Gout Clinical Update, August 11, 2011

Studies have shown an association between diabetes and cancer in Western countries. But researchers in Taiwan felt that this and the influence of associated metabolic factors, needed to be confirmed by a prospective study in other population groups.

After examining a large data set, the researchers found that only breast cancer did not show any clinical significance. The researchers, from the division of endocrinology and metabolism at Kaohsiung Medical University Hospital, found that there was an increased incidence of cancer at any site in the diabetic patients compared with non-diabetic subjects.

“The most common cancers were liver, colon, lung, breast, and prostate cancer; and except for breast cancer, their incidences increased independently of hypertension, dyslipidemia, and gout in patients with diabetes,” the researchers reported in the abstract of the study, which was published in Metabolism.

The researchers identified 985,815 subjects from a National Health Insurance database in 1997 and followed up from 1998 through 2009. The demographic characteristics between patients with diabetes and cancer, including age, sex, hypertension, dyslipidemia, and gout, were analyzed using the χ(2) test. Cox proportional hazard regression models were used to determine the independent effects of diabetes on the risks of cancer.

“A total of 104,343 diabetic patients were followed up from 1998 to 2009. After adjusting for sex, age, hypertension, dyslipidemia, and gout, the incidences of cancer at any site and in the liver, colon, lungs, and prostate in diabetic patients were independently higher, with risk ratios of 1.56 (95% confidence interval [CI], 1.43-1.71), 1.67 (95% CI, 1.39-2.01), 1.75 (95% CI, 1.49-2.06), 1.54 (95% CI, 1.26-1.88), and 1.56 (95% CI, 1.19-2.04), respectively,” the researchers wrote.

Chronic Kidney Disease in Gout in a Managed Care Setting

Serum uric acid control in gout was poor among patients without chronic kidney disease (CKD) and even worse among those with CKD. About two out of every five patients with gout in this population had CKD, and allopurinol doses were not adjusted in the majority of CKD patients, according to the results of a recent retrospective study.

The study, which was led by Mahesh Fuldeore, PhD, at Abbott Laboratories, used data from a large US health plan. Claims and laboratory data were analyzed for enrollees from the plan’s database from January 2002 through December 2005.

“Patients with gout were identified from pharmacy and medical claims data based on the presence of codes for gout diagnosis or medication. Severity of CKD was determined using the estimated glomerular filtration rate (eGFR). Allopurinol titration was defined as a change in average daily dose from first prescription to last prescription of 50 mg or more,” the authors wrote in the abstract for the study, which was published in BMC Nephrology.

A total of 3,929 patients were identified for inclusion in this study, 39% of whom had CKD (based on having an eGFR < 90 mL/min/1.73 m2). Subjects with CKD were older (P<0.01) and more likely to be women (P<0.01), had a greater number of comorbid conditions (P<0.01), and were more likely to be prescribed allopurinol (P<0.01) compared to those with no CKD.

“The average starting dose of allopurinol was lower among those with CKD, and it decreased with worsening kidney function. Among the 3,122 gout patients who used allopurinol, only 25.6% without CKD and 22.2% with CKD achieved a serum uric acid concentration of <6.0 mg/dL (p=0.0409). Also, only 15% of allopurinol users had an upward dose titration (by 50 mg or more), but the average increase in dose did not differ significantly between those with and without CKD,” the researchers concluded.

SourcesThe Association of Diabetes Mellitus with Liver, Colon, Lung, and Prostate Cancer is Independent of Hypertension, Hyperlipidemia, and Gout in Taiwanese Patients [Metabolism]Chronic Kidney Disease in Gout in a Managed Care Setting [BMC Nephrology]