Gout: can we create an evidence-based systematic approach to diagnosis and management?

Gout Treatment and Clinical Considerations: The Role of Pegloticase, Colchicine, and Febuxostat

Gout treatment has evolved rapidly in recent decades, and various drugs have been designed for acute and chronic management. Three medications used to treat gout include pegloticase, colchicine, and febuxostat. When prescribing these drugs, important factors to consider include pharmacokinetics, pharmacodynamics, population specifics, benefits, and contraindications. Pharmacokinetic considerations of each drug include absorption, distribution, metabolism, and elimination factors. Pharmacodynamics factors are assessed by their potential for toxicity and effects on serum uric acid levels. Additionally, the drug's targeted population must be considered to avoid unwanted complications in certain pre-existing conditions such as cardiovascular disease or glucose-6-dehydrogenase (G6PD) deficiency. In this paper, we aim to provide insight into the gout medications, pegloticase, colchicine, and febuxostat. This review will include their pharmacokinetics, pharmacodynamics, population specifics, benefits, and contraindications.

Mapping patients' experiences from initial symptoms to gout diagnosis: a qualitative exploration

OBJECTIVE

To explore patients' experiences from initial symptoms to receiving a diagnosis of gout.

DESIGN

Data from in-depth semistructured interviews were used to construct themes to describe key features of patients' experiences of gout diagnosis.

PARTICIPANTS AND SETTING

A maximum variation sample of 43 UK patients with gout (29 men; 14 women; age range 32-87 years) were recruited from general practices, rheumatology clinics, gout support groups and through online advertising.

RESULTS

Severe joint pain, combined with no obvious signs of physical trauma or knowledge of injury, caused confusion for patients attempting to interpret their symptoms. Reasons for delayed consultation included self-diagnosis and/or self-medication, reluctance to seek medical attention, and financial/work pressures. Factors potentially contributing to delayed diagnosis after consultation included reported misdiagnosis, attacks in joints other than the first metatarsophalangeal joint, and female gender. The limitations in using serum uric acid (SUA) levels for diagnostic purposes were not always communicated effectively to patients, and led to uncertainty and lack of confidence in the accuracy of the diagnosis. Resistance to the diagnosis occurred in response to patients' beliefs about the causes of gout and characteristics of the people likely to be affected. Diagnosis prompted actions, such as changes in diet, and evidence was found of self-monitoring of SUA levels.

CONCLUSIONS

This study is the first to report data specifically about patients' pathways to initial consultation and subsequent experiences of gout diagnosis. A more targeted approach to information provision at diagnosis would improve patients' experiences.

Initiation of allopurinol at first medical contact for acute attacks of gout: a randomized clinical trial

OBJECTIVE

Streamlining the initiation of allopurinol could result in a cost benefit for a common medical problem and obviate the perception that no treatment is required once acute attacks have resolved. Our objective was to test the hypothesis that there is no difference in patient daily pain or subsequent attacks with early versus delayed initiation of allopurinol for an acute gout attack.

METHODS

A total of 57 men with crystal-proven gout were randomized to allopurinol 300 mg daily or matching placebo for 10 days. All subjects received indomethacin 50 mg 3 times per day for 10 days, a prophylactic dose of colchicine 0.6 mg 2 times per day for 90 days, and open-label allopurinol starting at day 11. Primary outcome measures were pain on visual analogue scale (VAS) for the primary joint on days 1 to 10 and self-reported flares in any joint through day 30.

RESULTS

On the basis of 51 evaluable subjects (allopurinol in 26, placebo in 25), mean daily VAS pain scores did not differ significantly between study groups at any point between days 1 and 10. Initial VAS pain scores for allopurinol and placebo arms were 6.72 versus 6.28 (P=.37), declining to 0.18 versus 0.27 (P=.54) at day 10, with neither group consistently having more daily pain. Subsequent flares occurred in 2 subjects taking allopurinol and 3 subjects taking placebo (P=.60). Although urate levels decreased rapidly in the allopurinol group (from 7.8 mg/dL at baseline to 5.9 mg/dL at day 3), sedimentation rates and C-reactive protein levels did not differ between groups at any point.

CONCLUSIONS

Allopurinol initiation during an acute gout attack caused no significant difference in daily pain, recurrent flares, or inflammatory markers.

Clinical utility of dual-energy CT for evaluation of tophaceous gout

Although diagnosing gout generally is straightforward, atypical disease may present a challenge if it is associated with unusual symptoms or sites, discordant serum urate level, or mimics of gout. Dual-energy computed tomography (CT) may be used to differentiate urate crystals from calcium by using specific attenuation characteristics, which may help diagnose gout. In patients with known tophaceous gout, dual-energy CT may be used for serial volumetric quantification of subclinical tophi to evaluate response to treatment. Given the utility of dual-energy CT in challenging cases and its ability to provide an objective outcomes measure in patients with tophaceous gout, dual-energy CT promises to be a unique and clinically relevant modality in the diagnosis and management of gout.

Reproducibility of musculoskeletal ultrasound for determining monosodium urate deposition: concordance between readers

OBJECTIVE

Criteria for sonographic diagnosis of monosodium urate (MSU) crystal deposition have been developed, but the interreader reproducibility of this modality is not well established. We therefore assessed agreement using a systematic approach.

METHODS

Fifty male subjects ages 55-85 years were recruited during primary care visits to an urban Veterans Affairs hospital, and were assessed by musculoskeletal ultrasound (US) of the knees and first metatarsophalangeal (MTP) joints to evaluate for the double contour sign and tophi as evidence of MSU crystal deposition. Images were read by 2 blinded rheumatologists trained in musculoskeletal US, and the degree of concordance was determined for individual subjects, total joints, femoral articular cartilage (FAC), and first MTP joints. Subjects were further categorized into 3 diagnostic groups: gout, asymptomatic hyperuricemia (no gout, serum uric acid [UA] ≥6.9 mg/dl), and controls (no gout, serum UA ≤6.8 mg/dl), and reader concordance within these 3 groups was assessed.

RESULTS

We observed almost perfect agreement between readers for 1) individual subjects (yes/no; n = 50, 100% agreement, κ = 1.000), 2) total joints (n = 200, 99% agreement, κ = 0.942), 3) FAC (n = 100, 99% agreement, κ = 0.942), and 4) first MTP joints (n = 100, 99% agreement, κ = 0.942). Furthermore, findings by side (right/left) and diagnostic group (gout, asymptomatic hyperuricemia, control) showed substantial to almost perfect concordance for all measures. MSU deposition was seen most commonly in gout patients, and deposition was also seen in some subjects with asymptomatic hyperuricemia, but in only 1 control.

CONCLUSION

Musculoskeletal US is reliable for detecting MSU deposition in FAC and first MTP joints in gout and asymptomatic hyperuricemia.

Kristallarthropathien – alt, aber wichtig

Gout is the most common inflammatory arthropathy for men. Asymptomatic hyperuricemia, which should lead to diet, but not to medication, is much more common still. Increased uric acid levels mostly result from diminished renal excretion, which is more commonly familiar than secondary (renal failure, diuretics). With the first episode of often typical (red, hot, exquisitely painful first MTP joint) acute arthritis or with urate nephrolithiasis, increased uric acid turns pathological. Attacks are treated with NSAIDs or corticosteroids. More common attacks, chronic gout, or urate nephropathy are definite indications for long-term (at least 5 years) therapy with allopurinol or febuxostat. Additional anti-inflammatory medication will be necessary during the first months. Calcium pyrophosphate deposition arthropathy, the second common crystal-induced arthritis, is diagnosed by synovial fluid analysis or for chondrocalcinosis. Treatment for attacks resembles therapy of acute gout; causal therapy is possible in case of secondary forms (e.g. hypothyroidism. hyperparathyroidism, hemochromatosis).

The Value of Joint Aspirations in the Diagnosis and Management of Arthritis in a Hospital-based Rheumatology Service

Introduction: Although joint aspiration with synovial fluid analysis is useful in the diagnosis of crystal or septic arthritis, the frequency with which it provides a diagnosis or aids subsequent management of patients with arthritis has not been well quantified. We therefore evaluated the usefulness of joint aspiration in the diagnosis and management of patients with arthritis in a hospital-based rheumatology service. Materials and Methods: We reviewed records of all patients with joint aspiration performed by an inpatient rheumatology service in a tertiary referral hospital from November 2003 to December 2004. Data were extracted on the frequency with which joint aspiration provided a diagnosis or aided management. Results: Among 76 patients [mean ± standard deviation (SD), 60.9 ± 15.9 years; 41 males, 35 females, Chinese (50), Malay (20), Indian (4) and others (2)] with 86 joint aspirations, a definitive diagnosis was obtained in 44% of procedures which showed gout (n = 28), septic arthritis (n = 8) or pseudogout (n = 2). In another 47% of procedures, joint aspiration aided diagnosis by allowing categorisation of synovial fluid as inflammatory (n = 25), non-inflammatory (n = 16) or blood-stained (n = 2). Joint(s) aspirated were knees (71%), ankles (15%), elbows (8%), shoulders (2%) and wrists, metacarpo-phalangeal and metatarso-phalageal (approximately 1% each). Conclusion: Joint aspiration provides a definitive diagnosis or information that aids diagnosis in a significant number of patients in a hospital-based rheumatology service. Key words: Arthritis, Aspiration biopsy, Diagnosis, Rheumatology, Synovial fluid