The effect of acute gout on inflammatory markers in hyperuricemic patients

Abstract

Introduction: Gout is a painful form of acute inflammatory arthritis associated with elevated uric acid crystal deposition especially in the joints, but also in tendons and the kidney. Between 1 and 2% of Western populations are affected and in severe cases, gout sufferers can be completely incapacitated. Despite the number of gout sufferers, the high number of risk factors and high incidence of adverse drug reactions using the standard treatment regimens, little research involving gout has been done within the highly diverse multiracial and multicultural population of South Africa. Hypothesis: This study was a hypothesis generating observational study to assess whether serum levels of pro-inflammatory cytokines and acute phase protein levels could be used as markers of the gout status of a patient. Method: Thirty gout patients were enrolled onto the study and attended two visits. At the screening visit; medical history, vital signs and demographic details were collected from intercritical gout patients. At both visits, patients completed visual analogue scales; namely: subject’s assessment of pain and subject’s assessment of disease activity. A doctor completed the physician’s assessment of disease activity at both of the visits. At the end visit, patients experiencing an acute gout attack were asked to list various foods and beverages that triggered said attacks. Patients were requested to return for their second visit as soon as they experienced a gout attack, however, those patients that did not experience a gout attack were asked to return to the clinic to complete the follow up visit four months after their baseline visit. Uric acid, IL-1β, TNF-α and CRP were measured for each patient at both visits. Results: Many of the patients displayed risk factors for metabolic syndrome. The mean subject’s assessment of pain score increased from 31mm at the screening visit to 40mm at the end visit (p=0.1947; n=26), while the mean subject’s assessment of disease activity score and the mean physician’s assessment of disease activity increased from 30mm to 37mm (p=0.3196; n=26) and 23mm to 35 mm (p=0.0937; n=26) respectively. Uric acid levels decreased from 1.053mmol/L to 0.871mmol/L between visits (p=0.0926; n=25) while CRP concentrations increased significantly from 10.2mg/L to 26.6mg/L (p=0.0278, n=24). IL-1β concentrations remained similar (12.17pg/ml to 12.54pg/ml) while TNF-α concentrations decreased from 12.63pg/ml to 3.54pg/ml, however neither of these were statistically significant differences. Upon stratifying results into active and non-active patients, both IL-1β and TNF-α concentrations decreased between non-active and active patients, while CRP and urate concentrations increased. However, none of these differences were statistically significant. Conclusion: The visual analogue scales all showed an increase between the screening and final visits, although this was not statistically significant. Uric acid concentrations decreased between visits, however this increase was once again not statistically significant. There appears to be no association between inflammatory markers and the level of gout activity, although this needs to be tested in a larger sample population. Results in South African patients have confirmed results from previous studies where gout patients are at a higher risk of metabolic syndrome than the normal population. Copyright