Acute coronary syndrome in calcium pyrophosphate deposition disease patients: A US inpatient care cohort study.

OBJECTIVE: Recent studies have shown that CPPD might be associated with a higher risk of cardiovascular events related to inflammation. Thus, we aim to examine the outcomes of patients admitted for acute coronary syndrome (ACS) with and without CPPD. METHODS: We used data from the US National Inpatient Sample (NIS) Database to identify patients who were admitted for ACS between 2006 and 2019. The ICD-9 and -10 codes were used to determine the patients with ACS related hospitalizations and of those, we classified two groups of patients: those with and those without any CPPD code. Data collection included demographics and comorbidities. Outcomes were in-hospital mortality, length of stay, hospital charges, and in-hospital complications. Associations between CPPD and specific morbidity were evaluated with chi-square tests. T-tests were used for continuous variables. We have also presented odds ratio (OR) along with 95 % confidence intervals (CI) for the outcomes of interest. RESULTS: A total of 17,322,362 patients were admitted for ACS. Among them, 7,458 had CPPD, with a mean age of 75 years and 48 % were females. CPPD patients were more likely to be older (75 vs 68 years; p < 0.001) compared to non-CPPD patients. Among the comorbidities, chronic kidney disease was more frequently observed in CPPD patients. Regarding the inpatient complications, acute ischemic stroke and post-procedural hemorrhage were more frequently seen in CPPD patients. Interestingly, the in-hospital mortality was lower in the CPPD patients than the non-CPPD patients (OR: 0.77; CI 95 % 0.70-0.85). ACS in CPPD patients was associated with a longer mean length of stay than those without CPPD (OR: 3.35; 95 % CI 3.17-3.53). In addition, mean total charges were higher in the CPPD group (OR: 1.04; 95 % CI 1.01-1.10). CONCLUSION: ACS in CPPD patients is associated with higher healthcare utilization, including cost and length of hospital stay, and lower in-hospital mortality than non-CPPD patients.

Fractures in Patients With Acute Calcium Pyrophosphate Crystal Arthritis Versus Matched Comparators in a Large Cohort Study.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease was associated with osteopenia in two cross-sectional studies. We compared fracture risks in patients with acute calcium pyrophosphate (CPP) crystal arthritis versus matched comparators. METHODS: We performed a longitudinal cohort study using electronic health record data from a single large academic health system, with data from 1991 to 2023. Patients with one or more episodes of acute CPP crystal arthritis were matched to comparators on the index date (first documentation of "pseudogout" or synovial fluid CPP crystals or matched encounter) and first encounter in the health system. The primary outcome was first fracture at the humerus, wrist, hip, or pelvis. We excluded patients with fracture before the index date. Covariates included demographics, body mass index, smoking, comorbidities, health care use, glucocorticoids, and osteoporosis treatments. We estimated incidence rates and adjusted hazard ratios for fracture. Sensitivity analyses excluded patients prescribed glucocorticoids, patients prescribed osteoporosis treatments, or patients with rheumatoid arthritis and additionally adjusted for chronic kidney disease. RESULTS: We identified 1,148 patients with acute CPP crystal arthritis matched to 3,730 comparators, with a mean age of 73 years. Glucocorticoids and osteoporosis treatments were more frequent in the acute CPP crystal arthritis cohort. Fracture incidence rates were twice as high in the acute CPP crystal arthritis cohort (11.7 per 1,000 person-years) versus comparators (5.5 per 1,000 person-years). After multivariable adjustment, fracture relative risk was twice as high in the acute CPP crystal arthritis cohort (hazard ratio 1.8 [95% confidence interval 1.3-2.3]); results were similar in sensitivity analyses. CONCLUSION: In this first published study of fractures and CPPD, fracture risk was nearly doubled in patients with acute CPP crystal arthritis.

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.

Confirming Prior and Identifying Novel Correlates of Acute Calcium Pyrophosphate Crystal Arthritis.

OBJECTIVE: To investigate previously identified and novel correlates of acute calcium pyrophosphate (CPP) crystal arthritis among well-characterized cases. METHODS: In this case-control study, we identified cases of acute CPP crystal arthritis using a validated algorithm (positive predictive value 81%) applied in the Partners HealthCare electronic health record (EHR). Cases were matched to general patient controls on the year of first EHR encounter and index date. Prespecified potential correlates included sex, race, and comorbidities and medications previously associated with CPP deposition/acute CPP crystal arthritis in the literature. We estimated odds ratios (ORs) and 95% confidence intervals using conditional logistic regression models adjusted for demographic characteristics, comorbidities, medications prescribed in the past 90 days, health care utilization, and multimorbidity score. RESULTS: We identified 1,697 cases matched to 6,503 controls. Mean ± SD age was 73.7 ± 11.8 years, 56.7% were female, 80.8% were White, and 10.3% were Black. All prespecified covariates were more common in cases than controls. Osteoarthritis (OR 3.08), male sex (OR 1.35), rheumatoid arthritis (OR 2.09), gout (OR 2.83), proton pump inhibitors (OR 1.94), loop diuretics (OR 1.60), and thiazides (OR 1.46) were significantly associated with acute CPP crystal arthritis after full adjustment. Black race was associated with lower odds for acute CPP crystal arthritis compared to White race (OR 0.47). CONCLUSION: Using a validated algorithm to identify nearly 1,700 patients with acute CPP crystal arthritis, we confirmed important correlates of this acute manifestation of CPP deposition. This is the first study to report higher odds for acute CPP crystal arthritis among males.

Cardiovascular Disease Risk in Calcium Pyrophosphate Deposition Disease: A Nationwide Study of Veterans.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease represents a common crystalline arthritis with a range of manifestations. Our goal was to investigate risks for cardiovascular events in patients with CPPD. METHODS: We performed a retrospective matched cohort analysis in the Veterans Health Administration Corporate Data Warehouse, 2010-2014. CPPD was defined by ≥1 International Classification of Diseases, Ninth Revision codes for chondrocalcinosis or calcium metabolism disorder. CPPD patients were age- and sex-matched to approximately 4 patients without codes for CPPD; we excluded patients with a cardiovascular event during the 365 days prior to the index date. Demographic information, traditional cardiovascular risk factors, medications, and health care utilization were assessed at baseline. The primary outcome was a major adverse cardiovascular event (MACE: myocardial infarction, acute coronary syndrome, coronary revascularization, stroke, or death). Secondary outcomes included individual components of MACE. Cox proportional hazards models estimated fully adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs). RESULTS: We identified 23,124 CPPD patients matched to 86,629 non-CPPD patients with >250,000 person-years of follow-up. The study population was 96% male, mean age was 78 years, and 75% were White. The frequency of traditional cardiovascular risk factors was similar between the 2 cohorts. CPPD was not significantly associated with risk for MACE (HR 0.98 [95% CI 0.94-1.02]) in fully adjusted models, though risks of myocardial infarction, acute coronary syndrome, and stroke were significantly higher in the CPPD cohort compared to the non-CPPD cohort. CONCLUSION: CPPD did not confer an increased risk for MACE, a composite end point including all-cause mortality. Our results propose CPPD as a novel risk factor for MACE components, including myocardial infarction, acute coronary syndrome, and stroke.

Outcomes and resource utilization in calcium pyrophosphate deposition disease patients who underwent total knee arthroplasty: a cross-sectional analysis.

This cross-sectional study aims to evaluate the predictors, outcomes, and resource utilization of total knee arthroplasty (TKA) in calcium pyrophosphate deposition disease (CPPD) patients. We used the US National Inpatient Sample database to identify CPPD and non-CPPD who underwent TKA from 2006 to 2014. Data collection included patient demographics and comorbidities. Outcomes following TKA included in-hospital mortality, complications, length of hospitalization, hospital charges, and disposition. Among the 5,564,005 patients who have undergone TKA, 11,529 (0.20%) had CPPD, with a median age of 72 years, and 53.7% were females. Compared with non-CPPD, patients with CPPD were more likely to be older (mean 72 vs 66 years; p < 0.001), male, white, and have Medicare insurance. CPPD patients were more likely to have ≥ 2 comorbidities calculated by the Charlson Comorbidity Index and discharge to an inpatient/rehabilitation facility. Regarding inpatient complications, myocardial infarction and knee reoperation were significantly more common in CPPD patients. TKA in CPPD patients was associated with significantly higher odds of increased length of stay (> 3 days) than those without CPPD (OR 1.43, 95% CI 1.37-1.49). There was no significant difference in the in-hospital mortality even after adjusting for possible confounders. CPPD patients who underwent TKA were more likely to have a longer hospital stay and discharge to a non-home setting than non-CPPD. Also, CPPD patients had a higher comorbidity burden and risk for myocardial infarction and reoperation.Key Points• This is the largest study to analyze data of CPPD patients who underwent TKA and compare them with non-CPPD patients, using a large nationwide database.• Compared to non-CPPD patients, TKA in CPPD patients is associated with a greater length of stay and disposition to a nursing/rehabilitation facility.• In-hospital complications such as myocardial infarction and reoperation were more frequently observed in CPPD patients than non-CPPD.• The results of this study should alert healthcare providers to develop strategies in order to improve outcomes of CPPD patients undergoing TKA.

Calcium pyrophosphate crystal deposition in a cohort of 57 patients with Gitelman syndrome.

OBJECTIVE: Gitelman syndrome (GS) is the most frequent salt-wasting genetic tubulopathy and a source of hypokalaemia and hypomagnesemia. Chondrocalcinosis (CC) is a frequent feature of GS. The aim of our study was to determine the prevalence, distribution patterns, clinical phenotypes and risk factors for CC in GS. METHODS: This prospective study of a cohort of 57 patients with GS included a systematic screening for CC by peripheral joint radiography, cervical spine CT and joint US. The prevalence of cervical C1-C2 CC by CT was compared between 33 GS patients and sex- and age-matched controls. Clinical and biochemical features were analysed to identify factors associated with CC. RESULTS: Mean (s.d.) age of patients was 46.5 (12.4) years, 66.7% were women and 93.0% carried SLC12A3 mutations. Mean serum magnesium level was 0.60 (0.30) mmol/l. CC was observed in 79% of patients, with the highest prevalence at the cervical spine (81.8%) followed by the knee (52.6%), wrist (50.9%), ankle (38.6%), TM joint (36.4%), shoulder (33.3%), hip (22.8%), elbow (14.0%) and sclerochoroid (12.1%). Prevalence of CC at the C1-C2 level was higher in the GS cohort than control group (72.7% vs 9.1%) (adjusted odds ratio 21.0, 95% CI 2.8, 156.1, P = 0.003). Independent factors associated with CC were low serum magnesium level and age. CONCLUSION: GS was associated with widespread CC, favoured by aging and hypomagnesemia. The C1-C2 level was the most affected site. Follow-up of this unique cohort will help understanding the clinical consequences of CC, especially the precise characterization of pyrophosphate arthropathy.

Cartilage calcification is associated with histological degeneration of the knee joint: a highly prevalent, age-independent systemic process.

OBJECTIVES: To investigate if cartilage calcification (CC) is a systemic process, the purpose of this study was to determine the prevalence and the amount of meniscal/hyaline CC of the knee joint in the general population by high-resolution imaging (DCR) and to evaluate the association between CC with cartilage degeneration and age. METHODS: Cross-sectional DCR-study of 180 knee joints of 90 donors (42 female/48 male, mean age 62.3y). Histological hyaline (OARSI) and meniscal (Krenn) cartilage degeneration was determined of all knees. RESULTS: CC was observed in 100% of the donors (bilaterally in 98%), hyaline cartilage calcification (HCC) in 92% and meniscal calcification (MC) in 100%. CC was detected in more than three out of six distinct cartilage areas in 84.4% of all knees. The mean amount of CC correlated between both sides of donors, the different analyzed areas of the knee joint and between the various types of cartilage structures. There was more calcification in meniscal than in hyaline cartilage (factor 5.3) and in the medial than the lateral compartment (factor 1.2). HCC/MC were already detectable with only mild cartilage lesions and the amount correlated with histological cartilage degeneration, but not with age. CONCLUSIONS: The present study provides evidence that meniscal and hyaline CC occurs in a pattern that is compatible with CC being a systemically driven process and that meniscal fibrocartilage is more prone to calcification than hyaline cartilage. Furthermore, the age-independent association between the amount of CC and the grade of degeneration in both hyaline and meniscal cartilage, suggests that CC is an obligatory early event in initiating cartilage degeneration.

Association between serum zinc and copper concentrations and copper/zinc ratio with the prevalence of knee chondrocalcinosis: a cross-sectional study.

BACKGROUND: Patients with chondrocalcinosis may suffer from a series of symptoms resembling acute gouty arthritis or septic arthritis, but the aetiology and pathogenesis of chondrocalcinosis have not been fully elucidated yet. This study was aimed to assess serum zinc and copper concentrations, as well as the ratio of serum copper to zinc concentrations (Cu/Zn ratio), in relation to the prevalence of knee chondrocalcinosis. METHODS: Data included in this analysis were retrieved from a large population-based cross-sectional study. A bilateral knee anteroposterior radiograph was obtained from each subject. Radiographic knee chondrocalcinosis was diagnosed if definite linear cartilage calcification was detected. Serum zinc and copper concentrations were measured using the spectrophotometric flow injection methods by Roche modular P800. The relations of serum zinc and copper concentrations and Cu/Zn ratio to the prevalence of knee chondrocalcinosis were examined using generalized estimating equations, respectively. RESULTS: The prevalence of knee chondrocalcinosis was 1.2% in the sample of this study (n = 12,362). In comparison with the lowest tertile, the odds ratios (ORs) of knee chondrocalcinosis adjusted by age, sex and body mass index were 0.74 (95% CI 0.50-1.09) in the second and 0.56 (95% CI 0.36-0.86) in the third tertiles of serum zinc concentrations (P for trend = 0.009), were 1.26 (95% CI 0.77-2.05) in the second and 2.01 (95% CI 1.25-3.24) in the third tertile of serum copper concentrations (P for trend = 0.003), and were 1.02 (95% CI 0.61-1.69) in the second and 2.23 (95% CI 1.38-3.59) in the third tertile of Cu/Zn ratio (P for trend < 0.001) respectively. These findings were not materially altered by adjustment for potential confounders. CONCLUSIONS: The present study observed that higher serum zinc concentrations, lower serum copper concentrations or lower Cu/Zn ratio are associated with a lower prevalence of knee chondrocalcinosis in a dose-response relationship manner.

Patients Presenting with a Hot, Swollen Joint: A Single-Centre Retrospective Analysis.

BACKGROUND: A hot, swollen joint is a common clinical condition encountered in the ED and elective orthopaedic and rheumatology clinics. These patients can be difficult to manage and properly treat. AIMS AND OBJECTIVES: The aim of this study was to report a single centre retrospective analysis of patients presenting to our institution for a hot, swollen joint over a three-month period. METHODS: The study included patients presenting with a hot, swollen joint to ED or electively to clinics. The synovial fluid was aspirated and sent for microbiological and cytological investigation. P value was set to < 0.001. 36 patients (22 M, 14 F) with a mean age of 72.8 ± 17.4 years met our criteria. 20 cases (55.6 %) involved the knee joint, the wrist in 10 cases (27.8%), the elbow in 3 cases (8.3%) and the shoulder in 3 cases (8.3%). RESULTS: Of the 36 synovial fluid samples collected, only 7 (19.4%) reported evidence of infection. On cytological examination of the synovial fluid, 21 (58.3%) reported presence of calcium pyrophosphates crystals (Pseudogout), 4 (11.1 %) reported presence of uric acid crystals (Gout) and 11 (30.5%) reported absence of crystals. We found a significant correlation between age and the diagnosis of pseudogout and between previous antibiotic treatment and ED presentation. Our study sheds light on the high incidence of crystal-related pathologies. CONCLUSION: In order to improve our management of this common condition and enhance our understanding of the clinical diagnosis in certain patient population, further high-profile clinical studies are needed.

Acute Calcium Pyrophosphate Crystal Arthritis Flare Rate and Risk Factors for Recurrence.

OBJECTIVE: Little is known about acute calcium pyrophosphate (CPP) crystal arthritis flare rates and risk factors for recurrence. We characterized flares and determined the rate and predictors of acute CPP crystal arthritis flares in an academic medical center cohort. METHODS: We performed a retrospective cohort study among a random sample of patients with acute CPP crystal arthritis identified in the Partners HealthCare electronic medical record, 1991-2017. Flare was defined as self-limited, acute-onset synovitis with synovial fluid CPP crystals and/or chondrocalcinosis, not better explained by another cause. We calculated incidence rates (IR) for acute CPP crystal arthritis flare among all subjects and by sex. We estimated HR for recurrent flare using univariate Cox models that accounted for within-person correlated data. RESULTS: We identified 70 patients with acute CPP crystal arthritis with a total of 111 flares. Recurrent flares occurred in 24% of patients; half of flares occurred in a previously unaffected joint. The acute CPP crystal arthritis flare rate was 11.4 per 100 person-years overall (95% CI 8.2-15.4), 14.2 in women (95% CI 9.6-0.1), and 7.1 in men (95% CI 3.4-13.0). Cancer (HR 2.98, 95% CI 1.33-6.68) and chronic kidney disease (HR 2.92, 95% CI 1.10-7.76) were associated with a higher rate for recurrent flare. CONCLUSION: Recurrent flares occurred in about one-fourth of patients with acute CPP crystal arthritis and often occurred in previously unaffected joints. The acute CPP crystal arthritis flare rate was twice as high in women as in men.

Musculoskeletal disorders in hemodialysis patients: different disease clustering according to age and dialysis vintage.

Musculoskeletal disorders remain a major problem in hemodialysis patients. The aim of the study was to estimate the prevalence of musculoskeletal manifestations in hemodialysis patients and identify disease cluster profiles. We performed a cross-sectional study including all adult patients in the hemodialysis unit at Hotel-Dieu de France Hospital. We collected demographic characteristics, musculoskeletal symptoms, biologic parameters, and treatments. Musculoskeletal disorders were classified by a rheumatologist into predefined diagnostic categories. Prevalence was presented, and a cluster analysis was performed. Eighty-nine patients were included, mean age was 67.5 ± 12 years, and 43.8% were female. Dialysis vintage was 5.7 ± 5.37 years. Musculoskeletal symptoms were reported by 76.4% of the patients. Pain was the most frequent symptom (44.9%). The main diagnoses were osteoarthritis (53.9%) and fracture (27%). Musculoskeletal symptoms and disorders were significantly associated with dialysis vintage and age. Cluster analysis identified three patient profiles: younger with low calcium levels, younger but long dialysis vintage with osteoarthritis and carpal tunnel syndrome, and older with long dialysis vintage and fractures. The prevalence of musculoskeletal manifestations is high in the hemodialysis population and increases with dialysis vintage. Musculoskeletal disorders cluster according to age and dialysis vintage. Key Points• Musculoskeletal symptoms are highly prevalent among hemodialysis patients (76.4%).• All musculoskeletal disorders are associated with dialysis vintage and age.• Three clusters are identified among hemodialysis patients: young with low calcium levels, young but long dialysis vintage with osteoarthritis and carpal tunnel syndrome and old with long dialysis vintage with fractures.

Prevalence and incidence of non-gout crystal arthropathy in southern Sweden.

OBJECTIVE: To estimate the prevalence and incidence of non-gout crystal arthropathy in relation to socioeconomic factors in southern Sweden. METHODS: All patients (age ≥ 18 years) with at least one visit to a physician with the diagnosis of interest in the Skåne region (population of 1.3 million) in 1998-2014 were identified. Non-gout crystal arthropathy (ICD-10 codes M11.0-M11.9) was subclassified in four different groups: calcium pyrophosphate crystal deposition related arthropathy (CPPD), unspecified non-gout arthropathies, chondrocalcinosis, and hydroxyapatite crystal deposition disease. The crude and age-adjusted point prevalence on December 31, 2014, and the cumulative incidence during 2014 were calculated for all non-gout crystal arthropathies, CPPD, and other unspecified non-gout arthropathies overall and in relation to occupation, income, and level of education. RESULTS: The crude 2014 point prevalence (95% CI) and 2014 cumulative incidence (95% CI) of all non-gout crystal arthropathies were 0.23% (0.23-0.24) and 21.5 (19-25) cases/100,000 persons. Mean age (range) among all prevalent cases in 2014 was 71 (20-102) years and 56% were males. The point prevalence and cumulative incidence of CPPD were 0.09% (0.08-0.09) and 8 (7-10)/100,000 persons, respectively. The corresponding data for unspecified non-gout crystal deposition disease was 0.16% (0.16-0.17) and 15.6 (13-18)/100,000 persons, respectively. The prevalence and incidence of CPPD and unspecified non-gout crystal arthropathies were slightly higher in men and increased with age irrespective of gender. Unspecified non-gout crystal arthropathy but not CPPD was less prevalent in persons with ≥ 15 years of education, whereas there were no clear associations with occupation and income. CONCLUSION: The prevalence of all diagnosed non-gout crystal arthropathies was 0.23%, thus considerably less prevalent than gout in southern Sweden. CPPD and other unspecified non-gout crystal arthropathies are the predominant diagnoses, increasing with age and in men. With the exception for unspecified non-gout crystal arthropathies being inversely correlated to a higher level of education, no convincing association with the socioeconomic factors was found.

Association between chondrocalcinosis and osteoarthritis: A systematic review and meta-analysis.

AIM: To systematically examine the existing literature on the associations between chondrocalcinosis (CC) and osteoarthritis (OA) at different joints, and to quantify such associations through meta-analysis. METHODS: PubMed, Embase and Scopus databases were searched through from inception to June 2017. Cohort, case-control or cross-sectional studies were included if they examined the association between CC and OA. Data on the odds ratios (OR) and their 95% confidence intervals (CI) of the prevalence or progression of OA between the CC group and non-CC group with respect to the same joint were extracted. RESULTS: A total of 14 studies were identified. Twelve studies were eligible for assessing the association between knee CC and knee OA. The combined data showed a positive association between them (OR = 2.84; 95% CI, 2.12-3.81; P < 0.001). Three studies were eligible for assessing the association between hip CC and hip OA. The data on the OR could only be extracted from one study (OR = 0.92; 95% CI, 0.68-1.24; P = 0.59). Two studies were eligible for assessing the association between hand CC and hand OA, and the data on the OR could only be extracted from one study which reported significant associations between CC and OA at the metacarpophalangeal joint (OR = 4.75; 95% CI, 2.12-10.64; P < 0.001) and the wrist joint (OR = 4.44; 95% CI, 3.56-5.54; P < 0.001). CONCLUSION: This study established a strong association between knee CC and knee OA. However, the associations between CC and OA at the hip or hand still remain controversial and warrant further study.

Prevalence of chondrocalcinosis in a Mexican tertiary care institution of musculoskeletal disorders.

INTRODUCTION/OBJECTIVES: The prevalence of chondrocalcinosis (CC) was reported as variable according to the geographic populations. However, there are no data regarding its prevalence in Mexico. Thus, we decided to investigate the Mexican prevalence of CC in a cohort of patients from a tertiary health care institution. METHODS: A retrospective analysis of radiographs of knees and wrists from our institution was performed. Inclusion criteria included patients > 50 years old having radiographs of knees and wrists. Radiographic presence of CC was classified according to a dichotomous evaluation assayed by two rheumatologists experts on the area. RESULTS: A total of 3.350 radiographs from 1.602 patients were evaluated. Forty-seven patients showed calcifications in at least one knee or wrist for an overall prevalence of 3%, of which 23.4% were men and 76.6% women. The knee was more commonly affected than the wrist (85.1% and 14.9% respectively). The prevalence according to gender was 2.9% in women, whereas, it was 3.2% in men. Only two patients (4.3%) showed a contemporaneous presence of CC in both hands and both knees. At knee level, the prevalence was 2.7%, whereas at the wrist, we reported a prevalence of 4.9%. CONCLUSIONS: The prevalence of CC for Mexican population had not been reported so far. This a starting point to break the silence and encourage the knowledge of how this disease is associated with possible risk factors in Mexican population. Key Points •The prevalence of chondrocalcinosis in Mexico was 3%. •The prevalence of knee chondrocalcinosis increases according to the age in women's. •The nixtamalized meals could be a protective factor for CC in Mexican population.

Clinical features and risk of recurrence of acute calcium pyrophosphate crystal arthritis.

OBJECTIVES: It is unclear whether attack recurrence rates are similar between acute calcium pyrophosphate (CPP) crystal arthritis and gout. This study compared the clinical features and recurrence rates of both conditions. METHODS: In this retrospective study, we reviewed 106 patients with acute CPP crystal arthritis (based on the presence of CPP crystals and/or chondrocalcinosis) and 173 patients with gout (based on the presence of monosodium urate crystals). We analysed clinical variables and compared them between the two conditions. We identified factors associated with the recurrence of acute CPP crystal arthritis. RESULTS: Patients with acute CPP crystal arthritis were older (76.5 vs. 62 years, p<0.001) and female (69.8% vs. 6.9%, p<0.001); they had a lower body mass index (22.3 vs. 23.7, p=0.002), lower renal insufficiency rate (27.4% vs. 41.6%, p=0.016), and higher rate of preceding infection (22.6% vs. 11.0%, p=0.009) than those with acute gout. Recurrence rates were similar between the groups (19.1% vs. 22.9%, p=0.562). Use of proton pump inhibitors (PPIs) [hazard ratio (HR), 5.625; 95% CI, 1.672-18.925; p=0.005] and warfarin (HR, 7.301; 95% CI, 1.930-27.622; p=0.003) or exposure to chemotherapy (HR, 5.663; 95% CI, 1.180-27.169; p=0.03) were associated with acute CPP crystal arthritis recurrence. CONCLUSIONS: Acute CPP crystal arthritis was more common than acute gout in older women with preserved renal function. Physicians should be aware of the association between recurrence and PPI, warfarin, or chemotherapy use in these patients.

Incidence of knee chondrocalcinosis and its risk factors in a community-based cohort.

AIM: Chondrocalcinosis results from deposition of calcium pyrophosphate dihydrate in articular cartilage. It is a relatively common radiographic finding of the joints, especially the knee. This study investigated the incidence and the risk factors for the development of knee chondrocalcinosis in the general population. METHOD: We used a prospective, ongoing cohort, composed of 5018 people, which was established in 2001 to investigate the epidemiologic characteristics of major chronic diseases in the Republic of Korea. The incidence of knee chondrocalcinosis was assessed per 1000 person-years, and the risk factors were explored by Cox proportional hazard regression analyses. RESULTS: A total of 4543 patients who did not have knee chondrocalcinosis at enrollment, year 2001-2002, were evaluated with a mean follow-up duration of 8.4 ± 4.2 years. The crude incidence of knee chondrocalcinosis was 3.19 per 1000 person-years (women, 3.55; men, 2.70), and the whole cumulative incidence of knee chondrocalcinosis was 2.7%. Older age (> 55 years) and higher HbA1C were associated with increased risk of knee chondrocalcinosis. CONCLUSION: This is the first study to report the incidence of knee chondrocalcinosis in the general population of Korea. Older age and high HbA1C were independent risk factors for development of knee chondrocalcinosis.

Low prevalence of knee chondrocalcinosis and its catabolic association with serum matrix metalloproteinase 3: A rural Japanese population study.

AIM: This study aimed to elucidate the prevalence of radiographic knee chondrocalcinosis (CC) and to clarify whether CC is correlated with self-reported knee symptoms and a serum catabolic biomarker. METHODS: A total of 1278 volunteers participated. Plain radiographs of both knees were obtained. Identification of a linear calcification in the knee joint space was defined as CC. Patients with a Kellgren-Lawrence grade of 2 or more were considered to have knee osteoarthritis (OA). Symptoms were evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain scale, and serum matrix metalloproteinase-3 (MMP-3) concentration was determined. Multiple regression analysis was conducted to determine whether CC was correlated with OA, the KOOS Pain scale and MMP-3 concentration. RESULTS: Twenty-eight subjects were found to have CC (2.2%), and 389 had OA (30.4%). CC was correlated with OA (odds ratio: 5.797; P = 0.006). Additionally, CC was correlated with MMP-3 concentration (B = 11.415, ß = 0.059, P = 0.014), but not with KOOS Pain scale. CONCLUSIONS: The prevalence of CC was low in the Japanese population evaluated in this study. While CC was not correlated with self-reported knee symptoms, it was positively correlated with serum MMP-3 concentration.

Crystal arthritides - gout and calcium pyrophosphate arthritis : Part 1: Epidemiology and pathophysiology.

Gout and calcium pyrophosphate deposition disease (CPPD, pseudogout) are still the most frequent inflammatory arthritides in multimorbid elderly patients. Gout and CPPD are different diseases and based on different pathophysiological principles. Gout is closely associated with the metabolic syndrome and is an independent risk factor for cardiovascular mortality. The prevalence of asymptomatic hyperuricemia is estimated to be 10-20% of adults in industrial nations and prevalence is strongly associated with age. More than 7% of persons aged over 65 years suffer from clinically manifest gout. The underlying pathophysiological principle is an imbalance between the formation and elimination of uric acid. The degradation of the purine bases adenine and guanosine to uric acid is catalysed by xanthine oxidase and genetic polymorphisms and mutations play an important role in absorption and excretion processes. Furthermore, carrier proteins, such as URAT-1 or OAT-4 also have an influence on these processes. An imbalance of the physiological processes results in the solubility product being exceeded, which in consequence leads to crystallization of urate. This induces a cascade of massive inflammatory reactions at the molecular and cellular level with the activation of cytokines. The inflammatory process can be stopped by neutrophil extracellular traps (NETs) that modulate aggregation and degradation of chemokines and cytokines and partitioning of crystallized urate against immune cells. Calcium pyrophosphate dehydrate (CPP) crystals are formed in the cartilage and CPP deposition can be found in 30% of people aged over 80 years. Inorganic pyrophosphate (PPi) is synthesized in chondrocytes and plays an important part in the formation of calcium pyrophosphate crystals. The degradation is catalyzed by inorganic pyrophosphatases. If there is dysregulation of this homeostasis more PPi is produced, which ultimately contributes to the formation of the CPP crystals.

Calcium pyrophosphate deposition disease: a frequent finding in patients with long-standing erosive gout.

OBJECTIVE: To characterize patients with both monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals in their synovial fluid (SF). METHOD: Forty-nine gout patients with acute arthritis were included. Those patients with MSU crystals only in their SF were compared to those patients with both MSU and CPP crystals in their SF. RESULTS: A total of 36 out of 49 patients (73.5%) had only MSU crystals, whereas 13 out of 49 (26.5%) had both MSU and CPP crystals in their SF. Co-deposition of CPP crystals was associated with long-standing gout disease (p = 0.022), kidney dysfunction (p = 0.024), and erosive arthritis (p = 0.049), but not with age. CONCLUSION: Long-standing gout may be a risk factor for CPP deposition disease, and the frequency of CPP co-deposition may be higher than expected.