Psoriatic arthritis epidemiology

Recent studies have added to our knowledge of the epidemiology of psoriatic arthritis (PsA) across various populations. Absence of a standard case definition and the relative rarity of PsA may have contributed to the paucity of available data to date. Reported prevalence estimates appear to vary more than incidence estimates. Prevalence estimates may vary as a result of differences in genetic factors, exposure to environmental factors, and study methods. Although prevalence data among different subgroups and extrapolation from clinical and laboratory data allow some inferences about the role of various potential risk factors for PsA, only one study has investigated them specifically. Overall, quality of life in PsA appears similar to that in rheumatoid arthritis, whereas available data on the mortality impact of PsA are conflicting, preventing a unified conclusion. This review summarizes recent data on PsA epidemiology.     

Psoriatic arthritis in Reykjavik, Iceland: prevalence, demographics, and disease course

OBJECTIVE: To determine the prevalence, demographics, and course of psoriatic arthritis (PsA) in the Reykjavik area of Iceland. METHODS: In total 220 patients >/= 18 years of age living in the Reykjavik area of Iceland were located in a community registry of psoriatic patients and in hospital records. Of these, 156 (71%) were interviewed and examined for verification of skin and joint disease according to published criteria. RESULTS: Prevalence of PsA in the adult population was estimated to be 164 per 100,000 (95% CI 143-187), adjusted to 139 per 100,000 (95% CI 112-169) after exclusion of 25 individuals. The female to male ratio was close to 2:1. The mean age at skin disease onset was 23 years, with significantly earlier onset in women (age 20 yrs in women vs 26 yrs in men; p = 0.01), but there was no significant difference for age at the time of onset of joint disease. Mean duration of PsA was 20 years. Oligoarthritis was the most common (44%), followed by polyarthritis (31%), enthesitis (8%), and inflammatory back pain (7%). According to patients' recall of clinical features at onset, 78 patients (60%) had changed categories of PsA at the time of the study, most frequently from polyarthritis to oligoarthritis (48%), followed by oligoarthritis to polyarthritis (36%). These changes seemed independent of use of disease modifying drugs, which 54% had received. CONCLUSION: PsA in Reykjavik, Iceland, has a prevalence of at least 0.14% and is strikingly more common in women. The majority of patients reported a change in the pattern of affected joints during the course of their disease.     

Psoriatic arthritis clinical registries and genomics

To understand better a complex disease such as psoriatic arthritis (PsA), collection of a large amount of information on clinical, laboratory, and radiological features is required over an extended period of time. Longitudinal data can be effectively collected and stored in clinical registries and databases. This article reviews current databases in PsA and proposes a structure for an international PsA registry. Careful collection and analysis of patient data through collaborative efforts will likely advance our knowledge of pathogenesis and provide new and much needed insights about the course and prognosis of the disease.     

Psoriatic arthritis: clinical subgroups and histocompatibility antigens.

Histocompatibility antigens were determined in 60 patients with psoriatic arthritis. The patients were divided into clinical subgroups according to axial or peripheral joint involvement, disease severity based on number of peripheral joints involved, and the presence or absence of bone erosions. The total group showed a significant increase in frequency of HLA-A1, B17, B27, and DR7 when compared with a control population. The subgroup with spondylitis had a significant increase in frequency of HLA-B27 when compared with patients with peripheral arthritis (p less than 0.001). The subgroup with peripheral arthritis alone had a higher frequency of HLA-DR7 than the control group (p less than 0.001). There were also significant associations between HLA-DR7 and chronic severe disease (p less than 0.001) and between HLA-DR4 and the presence of erosions (p less than 0.05).     

Psoriatic arthritis: clinical aspects, genetics, and the role of T cells

In the last 2 years there has been considerable progress in investigating the genetic and immunologic background of psoriasis and psoriatic arthritis. This review focuses on genetics and the role of T-cells in the immunopathogenesis of the disease, with particular reference to psoriatic arthritis.     

Influenza: epidemiology, clinical features, therapy, and prevention

Influenza A and B are important causes of respiratory illness in all age groups. Influenza causes seasonal outbreaks globally and, less commonly, pandemics. In the United States, seasonal influenza epidemics account for >200,000 hospitalizations and >30,000 deaths annually. More than 90% of deaths occur in the elderly population. Interestingly, in the novel 2009 H1N1 influenza pandemic, attack rates were highest among children and young adults. Fewer than 10% of cases occurred in adults >60 years old, likely because preexisting antibodies against other H1N1 viruses afforded protection. Despite concerns about a high lethality rate with the novel 2009 H1N1 strain, most illnesses caused by the 2009 H1N1 viruses were mild (overall case fatality rate <0.5%). Clinical features of influenza infection overlap with other respiratory pathogens (particularly viruses). The diagnosis is often delayed due to low suspicion and the limited use of specific diagnostic tests. Rapid diagnostic tests are widely available and allow detection of influenza antigen in respiratory secretions within 1 hour; however, sensitivity ranges from 50 to 90%. Neuraminidase inhibitors (NAIs) (eg, oseltamivir and zanamivir) are effective for treating influenza A or B and for prophylaxis in selected adults and children. Resistance to NAIs is rare, but influenza strains resistant to oseltamivir have been detected. Vaccines are the cornerstone of influenza control. Currently, trivalent inactivated vaccine (TIV) and live attenuated influenza vaccine (LAIV) are available. These agents reduce mortality and morbidity in high-risk patients (i.e., the elderly or patients with comorbidities), and expanding the use of vaccines to healthy children and adults reduces the incidence of influenza, pneumonia, and hospitalizations due to respiratory illnesses in the community.     

Psoriatic arthritis assessment tools in clinical trials

In order to measure disease activity, progression, and change with therapy in psoriatic arthritis (PsA), it is important to use accurate, reliable, and feasible outcome measures that can ideally be employed in longitudinal cohorts, clinical trials, and clinical practice. Until recently, there has been little focus on this methodology in PsA. Clinical trials and long term clinical registries have used disparate outcome measures. With emerging therapies, the focus on the methodology of outcome assessment has increased to ensure that discriminant and responsive instruments are used. The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), in conjunction with the society, Outcome Measures in Rheumatology (OMERACT), is focused on refining and developing outcome measures for a variety of disease domains reviewed in this report. Key domains to assess include joints, skin, enthesitis, dactylitis, spine, joint damage as assessed radiologically, quality of life, and function. These domains can be assessed by individual and composite measures. A number of measures have been "borrowed" from the fields of rheumatoid arthritis, ankylosing spondylitis, and psoriasis and adapted to PsA. Others are being developed specifically for PsA. Few are validated but most have been shown to perform well in distinguishing placebo from treatment response. This report reviews the current state of the art of assessment in PsA and points toward future directions of development of this field.     

Streptococcus pneumoniae: epidemiology, risk factors, and clinical features

Streptococcus pneumoniae is the most common cause of both pneumonia overall and fatal pneumonia. Antibiotic resistance has developed worldwide and is most frequent in pneumococcal serotypes that are most prevalent in children (types/groups 6, 14, 19, and 23). The incidence of pneumococcal disease is the highest in children < 2 years of age and in adults > 65 years of age. Other important risk factors are chronic heart and lung disease, cigarette smoking, and asplenia. A 23-valent capsular polysaccharide vaccine and a heptavalent protein-polysaccharide conjugate vaccine are currently available. The latter is specially designed for pediatric use because small children respond poorly to polysaccharide antigens. Both vaccines are efficacious in prevention of invasive pneumococcal disease. The clinical presentation of pneumococcal pneumonia is variable, and neither clinical features nor laboratory or radiographic findings can reliably predict the etiology of pneumonia. Blood culture is the most important tool for establishing a definitive diagnosis, but Gram's stains and sputum culture are also of value in skilled hands. A recently developed urinary antigen test may provide a rapid diagnosis of pneumococcal pneumonia in adults. Penicillin (penicillin G/amoxicillin) remains the drug of choice for strains that are fully sensitive or have a moderately decreased susceptibility to penicillin, whereas cefotaxime and ceftriaxone are the first-line alternatives in cases with higher levels of resistance.     

Psoriasis: epidemiology, clinical features, and quality of life

Psoriasis is a common chronic, recurrent, immune mediated disease of the skin and joints. It can have a significant negative impact on the physical, emotional, and, psychosocial wellbeing of affected patients. Psoriasis is found worldwide but the prevalence varies among different ethnic groups. It has a strong genetic component but environmental factors such as infections can play an important role in the presentation of disease. There are several clinical cutaneous manifestations of psoriasis but most commonly the disease presents as chronic, symmetrical, erythematous, scaling papules and plaques. The epidemiology, clinical features, and impact on quality of life of psoriasis are reviewed.     

HIV-TB: epidemiology, clinical features and diagnosis of smear-negativeTB

TB remains an important public health problem in the world that has been exacerbated by the HIV epidemic. In 2000, while 9% of new TB infections worldwide were attributable to HIV, in Sub-Saharan Africa--a region with higher HIV prevalence--about 31% of new TB cases were attributable to HIV. Clinical presentation of TB in HIV-infected individuals depends on the severity of the suppression of immunological functions. In patients in early stages of HIV infection, TB clinical presentation resembles that of HIV-negative individuals with more pulmonary involvement and localized lesions. With the progressive suppression of immunological functions, TB tends to be more generalized affecting more than one organ. Classic TB symptoms are non-specific and may result in delayed diagnosis or misdiagnosis. Diagnosis of smear negative pulmonary TB is based on clinical and radiological features. Sputum culture and rapid diagnostic tests based on polymerase chain reaction can be used where available.     

Miliary tuberculosis: epidemiology, clinical manifestations, diagnosis, and outcome

During the early 1970s, attention was called to the changing demographics and poor prognosis of patients with miliary tuberculosis. Thirty-eight non-AIDS patients with miliary tuberculosis seen since 1975 are reviewed. Their average age was 60 years. Two-thirds of the patients had comorbid conditions. Presenting symptoms were nonspecific; fever, anorexia, sweats, and weight loss were the most frequent. Fever, tachypnea, rales, and altered mental status were the most commonly associated signs. Chest radiographs often showed miliary disease, but the remainder of the laboratory abnormalities were nonspecific. Seventy-six percent of sputum cultures, 75% of gastric aspirate cultures, 59% of urine cultures, and 54% of bronchial washings were positive for Mycobacterium tuberculosis. Biopsy specimens, including those obtained by transbronchial biopsy, were frequently abnormal histologically but were rarely culture-positive. Mortality attributable to miliary tuberculosis was 21%. Risk factors for death included female sex and altered mental status. No patient treated initially with a regimen that included streptomycin died whereas 21% of those treated with other regimens died. These data confirm and extend the results of earlier studies and suggest that miliary tuberculosis is a disease of the elderly and immunocompromised and is associated with significant morbidity and mortality. A high index of suspicion and diagnostic persistence are required for diagnosis.     

HLA markers and prediction of clinical course and outcome in rheumatoid arthritis

Objective. To evaluate HLA markers as early prognostic factors for disease severity in rheumatoid arthritis (RA). Methods. HLA genotyping was carried out in a retrospective analysis of 66 RA patients and in a prospective study of 55 RA patients and 87 healthy controls using polymerase chain reaction-based methods for HLA-DRB1 specificities, DR4 alleles, and their linked DQB1 alleles, as well as HLA-B27. The clinical course of RA was assessed by clinical and radiologic scores. The impact of HLA markers was evaluated by epidemiologic means in addition to modeling using multiple logistic regression analysis. Results. Shared epitope-positive (HVR3+) DR4 alleles and the HVR3 amino acid cassette QKRAA were associated with RA in both longstanding (relative risk [RR] 3.34 and 3.19) and recent-onset (RR 2.1 and 2.37) RA. In longstanding RA, radiologic evidence of severe joint destruction (Larsen score > 1.62) was seen more often in HVR3 shared epitope-positive patients than in epitope-negative patients (odds ratio [OR] = 25.67, X² = 13.59, P = 0.0003). Moreover, rank sum analysis of Larsen indices indicated significantly higher ranking for the presence of the RA-associated HVR3 cassettes (QKRAA, QRRAA) when expressed on a DR4 allele (P < 0.0001). In the prospective study, DR4-positive patients had a significantly increased risk (OR = 13.75, P = 0.00083) of developing bony erosions. In addition, HVR3 epitope-positive DR4-positive individuals had significantly higher Larsen indices than did epitope-negative patients (P = 0.0083). In particular, the presence of the HVR3 epitope on DR4 resulted in an increased a posteriori likelihood (0.91) of developing early erosive disease compared with an a priori risk of 0.62. Conversely, the likelihood decreased to a minimum of 0.35 when the HVR3 epitope was absent. Conclusion. While the contribution of HLA typing to establishing the diagnosis of RA is limited, HLA-DR genotyping and DR4 subtype determination provide valuable markers for the prognosis of joint destruction in RA.     

Psoriatic arthritis: imaging techniques

Imaging techniques to assess psoriatic arthritis (PsA) include radiography, ultrasonography (US), magnetic resonance imaging (MRI), computed tomography (CT) and bone scintigraphy. The radiographic hallmark of PsA is the combination of destructive changes (joint erosions, tuft resorption, osteolysis) with bone proliferation (including periarticular and shaft periostitis, ankylosis, spur formation and non-marginal syndesmophytes). US has an increasing important role in the evaluation of PsA. In fact, power Doppler US is useful mainly for its ability to assess musculoskeletal (joints, tendons, entheses) and cutaneous (skin and nails) involvement, to monitor efficacy of therapy and to guide steroid injections at the level of inflamed joints, tendon sheaths and entheses. MRI allows direct visualization of inflammation in peripheral and axial joints, and peripheral and axial entheses, and has dramatically improved the possibilities for early diagnosis and objective monitoring of the disease process in PsA. MRI has allowed explaining the relationships among enthesitis, synovitis and osteitis in PsA, supporting a SpA pattern of inflammation where enthesitis is the primary target of inflammation. CT has little role in assessment of peripheral joints, but it may be useful in assessing elements of spine disease. CT accuracy is similar to MRI in assessment of erosions in sacroiliac joint involvement, but CT is not as effective in detecting synovial inflammation. Bone scintigraphy lacks specificity and is now supplanted with US and MRI techniques.     

Psoriatic arthritis: genetics and pathogenesis

Psoriatic arthritis is a complex disease affecting primarily peripheral and axial joints and entheses together with the skin. The pathogenesis is characterized by a genetic background and by inflammatory mechanisms which may be triggered by environmental factors. Several susceptibility genes have been investigated; they include HLA genes, genes within the HLA region and genes outside the HLA region. T cells, including the recently described subset Th17, are thought to play an important role in the acute and chronic phases of the disease. Some of these findings allowed novel therapeutic interventions or opened new promising approaches in treatment. The most relevant data of the literature are summarized and discussed.     

Psoriatic arthritis: clinical response and side effects to methotrexate therapy.

In the last decade, methotrexate (MTX) has emerged as a useful second line agent for a variety of arthritides. However, there still exists some reluctance for its wider use mainly because of concerns about its liver side effects. We describe our clinical experience with this drug in psoriatic arthritis (PsA). The study group included 24 men and 16 women, with a mean age of 47 years (16-75), with oligoarticular (13) or polyarticular (27) involvement, with a mean disease duration of 12 years (1-36). Patients received a mean dose of 11.2 mg of MTX orally/week during a mean period of 34 months (6-132). Seven had been previously treated with other second line agents. Thirty-eight patients had an excellent or good response. In them, the erythrocyte sedimentation rate dropped in a mean of 38 mm/h. Only 2 patients had a rather poor response. Two patients discontinued the medication because of side effects: leukopenia in one and stomatitis in the other. Eleven patients presented with liver test abnormalities: 3 mild, 6 moderate and 2 severe. Seven patients had 11 liver biopsies. Except for one, none had evidence of cirrhosis or inflammation. Indeed, no changes were observed in the histopathology in those with repeated biopsies. The case reported as cirrhosis occurred very early in the course of MTX therapy. He continued taking MTX treatment without further deterioration of liver chemistry and/or histology. It is concluded that MTX is an effective and safe agent in PsA. Results also indicate that it is not necessary to perform liver biopsies on a routine basis.     

Psoriatic arthritis: Current topics

Psoriatic arthritis is a common inflammatory arthropathy that occurs in approximately 25% of psoriasis patients. Due to significant advances in therapeutics—mainly the advent of biologic therapy—the disease has been subject to intense investigation recently. This review summarizes recent investigations of disease pathogenesis and clinical treatment. Clinical responses to tumor necrosis factor-blocking agents appear robust and superior to traditional disease-modifying drug responses, whereas other interventions, such as costimulation blockade, require more investigation. The pathogenesis of the disease appears related to T helper 17-polarized immune responses that target skin, joints, and the enthesial compartment. Finally, new insights into the disorder’s genetic antecedents are emerging as more cohorts of patients undergo advanced genetic screening methods.     

Psoriatic arthritis: evolving concepts

Articles included in this review reflect the recent advances made in basic research and the clinical management of psoriatic arthritis in 1999. Some of these advances are destined to modify the current approach to the disease. The problems related to nosology and epidemiology, the two still controversial aspects, are discussed first. Genetic susceptibility to psoriasis and psoriatic arthritis, and the inciting role played by some bacteria, are confirmed, and attention is focused on the role of T cells, cytokines, adhesion molecules, and angiogenetic factors in the skin and synovial membrane. New classification criteria are provided and a simplified spectrum of the disease seems to emerge from clinical studies. Modern imaging techniques enable early articular changes to be discovered, support innovative pathogenetic hypotheses, and allow new therapeutic approaches.     

Psoriatic arthritis and myopathy

We describe a patient with psoriatic arthritis and a myopathy. The myopathy did not follow the time course of topical steroid treatment, nor did the patient display any features of hypercorticolism or local steroid excess. No evidence was found to support the diagnosis of polymyositis. Psoriatic myopathy is an uncommonly described condition. Steroid induced myopathy shares some nonspecific features with psoriatic myopathy, but can be differentiated by the clinical response to cessation of steroid therapy. Myalgia and 24 h urine creatine elevation are 2 features not previously described in association with psoriatic myopathy. The latter appears to correlate with muscle weakness and may be useful in following the course of this disease.