IL1RN genotype as a risk factor for joint pain in hereditary haemochromatosis?

Performance of Gout Impact Scale in a longitudinal observational study of patients with gout

OBJECTIVE

The aim was to evaluate the reliability, validity and responsiveness to change of the Gout Impact Scale (GIS), a disease-specific measure of patient-reported outcomes, in a multicentre longitudinal prospective cohort of gout patients.

METHODS

Subjects completed the GIS, a 24-item instrument with five scales: Concern Overall, Medication Side Effects, Unmet Treatment Need, Well-Being during Attack, and Concern Over Attack. The total GIS score was calculated by averaging the GIS scale scores. HAQ-Disability Index (HAQ-DI), Short Form (SF)-36 physical and mental component summaries (PCS and MCS) and physician and patient gout severity assessments were also completed. Reliability was assessed with Cronbach's α. Baseline GIS scores were compared in subjects with and without gout attacks in the past 3 months using Wilcoxon rank sum tests. Multivariate linear regression was used to evaluate predictors of total GIS. Pearson's correlation coefficients 0.24-0.36 were considered moderate and >0.37 considered large. The effect size for responsiveness to change was interpreted as follows: 0.20-0.49 small, 0.50-0.79 medium and >0.79 large.

RESULTS

In 147 subjects, reliability was acceptable for total GIS (0.93) and all GIS scales (0.82-0.94) except Medication Side Effects and Unmet Treatment Need. Total GIS and all scales except Medication Side Effects discriminated between subjects with and without recent gout attacks (P < 0.05). Total GIS showed moderate-to-large correlations with HAQ-DI, SF-36 PCS and MCS (0.33-0.46). Improvement in total GIS tracked with improved physician and patient severity scores. Worsening physician severity score and recent gout attack predicted worsening total GIS.

CONCLUSION

Total GIS score is reliable, valid and responsive to change in patients with gout, and differentiates between subjects with and without recent gout attacks.

New insights into the epidemiology of gout

Gout is a true crystal deposition disease caused by formation of monosodium urate crystals in joints and other tissues. It is a common inflammatory arthritis that has increased in prevalence in recent decades. Gout normally results from the interaction of genetic, constitutional and environmental risk factors. It is more common in men and strongly age related. A major determinant is the degree of elevation of uric acid levels above the saturation point for urate crystal formation, principally caused by inefficient renal urate excretion. Local joint tissue factors may influence the topography and extent of crystal deposition. Recent studies have provided information on dietary risk factors for gout: higher intakes of red meat, fructose and beer are independently associated with increased risk, whereas higher intakes of coffee, low-fat dairy products and vitamin C are associated with lower risk. Several renal urate transporters have been identified including URAT1 and SLC2A9 (GLUT9) and polymorphisms in these genes are associated with an increased risk of hyperuricaemia and gout. Many drugs influence serum uric acid levels through an effect on renal urate transport. Comorbidities, including the metabolic syndrome and impaired renal function are common in gout patients. The usual initial presentation of gout is with rapidly developing acute inflammatory monoarthritis, typically affecting the first MTP joint. If left untreated it may progress with recurrent acute attacks and eventual development of chronic symptoms and joint damage. New knowledge of the modifiable risk factors for gout can be integrated into the management strategy to optimize long-term patient outcomes.

Perceptions of disease and health-related quality of life among patients with gout

OBJECTIVE

To assess the impact of gout on health-related quality of life (HRQoL) among patients in three large US cities.

METHODS

Gout patients completed the Short Form-36 (SF-36) and a series of questions regarding their gout, comorbidities and demographics. Their physicians confirmed the gout diagnosis and evaluated the severity of patient's gout. The differences in mean norm-based SF-36 scores between the US norms and gout patients and between subgroups of gout patients were calculated. The relative weight and significance of gout-related characteristics associated with patients' HRQoL were also calculated.

RESULTS

The majority of the patients were males with a mean age of 62.2 years and median disease duration of 13.8 years. Most were overweight/obese with several comorbidities. Half of the patients experienced three or more gout attacks per year with a typical gout attack involving five joints and lasting for at least 4 days. The Physical Component Summary (PCS) and Mental Component Summary (MCS) was significantly lower for gout patients (P < 0.002 and P < 0.001, respectively). Among gout patients, the mean PCS and MCS were lower for those with more frequent gout attacks and greater number of affected joints (P < 0.005 and P < 0.001, respectively). After adjusting for age, gender and comorbidities, the number of joints involved during a typical and the worst gout attack had the greatest impact on patient's PCS and MCS.

CONCLUSION

Gout patients had clinically significant lower HRQoL than their age-matched US norm. Comorbidities and several additional gout-related factors significantly impacted the overall HRQoL.

Manifestations rhumatologiques de l'hémochromatose génétique

Rheumatic manifestations of genetic hemochromatosis are frequent. These manifestations are characterized by articular damage and osteoporosis. Clinicians must be aware of these presentations because they are sometimes the initial manifestation of hemochromatosis. Moreover, rheumatic pain causes substantial discomfort for patients and diminishes their quality of life.

Uricase and other novel agents for the management of patients with treatment-failure gout

Successful management of chronic gout depends on reducing body pools of urate. The benchmark of success is to maintain serum urate levels at less than 6 mg/dL using therapies such as probenecid or allopurinol. In a subset of patients with gout, these medications fail to achieve this benchmark, resulting in ongoing signs and symptoms characteristic of treatment-failure gout. Potential therapies now in clinical development show promise for treating this refractory patient population. In this article, we review the clinical characteristics associated with treatment-failure gout and discuss recent data from clinical trials of febuxostat and uricase.