Ischemia heart disease and greater waist circumference are risk factors of renal function deterioration in male gout patients

We examined the incidence of renal function deterioration (RFD) in a population of male gout patients and to identify associated risk factors. Subjects who had been regularly followed up for more than 2 years and had visited Chang Gung Memorial Hospital-Kaohsiung Medical Center Rheumatology Clinic between June 1, 2006 and January 31, 2007 were enrolled. Four subjects were excluded as secondary gout was suspected. Group I (Gr I) comprised subjects without RFD and group II (Gr II) comprised subjects with RFD during the follow-up period. RFD was defined as absolute increment in creatinine (Cr) levels over 0.4 mg/dl for subjects with baseline Cr levels <= 1.4 mg/dl or as more than 50% increment of baseline Cr level per 12-month interval in average for subjects with baseline Cr levels > 1.4 mg/dl. Clinical parameters were analyzed to study the potential risk factors of RFD. Of 318 male gout patients, 296 (93.1%) were categorized as Gr I, and 22 (6.9%) were categorized as Gr II. The observation periods for Gr I and Gr II were 81.20 +/- 53.29 and 92.41 +/- 46.72 months, respectively (p=0.338). Initial Cr levels are similar between the two groups (1.25 +/- 0.51 vs 1.25 +/- 0.61, p=0.963). Multiple logistic regression analysis revealed that current age, age at disease onset, disease duration, treatment duration, body weight, height, family history of gout, tophi, urolithiasis, tobacco use, alcohol consumption, history of cerebral vascular accident, hypertension, diabetes mellitus, dyslipidemia, base-line and final Cr, blood urea nitrogen level, serum uric acid level, and body-mass index were not independent risk factors. However, history of ischemic heart disease [IHD; odds ratio (OR) 7.68, 95% confidence interval (CI) 1.99-29.70] and greater waist circumference (WC; OR 1.06, 95% CI 1.01-1.11) were two independent risk factors of RFD. Additionally, the Cox multivariable analysis disclosed that IHD (p<0.001) and greater WC (p=0.011) deteriorated kidney function in these patients. The incidence of RFD in male gout patients is 6.9%. History of IHD and greater WC are two independent risk factors for developing RFD.