Gout
Purpose of the Review: We have reviewed the latest publications on epidemiology of gout; also there have been new insights into the regulation of the inflammation resulting from the regular interaction occurring between MSU crystals and cells in both asymptomatic and symptomatic gouty joints. Finally we review different publications of clinical interest.
Recent Findings: The incidence of gout has been found to be increasing, and the disease starts at an earlier age; this likely relates to changes in dietary habits that lead to the development of the insulin resistance syndrome to which hyperuricemia, and thus gout, relates. Dietary modifications to correct the insulin resistance syndrome and reduce uricemia by increasing renal clearance of urate have heath consequences that go far beyond their beneficial effect on gout. Monosodium urate crystals and cells interact in the asymptomatic joints of gouty patients. The mechanisms that trigger a gouty attack with this background and those responsible for the self-limitation of gouty attacks are not understood. The degree of maturation of the monocytes-macrophages present in the fluid appears to modulate the consequences of the crystal-cell interaction and gives a hint of how from the crystal-cell interaction may result in such divergent consequences as intense inflammation or the absence of symptoms. Interest in gout treatment continues, as shown by the number of papers on the subject reviewed. In most cases, gout is an easy disease to treat, but we do not have enough information about how to handle those few patients with difficult disease, and what we refer colloquially to as difficult gout has not been properly defined yet.
Summary: Gout incidence and severity appear to be increasing likely in relation to dietary habits. Switching the pattern of secretion of inflammatory mediators with maturating macrophages which contain MSU crystals may be the key to self limitation of gouty attacks. We must define better which gout is a difficult one.
Using the Rochester Epidemiology Project computerized medical record system, all potential cases of acute gout in the city of Rochester, MN, during the periods 1977 to 1978 and 1995 to 1996 were identified. It was found that there was a greater than twofold increase in the rate of primary gout in the later period when compared with the earlier one (P = 0.002). Of interest, the incidence of secondary diuretic-related gout did not increase (P = 0.140). In a large study from Taiwan, the clinical features of 1079 Chinese patients with gout seen by rheumatologists between 1993 and 2000 were analyzed and compared with earlier series; in one-fourth of the patients from the more recent group, the disease had started before age 30, and in the whole group, the first attack occurred between the third and fifth decades (68.2%) rather than between the fourth and sixth decades, as reported in older series. In addition, the incidence of gout in females had increased (8.0%), and the incidence of tophi was high (16.8%). A third study, also from Taiwan, compared the features of gout in patients diagnosed between 1983 and 1991 with those diagnosed between 1992 and 1999; in the latter group, the age of the patients at the beginning of the disease was 2.7 years younger with high significance, and the percentage of female and familial gout were higher as well. The percentages of obesity, hypertriglyceridemia, and nephrolithiasis were higher, although those of hypertension and high cholesterol levels were lower. These studies from different parts of the world suggest that the incidence and severity of gout may be increasing, and the already well-known association of hyperuricemia and gout with dietary habits and the resulting insulin resistance is a likely cause, as extensively reviewed this past year; in this setting, hyperuricemia results from poor renal clearance of uric acid, and low-calorie diets result in improvement of the renal clearance of uric acid and consequently a reduction of serum uric acid levels. The importance of alcohol intake was again outlined in another study, also from Taiwan, which found that the waist-to-height ratio, which indicates central obesity, has a significant linear effect on gout occurrence, independent of body mass index. Through its association with the insulin resistance syndrome, hyperuricemia and gout are associated with cardiovascular disease and reduced life span; in addition, hyperuricemia has been recognized as an independent risk factor for cardiovascular disease, although not all the studies find this independent association of hyperuricemia with cardiovascular disease. Rheumatologists must be aware of the risks associated with gout and hyperuricemia and actively join physicians from other fields in supporting preventive lifestyle measures to help patients with their gout, which have very important additional benefits.
Overactivity of phosphoribosylpyrophosphate synthetase was found in a young woman with renal stones and hyperuricemia; this defect had not been reported in women previously.
Abstract and Epidemiology
Abstract
Purpose of the Review: We have reviewed the latest publications on epidemiology of gout; also there have been new insights into the regulation of the inflammation resulting from the regular interaction occurring between MSU crystals and cells in both asymptomatic and symptomatic gouty joints. Finally we review different publications of clinical interest.
Recent Findings: The incidence of gout has been found to be increasing, and the disease starts at an earlier age; this likely relates to changes in dietary habits that lead to the development of the insulin resistance syndrome to which hyperuricemia, and thus gout, relates. Dietary modifications to correct the insulin resistance syndrome and reduce uricemia by increasing renal clearance of urate have heath consequences that go far beyond their beneficial effect on gout. Monosodium urate crystals and cells interact in the asymptomatic joints of gouty patients. The mechanisms that trigger a gouty attack with this background and those responsible for the self-limitation of gouty attacks are not understood. The degree of maturation of the monocytes-macrophages present in the fluid appears to modulate the consequences of the crystal-cell interaction and gives a hint of how from the crystal-cell interaction may result in such divergent consequences as intense inflammation or the absence of symptoms. Interest in gout treatment continues, as shown by the number of papers on the subject reviewed. In most cases, gout is an easy disease to treat, but we do not have enough information about how to handle those few patients with difficult disease, and what we refer colloquially to as difficult gout has not been properly defined yet.
Summary: Gout incidence and severity appear to be increasing likely in relation to dietary habits. Switching the pattern of secretion of inflammatory mediators with maturating macrophages which contain MSU crystals may be the key to self limitation of gouty attacks. We must define better which gout is a difficult one.
Epidemiology
Using the Rochester Epidemiology Project computerized medical record system, all potential cases of acute gout in the city of Rochester, MN, during the periods 1977 to 1978 and 1995 to 1996 were identified. It was found that there was a greater than twofold increase in the rate of primary gout in the later period when compared with the earlier one (P = 0.002). Of interest, the incidence of secondary diuretic-related gout did not increase (P = 0.140). In a large study from Taiwan, the clinical features of 1079 Chinese patients with gout seen by rheumatologists between 1993 and 2000 were analyzed and compared with earlier series; in one-fourth of the patients from the more recent group, the disease had started before age 30, and in the whole group, the first attack occurred between the third and fifth decades (68.2%) rather than between the fourth and sixth decades, as reported in older series. In addition, the incidence of gout in females had increased (8.0%), and the incidence of tophi was high (16.8%). A third study, also from Taiwan, compared the features of gout in patients diagnosed between 1983 and 1991 with those diagnosed between 1992 and 1999; in the latter group, the age of the patients at the beginning of the disease was 2.7 years younger with high significance, and the percentage of female and familial gout were higher as well. The percentages of obesity, hypertriglyceridemia, and nephrolithiasis were higher, although those of hypertension and high cholesterol levels were lower. These studies from different parts of the world suggest that the incidence and severity of gout may be increasing, and the already well-known association of hyperuricemia and gout with dietary habits and the resulting insulin resistance is a likely cause, as extensively reviewed this past year; in this setting, hyperuricemia results from poor renal clearance of uric acid, and low-calorie diets result in improvement of the renal clearance of uric acid and consequently a reduction of serum uric acid levels. The importance of alcohol intake was again outlined in another study, also from Taiwan, which found that the waist-to-height ratio, which indicates central obesity, has a significant linear effect on gout occurrence, independent of body mass index. Through its association with the insulin resistance syndrome, hyperuricemia and gout are associated with cardiovascular disease and reduced life span; in addition, hyperuricemia has been recognized as an independent risk factor for cardiovascular disease, although not all the studies find this independent association of hyperuricemia with cardiovascular disease. Rheumatologists must be aware of the risks associated with gout and hyperuricemia and actively join physicians from other fields in supporting preventive lifestyle measures to help patients with their gout, which have very important additional benefits.
Overactivity of phosphoribosylpyrophosphate synthetase was found in a young woman with renal stones and hyperuricemia; this defect had not been reported in women previously.