduction of the non-staining technique by Bély and Apáthy (2013) opened a new era in the microscopic diagnosis of crystal induced diseases, allowing the analysis of MSU (monosodium urate monohydrate) HA (calcium hydroxyapatite), CPPD (calcium pyrophosphate dihydrate) crystals, cholesterol, crystalline liquid lipid droplets, and other crystals in unstained sections of conventionally proceeded (aqueous formaldehyde fixed, paraffin-embedded) tissue samples. The aim of this study was to describe the characteristic histology of crystal deposits in AR, Ch-C, and prSynCh with traditional stains and histochemical reactions comparing with unstained tissue sections according to Bély and Apáthy (2013). Patients and methods: Tissue samples of 4 with apatite rheumatism (Milwaukee syndrome), 16 with chondrocalcinosis, and 20 with clinically diagnosed primary synovial chondromatosis were analyzed. Results and conclusion: Apatite rheumatism, chondrocalcinosis, and primary synovial chondromatosis are related metabolic disorders with HA and CPPD depositions. The authors assume that AR and Ch-C are different stages of the same metabolic disorder, which differ from prSynCh in amorphous mineral production, furthermore in the production of chondroid, osteoid and/or bone. prSynCh is a defective variant of HA and CPPD induced metabolic disorders with reduced mineralization capabilities, where the deficient mineralization is replaced by chondroid and/or bone formation. The non-staining technique of Bély and Apáthy proved to be a much more effective method for the demonstration of crystals in metabolic diseases than conventional stains and histochemical reactions.

[First classification criteria for diseases caused by calcium pyrophosphate deposition (CPPD)-Translation, explanation and assessment]. / Erste Klassifikationskriterien für durch Kalziumpyrophosphatablagerungen verursachte Erkrankungen ­ Übersetzung, Erläuterung und Bewertung.

AIM: For diseases caused by calcium pyrophosphate deposition (CPPD), validated classification criteria were previously lacking. In this article the recently developed and validated classification criteria are translated, explained, and assessed. METHODS: In recent years a multinational research group developed classification criteria for CPPD disease with the support by the European Alliance of Associations for Rheumatology (EULAR) and the American College of Rheumatology (ACR), following an established method. The developed criteria were finally validated in an independent cohort. The translation and annotation of the new first classification criteria were carried out in an iterative procedure in consensus with the authors. RESULTS: The presence of a crowned dens syndrome or calcium pyrophosphate crystals in the synovial fluid in patients with pain, swelling or sensitivity of the joints (entry criterion) is sufficient for the classification as CPPD disease, where the symptoms cannot be completely explained by another rheumatic disease (exclusion criterion). If these symptoms are not present, a count of more than 56 points based on weighted criteria comprised of clinical features and the results of laboratory and imaging investigations can be included for classification as a CPPD disease. These criteria had a sensitivity of 92.2% and a specificity of 87.9% in the derivation cohorts (190 CPPD cases and 148 mimics), whereas the sensitivity was 99.2% and the specificity 92.5% in the validation cohorts (251 CPPD cases and 162 mimics). CONCLUSION: The ACR/EULAR classification criteria 2023 of a CPPD disease will facilitate clinical research in this field. The use in the clinical routine will show how practical the criteria are.

Safety and efficacy of colchicine in crystal-induced arthritis flare in 54 patients with severe chronic kidney disease.

INTRODUCTION: Colchicine, commonly used in gout flare, is contraindicated in severe chronic kidney disease (CKD) (estimated glomerular filtration rate <30 mL/min). However, in this context, there are few alternatives, and colchicine use persists. We evaluated the tolerance of colchicine and its efficacy in patients with severe CKD. PATIENTS AND METHODS: All prescriptions of colchicine for managing crystal-induced arthritis flare (gout or calcium pyrophosphate deposition (CPPD) disease) in a hospitalised patient with severe CKD were screened from September 2020 to September 2021. After patient consent and treatment information, clinical and biological safety and efficacy data were prospectively collected from day 1 (D1) to D11. RESULTS: We included 54 patients (median age 75 years (IQR 67-83)) with 62 colchicine prescriptions (cases). Twelve (22%) patients were on dialysis. The main reason for hospitalisation was heart failure (31.5%), acute renal failure (22.2%), infection (18.5%) or an acute joint episode (9.3%). In total, 59.3% of patients had diabetes. The prescriptions concerned 58 cases of gout flares, 1 case of CPPD and 3 cases of both. Initial colchicine dosages were ≤0.5 mg/day in 47/62 (75.8%) cases; no dosage exceeded 1 mg/day (median duration of 6 days (IQR 3-11)). Colchicine was well tolerated in 47/61 (77%) cases. No serious adverse event was reported. Colchicine was considered completely effective by the medical team in 48/58 (83%) of cases. CONCLUSION: The use of colchicine, at reduced doses, was mostly effective to treat crystal-induced arthritis flare in 54 patients with severe CKD and was well tolerated, without any serious adverse events.

Ultrasound reveals a high prevalence of CPPD in consecutive patients with knee pain.

The objective of this study is to estimate the prevalence of US findings indicative of calcium pyrophosphate deposition (CPPD) in patients with knee pain. Consecutive patients with knee pain, equally distributed among males and females in seven different age-decades (21-90 years), were enrolled in a cross-sectional study. The presence of US OMERACT-defined CPPD (medial and lateral menisci and femoral hyaline cartilage) and osteophytes (medial and lateral compartments of the tibiofemoral joint) was scored as presence/absence in both knees. Four hundred twenty participants were enrolled (210 men/210 women). Fibrocartilage and hyaline cartilage CPPDs were detected by US in 94/420 (22.4%) and 41/420 (9.8%) participants, respectively. No significant sex differences were noted. The prevalence and the extent of CPPD increased with age. Fibrocartilage and hyaline cartilage CPPDs were identified in 0/60 participants in the third decade, and in 28/60 (46.7%) and 14/60 (23.3%) participants in the ninth decade, respectively (p for trend < 0.01). While fibrocartilage and hyaline cartilage CPPD is virtually absent in subjects younger than 40 and 50 years old, their prevalence steeply increases above from these age groups. Age (aIRR, 1.03; 95% CI, 1.02-1.05), osteophyte score (aIRR, 1.40; 95% CI, 1.22-1.60), and hyaline cartilage CPPD score (aIRR, 2.68; 95% CI, 2.06-3.49) were associated with fibrocartilage CPPD score, whereas age (aIRR, 1.02; 95% CI, 1.01-1.05) and fibrocartilage CPPD score (aIRR, 2.92; 95% CI, 2.29-3.72) were associated with hyaline cartilage CPPD score in multivariable negative binomial regression analyses. In conclusion, we report the US prevalence of CPPD in patients with knee pain. Fibrocartilage CPPD occurs at a younger age and is more prevalent than hyaline cartilage CPPD. Key points • Fibrocartilage CPPD occurs at a younger age and is more prevalent than hyaline cartilage CPPD. • Fibrocartilage and hyaline cartilage CPPDs are virtually absent in subjects younger than 40 and 50 years old. • In subjects older than 80 years, fibrocartilage and hyaline cartilage CPPD prevalence rises up to 46.7% and 23.3%, respectively.

Case Report and Literature Review of Parvimonas micra: Difficult-to-Treat Arthritis in Hiding.

Septic arthritis is a life-threatening rheumatological syndrome that is highly related to a patient's immune status and comorbidities, and although the most common clinical presentation is rapid-onset monoarthritis, it can also appear as subacute or chronic joint swelling. In these cases, differential diagnosis is more challenging, but early diagnosis and treatment is no less urgent to ensure a good global prognosis and the best outcome of the affected joint. Anaerobic microorganisms, such as Parvimonas micra, are an uncommon cause of septic arthritis (less than 5% of cases) but may be the cause of subacute arthritis. Knowledge about Parvimonas micra is important, as it is difficult to culture in the laboratory and generates a synovial fluid with atypical characteristics for septic arthritis so that, if not suspected, its diagnosis can be easily overlooked and underdiagnosed. We present the case of a 76-year-old woman with subacute arthritis of the left knee, describe the difficult diagnosis and treatment of its unexpected cause (Parvimonas micra), and review previously described cases, identifying the possible common comorbidities that may help clinicians easily find and treat this cause of subacute septic arthritis.

Outcomes of total hip arthroplasty in calcium pyrophosphate deposition disease patients.

OBJECTIVE: We aim to examine the demographics, clinical characteristics, outcomes, and resource utilization following total hip arthroplasty (THA) in patients with and without calcium pyrophosphate deposition (CPPD) disease. METHODS: We queried the National Inpatient Sample database to identify patients who underwent THA between 2006 and 2014. The ICD-9 code 81.51 was used to determine the patients who underwent THA, and of those, we classified 2 groups of patients: (i) those with ICD-9 codes defining CPPD and (ii) those without any CPPD code. Data collection included patient demographics and comorbidities. Outcomes post-THA were mortality, length of stay (LOS), and costs. Associations between CPPD and specific morbidity were evaluated with chi-square tests. T tests were used for continuous variables. RESULTS: Among the 4,111,808 patients who underwent THA, 6198 (0.15 %) had CPPD, with a mean age of 77 years and 64.2 % were females. CPPD patients were more likely to be older (mean age 77 vs 72.7 years; p<0.001) than non-CPPD patients. The Charlson Comorbidity Index score ≥ 2 was more frequently seen in CPPD, however, the mortality post-THA was lower in the CPPD patients (0.7 % vs 1.7 %, OR 0.35, 95 % CI 0.26- 0.47). THA in CPPD patients was associated with a longer mean length of stay (LOS) (6.04 vs 5.15 days, OR 1.15, 95 % CI 1.09-1.22) while mean total charges were not statistically different between the 2 groups (p = 0.344). CPPD patients were more likely to be discharged to rehabilitation or other nursing facilities (42.5 % vs 35.3 %, p<0.001). The number of THA procedures increased in both CPPD and non-CPPD patients over time. CONCLUSIONS: CPPD patients who underwent THA were more likely to be older, with a greater comorbidity burden, longer LOS and discharged to a non-home setting.

Diagnosis of calcium pyrophosphate crystal deposition disease by ultrasonography: how many and which sites should be scanned?

OBJECTIVE: To develop the optimal US scanning protocol for the diagnosis of CPPD disease. METHODS: In this cross-sectional study, consecutive patients with a crystal-proven diagnosis of CPPD disease, and age-, sex-matched disease controls and with a negative synovial fluid analysis were prospectively enrolled in two Italian Institutions. Four rheumatologists, blinded to patients' clinical details, performed US examinations using a standardised scanning protocol including 20 joints (shoulders, elbows, wrists, metacarpophalangeal joints from 2nd to 5th fingers, hips, knees, ankles). CPPD was identified as presence/absence, according to the OMERACT definitions. Reduced US scanning protocols were developed by selecting the most informative joints to be imaged by US using the LASSO technique. Patients were randomly divided into training and validation sets. Their diagnostic accuracy was tested comparing the area under the ROC curves. RESULTS: 204 participants were enrolled: 102 with CPPD disease and 102 disease controls [age (mean±standard deviation) 71.3 ± 12.0 vs 71.1 ± 13.5 years, female: 62.8% vs 57.8%].The median number of joints with US evidence of CPPD was 5 (IQR: 4-7) and 0 (IQR: 0-1) in patients with CPPD disease and controls, respectively (p< 0 01).The detection of CPPD in ≥ 2 joints using a reduced scanning protocol (bilateral assessment of knees, wrists, and hips) showed a sensitivity of 96.7% (95%CI: 82.8-99.9) and a specificity of 100 (95%CI: 88.8-100.0) for the diagnosis of CPPD disease and had good feasibility [(mean±standard deviation) 12.5 ± 5.3 min]. CONCLUSION: Bilateral US assessment of knees, wrists, and hips had excellent accuracy and good feasibility for the diagnosis of CPPD disease.

Orthostatic hypotension as an unusual presentation of spinal calcium pyrophosphate deposition disease: case report and review of literature.

Calcium pyrophosphate crystal deposition disease (CPPD), also known as pseudogout, with spinal involvement, is associated with clinical manifestations of acute nerve compression or chronic spinal stenosis. Precipitation of crystals of calcium pyrophosphate dihydrate in connective tissues can lead to acute inflammatory arthritis, degenerative chronic arthropathies, and radiographic evidence of cartilage calcification. We present a case of an 87-year-old woman, with unstudied chronic polyarthralgia and symptomatic orthostatic hypotension. It were documented acute calcium pyrophosphate deposition wrist arthritis, and cervical CT and MRI was suggestive of spinal involvement of CPPD. Workup excluded other causes of OH. Surgical approach could be indicated to minimize the symptoms, but it was contra-indicated due to the patient's performance status, so histological diagnosis was not possible. Muscle atrophy played an important part in the rapid progression of this insidious chronic disease. Conservative and symptomatic treatment achieve scarce short-term clinical improvement. Spinal involvement of CPPD was thought to be rare but recent studies show a higher prevalence than expected. We call for attention to the extent of structural changes that may occur when not early diagnosed nor treated. High clinical suspicion is required and this is, to our knowledge, the first report of orthostatic hypotension as a presentation of CPPD.

Acute Inflammatory Arthropathy and Hypercalcemia Leading to a Diagnosis of Primary Hyperparathyroidism in a Patient With Known Sarcoidosis.

Calcium pyrophosphate deposition disease (CPPD) is a crystal-induced arthropathy characterized by calcium pyrophosphate crystal deposition in joints and soft tissues. The diagnosis is suggested by the presence of chondrocalcinosis on x-ray but is most often diagnosed by synovial fluid analysis (SFA). CPPD is associated with aging and metabolic disorders such as hyperparathyroidism. In this case, we present an 87-year-old woman with known sarcoidosis who presented with acute arthropathy, hypercalcemia, and radiographic evidence of CPPD. Her hypercalcemia had been attributed to her sarcoidosis in the past without a full workup. Hypercalcemia in the setting of suspected CPPD led to a full workup for hypercalcemia and ultimately led to a diagnosis of primary hyperparathyroidism. This case highlights the importance of a complete evaluation for hypercalcemia in the setting of CPPD, even when another disease, such as sarcoidosis, could explain hypercalcemia. Ultimately, CPPD aided in diagnosing hyperparathyroidism in our patient with known sarcoidosis.

Lateral meniscus with tears or with histologic calcification does not increase the risk of lateral osteoarthritis after medial unicompartmental arthroplasty.

PURPOSE: Meniscal tears or histological meniscal calcifications (in the absence of radiological chondrocalcinosis) are frequent in osteoarthritis. Whether lateral meniscal lesions influence clinical outcomes after medial unicompartmental knee arthroplasty (UKA) is unknown. METHODS: We analyzed 130 patients (130 knees) with medial unicompartmental knee arthroplasties between 2005 and 2015. These 130 knees had full articular cartilage thickness in the lateral compartment and no radiological chondrocalcinosis on preoperative radiographs. The lateral meniscus was analyzed with preoperative MRI and a biopsy of the anterior horn at the time of surgery. Synovial fluid was collected and analyzed for calcium pyrophosphate dihydrate crystal deposition (CPPD crystals). Lateral meniscal tears were untreated when detected on MRI or during surgery, with the hypothesis that these tears on the opposite compartment would remain asymptomatic in medial UKA. At average 10-year follow-up, patients were evaluated with clinical and radiographic outcome, with a focus on the risk of joint space narrowing of the lateral femorotibial compartment. RESULTS: CPPD crystals were present in the synovial fluid of 70 knees. Lateral meniscal tears were seen on MRI in 34 (49%) normal meniscuses of the 60 knees without CPPD crystals and in six other knees without histological meniscal calcification despite CPPD crystals. Histological calcification was present on 61 lateral meniscuses with 53 meniscal tears. The results showed no significant differences in the clinical outcomes between knees with lateral meniscal tears or lateral meniscal histological chondrocalcinosis or both lesions and those without these conditions. Additionally, radiographic progression of osteoarthritis in the opposite femorotibial compartment of the knee was not more frequent in patients with these meniscal issues. The ten year cumulative survival rates, measured by the need for total knee arthroplasty, were 91% for knees without meniscal lesions and 92% for knees with these lesions. CONCLUSION: On this basis, treatment of meniscal tears of the lateral compartment and routine aspiration of the knee to assess for birefringent crystals in the planning of medial UKA do not appear necessary.

Patient-Reported Outcomes in Calcium Pyrophosphate Deposition Disease Compared to Gout and Osteoarthritis.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease prevalence is similar to that of gout and osteoarthritis (OA), yet CPPD outcomes research greatly lags behind research in these other forms of arthritis. We compared validated patient-reported outcome measures in patients with CPPD vs gout and OA. METHODS: Patients with CPPD were recruited from Brigham and Women's Hospital from 2018 to 2022. Presence of CPPD manifestations (acute calcium pyrophosphate [CPP] crystal arthritis, chronic CPP inflammatory arthritis, and/or OA with CPPD) was confirmed by medical record review. Baseline surveys included the Gout Assessment Questionnaire version 2.0, modified to ask about "pseudogout" rather than "gout"; Routine Assessment of Patient Index Data 3 (RAPID-3); and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). We compared responses in patients with CPPD against published gout and OA cohort studies. RESULTS: Among 47 patients with CPPD, the mean age was 71.9 years and 51% were female. Sixty-eight percent had at least 1 episode of acute CPP crystal arthritis, 40% had chronic CPP inflammatory arthritis, and 62% had OA with CPPD. Pain visual analog scale scores during a flare were similar in CPPD (mean 6.8 [SD 1.9]) and gout (mean 6.7 [SD 2.6]; P = 0.78). Patients with CPPD reported significantly greater unmet treatment need than patients with gout (P = 0.04). RAPID-3 scores in CPPD (mean 8.1 [SD 5.6]) were lower than in gout (mean 12.1 [SD 6.2]; P < 0.01) and similar in OA (mean 6.8 [SD 6.1]; P = 0.30). Patients with CPPD had significantly worse WOMAC stiffness scores than patients with mild OA, and significantly better WOMAC function scores than patients with severe OA. CONCLUSION: Patients with CPPD may experience pain comparable to that in gout and OA and reported substantial unmet treatment needs.