Cause-Specific Mortality in Patients With Gout in the US Veterans Health Administration: A Matched Cohort Study

Abstract

Objective: To compare all-cause and cause-specific mortality risk between patients with gout and patients without gout in the Veteran's Health Administration (VHA). Methods: We performed a matched cohort study, identifying patients with gout in the VHA from January 1999 to September 2015 based on the presence of ≥2 International Classification of Diseases, Ninth Revision codes for gout (274.X). Gout patients were matched up to 1:10 on birth year, sex, and year of VHA enrollment with patients without gout and followed until death or end of study (December 2017). Cause of death was obtained from the National Death Index. Associations of gout with all-cause and cause-specific mortality were examined using multivariable Cox regression. Results: Gout (n = 559,243) and matched non-gout controls (n = 5,428,760) had a mean age of 67 years and were 99% male. There were 246,291 deaths over 4,250,371 patient-years in gout patients and 2,000,000 deaths over 40,441,353 patient-years of follow-up in controls. After matching, gout patients had an increased risk of death (hazard ratio [HR] 1.09 [95% confidence interval (95% CI) 1.08–1.09]), which was no longer present after adjusting for comorbidities (HR 0.98 [95% CI 0.97–0.98]). The strongest association of gout with cause-specific mortality was observed with genitourinary conditions (HR 1.50 [95% CI 1.47–1.54]). Gout patients were at lower risk of death related to neurologic (e.g., Alzheimer's disease and Parkinson's disease) (HR 0.63 [95% CI 0.62–0.65]) and mental health (HR 0.66 [95% CI 0.65–0.68]) conditions. Conclusion: A higher risk of death among gout patients in the VHA was related to comorbidity burden. While deaths attributable to neurologic and mental health conditions were less frequent among gout patients, genitourinary conditions were the most overrepresented causes of death.