Mortality Risk Higher Among Gout Patients

Compared to the general population, patients with gout have more comorbidities—aside from cardiovascular (CV) diseases—and a greater risk of death, according to a recent study.

“Gout is the most common inflammatory arthritis, with 8.3 million affected adults in the US,” wrote the researchers, reporting in Arthritis & Rheumatology. “It is often associated with comorbidities, especially metabolic syndrome, cardiovascular (CV) diseases, and chronic kidney disease (CKD), while there is conflicting evidence regarding the association between gout and dementia.”

Therefore, the researchers sought to evaluate cause-specific mortality beyond CV diseases—particularly looking at renal disease, dementia, infection, diabetes, digestive system diseases, lung diseases, and neoplasm—as well as assess differences by sex.

The Skåne Healthcare Register was queried to collect data on all patients who received a new gout diagnosis between 2003 and 2013. Gout patients were age- and sex-matched to 10 non-gout patients. The Causes of Death Register was used to determine cause-specific mortality through Dec. 31, 2014.

The final analysis included 19,497 newly diagnosed gout patients and 194,947 non-gout controls. Two gout patients were matched to < 10 healthy patients, and one gout patient was not matched to any controls. Both cohorts had the same mean age (70 years) and were 68% male. Among the gout patients, females had a higher mean age at time of diagnosis (74.7 year) than males (67.9). With the exception of dementia, the gout cohort had a higher prevalence of all comorbidities compared to the non-gout group.

Mean follow-up time was similar between the gout (4.2 years) and non-gout (4.5 years) groups; 5,881 deaths occurred in the gout group, and there were 46,268 in the non-gout group. The gout patients had a higher all-cause mortality rate per 1,000 person years (63.6) compared to the non-gout patients (47.3)—equaling a 17% higher mortality hazard in the gout cohort.

In looking at sex-specific differences, the researchers observed, “The mortality increment related to gout was larger among women than men, with respective adjusted [hazard ratio] HR of 1.23 (95% confidence interval (CI) of 1.17 to 1.30) and 1.15 (95% CI 1.10-1.19), likely reflecting the lower background risk of mortality among women generally.”

In both cohorts, the leading cause of death was CV disease: 49.5% in the gout patients and 41.3% in the non-gout group; the HR for CV death in the gout group was 1.27 (95% CI of 1.22 to 1.33). The gout patients had a higher proportion of mortality due to renal diseases, while the non-gout group had a higher proportion of deaths due to dementia.

Other cause-specific HRs among the gout patients were: renal diseases, 1.78 (95% CI 1.34-2.35); digestive system diseases, 1.56 (1.34-1.83); and infections, 1.20 (1.06-1.35). Compared to healthy controls, the risk of death due to dementia was lower among gout patients (HR 0.83 [95% CI 0.72-0.97]).

Further, we found increased hazard of death due to renal diseases, with a HR of 1.78 (95% CI 1.34-2.35), diseases of the digestive system (see Appendix 1 for list of conditions) (HR 1.56, 1.34-1.83) and infections (HR 1.20, 1.06-1.35) in persons with gout as compared to those without. Gout was associated with lower hazard of dementia-related death, with a HR of 0.83 (95% CI 0.72-0.97).

The study authors concluded that “our findings suggest important comorbidities beyond CV that may lead to premature mortality in persons with gout, highlighting the need for better management of comorbidities.”