Hilal Maradit Kremers

Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II.

OBJECTIVE To provide a single source for the best available estimates of the US prevalence of and number of individuals affected by osteoarthritis, polymyalgia rheumatica and giant cell arteritis, gout, fibromyalgia, and carpal tunnel syndrome, as well as the symptoms of neck and back pain. A companion article (part I) addresses additional conditions. METHODS The National Arthritis Data Workgroup reviewed published analyses from available national surveys, such as the National Health and Nutrition Examination Survey and the National Health Interview Survey. Because data based on national population samples are unavailable for most specific rheumatic conditions, we derived estimates from published studies of smaller, defined populations. For specific conditions, the best available prevalence estimates were applied to the corresponding 2005 US population estimates from the Census Bureau, to estimate the number affected with each condition. RESULTS We estimated that among US adults, nearly 27 million have clinical osteoarthritis (up from the estimate of 21 million for 1995), 711,000 have polymyalgia rheumatica, 228,000 have giant cell arteritis, up to 3.0 million have had self-reported gout in the past year (up from the estimate of 2.1 million for 1995), 5.0 million have fibromyalgia, 4-10 million have carpal tunnel syndrome, 59 million have had low back pain in the past 3 months, and 30.1 million have had neck pain in the past 3 months. CONCLUSION Estimates for many specific rheumatic conditions rely on a few, small studies of uncertain generalizability to the US population. This report provides the best available prevalence estimates for the US, but for most specific conditions more studies generalizable to the US or addressing understudied populations are needed.

Is the incidence of rheumatoid arthritis rising?: Results from Olmsted County, Minnesota, 1955–2007

OBJECTIVE To examine trends in the incidence and prevalence of rheumatoid arthritis (RA) from 1995 to 2007. METHODS To augment our preexisting inception cohort of patients with RA (1955-1994), we assembled a population-based incidence cohort of individuals >or=18 years of age who first fulfilled the American College of Rheumatology 1987 criteria for the classification of RA between January 1, 1995 and December 31, 2007 and a cohort of patients with prevalent RA on January 1, 2005. Incidence and prevalence rates were estimated and were age-and sex-adjusted to the white population in the US in 2000. Trends in incidence rates were examined using Poisson regression methods. RESULTS The 1995-2007 incidence cohort comprised 466 patients (mean age 55.6 years), 69% of whom were female and 66% of whom were rheumatoid factor positive. The overall age- and sex-adjusted annual RA incidence was 40.9/100,000 population. The age-adjusted incidence in women was 53.1/100,000 population (versus 27.7/100,000 population in men). During the period of time from 1995 to 2007, the incidence of RA increased moderately in women (P = 0.02) but not in men (P = 0.74). The increase was similar among all age groups. The overall age- and sex-adjusted prevalence on January 1, 2005 was 0.72% (95% confidence interval [95% CI] 0.66, 0.77), which is an increase when compared with a prevalence of 0.62% (95% CI 0.55, 0.69) in 1995 (P < 0.001). Applying the prevalence on January 1, 2005 to the US population in 2005 showed that an estimated 1.5 million US adults were affected by RA. This is an increase from the previously reported 1.3 million adults with RA in the US. CONCLUSION The incidence of RA in women appears to have increased during the period of time from 1995 to 2007. The reasons for this recent increase are unknown, but environmental factors may play a role. A corresponding increase in the prevalence of RA was also observed.

Incidence and Clinical Predictors of Psoriatic Arthritis in Patients With Psoriasis: A Population-Based Study

OBJECTIVE To determine the incidence and disease-specific predictors of clinically recognized psoriatic arthritis (PsA) in patients with psoriasis. METHODS We identified an incidence cohort of psoriasis subjects age >/=18 years diagnosed between January 1, 1970 and December 31, 1999 in a population-based setting. Psoriasis diagnoses were validated by confirmatory diagnosis in the medical record. Incident and clinically recognized PsA subjects were classified according to the Classification of Psoriatic Arthritis (CASPAR) criteria. Cox proportional hazards models were used to identify predictors of PsA within the psoriasis cohort. RESULTS The psoriasis incidence cohort comprised 1,633 subjects. Of these, 40 were diagnosed with PsA concurrently with psoriasis and were excluded from analysis. The remaining 1,593 psoriasis subjects had a mean age of 43 years and 50% were men. Over 20,936 person-years of followup, 57 subjects were clinically recognized with new-onset PsA, with a cumulative incidence of 1.7% (95% confidence interval [95% CI] 1.0-2.3%), 3.1% (95% CI 2.2-4.1%), and 5.1% (95% CI 3.7-6.6%) at 5, 10, and 20 years following psoriasis incidence, respectively. Psoriasis features associated with higher risk of PsA were scalp lesions (hazard ratio [HR] 3.89, 95% CI 2.18-6.94), nail dystrophy (HR 2.93, 95% CI 1.68-5.12), and intergluteal/perianal lesions (HR 2.35, 95% CI 1.32-4.19). Calendar year was not associated with risk of PsA (P = 0.15), indicating that the likelihood of PsA in psoriasis subjects did not change over time. CONCLUSION In this population-based study, <10% of patients with psoriasis developed clinically recognized PsA during a 30-year period. Psoriasis features associated with a higher likelihood of PsA were nail dystrophy, scalp lesions, and intergluteal/perianal psoriasis.

Lipid paradox in rheumatoid arthritis: the impact of serum lipid measures and systemic inflammation on the risk of cardiovascular disease

Objective To examine the impact of systemic inflammation and serum lipids on cardiovascular disease (CVD) in rheumatoid arthritis (RA). Methods In a population-based RA incident cohort (1987 American College of Rheumatology criteria first met between 1988 and 2007), details were collected of serum lipid measures, erythrocyte sedimentation rates (ESRs), C-reactive protein (CRP) measures and cardiovascular events, including ischaemic heart disease and heart failure. Cox models were used to examine the association of lipids and inflammation with the risk of CVD and mortality, adjusting for age, sex and year of RA incidence. Results The study included 651 patients with RA (mean age 55.8 years, 69% female); 67% were rheumatoid factor positive. ESR was associated with the risk of CVD (HR=1.2 per 10 mm/h increase, 95% CI 1.1 to 1.3). Similar findings, although not statistically significant, were seen with CRP (p=0.07). A significant non-linear association for total cholesterol (TCh) with risk of CVD was found, with 3.3-fold increased risk for TCh <4 mmol/l (95% CI 1.5 to 7.2) and no increased risk of CVD for TCh ≥4 mmol/l (p=0.57). Low low-density lipoprotein cholesterol (LDL <2 mmol/l) was associated with marginally increased risk of CVD (p=0.10); there was no increased risk for LDL ≥2 mmol/l (p=0.76). Conclusion Inflammatory measures (particularly, ESR) are significantly associated with the risk of CVD in RA. Lipids may have paradoxical associations with the risk of CVD in RA, whereby lower TCh and LDL levels are associated with increased cardiovascular risk.

Prevalence of Total Hip and Knee Replacement in the United States

BACKGROUND Descriptive epidemiology of total joint replacement procedures is limited to annual procedure volumes (incidence). The prevalence of the growing number of individuals living with a total hip or total knee replacement is currently unknown. Our objective was to estimate the prevalence of total hip and total knee replacement in the United States. METHODS Prevalence was estimated using the counting method by combining historical incidence data from the National Hospital Discharge Survey and the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases from 1969 to 2010 with general population census and mortality counts. We accounted for relative differences in mortality rates between those who have had total hip or knee replacement and the general population. RESULTS The 2010 prevalence of total hip and total knee replacement in the total U.S. population was 0.83% and 1.52%, respectively. Prevalence was higher among women than among men and increased with age, reaching 5.26% for total hip replacement and 10.38% for total knee replacement at eighty years. These estimates corresponded to 2.5 million individuals (1.4 million women and 1.1 million men) with total hip replacement and 4.7 million individuals (3.0 million women and 1.7 million men) with total knee replacement in 2010. Secular trends indicated a substantial rise in prevalence over time and a shift to younger ages. CONCLUSIONS Around 7 million Americans are living with a hip or knee replacement, and consequently, in most cases, are mobile, despite advanced arthritis. These numbers underscore the substantial public health impact of total hip and knee arthroplasties.

High ten-year risk of cardiovascular disease in newly diagnosed rheumatoid arthritis patients: a population-based cohort study.

OBJECTIVE To estimate the 10-year absolute risk of cardiovascular (CV) events in newly diagnosed rheumatoid arthritis (RA) patients and the potential contribution of CV risk factors to absolute risk assessment. METHODS A population-based incidence cohort of RA patients (defined according to the American College of Rheumatology 1987 criteria) was assembled and compared with an age- and sex-matched non-RA cohort. Data were collected on CV risk factors and CV events. Cox regression models were used to estimate the 10-year risk of a combined CV end point, adjusting for CV risk factors. Subjects were classified into 5 risk categories based on their 10-year absolute risk. RESULTS The absolute CV risk in RA patients was similar to that in non-RA subjects who were 5-10 years older. The absolute risk varied substantially according to the presence of CV risk factors. The 10-year absolute CV risk among 60-69-year-old RA patients with no risk factors was 16.8%, but rose to 60.4% if risk factors such as smoking, hypertension, dyslipidemia, diabetes, and obesity were present. Among RA patients with a low body mass index, in addition to the above risk factors, the 10-year absolute CV risk rose to 86.2%. CONCLUSION More than half of the newly diagnosed RA patients who were 50-59 years of age and all of those >60 years of age had a >10% risk of CV disease within 10 years of their RA incidence and should be targeted for specific CV risk reduction strategies tailored to their personal risk profiles.

Total Cholesterol and LDL levels decrease before rheumatoid arthritis

Objectives To compare lipid profiles in patients with rheumatoid arthritis (RA) and in non-RA subjects during the 5 years before and 5 years after the RA incidence/index date. Methods Lipid measures were abstracted in a population-based incident cohort of patients with RA (1987 American College of Rheumatology criteria) first diagnosed between 1 January 1988 and 1 January 2008 and in non-RA subjects. Random-effects models adjusting for age, sex and calendar year were used to examine trends in lipid profiles, accounting for multiple measurements for each subject. Results The study population included a cohort of 577 patients with RA (a total of 3088 lipid measurements) and 540 non-RA subjects (a total of 3048 lipid measurements). There were significant decreases in total (TC) and low-density lipoprotein cholesterol (LDL) levels in the RA cohort during the 5 years before RA, compared with the non-RA cohort (p<0.001). Decreases of 0.58 mmol/l for TC and 0.61 mmol/l for LDL were noted in RA compared with decreases of 0.09 mmol/l for TC and 0.22 mmol/l for LDL in the non-RA cohort. Trends in other lipid measures (triglycerides (TGs) and high-density lipoprotein cholesterol (HDL)) were similar in RA and non-RA cohorts during the 5 years before and 5 years after the RA incidence/index date. During the 5 years before the RA incidence/index date, the proportion of patients with RA with elevated TC or LDL measures, but not with abnormal HDL and TG measures, significantly decreased compared with non-RA subjects. Lipid-lowering drugs (statins in particular) were less often prescribed to patients with RA than to non-RA subjects (34% vs 41%; p=0.02). Conclusion TC and LDL levels and the prevalence of abnormal TC or LDL measures decreased significantly during the 5 years before the RA incidence/index date in patients with RA as compared with the non-RA cohort. These trends in lipid profile in RA are unlikely to be solely due to lipid-lowering treatment.

Epidemiology and clinical characteristics of behçet's disease in the US: A population-based study

OBJECTIVE Behçets disease (BD) is a rare, multisystem inflammatory disorder of unknown cause. Although well-documented in Eastern populations, epidemiologic data is scarce in North American countries. Here we describe the incidence and prevalence of BD in Olmsted County, Minnesota over 45 years. METHODS We identified an incidence cohort of subjects age >/=18 years who had a clinical diagnosis of and/or fulfilled the International Study Group (ISG) criteria for BD from January 1, 1960 to January 1, 2005. Age- and sex-specific incidence and prevalence were estimated and age- and sex-adjusted to the 2000 US total population. RESULTS The study population was comprised of 13 subjects with BD; 11 fulfilled ISG criteria between 1960 and 2005. Mean +/- SD age was 31 +/- 9 years, and 69% were white. Point prevalence in 2000 was 5.2 per 100,000 population (95% confidence interval [95% CI] 0.64-9.84). The overall annual age- and sex-adjusted incidence of BD was 0.38 per 100,000 population (95% CI 0.17-0.59), with a higher incidence in women (0.51 per 100,000; 95% CI 0.17-0.84) than in men (0.26 per 100,000; 95% CI 0.004-0.52). Dermatologic lesions included oral ulcers (100%), genital ulcers (62%), erythema nodosum (46%), and papulopustular lesions (54%). Ocular lesions, vascular complications, and central nervous system involvement were present in 8, 3, and 3 subjects, respectively. CONCLUSION Our study shows an overall incidence of 0.38 per 100,000 population, which is comparable with other Western populations. The prevalence of 5.2 per 100,000 population is similar to estimates reported in Western countries, but lower than that in countries along the Silk Road.

TRENDS IN INCIDENCE OF ADULT-ONSET PSORIASIS OVER THREE DECADES: A POPULATION BASED STUDY

BACKGROUND Incidence studies of psoriasis are rare, mainly due to lack of established epidemiological criteria and the variable disease course. The objective of this study is to determine time trends in incidence and survival of psoriasis patients over three decades. METHODS We identified a population-based incidence cohort of 1633 subjects aged > or = 18 years first diagnosed with psoriasis between January 1, 1970 and January 1, 2000. The complete medical records for each potential psoriasis subject were reviewed and diagnosis was validated by either a confirmatory diagnosis in the medical record by a dermatologist or medical record review by a dermatologist. Age- and sex-specific incidence rates were calculated and were age- and sex-adjusted to the 2000 US white population. RESULTS The overall age- and sex-adjusted annual incidence of psoriasis was 78.9 per 100,000 (95% confidence interval [CI]: 75.0-82.9). When psoriasis diagnosis was restricted to dermatologist-confirmed subjects, the incidence was 62.3 per 100,000 (95% CI: 58.8-65.8). Incidence of psoriasis increased significantly over time from 50.8 in the period 1970-1974 to reach 100.5 per 100,000 in the 1995-1999 time period (P = .001). Although the overall incidence was higher in males than in females (P = .003), incidence in females was highest in the sixth decade of life (90.7 per 100,000). Survival was similar to that found in the general population (P = .36). LIMITATIONS The study population was mostly white and limited to adult psoriasis patients. CONCLUSION The annual incidence of psoriasis almost doubled between the 1970s and 2000. The reasons for this increase in incidence are currently unknown, but could include a variety of factors, including a true change in incidence or changes in the diagnosing patterns over time.

Autoantibodies and the risk of cardiovascular events

Objective. Inflammation and autoimmunity are associated with increased cardiovascular (CV) risk in patients with rheumatoid arthritis. This association may also be present in those without rheumatic diseases. Our purpose was to determine whether rheumatoid factor (RF), antinuclear antibody (ANA), and cyclic citrullinated peptide antibody (CCP) positivity are associated with increased risk of CV events and overall mortality in those with and without rheumatic diseases. Methods. We performed a population-based cohort study of all subjects who had a RF and/or ANA test performed between January 1, 1990, and January 1, 2000, and/or CCP test performed between September 1, 2003, and January 1, 2005, with followup until April 1, 2007. Outcomes were ascertained using diagnostic indices from complete medical records, including CV events [myocardial infarction (MI), heart failure (HF), and peripheral vascular disease (PVD)] and mortality. Cox models were used to analyze the data. Results. There were 6783 subjects with RF, 7852 with ANA, and 299 with CCP testing. Of these, 10.4%, 23.9%, and 14.7% were positive for RF, ANA, and CCP, respectively. Adjusting for age, sex, calendar year, comorbidity, and rheumatic disease, RF and ANA positivity were significant predictors of CV events [hazard ratio (HR) 1.24 and 1.26] and death (HR 1.43 and 1.18). Adjusting for age, CCP positivity was associated with CV events, but this association was not statistically significant (HR 3.1; 95% CI 0.8, 12.3). Conclusion. RF and ANA positivity are significant predictors of CV events and mortality in both those with and those without rheumatic diseases. These results support the role of immune dysregulation in the etiology of CV disease.