Epidemiology of gout: is the incidence rising?

OBJECTIVE

To determine whether the incidence of gout is higher in 1995-1996 compared to 1977-1978.

METHODS

Using the Rochester Epidemiology Project computerized medical record system, all potential cases of acute gout in the city of Rochester, Minnesota during the time intervals of 1977-1978 and 1995-1996 were identified. The complete medical records of all potential cases were screened and all who fulfilled the 1977 American College of Rheumatology proposed criteria for gout were included as incidence cases. Demographic data, body mass index, clinical presentation, and associated comorbid conditions were abstracted. The overall and age-gender adjusted incidence rates from the 2 cohorts were calculated and compared.

RESULTS

A total of 39 new cases of acute gout were identified during the 2 year interval 1977-1978 representing an age and sex-adjusted annual incidence rate of 45.0/100,000 (95% CI: 30.7, 59.3). For the interval 1995-1996, 81 cases were diagnosed, representing an annual incidence rate of 62.3/100,000 (95% CI: 48.4, 76.2). There was a greater than 2-fold increase in the rate of primary gout (i.e., no history of diuretic exposure) in the recent compared to the older time periods (p = 0.002). The incidence of secondary, diuretic related gout did not increase over time (p = 0.140).

CONCLUSION

Our results indicate that the incidence of primary gout has increased significantly over the past 20 years. While this increase might be a result of improved ascertainment of atypical gout, it may also be related to other, as yet unidentified, risk factors.