Crowson, Cynthia S.

ObjectiveTo evaluate the incidence and prevalence of juvenile idiopathic arthritis (JIA) in Olmsted County, Minnesota in 1994–2013 and trends in juvenile rheumatoid arthritis (JRA) in 1960–2013.MethodsCases of arthritis in 1994–2013 were identified by diagnosis code with medical chart review to confirm diagnosis separately for JIA and JRA. Overall incidence rates with 95% confidence intervals (95% CIs) were age and sex adjusted to the 2010 US white population. Comparisons were made with an earlier (1960–1993) cohort from this same population.ResultsSeventy‐one incident cases of JIA in 1994–2013 were identified, with an overall age‐ and sex‐adjusted incidence rate of 10.3 per 100,000 (95% CI 7.9–12.7). Forty‐two (59%) were female, with an incidence of 12.4 per 100,000 (95% CI 8.6–16.2), as compared to 8.3 per 100,000 (95% CI 5.2–11.3) in males. The most common subtype was oligoarthritis (63%). The mean ± SD age at diagnosis was 8.2 ± 5.3 years. The prevalence of JIA on January 1, 2000 and January 1, 2010 was 51.0 per 100,000 (95% CI 25.2–76.8) and 57.6 per 100,000 (95% CI 31.0–94.5), respectively. When the annual incidence of JRA was compared over time from 1960 to 2013, there was no significant change in incidence overall; however, the incidence decreased among females (P = 0.003). A cyclic pattern of incidence was observed, with peaks approximately every 10 years. Similar to the findings with regard to incidence, prevalence did not change overall, but decreased among females (P = 0.048). There were 4 deaths in the cohort of JRA patients diagnosed in 1960–2013; the standardized mortality ratio was 1.50 (95% CI 0.41–3.83).ConclusionIncidence of juvenile arthritis overall in Olmsted County, Minnesota has not changed significantly in the past 53 years. A consistent cyclic pattern was noted.

Objective To examine the influence of solar cycle and geomagnetic effects on the incidence of giant cell arteritis (GCA) and rheumatoid arthritis (RA). Methods We used data from patients with GCA (1950–2004) and RA (1955–2007) obtained from population-based cohorts. Yearly trends in age-adjusted and sex-adjusted incidence were correlated with the F10.7 index (solar radiation at 10.7 cm wavelength, a proxy for the solar extreme ultraviolet radiation) and AL index (a proxy for the westward auroral electrojet and a measure of geomagnetic activity). Fourier analysis was performed on AL, F10.7, and GCA and RA incidence rates. Results The correlation of GCA incidence with AL is highly significant: GCA incidence peaks 0–1 year after the AL reaches its minimum (ie, auroral electrojet reaches a maximum). The correlation of RA incidence with AL is also highly significant. RA incidence rates are lowest 5–7 years after AL reaches maximum. AL, GCA and RA incidence power spectra are similar: they have a main peak (periodicity) at about 10 years and a minor peak at 4–5 years. However, the RA incidence power spectrum main peak is broader (8–11 years), which partly explains the lower correlation between RA onset and AL. The auroral electrojets may be linked to the decline of RA incidence more strongly than the onset of RA. The incidences of RA and GCA are aligned in geomagnetic latitude. Conclusions AL and the incidences of GCA and RA all have a major periodicity of about 10 years and a secondary periodicity at 4–5 years. Geomagnetic activity may explain the temporal and spatial variations, including east-west skewness in geographic coordinates, in GCA and RA incidence, although the mechanism is unknown. The link with solar, geospace and atmospheric parameters need to be investigated. These novel findings warrant examination in other populations and with other autoimmune diseases.

Objectives To assess whether HOUSES (HOUsing-based index of socioeconomic status (SES)) is associated with risk of and mortality after rheumatoid arthritis (RA). Design We conducted a population-based case–control study which enrolled population-based RA cases and their controls without RA. Setting The study was performed in Olmsted County, Minnesota. Participants Study participants were all residents of Olmsted County, Minnesota, with RA identified using the 1987 American College of Rheumatology criteria for RA from 1 January 1988, to 31 December 2007, using the auspices of the Rochester Epidemiology Project. For each patient with RA, one control was randomly selected from Olmsted County residents of similar age and gender without RA. Primary and secondary outcome measure The disease status was RA cases and their matched controls in relation to HOUSES as an exposure. As a secondary aim, post-RA mortality among only RA cases was an outcome event. The associations of SES measured by HOUSES with the study outcomes were assessed using logistic regression and Cox models. HOUSES, as a composite index, was formulated based on a summed z-score for housing value, square footage and number of bedrooms and bathrooms. Results Of the eligible 604 participants, 418 (69%) were female; the mean age was 56±15.6 years. Lower SES, as measured by HOUSES, was associated with the risk of developing RA (0.5±3.8 for controls vs −0.2±3.1 for RA cases, p=0.003), adjusting for age, gender, calendar year of RA index date, smoking status and BMI. The lowest quartile of HOUSES was significantly associated with increased post-RA mortality compared to higher quartiles of HOUSES (HR 1.74; 95% CI 1.10 to 2.74; p=0.017) in multivariate analysis. Conclusions Lower SES, as measured by HOUSES, is associated with increased risk of RA and mortality after RA. HOUSES may be a useful tool for health disparities research concerning rheumatological outcomes when conventional SES measures are unavailable.

Objective. To investigate the incidence of atrial fibrillation (AF) among patients with rheumatoid arthritis (RA) compared to the general population.Methods. A population-based inception cohort of Olmsted County, Minnesota, residents with incident RA in 1980–2007 and a cohort of non-RA subjects from the same population base were assembled and followed until 12/31/2008. The occurrence of AF was ascertained by medical record review.Results. The study included 813 patients with RA and 813 non-RA subjects (mean age 55.9 (SD:15.7) years, 68% women in both cohorts). The prevalence of AF was similar in the RA and non-RA cohorts at RA incidence/index date (4% versus 3%;P=0.51). The cumulative incidence of AF during follow-up was higher among patients with RA compared to non-RA subjects (18.3% versus 16.3% at 20 years;P=0.048). This difference persisted after adjustment for age, sex, calendar year, smoking, and hypertension (hazard ratio: 1.46; 95% CI: 1.07, 2.00). There was no evidence of a differential impact of AF on mortality in patients with RA compared to non-RA subjects (hazard ratio 2.5 versus 2.8; interactionP=0.31).Conclusion. The incidence of AF is increased in patients with RA, even after adjustment for AF risk factors. AF related mortality risk did not differ between patients with and without RA.

ObjectiveThe role of cardiovascular disease (CVD) risk factors in psoriatic arthritis (PsA) is poorly understood. We examined the prevalence of CVD risk factors at initial onset of PsA and compared the observed incidence of CVD events with that predicted by the Framingham Risk Score (FRS) to determine its applicability in this patient population.MethodsA population‐based incidence cohort of 158 patients with PsA who fulfilled Classification of Psoriatic Arthritis criteria for PsA in 1989–2008 was assembled. Medical records were reviewed to ascertain CVD risk factors and CVD events. Future risk of CVD was estimated using the FRS algorithm.ResultsMean age was 43.4 years (range 19–74 years), 61% were men, and 44% were obese (body mass index ≥30 kg/m2). Fifty‐four patients (34%) presented with ≥2 CVD risk factors at PsA incidence. Among 126 patients ages ≥30 years at PsA incidence with no prior history of CVD, 33% had an FRS ≥10%, with 11% having an FRS ≥20%, and 18 experienced a CVD event in the first 10 years of disease duration. The 10‐year cumulative incidence of CVD events was 17% (95% confidence interval [95% CI] 10%–24%), almost twice as high as the predicted incidence based on the FRS (standardized incidence ratio 1.80, 95% CI 1.14–2.86; P = 0.012).ConclusionThe majority of newly diagnosed PsA patients have a >10% risk of CVD within 10 years of PsA incidence. The CVD risk in these patients is higher than expected and underestimated by the FRS.

Abstract Objective To examine the association of serum inflammatory markers (erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)) and serum lipid measures (low-density lipoprotein (LDL)- and high-density lipoprotein (HDL)-cholesterol) with risk of myocardial infarction (MI) and ischaemic stroke (IS) among rheumatoid arthritis (RA) patients. Methods We conducted a retrospective cohort study using 2005–2010 data from a US commercial health plan. Eligible patients had two or more physician diagnoses of RA during a baseline period of at least 180 days with continuous medical and pharmacy coverage. We computed age-adjusted incidence rates of MI and IS, and used spline regression to assess non-linear associations and Cox-regression to quantify the independent association between the laboratory values and the outcomes. Results We identified 44 418 eligible RA patients (mean age 49 years; 76% women). CRP>10 mg/L compared with <1 mg/L was associated with increased MI risk (HR 2.12; 95% CI 1.02 to 4.38). ESR>42 mm/h compared with <14 mm/h was associated with increased risk of MI (HR 2.53; 95% CI 1.48 to 4.31) and IS (HR 2.51; 95% CI 1.33 to 4.75) risk. HDL-cholesterol ≥60 mg/dL (1.6 mmol/L) compared with <40 mg/dL (1.0 mmol/L) was associated with reduced MI risk (HR 0.37; 0.21 to 0.66). The association between LDL and MI was not linear; the lowest risk was observed among patients with LDL between 70 mg/L (1.8 mmol/L) and 100 mg/L (2.6 mmol/L). We did not observe a significant association between LDL and IS. Conclusions This study provides evidence supporting the hypothesis that RA-related systemic inflammation plays a role in determining cardiovascular risk and a complex relationship between LDL and cardiovascular risk.

ObjectiveTo determine trends in the incidence and clinical presentation of ankylosing spondylitis (AS), the incidence of cardiovascular disease (CVD), and cardiovascular (CV) risk factors among patients with AS and compare the observed incidence of CVD with that predicted by the Framingham Risk Score (FRS).MethodsA population‐based inception cohort of residents of Olmsted County, Minnesota age ≥18 years who fulfilled Modified New York Criteria for AS in 1980–2009 was assembled. Clinical features at presentation were recorded. Age‐ and sex‐adjusted incidence rates and survival were estimated. Incident CVD and CV risk factors were identified. The 10‐year CVD risk was calculated using the FRS. Standardized incidence ratios (ratios of observed CVD in AS to that predicted by the FRS) were calculated.ResultsEighty‐six patients were diagnosed with AS over the study period with an age‐ and sex‐adjusted incidence of 3.1 per 100,000 (95% confidence interval [95% CI] 2.5–3.8). The mean age at diagnosis was 35 years (range 19–69 years). Inflammatory back pain, seen in 90% of patients, was the most common presenting manifestation. The 10‐year mean ± SD cumulative incidence of CVD was 15.8% ± 6.1%, three times higher than the predicted events based on the FRS (standardized incidence ratio 3.01, 95% CI 1.35–6.69; P = 0.007). Overall survival was similar to the general population.ConclusionAS occurs in approximately 3 persons per 100,000 per year. Clinical features, extraarticular manifestations, and interval from symptom onset to diagnosis have remained constant in this population over the study period. The CVD risk in these patients is higher than expected and underestimated by the FRS.

Objective Epidemiologic studies comparing the incidence and prevalence of systemic lupus erythematosus (SLE) and isolated cutaneous lupus erythematosus (CLE) are few. Olmsted County, Minnesota provides a unique setting for such a study owing to resources of the Rochester Epidemiology Project. We sought to describe and compare the incidence and prevalence of SLE and CLE from 1993–2005. Methods SLE cases were identified from review of medical records and fulfilled the 1982 American College of Rheumatology classification criteria. CLE cases included patients with classic discoid lupus erythematosus, subacute CLE, lupus panniculitis, and bullous lupus erythematosus. Age‐ and sex‐adjusted incidence and prevalence were standardized to the 2000 US white population. Results The age‐ and sex‐adjusted incidence of SLE (2.9 per 100,000; 95% confidence interval [95% CI] 2.0–3.7) was similar to that of CLE (4.2 per 100,000; 95% CI 3.1–5.2, P = 0.10). However, the incidence of CLE was 3 times higher than SLE in men (2.4 versus 0.8 per 100,000; P = 0.009). The age‐ and sex‐adjusted prevalence of CLE on January 1, 2006 was higher than that of SLE (70.4 versus 30.5 per 100,000; P < 0.001). The prevalences of CLE and SLE in women were similar, but the prevalence of CLE was higher in men than in women (56.9 versus 1.6 per 100,000; P < 0.001). The incidence of CLE rose steadily with age and peaked at 60–69 years. Conclusion The incidences of CLE and SLE are similar, but CLE is more common than SLE in men and in older adults. These findings may reflect differences in genetic or environmental etiology of CLE.

Objective. To evaluate whether hyperuricemia is a risk factor for cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA).Methods. A population-based inception cohort of patients diagnosed between 1980 and 2007 with adult-onset RA was assembled. A comparison cohort of age- and sex-matched subjects without RA (non-RA) was also assembled. All clinically obtained uric acid values were collected. CVD and noncardiac vascular events were recorded for each patient. Cox proportional hazards models were used to assess the impact of hyperuricemia on development of CVD, mortality, and noncardiac vascular disease.Results. In patients without RA, hyperuricemia was associated with heart failure (HR: 1.95; 95% CI: 1.13–3.39) and CVD (HR: 1.59; 95% CI: 0.99–2.55). In patients with RA, hyperuricemia was not significantly associated with CVD but was significantly associated with peripheral arterial events (HR: 2.52; 95% CI: 1.17–5.42). Hyperuricemia appeared to be more strongly associated with mortality among RA patients (HR: 1.96; 95% CI: 1.45–2.65) than among the non-RA subjects (HR: 1.57; 95% CI: 1.09–2.24).Conclusion. In patients with RA, hyperuricemia was a significant predictor of peripheral arterial events and mortality but not of CVD.

Objective To assess the occurrence of acute coronary syndrome (ACS) in patients with giant cell arteritis (GCA) compared to subjects without GCA. Methods We retrospectively reviewed a population‐based incidence cohort of Olmsted County, Minnesota residents with GCA diagnosed in 1950–2009. We compared this cohort with a cohort of patients without GCA of similar age, sex, and calendar year from the same population. Results The study included 245 patients with GCA and 245 non‐GCA subjects. The mean ± SD Framingham cardiovascular risk score was 30% ± 19% in GCA patients and 34% ± 23% in non‐GCA subjects ( P = 0.096) at the incidence/index date. Diabetes mellitus was significantly less common in GCA patients than non‐GCA subjects at the index date. The mean high‐density lipoprotein was higher and triglycerides were lower, with fewer patients taking lipid‐lowering medications in the GCA cohort compared to the non‐GCA cohort at the index date. During followup, no difference between the 2 cohorts was noted in the overall rate of ACS events (hazard ratio 0.74, 95% confidence interval 0.44–1.26). Overall thrombosis in myocardial infarction scores were similar in both cohorts. Revascularization procedures were done less frequently in GCA than in non‐GCA subjects (19% versus 50%; P = 0.015). Post‐ACS hospital length of stays and complications were similar in both cohorts. Conclusion Multiple cardiovascular risk factors are less atherogenic at incidence of GCA. There is no overall increased risk of ACS in patients with GCA.